The document provides an overview of human reproduction. It describes:
1) The male and female reproductive systems, including gamete formation (spermatogenesis and oogenesis), accessory ducts and glands.
2) The menstrual cycle in females, including the phases of menstruation, follicular development and ovulation.
3) Fertilization, implantation and the early stages of pregnancy such as embryonic development and parturition.
Phylum Annelida includes segmented worms such as earthworms, leeches, and polychaete worms. Their bodies are divided into many segments separated by internal walls. They play important ecological roles such as aerating soil, being a food source, and breaking down material. Their bodies have three layers, a coelom body cavity, complete digestive system, and sexual reproduction through cross-fertilization. They also have a closed circulatory system, nervous system, respiratory organs, excretory organs, and can live in soil, water, or as parasites on hosts. The three main classes are Oligochaeta (earthworms), Polychaeta (marine worms), and Hirudinea (lee
Kingdoms are the second highest rank in biological taxonomy. There are traditionally six kingdoms - Animalia, Plantae, Fungi, Protista, Archaea/Archaebacteria, and Bacteria/Eubacteria. However, some systems use five kingdoms excluding Archaea/Archaebacteria. The document then discusses Aristotle's early two-kingdom system and Linnaeus' two-kingdom system. It introduces Whittaker's influential five kingdom system of Monera, Protista, Fungi, Plantae, and Animalia based on cell structure, nutrition, and other characteristics. Each kingdom is then described in more detail covering key defining features.
Reproduction is essential for species survival as it allows the transmission of genetic material between generations. The life span of organisms can vary greatly from just a few minutes to thousands of years. Reproduction can occur asexually through processes like budding, fragmentation, and fission, or sexually which involves the fusion of male and female gametes. In sexual reproduction, gametes are produced through meiosis and then fuse during fertilization, either internally or externally, forming a diploid zygote. The zygote then undergoes embryogenesis developing into a new organism.
This document discusses the classification of animals in the kingdom Animalia. It covers the major animal phyla from Porifera to Chordata, including key characteristics used for classification such as symmetry, germ layers, body systems, and examples of each phylum. The major vertebrate groups are also summarized, from Cyclostomata to Mammalia. Classification is primarily based on levels of organization, body plan complexity, and characteristics of major organ systems.
Plant kingdom (11th Biology) for complete 11th and 12th notes 1999 and for PP...ASM NAFIS BIOLOGY
This document provides information about the plant kingdom and various plant groups. It discusses:
1. Algae are the simplest plant life, ranging from unicellular to multicellular forms. They reproduce sexually and asexually and have economic uses like food production and industrial products.
2. Bryophytes were the first plants to colonize land. They lack true roots and vascular tissues but have leaf-like structures. They reproduce sexually through sperm and eggs that require water.
3. Pteridophytes were the first vascular plants. They have true roots, stems and leaves with vascular tissues. They reproduce sexually through gametophytes that produce sperm and eggs requiring water for fertilization.
Reproduction in sycon, Asexual & Sexual reproduction, Gemmule processSoniaBajaj10
Sycon shows both asexual and sexual reproduction. Asexual reproduction occurs through budding and regeneration. Budding involves small projections growing from the basal region that later separate and attach to form new individuals. Regeneration allows cut pieces to regrow into complete sponges. Sexually, Sycon is hermaphroditic, producing both sperm and eggs from choanocytes or archaeocytes. Fertilization is internal, with sperm entering with water currents and fertilizing eggs. Development proceeds through cleavage, blastula, stomoblastula, and gastrulation stages to form a young sponge called an olynthus. Some sponges also form resistant gemmules for asexual reproduction during unfavor
1. Multicellular plants need transport systems to move water, minerals, and sugars throughout their large structures since single cells rely on diffusion.
2. Xylem tissue transports water and minerals up from the roots through the stem and into leaves. Phloem tissue transports sugars made in leaves to other plant parts.
3. In roots, xylem forms a cross-shape in the center with phloem between the arms. In stems, xylem and phloem bundles are arranged around the edges. In leaves, xylem is closer to the top surface and phloem is below.
Phylum Annelida includes segmented worms such as earthworms, leeches, and polychaete worms. Their bodies are divided into many segments separated by internal walls. They play important ecological roles such as aerating soil, being a food source, and breaking down material. Their bodies have three layers, a coelom body cavity, complete digestive system, and sexual reproduction through cross-fertilization. They also have a closed circulatory system, nervous system, respiratory organs, excretory organs, and can live in soil, water, or as parasites on hosts. The three main classes are Oligochaeta (earthworms), Polychaeta (marine worms), and Hirudinea (lee
Kingdoms are the second highest rank in biological taxonomy. There are traditionally six kingdoms - Animalia, Plantae, Fungi, Protista, Archaea/Archaebacteria, and Bacteria/Eubacteria. However, some systems use five kingdoms excluding Archaea/Archaebacteria. The document then discusses Aristotle's early two-kingdom system and Linnaeus' two-kingdom system. It introduces Whittaker's influential five kingdom system of Monera, Protista, Fungi, Plantae, and Animalia based on cell structure, nutrition, and other characteristics. Each kingdom is then described in more detail covering key defining features.
Reproduction is essential for species survival as it allows the transmission of genetic material between generations. The life span of organisms can vary greatly from just a few minutes to thousands of years. Reproduction can occur asexually through processes like budding, fragmentation, and fission, or sexually which involves the fusion of male and female gametes. In sexual reproduction, gametes are produced through meiosis and then fuse during fertilization, either internally or externally, forming a diploid zygote. The zygote then undergoes embryogenesis developing into a new organism.
This document discusses the classification of animals in the kingdom Animalia. It covers the major animal phyla from Porifera to Chordata, including key characteristics used for classification such as symmetry, germ layers, body systems, and examples of each phylum. The major vertebrate groups are also summarized, from Cyclostomata to Mammalia. Classification is primarily based on levels of organization, body plan complexity, and characteristics of major organ systems.
Plant kingdom (11th Biology) for complete 11th and 12th notes 1999 and for PP...ASM NAFIS BIOLOGY
This document provides information about the plant kingdom and various plant groups. It discusses:
1. Algae are the simplest plant life, ranging from unicellular to multicellular forms. They reproduce sexually and asexually and have economic uses like food production and industrial products.
2. Bryophytes were the first plants to colonize land. They lack true roots and vascular tissues but have leaf-like structures. They reproduce sexually through sperm and eggs that require water.
3. Pteridophytes were the first vascular plants. They have true roots, stems and leaves with vascular tissues. They reproduce sexually through gametophytes that produce sperm and eggs requiring water for fertilization.
Reproduction in sycon, Asexual & Sexual reproduction, Gemmule processSoniaBajaj10
Sycon shows both asexual and sexual reproduction. Asexual reproduction occurs through budding and regeneration. Budding involves small projections growing from the basal region that later separate and attach to form new individuals. Regeneration allows cut pieces to regrow into complete sponges. Sexually, Sycon is hermaphroditic, producing both sperm and eggs from choanocytes or archaeocytes. Fertilization is internal, with sperm entering with water currents and fertilizing eggs. Development proceeds through cleavage, blastula, stomoblastula, and gastrulation stages to form a young sponge called an olynthus. Some sponges also form resistant gemmules for asexual reproduction during unfavor
1. Multicellular plants need transport systems to move water, minerals, and sugars throughout their large structures since single cells rely on diffusion.
2. Xylem tissue transports water and minerals up from the roots through the stem and into leaves. Phloem tissue transports sugars made in leaves to other plant parts.
3. In roots, xylem forms a cross-shape in the center with phloem between the arms. In stems, xylem and phloem bundles are arranged around the edges. In leaves, xylem is closer to the top surface and phloem is below.
Peripatus is a genus of nocturnal, carnivorous velvet worms found in Central and South America. They live under rocks and wood in tropical regions. Peripatus have cylindrical, segmented bodies with 14 pairs of appendages along their sides. They exhibit traits linking them to both annelid worms and arthropods, making them an important example in evolutionary biology.
