Adrenal Gland

what is secreted in the adrenal medulla

epinephrine and norepinephrine are secreted whenever the sympathetic nervous system is activated

gonadocorticoids include both

estrogens (female sex hormones) and androgens (male sex hormones)

epinephrine and fat breakdown

fat breakdown is increased, skeletal muscles are tensed, and renin secretion from the kidney is increased

cortisol is considered as a

glucocorticoid

cortisol

glucocorticoids- produced by zona fasciculate, the middle layer, and the zona reticularis, the deep layer

epinephrine increases

heart rate, coronary blood flow, blood pressure, and respiration rate (improving cardiac function)

principle action of glucocorticoids

help promote normal metabolism, resistance to stress and counter inflammatory response

effect of cortisol

helps to keep blood glucose concentration within a normal range between meals

used for the relief of itching and inflammation caused by a wide variety of skin conditions (eg. insect bites, allergic reactions, and eczema)

hydrocortisone cream

cushing's disease

hyperfunction of the adrenal cortex

negative feedback by cortisol is on both the

pituitary and hypothalamus

adrenal medulla is stimulated by

preganglionic neurons directly, so controlled by the hypothalamus as if part of the autonomic nervous system, NOT by tropic hormones from pituitary

what is the precursor to all corticosteroid

prenenolone

secondary hypersecretion due to pituitary problem

CRH low ACTH high Cortisol high

testoserone

androgens- also produced by zona fasciculate and zona reticularis

adrenal medulla hormones

epinephrine norepinephrine

three initiating reasons different reasons need to be treated using different methods

1. secondary hypersecretion due to hypothalamic problem 2. secondary hypersecretion due to pituitary problem 3. primary hypersecretion due to problem with adrenal cortex

cortical hormone action has a lag time of at least

30 minutes

how much do adrenal glands weigh?

4 grams

secretion of cortisol is controlled almost entirely by

ACTH from the anterior pituitary

glucocorticoid control of secretion

ACTH is released in response to stress and low blood levels of glucocorticoids

primary hypersecretion due to problem with adrenal cortex

CRH low ACTH low Cortisol high

secretion of ACTH is controlled by

CRH from the hypothalamus

secondary hypersection due to hypothalamic problem

CRH levels high ACTH levels high Cortisol levels high

long term stress response

Mineralcorticoids: retention of sodium and water by kidney increase blood vol and BP Glucocorticoids proteins and fats converted to glucose or broken down for energy increased blood sugar suppression of immune system

the adrenal medulla acts like

a part of the sympathetic nervous system

the adrenal medulla secretes which hormones?

epinephrine and norepinephrine (Catecholamines) in response to sympathetic stimulation

the kidney is the target organ for what?

aldosterone

cortex three layers

aldosterone (mineralcorticoids) cortisol glucocorticoids) testosterone (androgens)

why is cortisol secreted?

almost any type of stress will cause an immediate and marked increase in CRH secretion by hypothalamus and ACTH secretion by the anterior pituitary gland, followed by greatly increased adrenocortical secretion of cortisol

tumors of the adrenal cortex cause an overproduction of

androgen hormones that produce secondary sexual character, for example, the appearance of heavy facial hair on a woman.

The two adrenal glands lie where

at the superior poles of the kidneys

mechanisms of reabsorption of sodium by kidney

basolateral membrane and luminal membrane

epinephrine does what with the sphincter?

causes contraction in the digestive system and urinary systems (slow down the functions of these two systems)

corticosteroid are all formed from the basic unit of

cholesterol

principle action of gonadocorticoids

concentrations secreted by adults are very low

aldosterone acts on the kidney to

decrease sodium excretion decrease water excretion increase potassium excretion

mineralcorticoid control of secretion

decreased blood volume or sodium level initiate renin-angiotensin pathway to stimulate aldosterone secretion; increased blood levels of potassium stimulate aldosterone secretion. ACTH has a minor effect in promoting aldosterone secretion

when aldosterone acts on the kidney to decrease sodium excretion, decrease water excretion, and increase potassium it results in

decreases plasma levels of potassium increase effective circulating volume increase extracellular fluid volume increase blood pressure

too much cortisol will induce

diabetes

cushing's disease 10-15 million of every million people

hyperfunction of the adrenal cortex-hypersecretion of cortisol too much of a good thing: upper body obesity, "central obesity"; rounded face, "moon face"; increased fat around the neck, "buffalo hump" thinning arms and legs; weakened skin; severe fatigue; weak muscle; high blood pressure and high blood glucose

