Anatomy

What are teratogens? List ten and discuss the principles of teratology

Definition: teratogens are factors that disrupt normal development resulting in abnormalities. List of Ten teratogens: A. Infectious agents: 1. Rubella virus 2. Cytomegalovirus 3. Toxoplasmosis B. Physical agents 4. X-rays 5. Hyperthermia C. Chemical agents: 6. Thalidomide 7. Aminopterin 8. Amphetamine D. Hormonal agents: 9. Diethyl stibesterol 10. Androgenic agents. Principles of tetralogy: Definition: tetralogy …

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Discuss twinning

Introduction: twinning is a type of multiple pregnancy in which two fetuses are growing in the uterus if a pregnant woman. Types: there are two types of twins: dizygotic twins (fraternal) and monozygotic twins (identical). 1. Dizygotic twins: they are the most common type. They result from simultaneous shedding if two oocyte and the fertilization …

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List the events that take place during the second week of development

Introduction: the implantation of the embryo ends at about  12 days after fertilization. The events of the second week development spans from the time implantation begins to the time the secondary yolk sac is formed. Events: 1. Formation of the cytotrophoblast from the trophoblast. 2. Formation of the bilaminar germ disc (hypoblast and epiblast from …

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Compare and contrast the histological features of the PCT and DCT

Introduction: The PCT, proximal convoluted tubule and DCT, distal convoluted tubule are the convoluted parts of the nephron. The other parts are the renal corpuscle, loop of Henle, collecting tubules and ducts. Proximal convoluted tubule: it is the longest and most convoluted part of the nephron. It is responsible for 75% reabsorption of ions and …

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Describe the microscopic features of the adenohypophysis

Introduction: the adenohypophysis or the anterior pituitary gland is the part of the pituitary gland that develops from the oral ectoderm. It arises from an epithelial up growth from the roof of the primitive oral cavity, Rathke’s pouch. Microscopic features: it has two types of secretary cells. I. Chromophobes: they occur in clusters and they …

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