All cells of a plant develop from the zygote. The zygote undergoes cell division and the cells differentiate into tissues and organs through the processes of growth and differentiation. During development, plants form complex structures like roots, leaves, flowers and fruits. Growth is defined as a permanent increase in size through cellular processes. There are different types of growth rates including arithmetic and geometric. Plant growth and development is regulated by plant growth regulators or phytohormones such as auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
This document discusses taxonomy, systematics, and taxonomic categories. It defines taxonomy as the classification of organisms based on observable characteristics into hierarchical taxa. Systematics is the study of relationships between organisms. There are defined taxonomic categories including species, genus, family, order, class, division/phylum, and kingdom. Each category represents a rank in the taxonomic hierarchy and groups organisms with decreasingly similar characteristics as the category level increases. The categories are used to systematically classify all known organisms.
if you want to be a champion in the kingdom Animalia, then it is best for you .
this slide show covers all important features , characteristics of organisms under kingdom animalia
The document discusses taxonomy, the science of classification. It describes the history of classification from ancient Greek philosophers to the modern system developed by Carolus Linnaeus, which uses a binomial nomenclature system and groups organisms into taxa based on structural similarities. The modern levels of classification are described from domain to species, and examples are given of the kingdoms used to classify organisms, including Monera, Protista, Fungi, Plantae, and Animalia.
The document discusses the phylum Annelida. It covers their introduction, unique characters, general characters, morphology and anatomy, classification, harmful effects, and benefits. Annelida are segmented worms with a coelom, metameric segmentation, and cephalization. They exhibit homonomous metamerism and have three main body regions. Their anatomy includes systems like integumentary, digestive, circulatory, excretory, nervous, and reproductive. They are classified into classes like Polychaeta, Hirudinea, and Oligochaeta.
Animals are made up of cells that are organized into tissues and organs. There are four main tissue types - epithelial tissue covers the outside of the body and lines organs, connective tissue provides structure and binds tissues together, muscle tissue powers movement, and nerve tissue senses stimuli and transmits signals. Organs consist of multiple tissue types working together and are organized into organ systems that perform major functions like digestion, respiration, circulation, reproduction and excretion. Reproduction involves the production of gametes through meiosis and either external or internal fertilization depending on the animal type. Hormones control development and reproductive cycles in males and females.
Gametogenesis is the process by which haploid gametes are formed from diploid germ cells in the gonads. There are two types: spermatogenesis and oogenesis. Spermatogenesis occurs in the testes and involves the formation of sperm from spermatogonia over 74 days, involving multiplication, growth, and maturation phases. Oogenesis occurs in the ovaries and also involves three phases to form ova from oogonia. The resulting gametes, sperm and ovum, differ in structure according to their roles in fertilization. Sperm are small, motile cells specialized for movement, while ovum are larger stationary cells specialized to receive sperm and support development.
Reproduction In Organisms-CBSE Class XII Biologyshivrajrath
This document summarizes reproduction in organisms for class 12 biology. It discusses the different types of reproduction including asexual and sexual reproduction. Asexual reproduction occurs through fission, budding, spore formation, or vegetative propagation. Sexual reproduction involves gametogenesis, gamete transfer through processes like pollination, syngamy and fertilization to form a zygote, and post-fertilization development of the zygote into an embryo. Sexual reproduction can be external or internal, and in animals it can result in oviparous offspring that are laid as eggs or viviparous offspring that develop internally.
This document provides an overview of the phylum Annelida, or segmented worms. It describes their general features, body structures, locomotion, organ systems, classification, and special characteristics. Key points include that Annelida includes over 9,000 species of metamerically segmented animals with a true coelom. They are bilaterally symmetrical, triploblastic, and have organ systems. The four main classes are Polychaeta, Oligochaeta, Hirudinea, and Archiannelida.
Biological classification involves the study and organization of organisms into a hierarchy of groups and taxa based on their evolutionary relationships and distinguishing characteristics. The main goals are to identify all organisms and determine their evolutionary history. Carl Linnaeus developed the binomial naming system in the 1700s that is still used today. There are several systems that have been proposed to classify life, with newer systems incorporating molecular evidence to revise the evolutionary relationships between domains, kingdoms, and taxa. Prokaryotes like bacteria and archaea are classified based on characteristics like shape, metabolism, and environment. Eukaryotes like protists, fungi, plants and animals are organized into domains, kingdoms and smaller taxa.
Respiration is the process by which organisms break down carbohydrates, proteins, and fats to release energy. There are two types of respiration: aerobic respiration, which uses oxygen to completely oxidize glucose and produce carbon dioxide, water, and ATP; and anaerobic respiration, which partially oxidizes glucose without oxygen to produce lactic acid, ethanol, or ATP. Aerobic respiration involves three stages - glycolysis, the Krebs cycle, and the electron transport system. Respiration is essential for releasing energy for cellular processes and maintaining carbon balance.
This document discusses the principles and methods of taxonomy, the science of classifying organisms. It describes the main goals of taxonomy as identification, nomenclature and classification of species. The hierarchical system of classification from lowest to highest is explained as species, genus, family, order, class, division/phylum and kingdom. The document also covers binomial nomenclature, biological species concepts, subspecies, numerical taxonomy and phylogenetic systematics.
The document describes procedures for testing foods for the presence of starch, glucose, proteins, and oils/fats. For each test, it provides the steps to perform the test along with the expected color change results for a positive or negative indication of the substance being tested. The tests involve adding reagents like iodine, Benedict's solution, Biuret reagent, or water and observing any color changes that confirm or rule out the presence of starch, glucose, proteins, or oils/fats.
An alien visiting Earth for the first time would see many differences between humans. While all members of a species are similar, there are two types of variation between individuals - discontinuous and continuous. Discontinuous variation results in distinct characteristics like blood type, while continuous variation shows a range of differences like height. The type of variation determines how the data can be represented graphically.
1. The document outlines different types of glands found in the skin, including simple and compound tubular and saccular glands.
2. Examples of simple tubular glands given are sweat glands and ceruminous glands, while mammary glands are identified as compound tubular glands.
3. The skin of mammals is described as the most complex, with two main layers - the epidermis and dermis, along with associated structures like hair, claws/nails, and glands.
This document provides an overview of the phylum Annelida, or segmented worms. It discusses their general characteristics such as segmentation, coelom, circulatory and excretory systems. It then describes the three main classes: Polychaeta (marine worms with many bristles), Oligochaeta (few bristled terrestrial and freshwater worms), and Hirudinea (leeches). Key details are provided on the morphology, habitat, reproduction and examples of representative species for each class.
1) The body of the earthworm is divided into over 100 segments that are similar. It has a clitellum, a prostomium, and genital openings.
2) The digestive system includes a mouth, pharynx, esophagus, crop, gizzard, midgut, and hindgut. The circulatory system is closed.
3) The excretory system includes nephridia and nephridiopores. Earthworms are hermaphrodites with both male and female reproductive organs.
The document is a presentation on the menstrual cycle that:
1) Explains the roles of hormones like FSH, LH, progesterone and estrogen in regulating the cycle and causing changes in the uterus and ovaries.
2) Describes the key stages of the cycle including menstruation, follicle development, ovulation and the luteal phase.
3) Provides diagrams and examples to illustrate ovulation and hormone level fluctuations over the course of a typical cycle.
If fertilization does not occur after ovulation:
1) The corpus luteum will degrade, stopping progesterone and estrogen production.
2) Without progesterone, the uterine lining will break down and be shed, resulting in menstruation.
3) Menstruation marks the end of the current cycle and the start of a new follicular phase under the influence of FSH.
Peripatus is a genus of nocturnal, carnivorous velvet worms found in Central and South America. They live under rocks and wood in tropical regions. Peripatus have cylindrical, segmented bodies with 14 pairs of appendages along their sides. They exhibit traits linking them to both annelid worms and arthropods, making them an important example in evolutionary biology.
