Endocrinology

Question 1

endocrine system

Answer 1

endocrine cells release hormones that are conveyed by blood stream and act on distant cells

Question 2

synergistic

Answer 2

2 hormones greater than 1 alone

Question 3

permissive

Answer 3

presence of one hormone necessary for another to have an effect

Question 4

antagonistic

Answer 4

2 hormones oppose each others effects

Question 5

competitive

Answer 5

2 hormones similar in structure compete

Question 6

3 classes of hormones

Answer 6

steroids - synthesised from cholesterol
peptides - synthesised from amino acids
amino acids - synthesised from tyrosine

Question 7

steroid hormones

Answer 7

small hydrophobic molecules
released immediately after synthesis
circulate in bound form
slow long lasting effects

Question 8

peptide hormones

Answer 8

synthesised as preprohormones and stored prior to release

act on cell surface receptors via 2nd messenger systems

Question 9

amino acids

Answer 9

stored for instant release

Question 10

pulsatile

Answer 10

hormone released in short bursts

Question 11

circadian

Answer 11

hormone released in 24 hour schedule e.g. melatonin

Question 12

posterior pit. gland

Answer 12

neurohypophysis

consists of axons and nerve endings

Question 13

anterior pit. gland

Answer 13

adenohypophysis
originates from Rathke’s ppouch
consists of endocrine tissue

Question 14

oxytocin

Answer 14

released from post. pit.
breast contraction
uterine contraction

Question 15

ADH

Answer 15

post. pit.

water regulation in kidney

Question 16

hypothalamic hormones

Answer 16

majority stimulate release of other hormone
e.g. GHRH stimulates GH
TRH stimulates TSH

Question 17

anterior pit. hormones

Answer 17

stimulate release of other hormones

e.g. corticotrophs = ACTH

Question 18

somatotrophs

Answer 18

stimulate release of growth hormone

Question 19

acute actions

Answer 19

release fatty acids from adipose tissue

Question 20

gonadotrophs

Answer 20

stimulate release of sex hormones

Question 21

T4

Answer 21

thyroxine

main product of thyroid gland

Question 22

T3

Answer 22

more active than T4 but less abundant

Question 23

calcitonin

Answer 23

maintains calcium homeostasis

Question 24

structure of thyroid cells

Answer 24

single layer of follicular cells surrounding pool of colloid

calcitonin cells interspersed

Question 25

thyroglobulin

Answer 25

glycoprotein synthesised by follicular cells and released into follicular lumen by exocytosis

Question 26

hypothalamic pituatary axis

Answer 26

hypothalamus released TRH Anterior pit. releases TSH TSH reaches the thyroid gland

Question 27

effects of TSH on thyroid gland

Answer 27

``` increased: iodine uptake thyroglobulin synthesis iodination of thyroglobulin pinocytosis of colloid lysomal activity size of thyroid cells ```

Question 28

1 5'deiodinase

Answer 28

step UP | provides T3 to plasma

Question 29

2 5'deiodinase

Answer 29

step UP | provides T3 in CNS

Question 30

3 5'deiodinase

Answer 30

step DOWN | inactivates T4 to rT3

Question 31

structure of cortex

Answer 31

zona glomerulosa produces aldosterone zona fasciculata produces cortisol and androgens zona reticularis produces cortisol and androgens

Question 32

why does zona glomurulosa produce aldosterone?

Answer 32

it lacks 17 alpha hydroxylase so it has to convert cholesterol to aldosterone

Question 33

cortisol

Answer 33

mediates stress response major glucocorticoid inhibits glucose uptake in muscle and adipose tissue

Question 34

gonads

Answer 34

testes | ovaries

Question 35

testes

Answer 35

lots of androgens | less oestrogens

Question 36

ovaries

Answer 36

lots of oestrogens less androgens progesterone

Question 37

oogenesis

Answer 37

oocytes formed in developing ovary | arrest in prophase of meiosis 1

Question 38

follicular phase

Answer 38

follicle maturation | several months

Question 39

ovulation

Answer 39

release of ovum from ovary into fallopian tube | few hours

Question 40

luteal phase

Answer 40

formation of corpus luteum and its fate

Question 41

pre antral phase (follicular phase 1)

Answer 41

primordial follicle developed into primary follicle | then becomes mature pre antral follicle

Question 42

antral phase (follicular phase 2)

Answer 42

appearance of fluid filled atria increased zona granulosa growth dependent on pit. FSH

Question 43

theca cells

Answer 43

catalyse androgen production from cholesterol

Question 44

granulosa cells

Answer 44

contain aramatose so they can convert androgen to oestrogen

Question 45

pre ovulatory phase

Answer 45

follicle response to LH surge arrests in metaphase 2 haploid secondary oocyte FSH increases

Question 46

ovulation

Answer 46

oocyte released into peritoneal cavity before being captured by oviduct remnants of follicle form corpus luteum

Question 47

luteal phase

Answer 47

``` corpus luteum develops granulosa cells fill with liquid major product = progesterone oestrogen decreases then rebounds no pregnancy = oestrogen and progesterone decrease, LHand FSH increase pregnancy = placenta releases HcG ```

Question 48

FSH

Answer 48

upregulates aramatose gene expression stimulates growth of immature follicles prevents apoptosis of antral follicles

Question 49

LH

Answer 49

acts on theca cells to promote androgen production | acts on granulosa cells to secrete progesterone

Question 50

oestrogen

Answer 50

prepares reproductive tract for fertilisation

Question 51

progesterone

Answer 51

promotes uterine secretion to support egg implantation