week 4

Question 1

2 hormones from posterior pituiatary and from what neurons

Answer 1

vasopressin (ADH) and oxytocine

magnocellular neurons (PVN and SON nuclei)

Question 2

PVN vs SON which secretes which hormones

Answer 2

▪ The PVN secretes mostly oxytocin, with a bit of ADH
▪ The SON secretes mostly ADH, with a little oxytocin

Question 3

vasopressin/ADH function

Answer 3

water regulation and vascoconstrist

Question 4

oxytocin function

Answer 4

milk letdown reflex and in the augmentation of labour

**smooth muscle contraction via ca2+

Question 5

2 stimuli for ADH release

Answer 5

1. Osmoreceptors (mainly) (osmolarirt)
2. baroreceptors (in response to decreased BP and blood volume)

Question 6

hormones of anterior pituitary

Answer 6

Prolactin, TSH, GH, FSH, LH, ACTH

Question 7

ADH stimulated by

Answer 7

increased ECF osmolarity
decrease BP/volume

Question 8

what makes the hormones in the tyroids

Answer 8

follicular cells make t3 and t4

Question 9

parafollikcular cells in thyroid make

Answer 9

calcitonin, regulate Ca2+

Question 10

2 things to make thyroid hormoens

Answer 10

tyrosine and iodine

Question 11

less active and more abundant thyroid homrone

Answer 11

t4

Question 12

how is t4 made into t3

Answer 12

deiodination

Question 13

how to iodinate tyrosine to make into thyroid homrones and at which carbons

Answer 13

MIT - 1 iodine at C3
DIT- iodine at C3 and C5

Question 14

T3 and T4 how many idoines

Answer 14

T3 - MIT + DIT = 3
T4= 2 DIT = 4

Question 15

where to tyrosines get iodinated

Answer 15

in colloid of thyroid follicles to make t3 and t4

Question 16

where does tyrosine come from

Answer 16

nitially part of a larger protein known as thyroglobuln

Question 17

how is iodine in diet absorbed

Answer 17

Na+ I symporter in follicular cells

Question 18

how does iodine get into the cell

and across apical membrane

Answer 18

NI+ S+ symptorter and then Na+ K+ atpase to

across the apical membrane (the side facing the follicular lumen) by the Cl−/I− exchanger, known as pendrin.

Question 19

thyroglobulin contains

Answer 19

tyrosyl groups (tyrosine residues) that will be iodinated to form thyroid hormones (T3 and T4).

Question 20

what enzyme to turn iodide into iodine

Answer 20

thyroid peroxidase (TPO)

Question 21

TPO needs

Answer 21

DUOX2 generates hydrogen peroxide (H2O2), which is necessary for TPO to oxidize iodide into the iodine radical.

Question 22

half life of t3 and t4

Answer 22

• T4 has a longer half-life
• T3 has a shorter half-life

Question 23

carriers for t3 and t4

Answer 23

albumin- low affinity

transthyretin (TTR)

thyroid-binding globulin- high affinity for t4

Question 24

once t4 enters target tissue how does it become more active form t3

Answer 24

deoiodanse type 1 and 2 (D1 and D2)

Question 25

D1 vs D2 vs D3 funciton

Answer 25

D1 and D2 turns T4 to T3

D3 turns T4 into reverse T3 (rT3)

Question 26

cofactor needed for deiodinases (D1, D2, and D3)

Answer 26

selenium

bc selenocysteine residues

Question 27

rT3 function

Answer 27

compete with T3 receptor and reduce metabolic activity in stress and calorie restrict

Question 28

hashimotos

Answer 28

cytotoxic T cells

Question 29

dequervains sub acute thyroididitis causes

Answer 29

viruses

neutrophils and lymphocytes

Question 30

diffuse non toxic goiter from

Answer 30

iodine defiicney

Question 31

myxoedema coma

Answer 31

long term hypothyroid PLUS infection

very serious

hypotension –> shock

Question 32

most common thyrotoxicosis (high levels of thyroid hormone)

Answer 32

graves disease

TSH receptor-stimulating immunoglobulins (TSIs) stimulate the TSH receptor and are not responsive to negative feedback

Question 33

anti thyroid drugs

Answer 33

propylthioural inhibits TPO and deiodination of T4 to T3

methimazole inhibits TPO

Question 34

radioactive iodine

Answer 34

for thydoi cancncer

Question 35

levothyroxine- synthetic t4 for

Answer 35

HYPOthryiod