All cells of a plant develop from the zygote. The zygote undergoes cell division and the cells differentiate into tissues and organs through the processes of growth and differentiation. During development, plants form complex structures like roots, leaves, flowers and fruits. Growth is defined as a permanent increase in size through cellular processes. There are different types of growth rates including arithmetic and geometric. Plant growth and development is regulated by plant growth regulators or phytohormones such as auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
This document discusses taxonomy, systematics, and taxonomic categories. It defines taxonomy as the classification of organisms based on observable characteristics into hierarchical taxa. Systematics is the study of relationships between organisms. There are defined taxonomic categories including species, genus, family, order, class, division/phylum, and kingdom. Each category represents a rank in the taxonomic hierarchy and groups organisms with decreasingly similar characteristics as the category level increases. The categories are used to systematically classify all known organisms.
if you want to be a champion in the kingdom Animalia, then it is best for you .
this slide show covers all important features , characteristics of organisms under kingdom animalia
The document discusses taxonomy, the science of classification. It describes the history of classification from ancient Greek philosophers to the modern system developed by Carolus Linnaeus, which uses a binomial nomenclature system and groups organisms into taxa based on structural similarities. The modern levels of classification are described from domain to species, and examples are given of the kingdoms used to classify organisms, including Monera, Protista, Fungi, Plantae, and Animalia.
The document discusses the phylum Annelida. It covers their introduction, unique characters, general characters, morphology and anatomy, classification, harmful effects, and benefits. Annelida are segmented worms with a coelom, metameric segmentation, and cephalization. They exhibit homonomous metamerism and have three main body regions. Their anatomy includes systems like integumentary, digestive, circulatory, excretory, nervous, and reproductive. They are classified into classes like Polychaeta, Hirudinea, and Oligochaeta.
Animals are made up of cells that are organized into tissues and organs. There are four main tissue types - epithelial tissue covers the outside of the body and lines organs, connective tissue provides structure and binds tissues together, muscle tissue powers movement, and nerve tissue senses stimuli and transmits signals. Organs consist of multiple tissue types working together and are organized into organ systems that perform major functions like digestion, respiration, circulation, reproduction and excretion. Reproduction involves the production of gametes through meiosis and either external or internal fertilization depending on the animal type. Hormones control development and reproductive cycles in males and females.
Gametogenesis is the process by which haploid gametes are formed from diploid germ cells in the gonads. There are two types: spermatogenesis and oogenesis. Spermatogenesis occurs in the testes and involves the formation of sperm from spermatogonia over 74 days, involving multiplication, growth, and maturation phases. Oogenesis occurs in the ovaries and also involves three phases to form ova from oogonia. The resulting gametes, sperm and ovum, differ in structure according to their roles in fertilization. Sperm are small, motile cells specialized for movement, while ovum are larger stationary cells specialized to receive sperm and support development.
Reproduction In Organisms-CBSE Class XII Biologyshivrajrath
This document summarizes reproduction in organisms for class 12 biology. It discusses the different types of reproduction including asexual and sexual reproduction. Asexual reproduction occurs through fission, budding, spore formation, or vegetative propagation. Sexual reproduction involves gametogenesis, gamete transfer through processes like pollination, syngamy and fertilization to form a zygote, and post-fertilization development of the zygote into an embryo. Sexual reproduction can be external or internal, and in animals it can result in oviparous offspring that are laid as eggs or viviparous offspring that develop internally.
This document provides an overview of the phylum Annelida, or segmented worms. It describes their general features, body structures, locomotion, organ systems, classification, and special characteristics. Key points include that Annelida includes over 9,000 species of metamerically segmented animals with a true coelom. They are bilaterally symmetrical, triploblastic, and have organ systems. The four main classes are Polychaeta, Oligochaeta, Hirudinea, and Archiannelida.
Biological classification involves the study and organization of organisms into a hierarchy of groups and taxa based on their evolutionary relationships and distinguishing characteristics. The main goals are to identify all organisms and determine their evolutionary history. Carl Linnaeus developed the binomial naming system in the 1700s that is still used today. There are several systems that have been proposed to classify life, with newer systems incorporating molecular evidence to revise the evolutionary relationships between domains, kingdoms, and taxa. Prokaryotes like bacteria and archaea are classified based on characteristics like shape, metabolism, and environment. Eukaryotes like protists, fungi, plants and animals are organized into domains, kingdoms and smaller taxa.
Respiration is the process by which organisms break down carbohydrates, proteins, and fats to release energy. There are two types of respiration: aerobic respiration, which uses oxygen to completely oxidize glucose and produce carbon dioxide, water, and ATP; and anaerobic respiration, which partially oxidizes glucose without oxygen to produce lactic acid, ethanol, or ATP. Aerobic respiration involves three stages - glycolysis, the Krebs cycle, and the electron transport system. Respiration is essential for releasing energy for cellular processes and maintaining carbon balance.
This document discusses the principles and methods of taxonomy, the science of classifying organisms. It describes the main goals of taxonomy as identification, nomenclature and classification of species. The hierarchical system of classification from lowest to highest is explained as species, genus, family, order, class, division/phylum and kingdom. The document also covers binomial nomenclature, biological species concepts, subspecies, numerical taxonomy and phylogenetic systematics.
The document describes procedures for testing foods for the presence of starch, glucose, proteins, and oils/fats. For each test, it provides the steps to perform the test along with the expected color change results for a positive or negative indication of the substance being tested. The tests involve adding reagents like iodine, Benedict's solution, Biuret reagent, or water and observing any color changes that confirm or rule out the presence of starch, glucose, proteins, or oils/fats.
An alien visiting Earth for the first time would see many differences between humans. While all members of a species are similar, there are two types of variation between individuals - discontinuous and continuous. Discontinuous variation results in distinct characteristics like blood type, while continuous variation shows a range of differences like height. The type of variation determines how the data can be represented graphically.
1. The document outlines different types of glands found in the skin, including simple and compound tubular and saccular glands.
2. Examples of simple tubular glands given are sweat glands and ceruminous glands, while mammary glands are identified as compound tubular glands.
3. The skin of mammals is described as the most complex, with two main layers - the epidermis and dermis, along with associated structures like hair, claws/nails, and glands.
This document provides an overview of the phylum Annelida, or segmented worms. It discusses their general characteristics such as segmentation, coelom, circulatory and excretory systems. It then describes the three main classes: Polychaeta (marine worms with many bristles), Oligochaeta (few bristled terrestrial and freshwater worms), and Hirudinea (leeches). Key details are provided on the morphology, habitat, reproduction and examples of representative species for each class.
1) The body of the earthworm is divided into over 100 segments that are similar. It has a clitellum, a prostomium, and genital openings.
2) The digestive system includes a mouth, pharynx, esophagus, crop, gizzard, midgut, and hindgut. The circulatory system is closed.
3) The excretory system includes nephridia and nephridiopores. Earthworms are hermaphrodites with both male and female reproductive organs.
The document is a presentation on the menstrual cycle that:
1) Explains the roles of hormones like FSH, LH, progesterone and estrogen in regulating the cycle and causing changes in the uterus and ovaries.
2) Describes the key stages of the cycle including menstruation, follicle development, ovulation and the luteal phase.
3) Provides diagrams and examples to illustrate ovulation and hormone level fluctuations over the course of a typical cycle.
If fertilization does not occur after ovulation:
1) The corpus luteum will degrade, stopping progesterone and estrogen production.
2) Without progesterone, the uterine lining will break down and be shed, resulting in menstruation.
3) Menstruation marks the end of the current cycle and the start of a new follicular phase under the influence of FSH.
In this PPT I completed that interesting topic In this PPT I completed that interesting topic , molecular embryology discussing this time molecular regulation of some other systems in the developing embryo, wishing that I could make this as simple as possible.
Ovarian cysts are fluid-filled sacs that can form on the ovaries. They are usually benign and noncancerous. Common symptoms include abdominal pain and swelling, nausea, and symptoms similar to pregnancy. The most common type is follicular cysts, which form during ovulation and contain clear fluid. Luteal cysts may rupture around menstruation. Polycystic ovary syndrome (PCOS) is a condition where women have an imbalance of sex hormones that can lead to cysts, irregular periods, excess hair growth, and difficulty getting pregnant. PCOS also increases the risk of diabetes, high blood pressure, high cholesterol, and obesity.
This document discusses the relationship between systemic conditions and periodontal disease. It states that periodontal disease is influenced by factors like diabetes, hormonal changes, hematological disorders, stress, and nutrition. Certain systemic conditions can impair host defenses and increase susceptibility to periodontal infections by reducing barrier integrity and immune response. The relationship between systemic and periodontal health is bidirectional, with systemic factors impacting local periodontal health and vice versa.
