Paraxial and intermediate mesoderm
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Paraxial mesoderm forms somites along the spine through somitogenesis. Somites differentiate into sclerotome, dermamyotome and myotome tissues. Sclerotome forms cartilage and bone of the vertebrae. Dermamyotome forms dermis and muscle lineages. Myotome separates into epaxial and hypaxial regions that form back muscles and body wall muscles. Intermediate mesoderm forms the urogenital system including pronephros, mesonephros and metanephros kidneys as well as gonads. The metanephros is the permanent kidney in amniotes.
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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.
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The document summarizes the formation of the bilaminar germ disc over 13 days:
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The document describes the development of the primitive digestive system from the yolk sac in three main sections - the foregut, midgut, and hindgut. Key points include:
- The primitive gut tube is divided into the foregut, midgut, and hindgut, which develop from the endoderm and mesoderm.
- The foregut develops into parts of the pharynx, esophagus, stomach, duodenum, liver, gallbladder, pancreas and spleen. The stomach rotates during development.
- The midgut forms a U-shaped loop that projects into the umbilical cord before developing into parts of the small intestine.
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The document summarizes key events during the first and second weeks of human embryonic development:
- In the first week, the fertilized egg undergoes cleavage and compaction to form a morula, which then develops into a blastocyst as it travels through the fallopian tube. The blastocyst implants in the uterine wall around day 6.
- In the second week, the blastocyst becomes fully embedded. The outer cell mass differentiates into trophoblast layers, while the inner cell mass forms the hypoblast and epiblast. Primary villi and the chorionic cavity develop as the embryo becomes established.
- By the end of the second week, the main cavities and cell layers
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The document provides information about mesoderm development in human embryos, including:
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- The mesoderm is initially divided into paraxial, intermediate and lateral mesoderm. Lateral mesoderm further splits into splanchnic and somatic mesoderm.
- The mesoderm gives rise to various tissues and organs, including muscle, bone, kidney and other parts of the urogenital system. It also forms the walls of body cavities.
Development of nervous system
The neural tube develops from the ectoderm and forms the central nervous system. Neurulation involves the formation of the neural plate which elevates and fuses to form the neural tube. Neural crest cells dissociate and give rise to many structures. The brain develops from three primary vesicles-the prosencephalon, mesencephalon, and rhombencephalon. The spinal cord arises from the lower neural tube. Neurons and glia differentiate and migrate within the neural tube. Fusion of the neural folds and closure of neuropores must occur properly to prevent neural tube defects.
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2. For resectable HB (PRETEXT I-II), chemotherapy before resection is unnecessary. Some image-unresectable cases may be cured with skilled resection.
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Lecture11 development of the heart and blood vessels
1. The heart develops from paired endocardial heart tubes that fuse to form a single heart tube.
2. The heart tube undergoes looping to form the basic S-shape. It also develops segments that will become the atria, ventricles, and outflow tract.
3. Septa form to divide the heart into four chambers. The interatrial and interventricular septa grow from the roof of the heart tube towards the atrioventricular canal.
Fetal Development
The document summarizes fetal development from the first through third trimesters of pregnancy in 3-4 week increments. In the first trimester, the embryo grows rapidly, forms major organs, and develops a placenta and circulatory system. By 8 weeks, the baby's sex and organ systems are developing. In the second trimester, the fetus' skeleton, hair, ears, eyes, and other features form and mature. Fat begins to form in weeks 17-19. In the third trimester, the baby practices breathing, regulates its body temperature, and is fully capable of opening its eyes and detecting light by weeks 30-33.
Embryology 2
This document provides an overview of general embryology, covering topics such as the development of embryology from early theories to modern experimental embryology. It discusses the processes of fertilization, formation of the blastocyst and implantation. It describes the formation of germ layers and differentiation of the trilaminar disc into embryonic structures. It also covers the development of fetal membranes and placenta, as well as twins and multiple births. The stages of preembryonic, embryonic and fetal periods are outlined.
1 embryology
1. The document provides a general overview of human embryological processes including germ cell formation and fertilization, prenatal development through the formation of three layers, induction and differentiation, formation of the neural crest, and folding of the embryo.
2. Key stages discussed include gametogenesis, fertilization of the ovum by sperm to form a zygote, formation of the morula and blastocyst, implantation in the uterus, formation of the bilaminar and trilaminar germ discs, and development of the three germ layers and tissues from each layer.
