Section 4-adrenal gland

Question 1

what hormone does zona glomerulosa produce and what is its function

Answer 1

aldosterone

• Recovery of Na+ in the kidney and enhanced K+secretion into the urine to balance charge difference
• Therefore, adjustment of extra-cellular fluid (ECF), including blood volume

Question 2

how physical attributes in homeostasis of blood correpsond to the control mechanisms of the system

Answer 2

Question 3

physiological changes that influence postively and negatively sodium appetite

Answer 3

and also thirst

Question 4

what is the primary resource to restire Na balance ( thirst of sodium appetite)

Answer 4

At first thirst increases and if it is not enough, then sodium increased

Question 5

what is the major determinant of the blood pressure

Answer 5

The diameter of arterioles (artery, arterioles, capillaries) is a major determinant of the
blood pressure in the arteries and controls the
distribution of the blood supply to tissues

Question 6

describe RAAS

Answer 6

v Renin from afferent arterioles in kidney
converts angiotensinogen to angiotensin I
v ACE from endothelial cells of lungs
converts angiotensin I to angiotensin II
v angiotensin II stimulates aldosterone
secretion

Question 7

does ACTH influence aldosterone secretion

Answer 7

Modest effect

Question 8

Angiotensin II function

Answer 8

v increases Na+ absorption and K+ excretion
v Water retention, higher blood pressure

Question 9

is angiotensin is secrted somewhere else int he body except kidney-liver-lung

Answer 9

Renin also found in the brain. Local
production of angiotensin II ? Induction of
thirst?

not sure about the answer

Question 10

what cells secrete renin

Answer 10

Juxtaglomerular cells

Question 11

what juxtaglomerular apparatus sence

Answer 11

v Macula densa cells detect Na+ levels in kidney tubule
v Juxtagolomerular cells detect blood pressure

Question 12

aldosterone is under the main influence of

Answer 12

RAAS

Question 13

how angiotensin is disactivated

Answer 13

Question 14

renin secretion is stimulated by

Answer 14

decreased renal arterial pressure

decreased sodium in renal tubualr fluid

increased renal sympathetic nerve activity

Question 15

what 2 destinies angiotensin II has

Answer 15

Question 16

angiotensin II can have 3 types of responses (speed)

Answer 16

rapid

slow

remodeling

Question 17

describe acute effects of angiotensin II

Answer 17

Sympathetic nervous system stimulation causes vasoconstriction of most blood vessels

Question 18

slow response of angiotensin II

Answer 18

Question 19

what does it mena that angiotensin II have remodeling effects

Answer 19

Question 20

how aldosterone functions

Answer 20

aldosterone through TF influence->action on structural protein of Na transport ( into the cells) and increasing regulatory proteins-kinases (SGK and K-Ras) that induces K-Na-ATPase

Question 21

sodium transport happens in

Answer 21

vNa+ transport in
vdistal tubules of kidney
vcolon
vSalivary and Sweat glands

aldosterone will influence all of them

Question 22

function of aldosterone on the distal tubule cells

Answer 22

Aldosterone activates apical channels and more Na gets into the cell, so more Na-K ATPase

• Na-K-ATPase , which keeps a particular voltage -60 mV),, will shuttle K from blood to the lumen of the distal tubule
• Because Na coming in, aquaporin open and leads to reabsoprtion of water ( increased volume and Na)

Question 23

aldosterone acts mainly on what types of cells

Answer 23

v Mainly: Distal tubules and collecting ducts of the kidney.
v Also on other secretory systems (sweat glands, salivary glands,colon)

Question 24

summarize what does aldosterone do what is the net effect and what is a lag period of aldosterone

Answer 24

v Promotes plasma retention of Na+ and excretion of K+
and H+ into the lumen of the tubules
v Sensitizes arterioles to vasoconstrictor agents (to modulate activity of catecholamines ,for example)
v Net effect: Rise in plasma volume and hence blood
pressure
v Response has a lag period of 1h, reflecting that
aldosterone induced enzymes have to be synthesized
de novo

Question 25

what is conn's syndrome

Answer 25

Hypersecretion of aldosterone usually caused by adrenal hyperplasia (60 %) or tumor (40%)

Question 26

what is happening in conn's syndrome

Answer 26

* vExcess excretion of K+ and H+ * vSerum alkalosis and neuropathy (hypocalcemia) * Increased water retention * Increased Na reabsorption * Increased blood pressure

Question 27

what are natriuretic peptides

Answer 27

peptides that increase the excretion of H2O and Na produced in the heart muscle and stored in granules

Question 28

How natriuretic peptides function and where the receptors for it are

Answer 28

* Receptors are present in the glomeruli, medullary collecting ducts of the kidney, the zona glomerulosa of the adrenal cortex and in peripheral arterioles * v Increases glomerular filtration * v Reduces blood volume and pressure

Question 29

where do sex steroids are normally synthesized and what role kidneys play in it

Answer 29

* Sex steroids are mainly synthesized in the gonads (Females: estrogens and progestogens; Males: androgens) –regulated by gonadotrophins * v Adrenal cortex (mainly zonareticularis) contributes to the production of DHEAS and androstenedione – regulated by ACTH and hypothalamic CRH. * v Can be converted to testosterone in peripheral tissues.