Variations in menstrual cycle mbbs lectures.-1Shamsuddin011
This document discusses variations in the menstrual cycle, including causes and treatments. It defines normal menstrual cycles and various types of irregularities including variations in frequency, amount, and duration. Common causes of irregularities include stress, excessive exercise, medications, medical conditions, and endocrine disorders. Dysfunctional uterine bleeding is described as abnormal bleeding without organic disease, often due to anovulation. Treatment depends on severity of anemia and may include oral contraceptives, iron supplementation, or blood transfusion in severe cases.
This document discusses the normal ultrasound appearance of the endometrium and ovaries throughout the menstrual cycle. It provides details on the expected endometrial thickness at different phases of the cycle. It also describes the sonographic signs of ovulation and the appearance and development of the corpus luteum. Post-menopausal endometrial thickness is also addressed. Failure of ovulation and the development of luteinized unruptured follicles are summarized at the end.
The menstrual cycle is regulated by hormones from the hypothalamus, pituitary gland, and ovaries. It involves both the ovarian cycle and uterine cycle. The ovarian cycle consists of the follicular phase leading up to ovulation on day 14, and the luteal phase after. The uterine cycle involves the menstrual, proliferative, and secretory phases. Hormones like FSH, LH, estrogen, and progesterone are involved in a feedback loop to regulate the cycle. Disorders of the menstrual cycle can cause problems like painful periods or abnormal bleeding.
The menstrual cycle is regulated by the hypothalamus, pituitary gland, and ovaries. It typically lasts 28 days and has two phases: the follicular phase where an egg is recruited and develops prior to ovulation on day 14, and the luteal phase where the corpus luteum forms and secretes progesterone to prepare the uterus if pregnancy occurs. If implantation does not happen, progesterone and estrogen levels fall causing menstruation. The endometrium thickens and breaks down cyclically in response to changing hormone levels throughout the cycle.
Understanding your-menstrual-cycle and body systemRufus Yamoah
This Slide Show Presentation is Pastor Derashay Zorn for LADY CARE COACHING. Learn how to manage your body and take care of yourself as a lady during menstrual cycle.
The menstrual cycle is controlled by hormones from the pituitary gland and ovaries. It aims to release an egg once a month to allow for potential fertilization and pregnancy. The cycle involves three phases - the menstrual, proliferative, and secretory phases. Estrogen stimulates growth of the uterine lining during the proliferative phase, while progesterone maintains the lining during the secretory phase in preparation for potential implantation. If implantation does not occur, progesterone and estrogen levels fall, causing the uterine lining to shed and result in menstruation, restarting the cycle.
The menstrual cycle involves coordinated changes in the ovaries and uterus driven by hormones. It typically lasts 28 days and includes a follicular phase where an egg matures and is released, ovulation, and a luteal phase where the corpus luteum develops. Hormones like FSH, LH, estrogen and progesterone regulate this cycle. The endometrium thickens during the follicular phase in response to rising estrogen, and further changes during the luteal phase due to progesterone to prepare for potential implantation. If implantation does not occur, hormone levels drop and the endometrium is shed as menstruation.
4.2 the role of hormones in the menstrual cyclehazirah HUSSIN
1. The document describes the female menstrual cycle, including the hormonal changes, development and release of eggs, and thickening and shedding of the uterine lining.
2. It also discusses the process of fertilization and early embryonic development, as well as methods to prevent or overcome infertility.
3. The menstrual cycle and fertility in women are controlled by hormones like FSH, LH, estrogen and progesterone that regulate the development of eggs and the uterine lining.
Embryology is the study of the development of an organism from conception to birth. The prenatal period lasts 38 weeks on average from conception to birth. During the first 8 weeks, called the embryonic period, all major organs form. The remaining 30 weeks make up the fetal period where organs grow larger and more complex. Fertilization occurs when sperm and egg join in the fallopian tube to form a zygote. Over the next 2 weeks the zygote divides and implants in the uterus, forming the 3 germ layers - ectoderm, endoderm, and mesoderm - from which all tissues and organs develop. By 8 weeks all major organs have formed in a rudimentary state
Functioning organisms - 06 ReproductionIan Anderson
Reproduction allows organisms to produce offspring and continue their species. There are two main types of reproduction: asexual reproduction which involves a single parent and produces offspring identical to the parent; and sexual reproduction which involves two parents fusing gametes to produce offspring with a unique combination of genes. Asexual reproduction methods include binary fission, budding and sporulation while sexual reproduction requires fertilization of an egg by sperm. Plants generally alternate between haploid and diploid generations while sexual reproduction in animals includes internal and external fertilization.
The menstrual cycle describes the monthly process a woman's body goes through to prepare for potential pregnancy. If pregnancy does not occur, the thickened uterine lining breaks down and is discharged as menstruation. The cycle is initiated by hormones that cause an egg to mature in one of the ovaries each month. If the egg is fertilized by a sperm, pregnancy will occur. Otherwise, without hormones to sustain it, the uterine lining breaks down and is shed, completing the cycle and preparing the body for the next potential pregnancy.
The document summarizes the female ovarian and menstrual cycle. It discusses the female reproductive organs and hormones involved in the monthly cycle. It describes the process of oogenesis where oogonia develop into oocytes in the ovaries from fetal life until ovulation. In contrast, spermatogenesis is a continual process in males where spermatogonia can produce millions of sperm daily. The cycle is regulated by levels of gonadotropins and hormones, with the corpus luteum developing after ovulation and menstruation occurring when stimulation decreases.
The menstrual cycle involves two main phases - the follicular phase and luteal phase. In the follicular phase, hormones stimulate the growth of follicles in the ovaries and thickening of the uterine lining. This culminates in a surge of LH which causes ovulation of an egg. In the luteal phase, the corpus luteum forms and produces progesterone and estrogen to prepare the uterus for potential implantation. If implantation does not occur, hormone levels fall and menstruation begins, restarting the cycle.
This document discusses the embryology of the excretory system, specifically summarizing the development of the kidneys and ureters from the pronephros and mesonephros stages in the 5th week through maturation of the metanephros in the 8th week. It also covers abnormalities that can occur such as cystic kidney disease, renal agenesis, ectopic or horseshoe kidneys, bifid ureters, and more. The development is described through diagrams and images at each stage of gestation.
Chapter 17 Reproduction in Humans Lesson 2 - The Menstrual Cyclej3di79
The document summarizes the key events of the human menstrual cycle. It describes how follicles in the ovaries mature and how hormones regulate the cycle. It explains that the ovarian follicle ruptures and releases an egg (ovulation) around day 14. If the egg is not fertilized, hormone levels drop and the uterine lining is shed through menstruation around day 28, starting a new cycle. Oral contraceptives work by inhibiting the hormones FSH and LH to prevent ovulation and therefore pregnancy.
01-02 human reproduction and reproductive health.pdfBSM27Nisarudheen
1. Human reproduction involves gametogenesis, fertilization, gestation and parturition. Gametogenesis includes spermatogenesis and oogenesis, which are the formation of sperm and eggs respectively.
2. The male reproductive system includes testes, ducts and glands. The testes produce sperm and hormones. Sperm travel through ducts and are mixed with fluids from glands to form semen.
3. The female reproductive system includes ovaries, ducts, uterus and external genitalia. The ovaries produce eggs and hormones. Eggs travel through ducts and the uterus provides gestation. The breasts produce milk after birth.
Embryology is the study of development from fertilization to organ formation. In humans, this encompasses the first 8 weeks and includes key stages like fertilization, implantation, formation of the three germ layers through gastrulation, and organogenesis from weeks 5-8. The development involves gamete formation, fertilization, cleavage, gastrulation establishing three germ layers, and organogenesis from these layers. Cell proliferation, migration and differentiation are essential cellular processes during development.
Anatomy & Physiology of Female Reproductive System 1Dr. Sarita Sharma
The document summarizes the anatomy and physiology of the female reproductive system. It describes the internal structures including ovaries, fallopian tubes, uterus, and vagina. It discusses their locations, layers, functions, and relationships to surrounding structures. It also describes the external female reproductive structures including the mons pubis, labia majora and minora, clitoris, and vestibule. Finally, it briefly discusses the bony pelvis and other supporting structures that protect the internal reproductive organs.