3. Neural crest formation involves the development of the neural plate and tube from ectoderm and the migration of neural crest cells to
Embryology
The document summarizes key stages in human embryonic development from fertilization through the first few weeks. It describes the progression from a fertilized egg to a blastocyst, implantation, formation of the three germ layers and early development of organ systems. It also reviews embryonic tissue development and the process of ossification.
Embryonic Development
A presentation (prepared by middle school life science students) on the process of embryonic development.
Embryonic and fetal growth and development
The document discusses human embryonic and fetal growth and development. It defines key terms and outlines the objectives of covering the stages of intrauterine development from zygote to fetus. It describes the three primary germ layers that develop into organ systems, and the changes that occur in each stage of embryonic and fetal growth. Finally, it provides detailed information about fetal growth and development in each lunar month of pregnancy.
Embryology
This document provides an overview of human embryology from fertilization through the seventh week of development. Key events include fertilization, cleavage, formation of the blastocyst and implantation, development of the three germ layers and formation of the notochord and neural tube, somite formation, and the establishment of major organ systems. The major developmental milestones that occur each week of the first seven weeks are described.
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Muscular system embryology for medical students
Muscular development begins with the formation of somites from paraxial mesoderm, which give rise to skeletal muscle fibers. Smooth muscle develops from splanchnic mesoderm and some ectoderm-derived tissues. Cardiac muscle originates from splanchnic mesoderm surrounding the heart tube. Key regulatory genes like MyoD and Myf5 activate muscle-specific genes that promote the differentiation of myoblasts into myofibers. Precise molecular signaling controls the patterning and migration of myoblasts. Abnormalities can occur if muscles fail to develop properly.
Lecture 12 the skeleton embryology pdf
1. The vertebral column is derived from sclerotomes of somites, with each vertebra formed by fusion of portions from two adjacent somites.
2. The ribs are derived from ventral extensions of sclerotomal mesenchyme. The sternum is formed by fusion of right and left sternal bars.
3. The skull develops from mesenchyme around the brain, with some bones forming in membrane and some in cartilage. The limbs first appear as outgrowths from the body wall that get subdivided to form parts.
BIO420 Chapter 17
The paraxial mesoderm lies just lateral to the notochord and gives rise to vertebrae, skeletal muscles, and skin connective tissue. It is divided into somites which then form dermomyotomes and sclerotomes. Dermomyotomes develop into dermatomes that make dermis and myotomes that form back, rib, and body wall muscles. Sclerotomes form the vertebrae and rib cage. Somitogenesis occurs through a clock-wavefront model where somites sequentially segment from cranial to caudal regions under the influence of signaling molecules like retinoic acid and FGF.
Muscular Integumentary system.ppt
The muscular system develops primarily from the mesodermal germ layer. It consists of skeletal, smooth, and cardiac muscle. Skeletal muscle develops from paraxial mesoderm and forms the musculature of the axial skeleton, body wall, and limbs. Smooth muscle develops from splanchnic mesoderm surrounding organs and the ectoderm of certain structures. Cardiac muscle develops from splanchnic mesoderm surrounding the heart tube. Muscle tissue develops from embryonic muscle cells called myoblasts that fuse to form long muscle fibers containing myofibrils. Precise molecular signaling regulates the development of each muscle type from precursor tissues and cells.
Somite differentiation and neural crest
Neural crest cells arise from the ectoderm layer and give rise to diverse cell lineages including melanocytes, craniofacial cartilage and bone, smooth muscle, and neurons. They have multipotent capability, migrate throughout the embryo, and are precisely regulated. The neural crest can be divided into four main regions that develop into different structures and tissues. Somites form from paraxial mesoderm and later split into dermatomes, myotomes, syndetomes, and sclerotomes which give rise to skin, skeletal muscle, tendons and cartilage, and bone, respectively.
Myogenesis.pptx
The document discusses myogenesis, or muscle formation, which occurs through somitogenesis. Mesoderm forms somites through periodic segmentation. Somites give rise to muscle precursor cells (myoblasts) that require growth factors and transcription factors like MyoD to differentiate into muscle cells. Myoblasts align and fuse to form multinucleated myotubes. Satellite cells reside alongside adult muscle fibers and regenerate muscle through similar myogenic pathways upon injury.
