Embryology

Question 1

Ectoderm derivatives

Question 2

Mesoderm derivatives

Answer 2

MESODERMAL CELLS

Myeloid stem cells
Erythroid stem cells
Spleen
gOnads
Dermis
Entire trunk
Renal system
Meninges
Adrenal cortex
Lymphoid stem cells

CVS
Endothelium (BVs and heart)
Lining of the body cavities (visceral and parietal)
Limbs and LNs
Smooth muscles of GIT

Question 3

Endoderm derivatives

Answer 3

Epithelial lining of GIT

Neck - thyroid, PT, thymus

Drainer - bladder, urethra

Organs assoc with GI tract

Question 4

MAC lost a pair of PANTs at the CAMPP.

Answer 4

MAC (adrenal cortex)
Mesoderm: adrenal cortex

PANT (Parathyroid, ant pit, eNdoderm, thyroid)
Endoderm: anterior pituitary, thyroid, parathyroid

CAMPP (eCtoderm, adrenal medulla, pos pit)
Ectoderm: posterior pituitary, adrenal medulla

Question 5

Embryonic development of fingers and toes from the limb buds involves apoptosis of cells between individual digits. What are the steps of apoptosis?

Answer 5

(1) Cell shrinkage: Cell cytoplasm condenses and organelles tightly packed
(2) Pyknosis: Chromatin condensation
(3) Blebbing: Small blebs in the plasma membrane form
(4) Budding: Formation of apoptotic bodies - portions of cytoplasm and intact organelles with or without DNA. Budding prevents release of cellular contents into the surrounding interstitium. Plasma membrane remains intact
(5) Phagocytosis: Macrophages quickly engulf apoptotic bodies. They do not release cytokines so there is no inflammatory response

Question 6

Functions of the yolk sac during early embryonic development:

Answer 6

Gas and nutrient exchange
Primordial germ cell production
Primitive haematopoiesis
Protein synthesis

Question 7

Excluding the epithelium, which germ cell layer does the urogenital system originate?

Answer 7

Intermediate mesoderm