Endocrine

Question 1

name the 4 main classes of hormones

Answer 1

modified amino acids
steroids
peptides
proteins

Question 2

what type of hormone is adrenaline

Answer 2

amino acid

Question 3

what type of hormone is cortisol or testosterone

Answer 3

steroids

Question 4

what type of hormone is ACTH or ADH

Answer 4

peptides

Question 5

what type of hormone is insulin

Answer 5

protein

Question 6

why is the signal transduction cascade that occurs when hormone binds to receptor important

Answer 6

it typically causes an amplification of signal

this amplification is important due to the scarcity of the original signal

Question 7

what makes the synthesis and release of steroid hormone different from that of amines, peptides and proteins?

Answer 7

steroid is synthesised and secreted upon demand
the others are presynthesised and stored in vesicles

steroid is hydrophobic, the rest are hydrophilic - steroid requires a carrier protein to travel in blood
the others are released via Ca2+ dependant exocytosis

Question 8

steroid hormones have the shortest 1/2 life and amines have the longest. true?

Answer 8

false - amines have the shortest, steroids have the longest

Question 9

which hormone receptor is activated by amines

Answer 9

G-protein coupled receptor

Question 10

which hormone receptor is activated by proteins/peptides

Answer 10

receptor kinases

Question 11

which receptors are cell surface receptors and have a hydrophilic ligand

Answer 11

GPCR

receptor kinases

Question 12

which hormone activates class I nuclear receptors

Answer 12

steroid hormones

Question 13

describe the movement of class I nuclear receptors in presence of activating ligand

Answer 13

in the absence of activating ligand = found in cytoplasm

when activated, they are bound to inhibitory heat shock proteins and move to nucleus

Question 14

what hormone activates class II nuclear receptors

Answer 14

lipids

Question 15

what hormones activate hybrid class nuclear receptors

Answer 15

thyroid hormones

Question 16

which hormone receptors are intracellular with a lipophilic ligand

Answer 16

all the nuclear receptors

Question 17

does the Gs protein increase or decrease cAMP production. what does this cause

Answer 17

increases production of PKA, causing MORE cellular effects

Question 18

does the Gi protein increase or decrease cAMP production. what does this cause

Answer 18

decreases production of PKA, causing LESS cellular effects

Question 19

what does Gq G protein convert. what does this do

Answer 19

INCREASES the conversion of PIP2 –> IP3 by phospholipase C

causes increased calcium release from ER
this causes increased cellular effects

Question 20

how does glucose enter the B cells and what is it phosphorylated by

Answer 20

through GLUT 2

phosphorylated by glucokinase into glucose - 6 phosphate

Question 21

what happens to the glucose-6-phosphate

Answer 21

it goes through the TCA cycle and produces 36 ATP

Question 22

in the process of insulin secretion, what does the increased ATP levels cause

Answer 22

inhibit the ATP-sensitive K+ channel (KATP), causing depolarisation of the cell membrane

this results in opening of the voltage gated Ca2+ channels
an increase in intracellular Ca2+ levels causes fusion of secretory vessels and release of insulin

Question 23

what are the 2 proteins that make up the KATP channel

Answer 23

KIR6- congenital mutations of this can lead to neonatal diabetes
SUR1

Question 24

what is the gist of diabetic ketoacidosis

Answer 24

a state of absolute insulin deficiency
if you have no insulin, GLUT2 won’t open, so no glucose can get into cells –> cells are starved of glucose

you get a build up of glucose in the blood, and an increase in production of counter-regulatory hormones

they make more glucose to try and get it into the cells and ketone levels in blood increases

Question 25

what are the counter regulatory hormones that are produced in DKA and what is their effect

Answer 25

glucagon, cortisol and GH they cause an increase in gluconeogenesis, glycogenolysis and lipolysis contributes to the hyperglycaemia and ketone overload in blood

