The male reproductive system produces sperm through the process of spermatogenesis. Sperm develop in the testes through meiosis and undergo maturation as they pass through the epididymis. Mature sperm are stored in the vas deferens until ejaculation. During sexual intercourse, sperm are ejaculated through the urethra along with fluids from the seminal vesicles, prostate, and bulbourethral glands. The alkaline fluids help activate the sperm. Capacitation allows the sperm to penetrate and fertilize an ovum in the female reproductive tract.
Steps of fertilization, where transport of gametes(oocyte and spermatozoon) , illustrated with images.
Differences in characteristics of egg and sperm of fertilization are tabulated.
Capacitation and acrosomal reaction are shown with diagrams to understand.
Barriers protecting female gamete shown with images.
Flowchart has been drawn to show the phases of fertilization and response of egg after entry of the sperm with explanation.
The result of fertilization is highlighted .
Ends
Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the fallopian tube. The result of this union is the production of a zygote cell, or fertilized egg, initiating prenatal development. .The process of fertilization involves a sperm fusing with an ovum. The stages of fertilization can be divided into four processes: 1) sperm preparation, 2) sperm-egg recognition and binding, 3) sperm-egg fusion and 4) fusion of sperm and egg pronuclei and activation of the zygote.
Effective public health programs, research, and policy relating to human sexuality, pregnancy, contraception, and the transmission of sexually transmitted infections depends upon knowledge of the structure (anatomy) and function (physiology) of the male and female reproductive systems.
Spermatogenesis in Domestic Animals - Dr. John J. ParrishGarry D. Lasaga
This presentation is an introduction to the principles of spermatogenesis of domestic animals by Dr. John J. Parrish of the University of Wisconsin-Madison (Animal Science Department).
All mammalian eggs are surrounded by a relatively thick extracellular coat, the zona pellucida, that plays vital roles during oogenesis, fertilization, and preimplantation development.
The strong membrane that forms around an ovum as it develops in the ovary. The membrane remains in place during the egg's travel through the fallopian tube. To fertilize the egg, a sperm must penetrate the thinning zona pellucida. If fertilization takes place, the zona pellucida disappears, to permit implantation in the uterus.
Steps of fertilization, where transport of gametes(oocyte and spermatozoon) , illustrated with images.
Differences in characteristics of egg and sperm of fertilization are tabulated.
Capacitation and acrosomal reaction are shown with diagrams to understand.
Barriers protecting female gamete shown with images.
Flowchart has been drawn to show the phases of fertilization and response of egg after entry of the sperm with explanation.
The result of fertilization is highlighted .
Ends
Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the fallopian tube. The result of this union is the production of a zygote cell, or fertilized egg, initiating prenatal development. .The process of fertilization involves a sperm fusing with an ovum. The stages of fertilization can be divided into four processes: 1) sperm preparation, 2) sperm-egg recognition and binding, 3) sperm-egg fusion and 4) fusion of sperm and egg pronuclei and activation of the zygote.
Effective public health programs, research, and policy relating to human sexuality, pregnancy, contraception, and the transmission of sexually transmitted infections depends upon knowledge of the structure (anatomy) and function (physiology) of the male and female reproductive systems.
Spermatogenesis in Domestic Animals - Dr. John J. ParrishGarry D. Lasaga
This presentation is an introduction to the principles of spermatogenesis of domestic animals by Dr. John J. Parrish of the University of Wisconsin-Madison (Animal Science Department).
All mammalian eggs are surrounded by a relatively thick extracellular coat, the zona pellucida, that plays vital roles during oogenesis, fertilization, and preimplantation development.
The strong membrane that forms around an ovum as it develops in the ovary. The membrane remains in place during the egg's travel through the fallopian tube. To fertilize the egg, a sperm must penetrate the thinning zona pellucida. If fertilization takes place, the zona pellucida disappears, to permit implantation in the uterus.
USMLE GENERAL EMBRYOLOGY 004 005 Spermatogenesis Oogenesis permatogenesis ...AHMED ASHOUR
Gametogenesis is the process by which specialized cells, called gametes, are produced in sexually reproducing organisms. Gametes are reproductive cells that carry genetic material and are involved in the formation of offspring during fertilization. In humans, gametogenesis occurs in the gonads—testes in males and ovaries in females—and involves the production of sperm and eggs, respectively.
Human reproduction is any form of sexual reproduction resulting in human fertilization. It typically involves sexual intercourse between a man and a woman. During sexual intercourse, the interaction between the male and female reproductive systems results in fertilization of the woman's ovum by the man's sperm.
