Lecture 23: Endocrine Microanatomy

Question 1

what are glands developed from

Answer 1

down growth of epithelium

Question 2

name the two types of glands

Answer 2

exocrine and endocrine

Question 3

give the main difference between exocrine and endocrine glands

Answer 3

exocrine maintain contact with epithelium surface while endocrine have no connection with epi surface (isolated mass with own blood supply)

Question 4

where is the pituitary located

Answer 4

sella turcica of sphenoid bone enclosed by CT capsule

Question 5

what is the embryological origin of the ant. pit.

Answer 5

• Buccal ectoderm

- upward extension of Rathke’s pouch (mouth)

Question 6

what is the embryological origin of the post. pit.

Answer 6

• down growth of neuroectoderm

Question 7

where is the hypothalamus located within the brain

Answer 7

on the floor of the third ventricle

Question 8

name the stalk that connects the hypothalamus and pituitary

Answer 8

infundibulum

Question 9

name the 3 parts of the ant. pit.

Answer 9

• pars tuberalis
• pars intermedia
• pars distalis

Question 10

what is the function of the pars intermedia

Answer 10

division between post. and ant. lobes of pit.

Question 11

name the 2 parts of the post. pit.

Answer 11

• infundibular stalk

- pars nervosa

Question 12

name the space between the pituitary and the sphenoid bone

Answer 12

hypophyseal fossa

Question 13

which lobe of pituitary stains lighter histologically and why

Answer 13

• post. pit.
• has lots of neurons
• ant. contains lots of glandular secretory cells that stain darker

Question 14

name the two types of cells in ant. pit. based on histochemical staining

Answer 14

• chromophils

- chromophobes

Question 15

outline the difference between chromophils and chromophobes

Answer 15

Chromophils:

• bright staining glandular cells arr. in nests or cords
• surrounded by many caps.
• two subtypes –> acidophils (red) and basophils (dark)

Chromophobes:

• pale staining
• exhausted or quiescent chromophils

Question 16

name the two subtypes of chromophils

Answer 16

• acidophils (red)

- basophils (dark)

Question 17

why do basophils stain darker than acidophils

Answer 17

they contain more granular content

Question 18

name the 5 different cell types that make up the ant. pit. and what hormone they secrete

Answer 18

• somatotrophs –> growth hormone
• mammotrophs –> prolactin
• corticotrophs –> ACTH
• thyrotrophs –> TSH
• gonadotrophs –> FSH and LH

Question 19

what hormone do axons from supraoptic nucleus produce

Answer 19

ADH

Question 20

what hormone do axons from paraventricular nucleus produce

Answer 20

oxytocin

Question 21

what are herring bodies

Answer 21

dilations of axons for storage of hormones

Question 22

what are pituicytes

Answer 22

support cells in post. pit. (similar to glial cells of CNS)

Question 23

describe the histology of post. pit.

Answer 23

• herring bodies
• unmyelinated axons
• pituicytes
• highly vascular

Question 24

through what vessel are hormones released from the pituitary

Answer 24

hypophyseal vein

Question 25

what is the embryological origin of the thyroid gland

Answer 25

fetal tongue down growth

Question 26

where is the thyroid gland located

Answer 26

anterior and lateral surface of upper trachea

Question 27

define goitre

Answer 27

swelling of neck - enlargement of thyroid

Question 28

name a function of parathyroid glands

Answer 28

calcium level regulation

Question 29

describe the thyroid histologically

Answer 29

follicular cells - apical surface lined w/ microvilli - simple cuboidal epi parafollicular (C cells) - produce calcitonin - located between follicles or at their periphery

Question 30

describe the function of calcitonin

Answer 30

decreases blood calcium by decreasing bone resorption by osteoclasts and ^ bone formation by osteoblasts

Question 31

describe the colloid in both hyper and hypo thyroidism

Answer 31

- hypo = ^ colloid | - hyper = decreased colloid

Question 32

where are adrenal glands located

Answer 32

embedded in perirenal fat at superior poles of kidneys

Question 33

what cell type makes up the adrenal medulla

Answer 33

neural crest cells

Question 34

describe the cells found in the different zones of adrenal cortex

Answer 34

ZG --> rounded groups of cells ZF --> large vacuolated cells in columns ZR --> cells arranged in branching irregular networks

Question 35

name the 4 cell types found in Islets of Langerhans of pancreas and the hormone they produce

Answer 35

- alpha --> glucagon - beta --> insulin - delta --> somatostatin - F cells --> pancreatic polypeptide

Question 36

describe the arr. of Enteroendocrine cells in the gastrointestinal Enteroendocrine pancreatic (GEP) system

Answer 36

diffusely arr. in GI epi