Question 26

which hormones are released by the anterior pituitary`ry

Answer 26

GH, TSH, ACTH, FSH

Question 27

which hormones are released by posterior pituitary

Answer 27

ADH and OT - synthesised in the hypothalamus

Question 28

what does pituitary lie immediately inferior to

Answer 28

the optic chiasm

Question 29

what is the function of leptin and how is it affected in obesity

Answer 29

it tells your body how full you are no leptin = brain thinks you're starving if you have lots of fat stores, leptin isn't as effective and causes a flat dose response curve this means that there is little increase in response over a wide range of doses

Question 30

what is adaptive thermogenesis

Answer 30

the body perceives weight loss as a threat to survival as you're eating less to lose weight, your body will lower metabolic rate, making it harder to lose the weight

Question 31

where is the thyroid found

Answer 31

on the 5th cervical/1st thoracic vertebrae | in between 2nd and 4th tracheal rings

Question 32

what gives parasympathetic innervation to the thyroid

Answer 32

the vagus nerve

Question 33

what gives sympathetic innervation to the thyroid

Answer 33

sympathetic fibres - superior, middle and inferior ganglia of sympathetic trunk

Question 34

what is the blood supply to the thyroid

Answer 34

superior and inferior thyroid arteries

Question 35

what does the colloid contain

Answer 35

tyrosine containing thyroglobulin

Question 36

what cells encapsulate the colloid

Answer 36

follicular cells

Question 37

what do the parafollicular C cells secrete

Answer 37

calcitonin

Question 38

what does iodine attach to when it enters the follicular cell and what does this form

Answer 38

attaches to tyrosine residues on thyroglobulin to form MIT and DIT

Question 39

what is T3 made up of

Answer 39

1x MIT | 1x DIT

Question 40

what is T4 made up of

Answer 40

2xDIT

Question 41

where are T3 and T4 stored until they are required

Answer 41

the colloid thyroglobulin

Question 42

are T3 and T4 hyrophobic or phillic

Answer 42

hydrophobic - they need to bind to plasma proteins to be transported

Question 43

does metabolic rate correlate more closely with free or bound thyroxine

Answer 43

free T3 and T4

Question 44

what causes an increase in total T4 but not in fT4

Answer 44

pregnancy, newborn state HEPA, chronic active hepatitis, biliary cirrhosis acute intermittent porphyria heroin.

Question 45

what causes a decrease in total T4 but not in fT4

Answer 45

androgens loss of glucocorticoids, Cushing's syndrome active acromegaly chronic liver disease, nephrotic syndrome severe systemic illness

Question 46

how do thyroid hormones increase responsiveness to adrenaline and noradrenaline

Answer 46

by increasing no of receptors | this is why you need to use B Blocker during initial therapy for hyperthyroidism

Question 47

what effect does stress have on TRH and TSH release

Answer 47

inhibits their release, causing hypothyroidism

Question 48

what enzymes are important in the activation/deactivation of thyroid hormones

Answer 48

deiodinase enzymes D2 activates T4 --> T3

Question 49

what is the pituitary derived from

Answer 49

rathke's pouch

Question 50

what are the 3 zones of the cortex in the adrenal gland and what does each produce

Answer 50

zona glomerulosa - produces aldosterone zona fasciculata -produces glucocorticoids zona reticularis - produces adrenal androgens

Question 51

what does the medulla of the adrenal gland produce

Answer 51

catchecolamines (epinephrine)

Question 52

what effect does the RAAS system have on ion levels

Answer 52

it causes K+ excretion | increased Na+ absorption (the water follows salt, so you get increased water reabsorption)

Question 53

what hormone is calcium absorption in small intestine controlled by

Answer 53

parathyroid hormone

Question 54

what effect does hypocalcemia have on PTH excretion

Answer 54

hypocalcemia causes INCREASED secretion of PTH

Question 55

what is calcitonin and where is it produced

Answer 55

it opposes the action of PTH (a parathyroid hormone antagonist) it is produced in the parafollicular cells in thyroid gland

Question 56

calcitonin is released in response to hypocalcemia? true?

Answer 56

no! calcitonin released in response to Hypercalcemia | it surpasses osteoclast activity

Question 57

what is bone mostly made up of and what is this compound composed of

Answer 57

hydroxyapatite made up of calcium phosphate

Question 58

what enzyme is responsible for the production of hydroxyapatite

Answer 58

alkaline phosphatase