7. Male and Female reproductive system.pptxAbhiDabra
The document provides an overview of the male and female reproductive systems. It describes the key organs involved in both systems, including their structure and functions. For the male system it covers the testes, spermatic cord, seminal vesicles, prostate gland, and urethra. For the female system it discusses the ovaries, fallopian tubes, uterus, vagina, and external genitalia. It also explains processes like the menstrual cycle, fertilization, pregnancy, and menopause.
The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction.
The reproductive events in human includes formation of gametes (gametogenesis) i.e sperms in males and ovum in females leading to the formation of zygote.
This document provides information about the female endocrine system, specifically the ovaries. It describes the anatomy and location of the ovaries. The ovaries contain ovarian follicles and have two layers - the medulla in the center and cortex on the outside. The ovaries secrete female sex hormones estrogen and progesterone. Estrogen is secreted by ovarian follicles and the corpus luteum, and functions include growth of follicles and secondary sex characteristics. Progesterone is secreted by the corpus luteum after ovulation and functions include uterine preparation for pregnancy.
The document summarizes the anatomy and structures of the female reproductive system. It describes the external structures including the vulva, labia majora and minora, clitoris, and perineum. It then details the internal structures such as the vagina, uterus, fallopian tubes, and ovaries. It explains the functions of each structure and how they work together in menstruation, pregnancy, and childbirth. The bony pelvis and ligaments are also summarized as providing support for the reproductive organs.
The document summarizes the anatomy and structures of the female reproductive system. It describes the external structures including the vulva, labia majora and minora, clitoris, and perineum. It then details the internal structures such as the vagina, uterus, fallopian tubes, and ovaries. It explains the functions of each structure and how they work together in menstruation, pregnancy, and childbirth. The bony pelvis and supporting ligaments are also summarized.
The document summarizes the anatomy and structures of the female reproductive system. It describes the external structures including the vulva, labia majora and minora, clitoris, and perineum. It then discusses the internal structures such as the vagina, uterus, fallopian tubes, and ovaries. It explains the functions of these structures including menstruation, pregnancy, childbirth, and sexual reproduction. The bony pelvis and supporting ligaments are also summarized for providing structure and protection to the reproductive organs.
The document summarizes the anatomy and structures of the female reproductive system. It describes the external structures including the vulva, labia majora and minora, clitoris, and perineum. It then details the internal structures such as the vagina, uterus, fallopian tubes, and ovaries. It explains the functions of each structure and how they work together in menstruation, pregnancy, and childbirth. The bony pelvis and supporting ligaments are also summarized for providing structure and protection to the reproductive organs.
Female reproductive system ibrahim mohammedbhmMhmm
The document provides information on the female reproductive system, including its external and internal structures and their functions. Externally, it describes the vulva and its parts like the labia, clitoris, and vaginal opening. Internally, it details the ovaries, fallopian tubes, uterus including the endometrium, myometrium and perimetrium layers, and vagina. The key functions of these structures include formation of eggs, reception of sperm, provision of an environment for fertilization and fetal development, childbirth, and lactation.
The female reproductive system produces eggs, provides an environment for embryo development, and expels the fetus at birth. It includes ovaries, fallopian tubes, uterus, vagina, and vulva. The ovaries contain eggs and produce hormones. The fallopian tubes connect the ovaries to the uterus. The uterus shelters and nourishes the developing embryo and fetus. The vagina allows for sexual intercourse and childbirth. Ligaments suspend the internal reproductive organs in the pelvis.
Anatomy physiology of female reproductive systemMonique Reyes
The document summarizes the anatomy and physiology of the female reproductive system. It describes the external structures including the vulva, labia majora, labia minora, clitoris, and vestibule. It then discusses the internal structures such as the vagina, uterus, fallopian tubes, and ovaries. It explains the functions of these organs and how they work together in menstruation, pregnancy, childbirth, and sexual reproduction. The document also briefly outlines the structures that provide support to the reproductive system, including the bony pelvis, sacrum, and coccyx.
The document summarizes key aspects of human reproduction. It describes the male and female reproductive systems and their components. Spermatogenesis and oogenesis are the processes by which sperm and eggs are produced. Fertilization occurs when a sperm fuses with an egg in the fallopian tubes. The fertilized egg undergoes cleavage and blastulation as it travels to the uterus. Implantation occurs as the blastocyst attaches to the uterine wall, initiating pregnancy. Pregnancy lasts about 9 months and has three trimesters of development.
The document summarizes the key components of the female reproductive system, including the ovaries which produce eggs (ova), the uterus where a fertilized egg implants and develops, and the three layers (perimetrium, myometrium, endometrium) that make up the uterine wall. It also describes a total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH BSO), a surgical procedure that removes the uterus, cervix, ovaries and fallopian tubes, and lists reasons for and risks associated with this operation.
ANATOMY & PHYSIOLOGY OF FEMALE REPRODUCTIVE ORGANS.pptxGalchuTeno3
The document describes the anatomy and physiology of the female reproductive organs. It discusses the external structures including the labia majora, labia minora, clitoris, and vestibule. It then explains the internal structures such as the ovaries, which produce eggs; the fallopian tubes, which connect to the ovaries and transport eggs; and the uterus, which provides nourishment for fetal growth. The document provides detailed information on the location, function, and development of each female reproductive structure.
The document provides information on the male and female reproductive systems. It describes the external and internal structures of both systems in detail. The female reproductive system includes the vulva, vagina, uterus, fallopian tubes, ovaries and breasts. The male reproductive system includes the scrotum, testes, seminal vesicles, prostate gland, urethra and penis. The functions of reproduction such as gamete formation, fertilization, gestation and lactation are enabled by these reproductive organs.
The document provides an overview of the male and female reproductive systems. It describes the key organs in both systems, including their structure and functions. In the male system, it discusses the testes, scrotum, sperm production, and the role of the prostate gland, seminal vesicles, and urethra during ejaculation. In the female system, it outlines the external genitalia (vulva), and internal organs including the vagina, uterus, uterine tubes, and ovaries. The purpose of both systems is to produce gametes and facilitate fertilization and fetal development.
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
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8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
Role of Mukta Pishti in the Management of Hyperthyroidism
03 human reproduction
1. CHAPTER 3
HUMAN REPRODUCTION
3.1 The Male Reproductive
System
3.2 The Female Reproductive As you are aware, humans are sexually reproducing and
System viviparous. The reproductive events in humans include
formation of gametes (gametogenesis), i.e., sperms in males
3.3 Gametogenesis and ovum in females, transfer of sperms into the female
3.4 Menstrual Cycle genital tract (insemination) and fusion of male and female
gametes (fertilisation) leading to formation of zygote. This
3.5 Fertilisation and
is followed by formation and development of blastocyst
Implantation
and its attachment to the uterine wall (implantation),
3.6 Pregnancy and embryonic development (gestation) and delivery of the
Embryonic Development baby (parturition). You have learnt that these reproductive
events occur after puberty. There are remarkable
3.7 Parturition and Lactation
differences between the reproductive events in the male
and in the female, for example, sperm formation continues
even in old men, but formation of ovum ceases in women
around the age of fifty years. Let us examine the male and
female reproductive systems in human.
3.1 THE MALE REPRODUCTIVE SYSTEM
The male reproductive system is located in the pelvis region
(Figure 3.1a). It includes a pair of testes alongwith
accessory ducts, glands and the external genitalia.
2. HUMAN REPRODUCTION
The testes are situated outside the
abdominal cavity within a pouch
called scrotum. The scrotum helps
in maintaining the low temperature
of the testes (2–2.5o C lower than
the normal internal body
temperature) necessary for
spermatogenesis. In adults, each
testis is oval in shape, with a length
of about 4 to 5 cm and a width of
about 2 to 3 cm. The testis is
covered by a dense covering. Each
testis has about 250 compartments
called testicular lobules Figure 3.1(a) Diagrammatic sectional view of male pelvis
(Figure 3.1b). showing reproductive system
Each lobule contains one to
three highly coiled seminiferous
tubules in which sperms are
produced. Each seminiferous tubule
is lined on its inside by two types
of cells called male germ cells
(spermatogonia) and Sertoli cells
(Figure 3.2 ). The male germ cells
undergo meiotic divisions finally
leading to sperm formation, while
Sertoli cells provide nutrition to the
germ cells. The regions outside the
seminiferous tubules called
interstitial spaces, contain small
blood vessels and interstitial cells
or Leydig cells (Figure 3.2). Leydig
cells synthesise and secrete
testicular hormones called Figure 3.1(b) Diagrammatic view of male reproductive system
(part of testis is open to show inner details)
androgens. Other immunologically
competent cells are also present.
