Endocrine - Embryology and Anatomy Flashcards Preview

USMLE > Endocrine - Embryology and Anatomy > Flashcards

Flashcards in Endocrine - Embryology and Anatomy Deck (43)
Loading flashcards...
1

Describe thyroid development

Thyroid diverticulum arises from floor of primitive pharynx, descends into the neck.

2

How is thyroid diverticulum connected to the tongue?

Thyroglossal duct

3

What is the pyramidal lobe of thyroid?

Persistent thyroglossal duct

4

What is the foramen cecum of thyroid?

Normal remnant of thyroglossal duct

5

Most common ectopic thyroid tissue site

Tongue

6

Describe thyroglossal duct cyst

Anterior midline neck mass that moves with swallowing or pertrusion of the tongue

7

How is thyroglossal duct cyst different from a brachial cleft cyst?

Brachial cleft cyst - persistent cervical sinus
Lateral neck (vs midline for thyroglossal duct cyst)

8

Describe fetal adrenal gland

Consists of an outer adult zone and inner active fetal zone.
Adult zone is dormant during early fetal life but begins to secrete cortisol late in gestation.

9

What controls cortisol secretion in the fetus?

ACTH and CRH from fetal pituitary and placenta

10

Role of cortisol in the fetus

Fetal lung maturation and surfactant production

11

What are the embryologic derivatives of the adrenal cortex and medulla?

Cortex - mesoderm
Medulla - neural crest

12

What are the layers of adrenal gland?

Capsule
Zona glomerulosa
Zona fasciculata
Zona reticularis
Medulla (Chromaffin cells)

13

Primary regulatory control and secretory products of: Zona glomerulosa

Regulation: Renin-Angiotensin-Aldosterone System

Secretion: Aldosterone

14

Primary regulatory control and secretory products of: Zona fasciculata

Regulation: ACTH and CRH

Secretion: glucocorticoids (cortisol)

15

Primary regulatory control and secretory products of: Zona reticularis

Regulation: ACTH and CRH

Secretion: sex steroids (androgens)

16

Primary regulatory control and secretory products of: Adrenal medulla (Chromaffin cells)

Regulation: Pre-ganglionic sympathetic fibers (acetylcholine)

Secretion: Catecholamines (Epi, NE)

17

What is the most common tumor of adrenal medulla in adults? And in children?

How are they different?

Adult: pheochromocytoma
Children: neuroblastoma

Pheochromocytoma causes episodic hypertension; Neuroblastoma does not

18

Describe adrenal gland drainage

Left adrenal -> Left adrenal vein -> Left renal -> IVC

Right adrenal -> Right adrenal vein -> IVC

Same as left and right gonadal veins

19

What are the embryologic derivatives of anterior and posterior pituitary?

Anterior pituitary (Adenohypophysis): oral ectoderm (Rathke's pouch)

Posterior pituitary (neurohypophysis): neuroectoderm

20

Function of posterior pituitary gland

Secretes vasopressin and oxytocin made in hypothalamus and shipped to posterior pituitary through neurophysins (carrier proteins)

21

Function of anterior pituitary gland

Secretes FSH, LH, ACTH TSH, prolactin, GH, melanotropin (MSH)

22

Describe structure of TSH, LH, FSH, hCG

Alpha and Beta subunit
Alpha: common to all
Beta: determines hormone specificity

23

How do pituitary acidophils appear on histology and what do they make?

Pink
Prolactin, GH

24

How do pituitary basophils appear on histology and what do they make?

Blue
FSH, LH, ACTH, TSH

25

Describe organization of islets of langerhans

Alpha cells in periphery
Beta cells central
Delta cells interspersed

26

What are the different cell types of islets of langerhans and what do they secrete?

Alpha: glucagon
Beta: insulin
Delta: somatostatin

27

What does the islets of langerhans arise from?

Pancreatic buds

28

Structure of insulin

Alpha and Beta chains connected by sulfur bonds

29

Describe insulin secretion in the pancreatic beta-cell

1. Glucose enter cell
2. Glycolysis increases ATP/ADP ratio
3. ATP closes ATP-sensitive K+ channels
4. Depolarization of cell
5. Influx of Ca2+ through voltage-gated Ca2+ channels
6. Exocytosis of insulin granules into blood vessel

30

Does insulin cross the placenta?

No