Reproductive and hormonal functions of the male Maryam Fida
Reproductive and hormonal functions of the male 1. Primary Sex Organs
Testes are the primary sex organs or gonads in males.
Accessory Sex Organs
Accessory sex organs in males are:
1. Seminal vesicles 2. Prostate gland
3.Urethra 4. Penis
Testis contain Seminiferous Tubules. Sperms are formed in seminiferous tubules. Testis has two important types of cells. 1.Sertoli cells are the supporting cells in seminiferous tubules. Sertoli cells provide support, protection and nourishment for the spermatogenic cells present in seminiferous tubules. Sertoli cells contain hormone “INHIBIN”. 2. Leydig cells. When stimulated by LH, they secrete:
Testosterone
Androstenedione
Dehydroepiandrosterone (DHEA)
The portion of the nervous system that controls most visceral functions of the body that are generally not under conscious control is called the autonomic nervous system.
This system helps to control arterial pressure,
Gastrointestinal motility,
Gastrointestinal secretion,
Urinary bladder emptying,
Sweating,
Body temperature,
"Complement" describes a system of about 20 proteins, many of which are enzyme precursors. The principal actors in this system are 11 proteins designated C1 through C9, B, and D,
All these are present normally among the plasma proteins in the blood as well as among the proteins that leak out of the capillaries into the tissue spaces.
The enzyme precursors are normally inactive, but they can be activated mainly by the so-called classic pathway.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
4. Reproduction (or procreation) is the
biological process by which new
"offspring" individual organisms are
produced from their "parents".
Reproduction is a fundamental
feature of all known life;
5. Human reproduction
• Human reproduction is any form of sexual
reproduction
• resulting in the conception of a child, typically
involving sexual intercourse between a man and
a woman.
• During sexual intercourse, the interaction
between the male reproductive system and the
female reproductive system results in fertilization
of the woman's ovum by the man's sperm,
• which after a gestation period is followed by
childbirth.
15. Function: Produce 60% of
alkaline semen including
fructose to provide energy for
sperm.
Seminal
Vesicles
Ejaculatory Duct
16. Function: Produces up to 1/3 of
the semen & includes nutrients
& enzymes to activate sperm.
Prostate
17. Function: Secretes mucous &
alkaline buffers to neutralize
acidic conditions of urethra.
Cowper’s Gland
18. Male reproductive system
• Definition
• The male reproductive system is a union
of organs and tissues that produces
gametes (reproductive cells known as
sperm). The male reproductive system
consists of the penis, testes, scrotum,
glands and ductus deferens.
19. Major Subdivisions
• The reproductive functions of the male
can be divided into three major
subdivisions:
1. spermatogenesis, which means simply
the formation of sperm;
2. performance of the male sexual act;
3. Regulation of male reproductive
functions by the various
hormones.
20. Physiologic Anatomy of the Male Sexual Organs
• The testis is composed of up
to 900 coiled seminiferous
tubules, each averaging one
half meter long, in which the
sperm are formed.
• The sperm then empty into
the epididymis, another coiled
tube about 6 meters long.
• The epididymis leads into the
vas deferens, which enlarges
into the ampulla of the vas
deferens immediately before
the vas enters the body of the
prostate gland.
21. • Two seminal vesicles, one
located on each side of the
prostate, empty into the
prostatic end of the ampulla,
• The contents from both the
ampulla and the seminal
vesicles pass into an
ejaculatory duct
• leading through the body of
the prostate gland and then
emptying into the internal
urethra.
• Prostatic ducts, too, empty
from the prostate gland into
the ejaculatory duct and from
there into the prostatic
urethra.
• Finally, the urethra is the last
connecting link from the testis
to the exterior.
22. • The urethra is supplied
with mucus derived
from a large number of
minute urethral glands
located along its entire
extent and even more
so from bilateral
bulbourethral glands
(Cowper's glands)
located near the origin
of the urethra.
23. Spermatogenesis
• During formation of the
embryo, the primordial
germ cells migrate into
the testes and become
immature germ cells
called spermatogonia
which lie in two or three
layers of the inner
surfaces of the
seminiferous tubules
• The spermatogonia
begin to undergo mitotic
division, beginning at
puberty,
24. Steps of Spermatogenesis
• Spermatogenesis occurs in the
seminiferous tubules during active
sexual life as the result of
stimulation by anterior pituitary
gonadotropic hormones,
• beginning at an average age of 13
years and continuing throughout
most of the remainder of life but
decreasing markedly in old age.
