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15 Cards in this Set
- Front
- Back
- 3rd side (hint)
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When do all major organs form?
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week 4-8
what is their function at this point? |
function is minimal; although the critical time period for growth:
Where risk for anomalies are high; etc. |
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What are the phases of human development?
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Growth, morphogenesis, differentiation
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How does the embryonic folding occur?
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Cranially, Caudally, Laterally
What causes each folding? What happens nearby? |
Cranial: growth of neural plate, which thickens into primordial brain
Caudal: growth of primitive streak; connecting stalk attaches to ventral surface forming umbilical cord Lateral: growth of somites and spinal cord; endoderm incorporated into midgut, lateral walls formed |
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Growth of Amnion
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Forms lateral walls
Umbilical cord forms from connecting stalk Amniotic cavity obliterates extraembyonic coelom Amnion covers umbilical cord What if lateral folds don't fuse? |
Abdominal walls don't close: Omphalocele: failure of cephalic and lateral folds: ectopia cordis, sternal and diaphragmatic defects
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What do the lateral and intermediate mesoderms form?
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intermediate: urogenital system including gonads, ducts, accessory glands
Lateral: Connective tissue, muscle of viscera and limbs, serous membranes of pleura, pericardium, peritoneum, blood and lymph cells, cardiovascular and lymphatic systems, spleen, adrenal cortex What if migration of these mesoderm cells is abnormal? |
intermediate mesoderm: abnormalities in the kidneys
lateral mesoderm: abnormalities in the limbs |
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What guides embryonic development? (who does what to who?)
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Inductors make earlier pluripotent cells more restricted and differentiated
Cues from immediate surroundings Change course of development Examples of molecules? Actual processes? |
Molecules: Shh, Wnt, FGF1,2,3,10, TGF-β
Processes: Optic cup inducing lens |
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Mechanisms of signal transfer between inductors and responding tissues
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1) Diffusion
2) Extracellular Matrix secreted by inductor 3) Cell contact-mediated contact between inductor and responder examples for 1) and 3) ? |
1) Shh, Wnt, FGF1,2,3,10, TGF-β
3) Notch receptor |
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Principles of Tissue Induction
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1) Specificity of an induction is a property of the reacting tissue not the inductor
2) Inductions occur in sequential manner 3) Reacting tissue must have appropriate components to respond 4) Reactions may be reciprocal 5) Time and space limited Examples of 2)? 4)? |
2) e.g. optic cup wouldn't
form unless it had come in contact with the neural plate; 4) e.g. metanephric bud inducing tubules, etc... |
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Pharyngeal arches components
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Arches, pouches, grooves, membranes
How many arches? Derived from? Consist of? |
5 arches: 1st, 2nd, 3rd, 4th, 6th
Derived from neural crest cells Consist of mesenchymal core covered externally by ectoderm and internally by endoderm. Contains aortic artery from promordial heart, Cartilaginous rod, Muscle (of head and neck), Sensory and Motor Nerves (from neuroectoderm) |
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Fate of pharyngeal arches
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2ND arch overgrows 3rd and 4th forming cervical sinus
By 7th week, 2nd-4th grooves and cervical sinus disappear If it doesn't disappear? |
Branchial/Cervical cyst
Anterior to sternocleidomastoid Leak mucus from pharynx onto neck |
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Treacher Collins Syndrome
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Mandibulofacial dysostosis:
Abnormal bilateral 1st and 2nd branchial arch development Caused by? |
Mutation in gene coding for protein “treacle” – peak expression in neural crest cells of branchial arches
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What does pharyngeal apparatus 1 form?
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arch forms maxillary and mandibular prominence
cartilage forms malleus and incus muscle forms temporalis masseter cranial nerve forms V (s: head, m: mastication) pouch forms eustacian tube tympanic cavity groove membrane forms ear canal and tympanic membrane |
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What does pharyngeal apparatus 2 form?
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arch overgrows others
cartilage forms stapes, styloid, hyoid muscles form many facial muscles cranial nerve form VII (facial) pouch forms pallatine tonsils |
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What does pharyngeal apparatus 3 form?
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cartilage forms hyoid
muscle forms stylo-pharyngeus in neck cranial nerve forms IX glossopharyngeal Pouch forms inferior parathyroid |
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What do pharyngeal apparatus 4-6 form?
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cartilage for thyroid, cricoid, artenoid
muscle forms pharyngeal cranial nerve forms X (Vagus) Pouch forms superior parathyroid |
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