Physiology 2

Front 1

What are the three layers of the adrenal cortex?

Back 1

zona glomerulosa
zona fasciculata
zona reticularis

Front 2

This layer of the adrenal _______ produces mineralcorticoids: aldosterone/DOC:

Back 2

cortex, zona glomerulosa

Front 3

This layer of the adrenal _______ produces glucocorticoids: cortisol.

Back 3

cortex, zona fasciculata

Front 4

This layer of the adrenal _______ produces gonadocorticoids: androgens.

Back 4

cortex, zona reticularis

Front 5

Contains chromaffin cells secreting mainly epinephrine & small amounts of norepinephrine.

Back 5

adrenal medulla

Front 6

These cells of the adrenal medulla secrete mainly epi and small amounts of norepi:

Back 6

chromaffin cells

Front 7

All adrenal hormones are _________, made from __________.

Back 7

steroids, cholesterol

Front 8

Synthesis of Adrenal Cortex Hormones

The specific hormone that is ultimately secreted once ______________ is formed is determined by the enzymatic makeup of the particular cells involved.

Back 8

pregnenolone

Front 9

Adrenal steroid hormones are transported in blood bound to a specific plasma protein called __________ or ___________________ and to a lesser extent to albumin.

Back 9

transcortin, corticosteroid binding globulin (CBG)

Front 10

Like albumin, CBG (________________) is synthesized and secreted by the _____, but its concentration is only about 1000th that of albumin.

Back 10

corticosteroid binding globulin, liver

Front 11

About ___% of the glucocorticoids and about ___% of the aldosterone in blood are bound to protein. For this reason, adrenal steroids have a relatively long half-life in blood -- about 90 minutes for cortisol and about 30 minutes for aldosterone.

Back 11

95%, 60%

Front 12

The adrenal medulla is in effect a _________________ ganglion in which the post-ganglionic neurons have lost thier axons and become secretory cells.

Back 12

sympathetic

Front 13

The adrenal medulla cells secrete when stimulated by the pre-ganglionic neurons that reach the adrenal gland via the ___________ nerves.

Back 13

splanchnic

Front 14

These hormones are from the adrenal cortex and are essential for the maintenace of sodium balance and ECF volume.

Back 14

mineralcorticoids

Front 15

These are adrenal cortex hormones that have widespread effects on the metabolism of carbohydrates and proteins.

Back 15

glucocorticoids

Front 16

Secretion of glucocorticoids and sex steroids are mainly controlled by _____ from the ________.

Back 16

ACTH, anterior pituitary

Front 17

Mineralcorticoid secretion is subjected to independent control by substances in the circulation, of which the most important is _______________, a peptide formed in the ____________.

Back 17

agiontensin II, bloodstream

Front 18

The adrenal veins drain venous blood, but do so in an asymmetrical fashion. On the right side, the adrenal vein directly enters the ____________, whereas on the left, it usually drains into the _______________.

Back 18

inferior vena cava, left renal vein

Front 19

The adrenal medulla accounts for ________% of the mass of the adrenal gland.

Back 19

10-20%

Front 20

The rate-limiting step of steroid hormone biosynthesis is the conversion of the 27-carbon cholesterol molecule to the 21-carbon ___________ molecule.

Back 20

pregnenolone

Front 21

This is the common precursor of all steroid hormones produces by the adrenals as well as the gonads.

Back 21

pregnenolone

Front 22

The major glucocorticoid in humans is _______. Its secretion is strongly stimulated by ____ from the ________.

Back 22

cortisol, ACTH, anterior pituitary

Front 23

Basal secretion of ACTH follows a ________ rhythm driven by the ____.

Back 23

diurnal (Activity is defined at certain parts of the day), CRH

Front 24

Activity is defined at certain parts of the day

Back 24

diurnal

Front 25

Although named for their critical role in maintaining carbohydrate reserves, _____________ produce a number of diverse physiological actions, many of which are still not well understood. Virtually every tissue of the body is affected by an excess or deficiency of _________. If any simple phrase could describe the role of __________, it would be "coping with _______". Even if carbohydrate intake were adequate, individuals suffering from adrenal insufficiency would still teeter on the brink of disaster when faced with a threatening situation.

Back 25

glucocorticoids, glucocorticoids, glucocorticoids, adversity

Front 26

Physiological Effects of Glucocorticoids Effects on Metabolism
- 3 things -

Back 26

-Increased protein catabolism (proteolysis)
-Increased lipolysis
-Increased gluconeogenesis by the liver

Front 27

The bottom line is that _________ protects against hypoglycemia by increasing glucose production by the liver, increasing protein breakdown and elevating FFA levels.

