Lecture 6+7

Question 1

What regulates aldosterone?

what part of the adrenal again?

Answer 1

regulated by Ag II and K+

zona glomerulosa

Question 2

what regulates cortisol and androgens?

what parts of the zona?

Answer 2

ACTH

Fasciculata: cortisol

reticularis: androgens

Question 3

hormones of the medulla? what controls?

Answer 3

releases epinephrine and norepinephrine

under sympathetic control

Question 4

what is the blood supply of the adrenal gland?

Answer 4

superior, middle, and inferior suprarenal A.

venous: drain to IVC and renal vein

medulla has a dual blood supply

Question 5

regulation of cortisol?

Answer 5

paraventricular nucleus secrete CRH

corticotropes respond to CRH by releasing ACTH

ACTH will target adrenal cortex

free cortisol will neg feedback on hypothalamus and anterior pituitary

Question 6

mechanism of CRH

Answer 6

bind to receptor

increase cAMP and calcium

fusion of ACTH vesicles and exocytosis

Question 7

short term and long term effects of ACTH?

Answer 7

short: increased conversion of cholesterol to pregnenolone
long: increased LDL-R and increased enzymes

Question 8

effect of Ag II on the cell?

Answer 8

increase DAG and IP3 and PKA activation
increase Ca

stimulation of aldosterone synthesis
release of aldosterone (restore blood volume)

Question 9

effect of hyperkalemia on the cell? aldosterone?

Answer 9

increased K depolarizes the cell

increased Ca

activation of aldosterone synthesis and release

increase K+ excretion in the urine
Na reabsorption into the blood

Question 10

Hyperaldosteronism
primary and secondary?
symptoms?

Answer 10

increased secretion of aldosterone from the adrenal cortex

hypertension, deceased K, metabolic alkalosis

primary: Conn’s syndrome
adrenal adenoma
or idiopathic hyperplasia of zona G
increased Aldo, decreased renin

secondary:
increased aldosterone and renin

Question 11

how to tell between primary and secondary hyperaldosteronism?

Answer 11

primary: renin is low
secondary: renin is high

Question 12

hypoaldosteronism?

Answer 12

hyperkalemia
metabolic acidosis
hyponatremia

Question 13

the process of catecholamine release from the adrenal medulla?

Answer 13

1. ACh from sympathetic preganglionic neuron stimulated nicotinic receptors
2. Na influx in the chromaffin cell
3. depolarization of chromaffin cell
4. Ca influx
5. fusion of vesicles and exocytosis

Question 14

short term and long term response to stress?

Answer 14

short: sympathoadrenergic system 
HR and BP increases 
metabolic rate increase
bronchodilation 
increased blood glucose 

long: ACTH-cortisol system (adrenocortical system) 
protein breakdown 
fat lipolysis
immune suppression 
increased BP

Question 15

what hormone is a tripeptide

Answer 15

TRH or thyrotropin releasing hormone

Question 16

mechanism and target of TRH?

Answer 16

thryotroph’s are the target

bind to receptor
increase IP3 and DAG
increase Ca
release TSH

Question 17

action of TSH on the thyroid

Answer 17

bind to receptor
increase cAMP and maybe PLC
modulation of many cellular processes

Question 18

the importance of iodine

Answer 18

the synthesis of thyroid hormones requires Iodine
need at least 150ug per day

pregnant or lactating women need more

Question 19

what are the steps of thyroid hormone synthesis?

Answer 19

1. synthesis and extrusion of TH into the lumen (happens in RER and golgi)
2. pull I into the cell with Na
3. oxidize I at apical membrane
4. organification of I2 to MIT and DIT
5. couple MIT and DIT
6. endocytosis of TH
7. hydrolyze T4 to T3
8. deiodination of MIT and DIT (to reuse)

Question 20

what are some inhibitors of the production of TH?

at the Na-I pump? oxidation step?

Answer 20

high levels of I-, thyrocyanate, and perchlorate inhibit the channel

oxidation and other steps can be inhibited by PTU

Question 21

what are the whole body effects of TH?

Answer 21

increase basal metabolic rate

promote bone formation

increase O2 consumption

Question 22

TH effects on the heart?

Answer 22

increase SV and HR, thus CO is increased

Question 23

what effects TBG levels?

Answer 23

pregnancy and estrogen increase TBG

liver disease will lower TBG levels

Question 24

hyperthyroidism
possible diseases?
symptoms?

Answer 24

increase levels of TH in the blood

can have thyroid enlargement (graves)
overactive lump (plummer’s disease)
toxic goiter

symptoms: 
irritability 
weight loss
CHF in older people
palpations
amenorrhea
increased bowel movements (not loose) 
sweaty

Question 25

Graves disease
how?
symptoms?

Answer 25

autoimmune
more likely in females
due to antibody that mimics TH

symptoms: 
thyroid enlargement 
opthalmopathy 
pretibial myxedema 
low levels of TRH and TSH, but high TH

Question 26

hypothyroidism?

how? primary and secondary causes?

Answer 26

low levels of TH in the blood 
can be due to:
hashimoto's thyroiditis
thyroidectomy 
iodine deficiency 

secondary:
insufficient pituitary action
resistance to TH

Question 27

hypothyroidism in newborns?
how?
symptoms?

Answer 27

may be due to iodine deficiency
placental transfer of TSH antibody

symptoms? 
respiratory issues
jaundice
poor feeding 
reduction in bone development

Question 28

TH deficiency in children?

Answer 28

growth and mental disability

Question 29

adults with hypothyroidism? symptoms?

Answer 29

fatigue
cold intolerance
weight gain 
menstrual issues 
constipation 
dry skin 
bradycardia 
puffiness due to GAG accumulation