• In the first stage of
spermatogenesis, the
spermatogonia migrate among
Sertoli cells toward the central
lumen of the seminiferous tubule.
• The Sertoli cells are very large,
with overflowing cytoplasmic
envelopes that surround the
developing spermatogonia all the
way to the central lumen of the
tubule.
25. Meiosis
• Spermatogonia that cross the barrier into
the Sertoli cell layer become
progressively modified and enlarged to
form large primary spermatocytes
• Each of these, in turn, undergoes meiotic
division to form two secondary
spermatocytes.
• After another few days, these too divide
to form spermatids that are eventually
modified to become spermatozoa
(sperm).
• During the change from the spermatocyte
stage to the spermatid stage, the 46
chromosomes (23 pairs of
chromosomes) of the spermatocyte are
divided, so that 23 chromosomes go to
one spermatid and the other 23 to the
second spermatid.
• This also divides the chromosomal
genes so that only one half of the genetic
characteristics of the eventual fetus are
provided by the father, while the other
half are derived from the oocyte provided
by the mother.
• The entire period of spermatogenesis,
from spermatogonia to spermatozoa,
takes about 74 days.
27. Sex Chromosomes.
• In each spermatogonium, one of the 23 pairs of
chromosomes carries the genetic information that
determines the sex of each eventual offspring.
• This pair is composed of one X chromosome, which is
called the female chromosome, and one Y chromosome,
the male chromosome.
• During meiotic division, the male Y chromosome goes to
one spermatid that then becomes a male sperm, and the
female X chromosome goes to another spermatid that
becomes a female sperm.
• The sex of the eventual offspring is determined by which
of these two types of sperm fertilizes the ovum.
28. Sperm.
• Each spermatozoon is composed
of a head and a tail.
• The head comprises the
condensed nucleus of the cell with
only a thin cytoplasmic and cell
membrane layer around its
surface.
• On the outside of the anterior two
thirds of the head is a thick cap
called the acrosome that is formed
mainly from the Golgi apparatus.
• This contains a number of
enzymes similar to those found in
lysosomes of the typical cell,
including hyaluronidase (which can
digest proteoglycan filaments of
tissues) and powerful proteolytic
enzymes (which can digest
proteins).
• These enzymes play important
roles in allowing the sperm to enter
the ovum and fertilize it.
29. YouTube - Normal Human sperms.flv
YouTube - Normal Human sperms.flv
31. Tail of the sperm
• also called the flagellum, has
three major components:
• (1) a central skeleton
constructed of 11
microtubules, collectively
called the axoneme-the
structure of this is similar to
that of cilia found on the
surfaces of other types of
cells
• (2) a thin cell membrane
covering the axoneme; and
• (3) a collection of
mitochondria surrounding the
axoneme in the proximal
portion of the tail (called the
body of the tail).
32. • Back-and-forth movement
of the tail (flagellar
movement) provides
motility for the sperm.
• The energy for this
process is supplied in the
form of adenosine
triphosphate that is
synthesized by the
mitochondria in the body
of the tail.
• Normal sperm move in a
fluid medium at a velocity
of 1 to 4 mm/min. This
allows them to move
through the female
genital tract in quest of
the ovum.
33. Hormonal Factors That Stimulate Spermatogenesis
• Testosterone, secreted by the Leydig cells located in the interstitium of the
testis, is essential for growth and division of the testicular germinal cells,
which is the first stage in forming sperm.
• Luteinizing hormone, secreted by the anterior pituitary gland, stimulates the
Leydig cells to secrete testosterone.
• Follicle-stimulating hormone, also secreted by the anterior pituitary gland,
stimulates the Sertoli cells; without this stimulation, the conversion of the
spermatids to sperm (the process of spermiogenesis) will not occur.
• Estrogens, formed by the Sertoli cells when they are stimulated by follicle-
stimulating hormone, are probably also essential for spermiogenesis.
• Growth hormone (as well as most of the other body hormones) is necessary
for controlling background metabolic functions of the testes. Growth
hormone specifically promotes early division of the spermatogonia
themselves; in its absence, as in pituitary dwarfs, spermatogenesis is
severely deficient or absent, thus causing infertility.
34. Maturation of Sperm in the Epididymis
• After formation in the
seminiferous tubules, the
sperm require several days to
pass through the 6-meter-
long tubule of the epididymis.