Bone-1.ppt
Bones have several key functions: support, protection, movement, mineral storage, and blood cell formation. There are four main types of bones based on shape: long, short, flat, and irregular. Bone anatomy includes the diaphysis, epiphysis, growth plate, periosteum, marrow cavity, and endosteum. Bones are supplied by blood vessels that enter through the periosteum and Volkmann's canals. There are two types of bone tissue: compact bone made up of concentric osteons, and spongy/cancellous bone made of trabeculae within the marrow cavity. Bone is remodeled throughout life by osteoclasts that resorb bone and osteoblasts that
embryology of head region
1. The primitive streak forms in the blastula and establishes bilateral symmetry and the site of gastrulation. It initiates formation of the three germ layers - ectoderm, endoderm, and mesoderm.
2. The notochord induces neural plate formation and provides organizational signals for head development. It lies along the embryo's axis and gives rise to the vertebral column.
3. Neural crest cells migrate extensively and give rise to many tissues, including those that form the skeleton and connective tissues of the head.
E&d of h.skeleton
This document provides a summary of human skeleton development from embryology through adulthood. It describes how:
- The skeleton initially has 300 bones at birth, reducing to 206 bones in adulthood as some fuse together.
- The skeleton is divided into the axial skeleton (80 bones including the skull, vertebral column, ribs, and sternum) and appendicular skeleton (126 bones including the pectoral and pelvic girdles and upper and lower limbs).
- Bones develop through two processes - intramembranous ossification where bones are formed within connective tissue membranes, and endochondral ossification where cartilage models are replaced by bone.
- Long bones in the limbs form from
bones & cartilage-1.ppt Abcdefghijklmnopqrstuvwxyz
The human skeletal system includes bones and cartilages which provide structure and support to the body. Bones are living tissues composed of cells, fibers and minerals that allow the skeleton to function in movement, protection and mineral storage. There are over 200 bones in the adult skeleton which are classified by region, shape, development and structure. Long bones like the femur develop from cartilage models and contain compact bone on the outside and cancellous bone on the inside. Bones and cartilages are constantly remodeled throughout life and can heal after fractures.
17. male
This document provides an overview of the histology and histophysiology of the male reproductive system. It describes the key structures and functions of the testes, seminiferous tubules, spermatogenic cells, Leydig cells, and spermatozoa. The testes contain seminiferous tubules that produce spermatozoa through spermatogenesis. Sertoli cells nurture developing spermatogenic cells and form the blood-testis barrier. Leydig cells respond to LH to synthesize testosterone, which supports spermatogenesis. Upon maturation, spermatids are transformed into motile spermatozoa through spermiogenesis.
development of musculoskeletal system.ppt
The document summarizes the development of the musculoskeletal system from mesenchymal tissues. It describes how:
1. Somites differentiate into sclerotome which forms bones and dermomyotome which forms muscles and dermis.
2. The skull develops from both endochondral and intramembranous ossification, with parts originating from neural crest and paraxial mesoderm.
3. The vertebral column develops through endochondral ossification, forming cartilage models that are later replaced with bone.
4. Ribs develop from costal processes of vertebrae, while the sternum develops from sternal bars.
5. Muscles develop from dermomyotome splitting
Embryology of skeletal system
The skeletal system develops from mesenchyme tissue which originates from the mesoderm. Mesenchyme cells migrate and form cartilage and bone. Bones develop through two types of ossification - membranous and endochondral. The axial skeleton develops from somites which form vertebrae and ribs. Limbs develop from limb buds which are outgrowths that form the bones of the arms and legs. Joints form as cartilage develops between bone ends. Developmental anomalies can occur in bones, vertebrae, ribs and limbs.
Histology of growth plate (2)n
Bones are composed of both organic and inorganic components. The inorganic component is mainly calcium and phosphorus in the form of hydroxyapatite crystals. The organic component includes collagen fibers and cells. There are four main cell types in bone: osteoblasts which form new bone, osteocytes embedded in the bone matrix, osteoclasts which resorb bone, and osteoprogenitor cells which differentiate into osteoblasts. Bones develop through either intramembranous or endochondral ossification, which involve the differentiation of mesenchymal stem cells into osteoblasts and the deposition of bone matrix. Growth plates located near the ends of long bones facilitate bone growth and consist of columns of chondrocytes at
formations of tissues of body
Highlights
• Epithelia
• Glands
• Mesenchyme
• Connective tissue
• Formation of blood
• Formation of cartilage
• Bone
• Formation of muscle
• Nervous tissue
• Skeletal muscle
• Is derived partly from somites and partly from
mesenchyme of origin.