The male sex accessory ducts include rete testis, vasa efferentia,
epididymis and vas deferens (Figure 3.1b). The seminiferous tubules of
the testis open into the vasa efferentia through rete testis. The vasa efferentia
leave the testis and open into epididymis located along the posterior surface
43
of each testis. The epididymis leads to vas deferens that ascends to the
abdomen and loops over the urinary bladder. It receives a duct from seminal
vesicle and opens into urethra as the ejaculatory duct (Figure 3.1a). These
ducts store and transport the sperms from the testis to the outside through
urethra. The urethra originates from the urinary bladder and extends
through the penis to its external opening called urethral meatus.
3. BIOLOGY
Figure 3.2 Diagrammatic sectional view of seminiferous tubule
The penis is the male external genitalia (Figure 3.1a, b). It is made up
of special tissue that helps in erection of the penis to facilitate insemination.
The enlarged end of penis called the glans penis is covered by a loose fold
of skin called foreskin.
The male accessory glands (Figure 3.1a, b) include paired seminal
vesicles, a prostate and paired bulbourethral glands. Secretions of these
glands constitute the seminal plasma which is rich in fructose, calcium
and certain enzymes. The secretions of bulbourethral glands also helps
in the lubrication of the penis.
3.2 THE FEMALE REPRODUCTIVE SYSTEM
The female reproductive system consists of a pair of ovaries alongwith a pair
of oviducts, uterus, cervix, vagina and the external genitalia located in
pelvic region (Figure 3.3a). These parts of the system alongwith a pair of the
mammary glands are integrated structurally and functionally to support
the processes of ovulation, fertilisation, pregnancy, birth and child care.
Ovaries are the primary female sex organs that produce the female
44 gamete (ovum) and several steroid hormones (ovarian hormones).
The ovaries are located one on each side of the lower abdomen
(Figure 3.3b). Each ovary is about 2 to 4 cm in length and is connected to
the pelvic wall and uterus by ligaments. Each ovary is covered by a thin
epithelium which encloses the ovarian stroma. The stroma is divided into
two zones – a peripheral cortex and an inner medulla.
4. HUMAN REPRODUCTION
Figure 3.3 (a) Diagrammatic sectional view of female pelvis showing
reproductive system
The oviducts (fallopian tubes), uterus and vagina constitute the female
accessory ducts. Each fallopian tube is about 10-12 cm long and extends
from the periphery of each ovary to the uterus (Figure 3.3b), the part closer
to the ovary is the funnel-shaped infundibulum. The edges of the
infundibulum possess finger-like projections called fimbriae, which help in
collection of the ovum after ovulation. The infundibulum leads to a wider
45
Figure 3.3 (b) Diagrammatic sectional view of the female reproductive system
5. BIOLOGY
part of the oviduct called ampulla. The last part of the oviduct, isthmus has
a narrow lumen and it joins the uterus.
The uterus is single and it is also called womb. The shape of the uterus
is like an inverted pear. It is supported by ligaments attached to the pelvic
wall. The uterus opens into vagina through a narrow cervix. The cavity of
the cervix is called cervical canal (Figure 3.3b) which alongwith vagina
forms the birth canal. The wall of the uterus has three layers of tissue. The
external thin membranous perimetrium, middle thick layer of smooth
muscle, myometrium and inner glandular layer called endometrium that
lines the uterine cavity. The endometrium undergoes cyclical changes during
menstrual cycle while the myometrium exhibits strong contraction during
delivery of the baby.
The female external genitalia include mons pubis, labia majora, labia
minora, hymen and clitoris (Figure 3.3a). Mons pubis is a cushion of fatty
tissue covered by skin and pubic hair. The labia majora are fleshy folds of
tissue, which extend down from the mons pubis and surround the vaginal
opening. The labia minora are paired folds of tissue under the labia majora.
The opening of the vagina is often covered partially by a membrane called
hymen. The clitoris is a tiny finger-like structure which lies at the upper
junction of the two labia minora above the urethral opening. The hymen is
often torn during the first coitus (intercourse). However, it can also be broken
by a sudden fall or jolt, insertion of a vaginal tampon, active participation
in some sports like horseback riding, cycling, etc. In some women the hymen
persists even after coitus. In fact, the presence or absence of hymen is not
a reliable indicator of virginity or sexual experience.
46
Figure 3.4 A diagrammatic sectional view of Mammary gland
6. HUMAN REPRODUCTION
A functional mammary gland is characteristic of all female mammals.
The mammary glands are paired structures (breasts) that contain
glandular tissue and variable amount of fat. The glandular tissue of each
breast is divided into 15-20 mammary lobes containing clusters of cells
called alveoli (Figure 3.4). The cells of alveoli secrete milk, which is stored
in the cavities (lumens) of alveoli. The alveoli open into mammary tubules.
The tubules of each lobe join to form a mammary duct. Several mammary
ducts join to form a wider mammary ampulla which is connected to
lactiferous duct through which milk is sucked out.
3.3 GAMETOGENESIS
The primary sex organs – the testis in the males and the ovaries in the
females – produce gametes, i.e, sperms and ovum, respectively, by the
process called gametogenesis. In testis, the immature male germ cells
(spermatogonia) produce sperms by spermatogenesis that begins at
puberty. The spermatogonia (sing. spermatogonium) present on the
inside wall of seminiferous tubules multiply by mitotic division and
increase in numbers. Each spermatogonium is diploid and contains 46
chromosomes. Some of the spermatogonia called primary
spermatocytes periodically undergo meiosis. A primary spermatocyte
completes the first meiotic division (reduction division) leading to
formation of two equal, haploid cells called
secondary spermatocytes, which have only
23 chromosomes each. The secondary
spermatocytes undergo the second meiotic
division to produce four equal, haploid
spermatids (Figure 3.5). What would be the
number of chromosome in the spermatids?
The spermatids are transformed into
spermatozoa (sperms) by the process called
spermiogenesis. After spermiogenesis,
sperm heads become embedded in the
Sertoli cells, and are finally released from
the seminiferous tubules by the process
called spermiation.
Spermatogenesis starts at the age of
Figure 3.5 Diagrammatic sectional view of a
puberty due to significant increase in the seminiferous tubule (enlarged)
secretion of gonadotropin releasing hormone
(GnRH). This, if you recall, is a hypothalamic hormone. The increased 47
levels of GnRH then acts at the anterior pituitary gland and stimulates
secretion of two gonadotropins – luteinising hormone (LH) and follicle
stimulating hormone (FSH). LH acts at the Leydig cells and stimulates
synthesis and secretion of androgens. Androgens, in turn, stimulate the
process of spermatogenesis. FSH acts on the Sertoli cells and stimulates
7. BIOLOGY
secretion of some factors which help in the
process of spermiogenesis.
Let us examine the structure of a sperm. It
is a microscopic structure composed of a head,
neck, a middle piece and a tail (Figure 3.6). A
plasma membrane envelops the whole body of
sperm. The sperm head contains an elongated
haploid nucleus, the anterior portion of which
is covered by a cap-like structure, acrosome.
The acrosome is filled with enzymes that help
fertilisation of the ovum. The middle piece
possesses numerous mitochondria, which
produce energy for the movement of tail that
facilitate sperm motility essential for fertilisation.
The human male ejaculates about 200 to 300
million sperms during a coitus of which, for
normal fertility, at least 60 per cent sperms
must have normal shape and size and for at
least 40 per cent of them must show vigorous
motility.