Sperm removed from the
seminiferous tubules and
from the early portions of the
epididymis are nonmotile,
and they cannot fertilize an
ovum. However, after the
sperm have been in the
epididymis for some 18 to 24
hours, they develop the
capability of motility, even
though several inhibitory
proteins in the epididymal
fluid still prevent final motility
until after ejaculation.
35. Storage of Sperm.
• The two testes of the human adult form up to 120 million
sperm each day.
• A small quantity of these can be stored in the
epididymis, but most are stored in the vas deferens.
• T hey can remain stored, maintaining their fertility, for at
least a month.
• After ejaculation, the sperm become motile, and they
also become capable of fertilizing the ovum, a process
called maturation.
• The Sertoli cells and the epithelium of the epididymis
secrete a special nutrient fluid that is ejaculated along
with the sperm.
• This fluid contains hormones (including both
testosterone and estrogens), enzymes, and special
nutrients that are essential for sperm maturation.
36. Physiology of the Mature Sperm.
• The normal motile, fertile sperm are capable of
flagellated movement though the fluid medium at
velocities of 1 to 4 mm/min.
• The activity of sperm is greatly enhanced in a
neutral and slightly alkaline medium, as exists in
the ejaculated semen, but it is greatly depressed
in a mildly acidic medium.
• A strong acidic medium can cause rapid death
of sperm
• The activity of sperm increases markedly with
increasing temperature, but so does the rate of
metabolism, causing the life of the sperm to be
considerably shortened.
• life expectancy of ejaculated sperm in the
female genital tract is only 1 to 2 days.
37. Function of the Seminal Vesicles
• Each seminal vesicle is a tortuous, loculated tube lined
with a secretory epithelium that secretes a mucoid
material containing an abundance of fructose, citric acid,
and other nutrient substances, as well as large quantities
of prostaglandins and fibrinogen.
• During the process of emission and ejaculation, each
seminal vesicle empties its contents into the ejaculatory
duct shortly after the vas deferens empties the sperm.
• This adds greatly to the bulk of the ejaculated semen,
and the fructose and other substances in the seminal
fluid are of considerable nutrient value for the ejaculated
sperm until one of the sperm fertilizes the ovum.
38. Function of the Prostaglandins
• Prostaglandins are believed to aid fertilization in
two ways:
• (1) by reacting with the female cervical mucus to
make it more receptive to sperm movement and
• (2) by possibly causing backward, reverse
peristaltic contractions in the uterus and
fallopian tubes to move the ejaculated sperm
toward the ovaries (a few sperm reach the upper
ends of the fallopian tubes within 5 minutes).
39. Function of the Prostate Gland
• The prostate gland secretes a thin, milky fluid that
contains calcium, citrate ion, phosphate ion, a clotting
enzyme, and a profibrinolysin.
• A slightly alkaline characteristic of the prostatic fluid
may be quite important for successful fertilization of
the ovum,
• fluid of the vas deferens is acidic due to the presence
of citric acid and metabolic end products of the sperm
inhibit sperm fertility.
• vaginal secretions of the female are acidic (pH of 3.5
to 4.0). For optimal motility of sperm the required pH
of the surrounding fluids is 6.0 to 6.5.
• the slightly alkaline prostatic fluid neutralize the acidity
of the seminal fluids during ejaculation, and thus
enhances the motility and fertility of the sperm.
40. Composition of SemenComposition of Semen
60 per cent fluid from
the prostate gland
Semen, is composed of the fluid and
sperm from the vas deferens
10 per cent of the total fluid
from the seminal vesicles
•and small amounts from the mucous
glands, especially the bulbourethral
glands.
The average pH of
semen is about 7.5
41. Semen
• PH the alkaline prostatic fluid neutralized the
mild acidity of the semen. 7.5
• COLOUR The prostatic fluid gives the semen
a milky appearance,
• Consistency. Fluid from the seminal vesicles
and mucous glands gives the semen a
mucoid consistency.
• Clotting enzyme fibrinogen form a weak fibrin
coagulum that holds the semen in the deeper
regions of the vagina where the uterine cervix
lies.
42. Life span sperm
• sperm live for many weeks in the male
genital ducts, once ejaculated in the
semen, their maximal life span is only 24
to 48 hours at body temperature.
• At lowered temperatures, however, semen
can be stored for several weeks,
• and when frozen at temperatures below
-100°C, sperm have been preserved for
years.