Back 27

cortisol

Front 28

Many of the effects of cortisol serve to generate high levels of precursors for ________________. This should make sense considering how cortisol is referred to a hormone that protects us in the face of stress. However, this also means that cortisol confers a tendency to hyperglycemia and decreased carbohydrate tolerance, which can cause problems (e.g. -- for patients with diabetes mellitus who are placed on high doses of glucocorticoids).

Back 28

hepatic gluconeogenesis

Front 29

__________ is needed to maintain normal vascular integrity and responsiveness. In the absence of ________, abnormal ______________ occurs, so that even without an external loss of fluid, the filling of the vascular bed is reduced and blood pressure falls.

Back 29

cortisol, cortisol, vasodilation

Front 30

Normal _____ function requires cortisol. In its absence, glomerular filtration rate _____ and water cannot be excreted as rapidly.

Back 30

renal, falls

Front 31

Cortisol also has a ________________ effect that is partly responsible for normal sodium retention and potassium excretion. Although aldosterone is some 300-600 times more potent a ___________ than cortisol, under normal circumstances 200 times more cortisol than aldosterone is secreted. Therefore, a substantial part of overall _____________activity is derived from cortisol.

Back 31

mineralcorticoid, mineralcorticoid, mineralcorticoid

Front 32

When blood pressure is reduced, the ___________________ mechanism is activated to stimulate aldosterone secretion and not cortisol. Thus, when extra mineralocorticoids are needed, aldosterone and not cortisol serves that function.

Back 32

renin-angiotensin-aldosterone

Front 33

_____________ inhibit the inflammatory response to tissue injury by inhibiting the production of many inflammatory mediators such as histamine, cytokines, leukotrines and prostaglandins. This effect requires high levels of circulating ______________ and cannot be produced by administering steroids without producing the other manifestations of ____________ excess. However, local administration of ________________ -- e.g. by injection into an inflamed joint or near an irritated nerve-- produces a high local concentration of the steroid, often without enough systemic absorption to cause serious side effects.

Back 33

Glucocorticoids, glucocorticoids, glucocorticoids, glucocorticoids

Front 34

The actions of _____________ in patients with bacterial infections are dramatic but dangerous. Not only does cortisol decrease the formation of inflammatory mediators, but it also decreases the migration of many ___ to sites of injury. This is also a major mechanism of the anti-inflammatory actions of cortisol, BUT it also increases the susceptibility to infection that can occur following chronic secretion of cortisol or chronic exogenous administration.

Back 34

glucocorticoids, WBCs

Front 35

_________ are the hormones that exert masculinizing effects, and they promote protein anabolism and growth.

Back 35

Androgens

Front 36

Testosterone from the testes is the most active androgen, and the adrenal androgens (_______________ and _______________) have less than 20% of its activity.

Back 36

androstenedione & DHEA- dehydroepiandrosterone

Front 37

Secretion of the adrenal androgens is controlled by ______, but not by the ________ (FSH & LH). The plasma level of DHEA peaks around age 25 in normal men and women and declines steadily thereafter to low values in old age. The secretion of adrenal androgens is nearly as great in castrated males as it is in normal males, so it is clear that these hormones exert very little masculinizing effects when secreted in normal amounts. However, they can produce appreciable masculinization when secreted in excessive amounts. In adult males, excess adrenal androgens merely accentuate existing characteristics; but in prepubertal boys, they can cause sex characteristics without testicular growth (______________). In females, they cause female _____________ and adrenogenital syndrome.

Back 37

ACTH, gonadotropins, precocious pseudopuberty, pseudohermaphroditism

Front 38

The adrenal androgen ________ is converted to testosterone and to estrogens in the circulation. It is an important source of estrogens in men and postmenopausal women.

Back 38

androstenedione

Front 39

Aldosterone is the primary _____________. The major function of aldosterone is to control body fluid volume by increasing the reabsorption of ___________ by the kidneys. At the same time, aldosterone also promotes the excretion of _____ via the kidneys.

Back 39

mineralcorticoid, sodium, potassium

Front 40

The stimulus for aldosterone secretion originates in the kidneys when cells in the _______________ synthesize and secrete renin into the blood.

Back 40

juxtaglomerular (JG) apparatus

Front 41

_____ secretion is stimulated by such things as sodium depletion, hypotension, hemorrhage and dehydration.

Back 41

Renin

Front 42

What is produced by the juxtaglomerular (JG) apparatus?

Back 42

renin

Front 43

The kidneys posses __________________ that sense changes in blood pressure.

Back 43

intrarenal baroreceptors

Front 44

In the blood, renin splits off ________________ from its substate ____________, a protein synthesized by the liver. __________ is biologically inactive but is rapidly converted into the active compound _______________ by the action of ___________________________.

Back 44

angiotensin I, angiotensinogen, angiotensin I, angiotensin II, angiotensin converting enzyme (ACE)

Front 45

Most of the ACE that forms angiotensin II in circulation is located in __________ cells. Much of the conversion occurs as blood passes through the ________, but there is also conversion in many other parts of the body.