• Most Smooth muscle
• Is derived from mesenchyme related to viscera, and
blood vessels.
• Cardiac muscle
• Is derived from mesoderm related to the developing
heart.
Orofacial musculatue
This document provides an overview of the oro-facial musculature. It begins with an introduction and classification of muscles, followed by the embryology of muscle development. It then describes the anatomy, innervation and actions of specific muscle groups including the scalp, ear, eyelid, extraocular, nose, mouth, neck and tongue muscles. It discusses the origins of cranio-facial muscles and compares muscle fiber types. Finally, it provides brief descriptions of some clinical considerations related to injuries of the scalp and face.
9. Bone tissue.pptx
Bone tissue is a highly vascular, mineralized connective tissue consisting of cells and extracellular matrix. There are three main cell types - osteoblasts which form bone, osteocytes embedded in bone matrix, and osteoclasts which resorb bone. Bone has a gross structure of either compact or cancellous bone and a microstructure of lamellar or woven bone. Bone forms through either intramembraneous or endochondral ossification and is remodeled throughout life by the balanced activities of osteoblasts and osteoclasts. Bones provide structure, protection, calcium storage and leverage for movement. Bone diseases result from issues with formation, mineralization or remodeling.
Cerebellum.pptx
The cerebellum is located in the posterior cranial fossa below the tentorium. It coordinates voluntary motor activity and maintains posture and balance. It has three layers - the outer molecular layer, middle Purkinje cell layer, and inner granular layer. The cerebellum receives inputs from mossy fibers and climbing fibers and its sole output is via Purkinje cells to the deep cerebellar nuclei. The cerebellum is divided into three functional parts - the archicerebellum controls eye movements and balance, the paleocerebellum coordinates muscle tone and posture, and the neocerebellum influences fine motor control.
Basic Body Tissue + Skin Pdf
1. Tissues in the body form from three germ layers - ectoderm, endoderm and mesoderm. Epithelia can form from any germ layer, while glands often form as outgrowths of epithelia.
2. Mesenchyme cells derived from mesoderm can form many cell types including bone, cartilage, muscle and blood. Blood islands containing precursor blood and vessel cells first form in the yolk sac.
3. Cartilage forms from mesenchymal condensation where mesenchymal cells become chondroblasts surrounded by intercellular substance and perichondrium.
Basicbodytissueskinpdf 100330065419-phpapp01
The document summarizes the formation of tissues in the body from precursor cells. It discusses how epithelia, glands, connective tissue, blood, cartilage, bone and muscle develop. Epithelia can originate from ectoderm, endoderm or mesoderm. Glands develop from epithelial diverticula. Mesenchyme gives rise to connective tissue, blood cells, cartilage, bone and muscle. Bones form through endochondral or intramembranous ossification. Long bones develop from mesenchymal condensations and grow in length through ossification at the epiphyseal plate separating the diaphysis and epiphysis.
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The document summarizes the key components and functions of the human endocrine system. It describes the major endocrine glands, including the pituitary gland, hypothalamus, thyroid gland, parathyroid glands, adrenal glands, pancreas, and reproductive glands. It explains that the endocrine glands release hormones like thyroxine and insulin to regulate processes throughout the body, such as metabolism and calcium levels, and that the hypothalamus and pituitary gland help coordinate the endocrine and nervous systems. Feedback loops work to maintain homeostasis by inhibiting or stimulating hormone release based on levels in the bloodstream.
Kingdom Animalia
Animals are multicellular, heterotrophic eukaryotes that lack cell walls. They digest food internally and have muscle and nerve cells. Most animals reproduce sexually and go through developmental stages like fertilization, gastrulation, and metamorphosis. The document describes several animal phyla including poriferans like sponges, cnidarians like jellyfish, molluscs like snails and clams, flatworms, and others. It covers characteristics like body structure, symmetry, tissues, and life cycles.
Reproductive system
The document summarizes the key components and functions of the human endocrine system. It describes the major endocrine glands, including the pituitary gland, hypothalamus, thyroid gland, parathyroid glands, adrenal glands, pancreas, and reproductive glands. It explains that the endocrine glands release hormones like thyroxine and insulin to regulate processes throughout the body, such as metabolism and calcium levels, and that the hypothalamus and pituitary gland help coordinate the endocrine and nervous systems. Feedback loops work to maintain homeostasis by inhibiting or stimulating hormone release based on levels in the bloodstream.