Figure 3.6 Structure of a sperm
Sperms released from the seminiferous
tubules, are transported by the accessory
ducts. Secretions of epididymis, vas deferens, seminal vesicle and
prostate are essential for maturation and motility of sperms. The seminal
plasma along with the sperms constitute the semen. The functions of
male sex accessory ducts and glands are maintained by the testicular
hormones (androgens).
The process of formation of a mature female gamete is called oogenesis
which is markedly different from spermatogenesis. Oogenesis is initiated
during the embryonic development stage when a couple of million gamete
mother cells (oogonia) are formed within each fetal ovary; no more oogonia
are formed and added after birth. These cells start division and enter into
prophase-I of the meiotic division and get temporarily arrested at that stage,
called primary oocytes. Each primary oocyte then gets surrounded by a
layer of granulosa cells and then called the primary follicle (Figure 3.7).
A large number of these follicles degenerate during the phase from birth to
puberty. Therefore, at puberty only 60,000-80,000 primary follicles are
left in each ovary. The primary follicles get surrounded by more layers of
granulosa cells and a new theca and called secondary follicles.
The secondary follicle soon transforms into a tertiary follicle which is
48 characterised by a fluid filled cavity called antrum. The theca layer is
organised into an inner theca interna and an outer theca externa. It is
important to draw your attention that it is at this stage that the primary
oocyte within the tertiary follicle grows in size and completes its first meiotic
division. It is an unequal division resulting in the formation of a large
haploid secondary oocyte and a tiny first polar body (Figure 3.8b). The
8. HUMAN REPRODUCTION
secondary oocyte retains bulk of the
nutrient rich cytoplasm of the primary
oocyte. Can you think of any advantage
for this? Does the first polar body born
out of first meiotic division divide further
or degenerate? At present we are not
very certain about this. The tertiary
follicle further changes into the mature
follicle or Graafian follicle (Figure 3.7).
The secondary oocyte forms a new
membrane called zona pellucida
surrounding it. The Graafian follicle now
ruptures to release the secondary oocyte
(ovum) from the ovary by the
process called ovulation. Can you Figure 3.7 Diagrammatic Section view of ovary
identify major differences between
spermatogenesis and oogenesis? A diagrammatic representation of
spermatogenesis and oogenesis is given below (Figure 3.8).
(a) (b)
Figure 3.8 Schematic representation of (a) Spermatogenesis; (b) Oogenesis
3.4 MENSTRUAL CYCLE
49
The reproductive cycle in the female primates (e.g. monkeys, apes and
human beings) is called menstrual cycle. The first menstruation begins
at puberty and is called menarche. In human females, menstruation
is repeated at an average interval of about 28/29 days, and the cycle of
events starting from one menstruation till the next one is called the
menstrual cycle. One ovum is released (ovulation) during the middle
9. BIOLOGY
Figure 3.9 Diagrammatic presenation of various events during a menstrual cycle
of each menstrual cycle. The major events of the menstrual cycle are
shown in Figure 3.9. The cycle starts with the menstrual phase, when
menstrual flow occurs and it lasts for 3-5 days. The menstrual flow
results due to breakdown of endometrial lining of the uterus and its
blood vessels which forms liquid that comes out through vagina.
Menstruation only occurs if the released ouvm is not fertilised. Lack of
menstruation may be indicative of pregnancy. However, it may also be
caused due to some other underlying causes like stress, poor health etc.
50 The menstrual phase is followed by the follicular phase. During
this phase, the primary follicles in the ovary grow to become a
fully mature Graafian follicle and simultaneously the endometrium
of uterus regenerates through proliferation. These changes in the
ovary and the uterus are induced by changes in the levels of
pituitary and ovarian hormones (Figure 3.9). The secretion of
10. HUMAN REPRODUCTION
gonadotropins (LH and FSH) increases gradually during the follicular
phase, and stimulates follicular development as well as secretion of
estrogens by the growing follicles. Both LH and FSH attain a peak level
in the middle of cycle (about 14th day). Rapid secretion of LH leading to
its maximum level during the mid-cycle called LH surge induces rupture
of Graafian follicle and thereby the release of ovum (ovulation). The
ovulation (ovulatory phase) is followed by the luteal phase during which
the remaining parts of the Graafian follicle transform as the corpus
luteum (Figure 3.9). The corpus luteum secretes large amounts of
progesterone which is essential for maintenance of the endometrium.
Such an endometrium is necessary for implantation of the fertilised
ovum and other events of pregnancy. During pregnanacy all events of
the menstrual cycle stop and there is no menstruation. In the absence
of fertilisation, the corpus luteum degenerates. This causes disintegration
of the endometrium leading to menstruation, marking a new cycle. In
human beings, menstrual cycles ceases around 50 years of age; that is
termed as menopause. Cyclic menstruation is an indicator of normal
reproductive phase and extends between menarche and menopause.
3.5 FERTILISATION AND IMPLANTATION
During copulation (coitus) semen is released by the penis into the vagina
(insemination). The motile sperms swim rapidly, pass through the cervix,
enter into the uterus and finally reach the junction of the isthmus and
ampulla (ampullary-isthmic junction) of the fallopian tube (Figure 3.11b).
The ovum released by the ovary is also
transported to the ampullary-isthmic
junction where fertilisation takes
place. Fertilisation can only occur if
the ovum and sperms are transported
simultaneously to the ampullary-
isthmic junction. This is the reason
why not all copulations lead to
fertilisation and pregnancy.
The process of fusion of a sperm
with an ovum is called fertilisation.
During fertilisation, a sperm comes in
contact with the zona pellucida layer
of the ovum (Figure 3.10) and induces
changes in the membrane that block 51 51
the entry of additional sperms. Thus,
it ensures that only one sperm can
fertilise an ovum. The secretions of the
acrosome help the sperm enter into the
cytoplasm of the ovum through the
Figure 3.10 Ovum surrounded by few sperms
zona pellucida and the plasma
11. BIOLOGY
membrane. This induces the completion of the meiotic division of the
secondary oocyte. The second meiotic division is also unequal and results
in the formation of a second polar body and a haploid ovum (ootid). Soon
the haploid nucleus of the sperms and that of the ovum fuse together to
form a diploid zygote. How many chromosomes will be there in the zygote?
One has to remember that the sex of the baby has been decided at this
stage itself. Let us see how? As you know the chromosome pattern in the
human female is XX and that in the male is XY. Therefore, all the haploid
gametes produced by the female (ova) have the sex chromosome X whereas
in the male gametes (sperms) the sex chromosome could be either X or Y,
hence, 50 per cent of sperms carry the X chromosome while the other 50 per
cent carry the Y. After fusion of the male and female gametes the zygote
would carry either XX or XY depending on whether the sperm carrying X
or Y fertilised the ovum. The zygote carrying XX would develop into a female
baby and XY would form a male (you will learn more about the chromosomal
patterns in Chapter 5). That is why, scientifically it is correct to say that the
sex of the baby is determined by the father and not by the mother!
The mitotic division starts as the zygote moves through the isthmus
of the oviduct called cleavage towards the uterus (Figure 3.11) and forms
2, 4, 8, 16 daughter cells called blastomeres. The embryo with 8 to 16
52
Figure 3.11 Transport of ovum, fertilisation and passage of growing embryo through fallopian tube
12. HUMAN REPRODUCTION
blastomeres is called a morula (Figure 3.11e). The morula continues to
divide and transforms into blastocyst (Figure 3.11g) as it moves further
into the uterus. The blastomeres in the blastocyst are arranged into an
outer layer called trophoblast and an inner group of cells attached to
trophoblast called the inner cell mass. The trophoblast layer then gets
attached to the endometrium and the inner cell mass gets differentiated
as the embryo. After attachment, the uterine cells divide rapidly and covers
the blastocyst. As a result, the blastocyst becomes embedded in the
endometrium of the uterus (Figure 3.11h). This is called implantation
and it leads to pregnancy.
3.6 PREGNANCY AND EMBRYONIC DEVELOPMENT
After implantation, finger-like projections appear on the trophoblast called
chorionic villi which are surrounded by the uterine tissue and maternal
blood. The chorionic villi and uterine tissue become interdigitated with
each other and jointly form a structural and functional unit between
developing embryo (foetus) and maternal body called placenta (Figure 3.12).