43. Capacitation
• spermatozoa are said to be
"mature" when they leave the
epididymis,
• their activity is held in check
by multiple inhibitory factors
secreted by the genital duct
epithelia.
• when first expelled in the
semen, they are unable to
fertilizing the ovum.
• contact with the fluids of the
female genital tract, activate
the sperm for fertilization.
• These collective changes are
called capacitation of the
spermatozoa.
• This normally requires from 1
to 10 hours.
• these changes are
44. • The uterine and fallopian tube fluids wash
away the various inhibitory factors that
suppress sperm activity in the male genital
ducts.
• remain in the fluid of the male genital
ducts, spermatozoa are exposed to vesicle
contain cholesterol. This cholesterol is
added to acrosome, toughening this
membrane and preventing release of its
enzymes.
• calcium enters the sperm changes the
activity of the flagellum, giving it a powerful
whiplash motion in contrast to its weak
undulating motion.
• In addition, the calcium ions cause
changes in the cellular membrane of the
acrosome, the acrosome release its
enzymes as the sperm penetrates the
granulosa cell ,zona pellucida of the
ovum itself.
Penetrate the Ovum
45. Acrosome Enzymes "Acrosome Reaction," and Penetration of the OvumAcrosome Enzymes "Acrosome Reaction," and Penetration of the Ovum
acrosome contain largeacrosome contain large
quantities ofquantities of hyaluronidasehyaluronidase
andand proteolytic enzymesproteolytic enzymes..
HyaluronidaseHyaluronidase depolymerizesdepolymerizes
thethe hyaluronic acidhyaluronic acid in thein the
intercellular cement that holdintercellular cement that hold
the ovarian granulosa cellsthe ovarian granulosa cells
together.together.
hyaluronidase is especiallyhyaluronidase is especially
important in openingimportant in opening
pathways between thepathways between the
granulosa cells so that thegranulosa cells so that the
sperm can reach the ovum.sperm can reach the ovum.
proteolytic enzymesproteolytic enzymes digestdigest
proteins in the structuralproteins in the structural
elements of tissue cells thatelements of tissue cells that
still adhere to the ovum.still adhere to the ovum.
46. "Acrosome Reaction,"
• Within minutes,
these enzymes open
a penetrating
pathway for passage
of the sperm head
through the zona
pellucida to the
inside of the ovum.
47. • Within another 30 minutes,
the cell membranes of the
sperm head and of the
oocyte fuse with each other
to form a single cell.
• At the same time, the
genetic material of the sperm
and the oocyte combine to
form a completely new cell
genome, containing equal
numbers of chromosomes
and genes from mother and
father.
48. Why does only one sperm enter the oocyte?
• The reason is not entirely
known,
• but within a few minutes
after the first sperm
penetrates the zona
pellucida of the ovum,
calcium ions diffuse inward
through the oocyte
membrane and cause
multiple cortical granules by
exocytosis from the oocyte
• These granules contain
substances that permeate all
portions of the zona pellucida
and prevent binding of
additional sperm,
49. Abnormal Spermatogenesis and Male Fertility
• The seminiferous tubular epithelium can be
destroyed by a number of diseases.
• bilateral orchitis of the testes resulting from
mumps causes sterility in some affected males.
• Also, some male infants are born with
degenerate tubular epithelia as a result of
strictures in the genital ducts or other
abnormalities.
• Finally, another cause of sterility, usually
temporary, is excessive temperature of the
testes.
50. Effect of Temperature on
Spermatogenesis.
• Increasing the temperature of the testes can prevent
spermatogenesis by causing degeneration of most cells
of the seminiferous tubules besides the spermatogonia.
• It has often been stated that the reason the testes are
located in the dangling (swinging) scrotum is to maintain
the temperature of these glands below the internal
temperature of the body, although usually only about 2°C
below the internal temperature. On cold days, scrotal
reflexes cause the musculature of the scrotum to
contract, pulling the testes close to the body to maintain
this 2° differential. Thus, the scrotum theoretically acts
as a cooling mechanism for the testes (controlled
cooling), without which spermatogenesis might be
deficient during hot weather.
51. Cryptorchidism
• Cryptorchidism means
failure of a testis to descend
from the abdomen into the
scrotum at or near the time
of birth of a fetus.
• testes are derived from the
genital ridges in the
abdomen.
• 3 weeks to 1 month before
birth of the baby, the testes
normally descend through
the inguinal canals into the
scrotum.
