4: Pancreas, Thyroid, Parathyroid - Patestas

Question 1

represent the inferior end of teh thyroglossal duct that persists after the remainder of the thyroglossal duct has degenerated

Answer 1

pyramidal lobe of thyroid

present in about 40% of individuals

Question 2

thyroglossal duct =

Answer 2

developmental remnant: fibrous cord that extends from the fully-developed thyroid gland to foramen cecum in dorsum of tongue

Question 3

thyroid capsule is derived from..

Answer 3

deep cervical fascia

consists of dense irregular collagneous connective tissue and gives rise to trabecula/septa that partition the gland into lobules

Question 4

where are parathyroid glands located?

Answer 4

within the capsule covering the posterior surface of the thyroid gland

Question 5

3 hormones synthesized by the thyroid gland

Answer 5

T3
T4
calcitonin

Question 6

basic structural and functional unit of the thyroid gland

Answer 6

thyroid follicle

Question 7

where is glandular secretory product of thyroid stored?

Answer 7

in follicular lumen (extracellulary)

all other endocrine glands accumulate product in the parenchma(within cell)

Question 8

what type of follicular cell would indicate that highly active?

Answer 8

• simple squamous - low level of activity*
• simple cuboidal - normal level of activity*
• simple columnar - highly active*

Question 9

vesicles of follicular epithelium contain…

Answer 9

thyroglobulin

Question 10

parafollicular cells are derived from…

Answer 10

neural crest cells

Question 11

are parafollicular cells exposed to colloid?

Answer 11

no

they are wedged between follicles and lie within basal lamina surrounding follicle, are near many capillaries

Question 12

peptide hormone released by parafollicular cells when blood calcium levels are high

Answer 12

calcitonin

Question 13

how does calcitonin lower blood calcium levels?

Answer 13

• inhibits bone breakdown by osteoclasts

- promotes calcium deposition in bones

Question 14

follicular lumen contains…

Answer 14

colloid with thyroglobulin and T3 and T4

Question 15

iodide from the bloodstream is oxidized ____-

Answer 15

on the apical cell membrane facing the colloid into its active form (iodine)

**oxidation of iodide takes place in the active sites of thyroid peroxidase (a membrane-bound enzyme) on the follicular APICAL cell membrane, facing the colloid

Question 16

where does TSH come from?

Answer 16

anterior pituitary basophils secrete TSH

Question 17

MIT + DIT = triiodinated tyrosine, when it is cleaved from the thyroglobulin it is called

Answer 17

T3

triiodothyronine

Question 18

most T3 is produced via..

Answer 18

conversion from T4 by the kidney and heart

follicular cells produce way more T4 than T3

Question 19

T3 is _____ potent than T4

Answer 19

5 time more potent

Question 20

metabolic effects of T3

Answer 20

• increase cellular metabolism
• increase growth rate
• increase mental activity
• decrease formation of phospholipid and triglycerides to enhance the production of endogenous cholesterol

Question 21

increase of thyroid hormone synthesis results in __________ body weight

Answer 21

decreased

increases HR, metabolism, respiration, muscle function and appetite

Question 22

which cells of the parathyroid gland contain PTH?

Answer 22

chief cells
eosinophilic

the other cells are oxyphil cells and intermediate cells with unknown functions

Question 23

action of PTH

Answer 23

increases blood calcium level and simultaneously decreases serum phosphate

Question 24

action of PTH in bone

Answer 24

causes osteoblassts to release osteoclast stimulating factor –> bone breakdown –> increase blood calcium

Question 25

action of PTH in kidney

Answer 25

prevents calcium loss in urine and promotes phosphate loss in urine

Question 26

action of PTH in GI

Answer 26

regulates formation of vtiamin D which increases calcium absorption from GI

Question 27

compete removal of parathyroid glands =

Answer 27

drop blood calcium level (no PTH) –> tetanic contraction of muscles and death

Question 28

islet of langerhans indicate

Answer 28

endocrine pancreas

Question 29

alpha cells pancreas =

Answer 29

glucagon (increase blood glucose levels)

Question 30

beta cells pancreas =

Answer 30

insulin (decrease blood glucose levels)

Question 31

delta cells pancreas =

Answer 31

somatostatin (inhibits glucagon and insulin) ( reduces GI motility)

Question 32

when is somatostatin released?

Answer 32

after eating in response to elevation of blood glucose, amino acids or chylomicrons

Question 33

PP/F cells of pancreas =

Answer 33

pancreatic peptide

inhibits pancreatic exocrine secretions

Question 34

G cells of pancreas =

Answer 34

gastrin (stimulates HCl by parietal cells)