Back 45

endothelial, lungs

Front 46

__________ cells line the entire circulatory system, from the heart to the smallest capillary

Back 46

Endothelial

Front 47

Angiotensin II exerts two major actions, one as a direct arteriolar ______________ and the other as a stimulus to ___________ secretion.

Back 47

vasoconstrictor, aldosterone

Front 48

_____________ are a class of anti-hypertensive drugs that block the conversion of angiotensin I into angiotensin II. Examples of ACE inhibitors include captopril and enalapril. Another class of anti-hypertensives is the angiotensin II receptor blockers, such as losartan.

Back 48

ACE inhibitors

Front 49

__________ specifically refers to a tumor in the pituitary gland that stimulates excessive release of cortisol from the adrenal gland by releasing large amounts of ACTH.

Back 49

Cushing's disease

Front 50

Symptoms include rapid weight gain, particularly of the trunk and face with sparing of the limbs (central obesity), a round face often referred to as a "moon face", excess sweating, telangiectasia (dilation of capillaries), thinning of the skin (which causes easy bruising) and other mucous membranes, purple or red striae (also caused by thinning of the skin) on the trunk, buttocks, arms, legs or breasts, proximal muscle weakness (hips, shoulders), and hirsutism (facial male-pattern hair growth). A common sign is the growth of fat pads along the collar bone and on the back of the neck (known as a buffalo hump). The excess cortisol may also affect other endocrine systems and cause, for example, reduced libido, impotence, amenorrhoea and infertility. Patients frequently suffer various psychological disturbances, ranging from euphoria to frank psychosis. Depression and anxiety, including panic attacks, are common.

Other signs include persistent hypertension (due to the aldosterone-like effects) and insulin resistance, leading to hyperglycemia (high blood sugars) which can lead to diabetes mellitus. Untreated Cushing's syndrome can lead to heart disease and increased mortality. Cushing's syndrome due to excess ACTH may also result in hyperpigmentation of the skin, due to its ability to stimulate melanocyte receptors.

Back 50

Cushing's disease

Front 51

intentional exogenous administration of hormone

Back 51

Iatrogenic

Front 52

A rare endocrine disorder in which the adrenal gland produces insufficient amounts of steroid hormones (glucocorticoids and often mineralocorticoids). It may develop in children as well as adults, and may occur as the result of a large number of underlying causes.

Back 52

Addison's disease

Front 53

____ is a 39-amino acid peptide hormone processed from a large precursor molecule, pro-opiomelanocortin (POMC). Within the corticotropes, a single mRNA directs the synthesis and processing of POMC into smaller biological active fragments which include b-LPH, a-MSH and b-endorphin. ACTH is the only product of POMC whose physiological role is clearly established in humans.

Back 53

ACTH

Front 54

Tumor of adrenal medulla: epi and norepi
Interesting tumors: waxing and waning up dumping of epi and norepi – exagerated SNS response. High BP, HR, sweat a lot.

Back 54

Pheochromocytoma

Front 55

A neuroendocrine tumor of the medulla of the adrenal glands originating in the chromaffin cells, which secretes excessive amounts of catecholamines, usually adrenaline and noradrenaline (epinephrine and norepinephrine in the US

Back 55

Pheochromocytoma

Front 56

Originally thought to come from the brain. Unique marker in blood, elevations can indicate CHF. Can cause Na loss but main stimulus is volume expansion.

Back 56

B-type natriuretic peptide (BNP)

Front 57

Recently, a hormone produced by the ventricles of the heart, ______________ has been shown to increase in response to ventricular volume expansion and pressure overload.

Back 57

B-type natriuretic peptide (BNP)

Front 58

______ is a marker of ventricular systolic and diastolic dysfunction. This test is useful in diagnosing congestive heart failure. It is not useful for diagnosing other heart conditions.

Back 58

B-type natriuretic peptide (BNP)

Front 59

_____________ is a protein hormone synthesized and secreted by the muscle cells in the atria (and to a much lesser extent in the ventricles) of the heart.

Back 59

Atrial natriuretic peptide (ANP)

Front 60

Increases in blood volume and blood pressure as well as increases in plasma sodium stimulate the secretion of ______.

Back 60

Atrial natriuretic peptide (ANP)

Front 61

Opposite of aldosterone.

Back 61

Atrial natriuretic peptide (ANP)

Front 62

-stimulates urinary excretion of Na+ by inhibiting Na+ reabsorption

Back 62

Atrial natriuretic peptide (ANP)

Front 63

-stimulates a diuresis
relaxes smooth muscle of arterioles
-inhibit renin release
inhibits ADH release from the posterior pituitary

Back 63

Atrial natriuretic peptide (ANP)