• Occasionally this descent
does not occur or occurs
incompletely, so that one or
both testes remain in the
abdomen, in the inguinal
canal, or elsewhere along
the route of descent.
52. Adverse effects of cryptorchid
• A testis that remains throughout life in the abdominal
cavity is incapable of forming sperm.
• The tubular epithelium becomes degenerate, leaving
only the interstitial structures of the testis.
• higher temperature in the abdomen cause this
degeneration of the tubular epithelium and,
consequently, sterility,
• operations to relocate the cryptorchid testes from the
abdominal cavity into the scrotum before the beginning
of adult sexual life are frequently performed on boys who
have undescended testes
53.
54. Effect of Sperm Count on Fertility.
• The averages quantity of semen ejaculated during each
coitus is about 3.5 milliliters,
• Each milliliter of semen have about 120 million sperm, in
"normal" males
• vary from 35 million to 200 million.
• 400 million sperm are present in each ejaculate.
• When the number of sperm in each milliliter falls below
about 20 million, the person is likely to be infertile.
• Thus, even though only a single sperm is necessary to
fertilize the ovum, for reasons not understood, the
ejaculate usually must contain a tremendous number of
sperm for only one sperm to fertilize the ovum.
55. Effect of Sperm Morphology and Motility on Fertility.
• Occasionally a man has a normal
number of sperm but is still
infertile.
• When this occurs, sometimes as
many as one half the sperm are
found to be abnormal physically,
having two heads,
• abnormally shaped heads, or
abnormal tails,
• At other times, the sperm appear
to be structurally normal, but for
reasons not understood, they are
either entirely nonmotile or
relatively nonmotile.
• Whenever the majority of the
sperm are morphologically
abnormal or are nonmotile, the
person is likely to be infertile, even
though the remainder of the sperm
appear to be normal.
Editor's Notes
As you will be required to identify from diagrams of the male reproductive system, specific organs and describe their functions, this and the next series of figures will go over these. The penis * * is an organ for the discharge of urine * and for the deposition of sperm into the vagina of the female during copulation. *
The urethra * * transports urine from the urinary bladder * and sperm and semen * produced by other organs of the male reproductive system. *
The scrotum * * is where the testes are located. Its function is to provide an environment for the testes that is approximately 3 0 Celcius belowthe normal temperature of the body. * Thislower temperature is necessary for the production of viable sperm within the testes. *
You may recall from your dissection of the fetal pig in your A & P I class, that often the testes had not descended completely from the pelvic cavity into the scrotum. The canal through which the testes must descend through to the scrotum is called the inguinal canal. * It not only provides a pathway for the testes but serves as a pathway through which the blood vessels, nerves, muscles and the tube which connects the testes to the urethra are found. *
The testes * * have two primary functions. They produce sperm * and the male hormone, testosterone. *
Each testis is filled with tiny tubules * * called seminiferous tubules. * It is within the seminiferous tubules that sperm are produced through the process of spermatogenesis which occurs from puberty on. *
Shown here * is a cross section through a testis showing the seminiferous tubules. The white spaces * represent the central opening or lumen of each tubule. * In this more highly magnified view of seminiferous tubules, you can visualize the development of sperm cells in the walls of the seminiferous tubules. * By the time the sperm cells are fully developed, they are located in the lumen of the tubule. * Between the seminiferous tubules are groups of cells called interstitial cells. * * These are responsible for the production of the male hormone testosterone within the testes. * *
The seminiferous tubules all eventually lead to the epididymis. * * The sperm are stored within the epididymis,* where they also complete their maturation. *
The vas deferens * *is the duct that connects the epididymis to the urethra. * It provides the passageway for sperm to the urethra. *
A seminal vesicle gland lies on each side of the posterior wall of the bladder. * * These glands produce approximately 60% of the semen. * The semen produced by the seminal vesicle gland is introduced into the vas deferens to form the ejaculatory duct * which connects to the urethra. Semen produced by the seminal vesicle glands is alkaline and contains the sugar fructose which supplies energy for sperm cell movement. *
The single prostate gland encircles the urethra just below the bladder. * * The semen produced by the prostate gland contains enzymes and nutrients which are necessary to activate sperm. * Approximately 1/3 of the semen is produced by the prostate gland. *
The Cowper’s or bulbourethral glands are located below the prostate. * * Their purpose is to produce mucous prior to ejaculation which contains alkaline buffers to neutralize the acidic conditions within the urethra. * *