Circulatory system
The circulatory system transports blood throughout the body via the heart and blood vessels. The heart has four chambers and uses valves to pump oxygenated blood from the lungs and deoxygenated blood to the lungs. Blood flows through arteries, capillaries, and veins. The respiratory system exchanges gases through the nose, pharynx, trachea, bronchi, and alveoli in the lungs. Breathing is controlled by the medulla oblongata and diaphragm. Smoking damages lungs and increases risk of diseases like cancer, emphysema, and bronchitis.
Circulatory system
The circulatory system is responsible for transporting substances like oxygen, nutrients, hormones around the body, and removing carbon dioxide and wastes to be eliminated. It has three main components: blood, blood vessels, and the heart. Blood carries oxygen from the lungs to tissues, nutrients from the intestines to cells, and waste products to the kidneys. It also regulates temperature, transports hormones, and protects the body from pathogens. The heart has four chambers and valves that pump blood through two circuits - pulmonary circulation to the lungs and systemic circulation to the rest of the body. An aneurysm is a bulge or weakening in an artery wall often caused by high blood pressure or other factors.
Kingdom Animalia
This document provides information about the characteristics of animals and describes several animal phyla. It begins by defining animals as eukaryotic, multicellular, heterotrophic organisms that ingest nutrients and digest food internally. It then discusses invertebrate phyla including sponges, cnidarians, molluscs, flatworms, annelids, roundworms, and arthropods, providing details on key characteristics and examples for each. It also addresses animal phylogeny and classification.
Ecosystem
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The reproductive system
There are several types of reproduction that can result in multiple births. Some types of multiple births include twins, triplets or more. The main types are fraternal twins which come from two separate eggs and identical twins which come from the same egg splitting in two.
Endocrine System
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
Circulatory system
The circulatory system is responsible for transporting substances like oxygen, nutrients, hormones around the body, and removing carbon dioxide and wastes to be eliminated. It has three main components: blood, blood vessels, and the heart. Blood carries oxygen from the lungs to tissues, and carbon dioxide from tissues back to the lungs. It also transports nutrients, waste, secretions, and helps regulate temperature and fluid balance. The heart has four chambers and valves that pump blood through two circuits - pulmonary circulation to the lungs and systemic circulation to the body. An aneurysm is a bulge or weakening in an artery wall.
science, technology and society
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science, technology and society
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History of educational technology
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Solstice and equinox
Equinoxes occur twice yearly when the sun is directly above the equator and day and night are approximately equal in length. Solstices occur twice yearly when the sun reaches its highest or lowest point in the sky, resulting in the longest and shortest days of the year in the summer and winter respectively in each hemisphere. The document then provides details on the timing and effects of the summer and winter solstices and spring and autumn equinoxes in both hemispheres.
Our moon
The three main hypotheses for the origin of the moon are that it was either 1) a small planet captured by Earth's gravity, 2) formed alongside Earth from the same dust and gas cloud, or 3) ripped away from the Earth as a bulge when the young Earth spun faster. The moon has dark lava plains called maria, ancient highlands made of different rock, and many circular craters from impacts. It rotates in sync with its orbit around Earth, always keeping the same face toward our planet and exhibiting phases from new to full.
Motion of the earth
The Giant Impact Theory proposes that the Moon was formed about 4.5 billion years ago from the debris of a collision between the early Earth and a Mars-sized protoplanet. This collision created a disk of molten rock and debris that eventually consolidated to form the Moon. Some earlier ideas on the Moon's formation included it forming alongside Earth or being captured after forming elsewhere in the solar system.
Lunar eclipses
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Motion
This document contains definitions and examples related to motion concepts including speed, average speed, velocity, and acceleration. It defines average speed as total distance traveled divided by total time. It provides an example of calculating average speed when speeds vary throughout a trip. It also defines velocity as a measure of both speed and direction of motion. Velocity is defined as distance divided by time. The document provides examples of calculating acceleration from changes in speed over time.
Intro to physics and measurements
This document provides an introduction to physical science. It begins by defining science and listing the main branches - biological science, physical science, and social science. Biological science deals with living things, social science deals with human behavior and societies. Physical science deals with non-living things, their properties, structures, and changes.