The placenta facilitate the supply of oxygen and nutrients to the
embryo and also removal of carbon dioxide and excretory/waste materials
produced by the embryo. The placenta is connected to the embryo through
an umbilical cord which helps in the transport of substances to and from
the embryo. Placenta also acts as an endocrine tissue and produces
several hormones like human chorionic gonadotropin (hCG), human
placental lactogen (hPL), estrogens, progestogens, etc. In the later
phase of pregnancy, a hormone called relaxin is also secreted by
the ovary. Let us remember
that hCG, hPL and relaxin
are produced in women
only during pregnancy. In
addition, during pregnancy
the levels of other hormones
like estrogens, progestogens,
cortisol, prolactin, thyroxine,
etc., are increased several-
folds in the maternal blood.
Increased production of these
hormones is essential for
supporting the fetal growth,
metabolic changes in the 53
mother and maintenance of
pregnancy.
Immediately after
implantation, the inner cell
mass (embryo) differentiates Figure 3.12 The human foetus within the uterus
13. BIOLOGY
into an outer layer called ectoderm and an inner layer called endoderm. A
mesoderm soon appears between the ectoderm and the endoderm. These
three layers give rise to all tissues (organs) in adults. It needs to be mentioned
here that the inner cell mass contains certain cells called stem cells which
have the potency to give rise to all the tissues and organs.
What are the major features of embryonic development at various
months of pregnancy? The human pregnancy lasts 9 months. Do you
know many months pregnancy last in dogs, elephants, cats? Find out.
In human beings, after one month of pregnancy, the embryo’s heart is
formed. The first sign of growing foetus may be noticed by listening to the
heart sound carefully through the stethoscope. By the end of the second
month of pregnancy, the foetus develops limbs and digits. By the end of
12 weeks (first trimester), most of the major organ systems are formed,
for example, the limbs and external genital organs are well-developed.
The first movements of the foetus and appearance of hair on the head are
usually observed during the fifth month. By the end of 24 weeks (second
trimester), the body is covered with fine hair, eye-lids separate, and
eyelashes are formed. By the end of nine months of pregnancy, the foetus
is fully developed and is ready for delivery.
3.7 PARTURITION AND LACTATION
The average duration of human pregnancy is about 9 months
which is called the gestation period. Vigorous contraction of the uterus at
the end of pregnancy causes expulsion/delivery of the foetus. This process
of delivery of the foetus (childbirth) is called parturition. Parturition is
induced by a complex neuroendocrine mechanism. The signals for
parturition originate from the fully developed fetus and the placenta which
induce mild uterine contractions called foetal ejection reflex. This triggers
release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine
muscle and causes stronger uterine contractions, which in turn stimulates
further secretion of oxytocin. The stimulatory reflex between the uterine
contraction and oxytocin secretion continues resulting in stronger and
stronger contractions. This leads to expulsion of the baby out of the uterus
through the birth canal – parturition. Soon after the infant is delivered, the
placenta is also expelled out of the uterus. What do you think the doctors
inject to induce delivery?
The mammary glands of the female undergo differentiation during
pregnancy and starts producing milk towards the end of pregnancy by
54 the process called lactation. This helps the mother in feeding the new-
born. The milk produced during the initial few days of lactation is called
colostrum which contains several antibodies absolutely essential to
develop resistance for the new-born babies. Breast-feeding during the
initial period of infant growth is recommended by doctors for bringing up
a healthy baby.
14. HUMAN REPRODUCTION
SUMMARY
Humans are sexually reproducing and viviparous. The male
reproductive system is composed of a pair of testes, the male sex
accessory ducts and the accessory glands and external genitalia. Each
testis has about 250 compartments called testicular lobules, and each
lobule contains one to three highly coiled seminiferous tubules. Each
seminiferous tubule is lined inside by spermatogonia and Sertoli cells.
The spermatogonia undergo meiotic divisions leading to sperm formation,
while Sertoli cells provide nutrition to the dividing germ cells. The Leydig
cells outside the seminiferous tubules, synthesise and secrete testicular
hormones called androgens. The male external genitalia is called penis.
The female reproductive system consists of a pair of ovaries, a pair
of oviducts, a uterus, a vagina, external genitalia, and a pair of
mammary glands. The ovaries produce the female gamete (ovum) and
some steroid hormones (ovarian hormones). Ovarian follicles in different
stages of development are embedded in the stroma. The oviducts, uterus
and vagina are female accessory ducts. The uterus has three layers
namely perimetrium, myometrium and endometrium. The female
external genitalia includes mons pubis, labia majora, labia minora,
hymen and clitoris. The mammary glands are one of the female
secondary sexual characteristics.
Spermatogenesis results in the formation of sperms that are
transported by the male sex accessory ducts. A normal human sperm
is composed of a head, neck, a middle piece and tail. The process of
formation of mature female gametes is called oogenesis. The
reproductive cycle of female primates is called menstrual cycle.
Menstrual cycle starts only after attaining sexual maturation (puberty).
During ovulation only one ovum is released per menstrual cycle. The
cyclical changes in the ovary and the uterus during menstrual cycle
are induced by changes in the levels of pituitary and ovarian hormones.
After coitus, sperms are transported to the junction of the isthmus and
ampulla, where the sperm fertilises the ovum leading to formation of a
diploid zygote. The presence of X or Y chromosome in the sperm
determines the sex of the embryo. The zygote undergoes repeated mitotic
division to form a blastocyst, which is implanted in the uterus resulting
in pregnancy. After nine months of pregnancy, the fully developed foetus
is ready for delivery. The process of childbirth is called parturition which
is induced by a complex neuroendocrine mechanism involving cortisol,
estrogens and oxytocin. Mammary glands differentiate during pregnancy
and secrete milk after child-birth. The new-born baby is fed milk by the
mother (lactation) during the initial few months of growth.
EXERCISES
1. Fill in the blanks:
55
(a) Humans reproduce _____________ (asexually/sexually)
(b) Humans are _____________ (oviparous, viviparous, ovoviviparous)
(c) Fertilisation is _____________ in humans (external/internal)
(d) Male and female gametes are _____________ (diploid/haploid)
(e) Zygote is _____________ (diploid/haploid)
15. BIOLOGY
(f) The process of release of ovum from a mature follicle is called
_____________
(g) Ovulation is induced by a hormone called _____________
(h) The fusion of male and female gametes is called _____________
(i) Fertilisation takes place in _____________
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus
and uterus is called _____________
2. Draw a labelled diagram of male reproductive system.
3. Draw a labelled diagram of female reproductive system.
4. Write two major functions each of testis and ovary.
5. Describe the structure of a seminiferous tubule.
6. What is spermatogenesis? Briefly describe the process of spermatogenesis.
7. Name the hormones involved in regulation of spermatogenesis.
8. Define spermiogenesis and spermiation.
9. Draw a labelled diagram of sperm.
10. What are the major components of seminal plasma?
11. What are the major functions of male accessory ducts and glands?
12. What is oogenesis? Give a brief account of oogenesis.
13. Draw a labelled diagram of a section through ovary.
14. Draw a labelled diagram of a Graafian follicle?
15. Name the functions of the following:
(a) Corpus luteum (b) Endometrium
(c) Acrosome (d) Sperm tail
(e) Fimbriae
16. Identify True/False statements. Correct each false statement to make
it true.
(a) Androgens are produced by Sertoli cells. (True/False)
(b) Spermatozoa get nutrition from Sertoli cells. (True/False)
(c) Leydig cells are found in ovary. (True/False)
(d) Leydig cells synthesise androgens. (True/False)
(e) Oogenesis takes place in corpus luteum. (True/False)
(f) Menstrual cycle ceases during pregnancy. (True/False)
(g) Presence or absence of hymen is not a reliable indicator of virginity
or sexual experience. (True/False)
17. What is menstrual cycle? Which hormones regulate menstrual cycle?
18. What is parturition? Which hormones are involved in induction of parturition?
19. In our society the women are often blamed for giving birth to daughters.
56 Can you explain why this is not correct?
20. How many eggs are released by a human ovary in a month? How many
eggs do you think would have been released if the mother gave birth to
identical twins? Would your answer change if the twins born were
fraternal?
21. How many eggs do you think were released by the ovary of a female dog
which gave birth to 6 puppies?