Question 30

what is the role of sex steroids produced in adrenal gland

Answer 30

Role not entirely clear. Important for body hair growth in females . v Responsible for growth spurt in middle childhood (adrenarche) -Adrenarche occurs independently of an increase of estrogens, androgens, or gonadotropins associated with puberty

Question 31

what is congenital adrenal hyperplasia

Answer 31

Excessive androgen production-\> Masculinization of genitalia

Question 32

explain what hormally happens during congention and why there is CAH

Answer 32

Question 33

what defect in the organism happens that causes congenital adrenal hyperplasia

Answer 33

Question 34

why congenital adrenal hyperplasia occur, is it frequent , how treated

Answer 34

Frequency of classical CAH 1:13000 in general population v Both copies of 21-hydroxylase (P450c21) mutated v Many mutations result in partial loss of function v And masculinization is not as extreme v Trt: surgical correction at birth

Question 35

total mass of medulla is

Answer 35

1 g

Question 36

how adrenal medulla get its tasks

Answer 36

* vAdrenal medulla and chromaffin cells are part of the sympathetic nervous system (CNS) * vCoordinate fight-flight response to alarm by increasing b. p. and cardiac output, and dilating pupils * vPreganglionic neurons release acetylcholine to stimulate medulla cells to release hormones (catecholamines)

Question 37

2 types of catecholamines synthesized in medulla, the pathway, what is the rate limiting step, how epinephrine is converted to noreponephrine and what is the proportion of epinephrine to norepinephrine

Answer 37

* Catecholamines (norepinephrine and epinephrine) synthesized from tyrosine * Hormones in the adrenal medulla are released in response to appropriate stimuli * 80 % of released catecholamines are epinephrine to 20 % norepineprine * tyrosine-\> dopamine-\>norepinephrine

Question 38

how epineprine and norpinephrine are disactivated

Answer 38

Inactivated by monoamine oxidase (MAO) and COMT (catechol-O-methyltransferase) pathways

Question 39

what other hormones are secreted from medulla (apart from adrenalin and noradrenalin)

Answer 39

vGranules also contain met-enkephalin and and leu-enkephalin (related to endorphins). vThey are co-excreted with the catecholamines vEnkephalins may block neurotransmitters (like morphine) v act as an endogenous analgesics (runners overcoming pain and being euphoric)

Question 40

how fight-or-flight response function

Answer 40

Question 41

what are acute effects of adrenalin and noradrenalin

Answer 41

Acute: integrated adjustment of many complex processes in organs vital to the response (e.g., brain, muscles, cardiopulmonary system, liver)

Question 42

actiovation of organs during fight-or flight happens at the expense of

Answer 42

Occurs at the expense of other organs less immediately involved (e.g., skin, GI).

Question 43

what is epinephrine and noradrenalin role in the body

Answer 43

* Epinephrine: rapidly mobilizes fatty acids as the primary fuel for muscle action 1. v increases muscle glycogenolysis 2. v mobilizes glucose for the brain by increasing hepatic glycogenolysis and gluconeogenesis 3. v preserves glucose for CNS by decreasing insulin release leading to reduced glucose uptake by muscle/ adipose 4. v Increases cardiac output * v Norepinephrine elicits responses of the CV system - increasing blood flow and decreasing insulinsecretion.

Question 44

what receptors bind to adrenalin and noradrenalin

Answer 44

vα and β1 receptors bind epinephrine and norepinephrine. β2 receptors bind primarily epinephrine (GPCR)

Question 45

what is the drug salbutamol and what is it used for

Answer 45

Salbutamol activates β2 receptors and dilates bronchioles (relief of asthma); but does not affect beta1 receptors in the heart.

Question 46

aplha, beta 1 and 2: potency for e and NE, action and target tissue/cells

Answer 46

Question 47

differences between epinephrine and NE

Answer 47

v Epinephrine \>\> norepinephrine – in terms of cardiac stimulation leading to greater cardiac output (b stimulation) v Epinephrine \< norepinephrine – in terms of constriction of blood vessels – leading to increased peripheral resistance – increased arterial pressure v Epinephrine \>\> norepinephrine –in terms of increasing metabolism

Question 48

adrenomedullary deficiency can happen due to

Answer 48

surgery, trauma.etc. v Also if cortisol levels are suppressed for any reason (high concentration of cortisol req’d for transcription of PNMT) resulting in epinephrine deficiency

Question 49

adrenomedullary disorders can happen due to

Answer 49

Hypotension, hypoglycemia (CNS and glucocorticoids are more susceptible)

Question 50

can we live without E and NE

Question 51

what is pheochromocytoma

Answer 51

tumor overproducing catecholamines

Question 52

what is the prevalence of pheochromocytoma and its symptoms

Answer 52

Relatively rare but often not diagnosed until autopsy (about 200-1000 per million) and about 1/3 cause death prior to diagnosis • headache • hypertension • sweating • palpitations • chest pain • anxiety • glucose intolerance • increased metabolic rate