The main branches of physical science are then outlined as chemistry, physics, astronomy, geology, and meteorology. Chemistry studies matter and its properties and changes. Physics studies matter and energy. Astronomy studies the universe and celestial bodies. Geology studies Earth materials, structures, and processes. Meteorology studies the atmosphere and weather/climate.
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When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
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Exposé invité Journées Nationales du GDR GPL 2024
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What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Nucleophilic Addition of carbonyl compounds.pptx
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
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The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptx
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
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The Petroleum System of the Çukurova Field - the Shallowest Oil Discovery of Türkiye, Adana
Equivariant neural networks and representation theory
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
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Paraxial and intermediate mesoderm
- 3. Paraxial Mesoderm • Forms the back of the embryo, along the spine • Somites - a series of dorsal paired segments occurring along the notochord in vertebrate embryos.
- 5. Somitogenesis 50 – chicks 65 – mice 500 – snakes
- 6. Periodicity Somites are formed by the: Notch pathway – induces hairy1 expression
- 7. Separation Ephrin tyrosine kinase receptors (Eph A4) and their ligands (Ephrin B2) are able to elicit cell- cell repulsion between posterior somite and migrating neural crest cells.
- 8. Epithelialization • Synthesis of extracellular matrix proteins, Fibronectin and N-cadherin will form tight junctions and generate their own basal laminae • Paraxis gene encodes for the transcription of the ECM proteins.
- 9. Axial specification – Each somite forms a specific type of vertebrae • Thoracic vertebrae: ribs • Cervical vertebrae: neck – Somites are specified according to the Hox genes they express Thoracic somite
- 10. Differentiation • Sclerotome - cartilage of vertebrae and part of rib • Dermamyotome - remaining portion of the somite contains precursors for: • Dermatome – dermis (mesenchymal connective tissue of the skin)
- 11. • Primaxial (epaxial) myotome – intercostal muscles of the ribs; deep muscles of the back • Abaxial (hypaxial) myotome – body wall, limbs, tongue
- 12. Determination of Somites Sclerotome – Shh (high) from the notochord and neural tube floor plate - Sclerotome cells secrete Pax1 (transcription factor) cartilage/ vertebrae formation Dermatome – neurotrophin3 (NT3) and Wnt1 from neural roof plate, forms dermis
- 13. Myotome: • Abaxial - Wnt1, Wnt3a from the neural tube, forms body wall, limbs, tongue • Primaxial - Shh (low), Wnt (epidermis) + BMP4 (lateral plate mesoderm), forms muscle of the back Notochord : degenerates through apoptosis (remnants remain as nucleus pulposus)
- 14. Myogenesis • Muscle formation • Specification and differentiation of myogenic BHLH (basic helix-loop-helix) proteins
- 15. Myogenesis
- 17. Osteogenesis Bones – The skeleton is generated from: • Somites→ vertebrae • Lateral plate mesoderm → limb bones • Neural crest cells → brachial arch, craniofacial bones
- 18. • Intramembranous Ossification – The direct conversion of mesenchymal tissue into bone – This process occurs primarily in the bones of the skull
- 19. • BMP activate Cbfa1, a transcription factor that transforms mesenchymal cells to osteoblasts • Absence of Cbfa1 is the elimination of ossification
- 20. • Endochondral Ossification – Mesenchymal cells differentiate into cartilage, and this cartilage is later replaced by bone. – Bone formation characteristic of the vertebrae, limbs, and ribs.
- 24. Kidney • Generates the urogenital system, the kidneys and gonads • Nephron – functional unit, contains over 10,000 cells with at least 12 different cell types
- 25. 1. Pronephros - pronephric duct arises in the intermediate mesoderm - duct cells migrate caudally - anterior of the duct induced the adjacent mesenchyme to form pronephric tubules - pronephros forms functioning kidney of fish larvae and amphibian larvae
- 26. as the pronephric tubules degenerate, middle portion of nephric duct induces a new set of kidney tubules in the adjacent mesenchyme: 2. mesonephros - as more tubules are induced caudally, anterior tubules begin to regress via apoptosis - mesonephros function as one of the main sources of the hematopoietic stem cells
- 27. 3. metanephros - permanent kidney of amniotes - metanephrogenic mesenchyme is committed and forms in the posterior regions of the intermediate mesoderm - induces the formation of a branch from each of the paired nephric ducts - ureteric buds eventually separate form the nephric duct; become collecting ducts and ureters that take urine to the bladder
- 28. WT1 → secrete GNDF and HGF → uteric bud formation