addison's disease 1 in 100,00 people

hypofunction- of the adrenal cortex-hyposecretion of cortisol and sometimes aldosterone: weight loss; muscle weakness; fatigue; low blood pressure

short term stress --- from diagram

hypothalamus --> nerve impulses---> spinal cord --> preganglionic sympathetic fibers --> adrenal medulla ---> catecholamines (epi and norepinephrine)

combat stress

increase availability nutrients for energy increase susceptibility of blood vessels to constriction reduce inflammation

principal action of mineralcorticoids

increase plasma levels of sodium and water and decrease plasma levels of potassium

action of aldosterone on the renal tubule

increase the formation of Na+ -K+ -ATPase at the basolateral membranes of the renal tubular cells increase the formation of sodium channels at the luminal membranes of the renal tubular cells

short term stress response

increased heart rate increased blood pressure liver converts glycogen to glucose and releases glucose to blood dilation of bronchioles changes in blood flow patterns leading to increased alertness and decreased digestive and kidney activity increased metabolic rate

cortisol increases amino acid concentration in the blood by

inhibiting protein synthesis in select tissues

adrenal cortex is essential for

life-- if removed or damaged severely, death occurs unless hormones are replaced artificially

what does aldosterone do?

maintains blood volume by regulating renal sodium reabsoprtion in the kidney. Aldosterone also regulates renal potassium excretion

aldosterone is necessary to maintain

mineral balance for sodium and potassium

aldosterone

mineralcorticoids -- produced by zona glomerulosa, the outermost layer

adrenal cortex hormones

mineralocorticoids (aldosterone) glucocorticoids (cortisol) gonadocorticoids (androgen)

adrenal medullae are actually

modified sympathetic ganglia

is the adrenal medulla required for survival?

no- as long as the rest of the sympathetic nervous system is intact.

adrenal medulla secretes two amines

norepinephrine 20% epinephrine 80%

All the target organs of sympathetic nerve can receive the control of

norepinephrine from adrenal medulla

adrenal androgens mediate some changes which occur in

puberty, but for the most part the secretion of adrenal sex hormones are insignificantly small compared to the amounts produced from the ovaries or testes

long term stress-- from diagram

releasing hormone --> cortricotrope cells of anterior pituitary --> adrenal cortex--> mineralocorticoids or glucocorticoids

epinephrine decreases

skin blood flow - (blood redistribution)

the adrenal medulla neurotransmitters and target receptors:

somatic nervous system: acteylcholine (N1) receptor parasympathetic nervous system: acetylcholine (M) receptor sympathetic nervous system: norepinephrine (alpha and beta receptors) adrenal medulla: epinephrine and norepinephrine (alpha and beta receptors)

all of the hormones synthesized by the adrenal cortex are from

steroid cholesterol, and they all have similar chemical formulas.

anti inflammatory

suppresses immune system function

epinephrine control of secretion

sympathetic nervous system SNA

norepinephrine control of secretion

sympathetic nervous system SNS

principle action of norepinephrine

sympathomimetic that is, produces effects that mimic those of SNS during stress

principle actions of epinephrine

sympathomimetic that is, produces effects that mimic those of SNS during stress

the hormones secreted by the adrenal medulla are

sympathomimetic- that is, the actions of adrenal medulla hormones "mimic" sympathetic nervous system activation

at the luminal membrane of the renal tubular cells what happens?

the Na+ diffuses from distal tubular urine into the cytoplasm via the Na+ channels. The K+ permeates from the cytoplasm into the distal tubular urine.

aldosterone is produced by

the adrenal cortex -- zona glomerulosa

each adrenal gland is composed of two distinct parts

the adrenal medulla, and the adrenal cortex

adrenal medulla

the central 20% of the gland, is functionally related to the sympathetic nervous system.

cortisol stimulates

the liver to sythesize glucose (not from carbs, but from amino acids and glycerol) called gluconeogenesis.

during a stressful situation which hormones released take effect in seconds?

the medullary hormones

adrenal cortex

the peripheral 80% of the gland, secretes entirely different group of steroid hormones, called corticosteriods.

aldosterone is secreted in response to

the renin angiotensin pathway stimulates aldosterone secretion (renin angiotensin aldosterone system) ACTH has a effect in promoting aldosterone secretion increased plasma potassium (major effect) decreased blood plasma (also for ADH) decreased plasma sodium

at the basolateral membranes of the renal tubular cells what happens?

the sodium potassium adenosine triphosphatase (Na+ -K+ -ATpase) pump the Na+ from cytoplasm into the blood, at the same time the K+ from blood into cytoplasm

if you're a smoker what does nicotine stimulate?

the sympathetic nervous system and causes a slight increase in epinephrine release. This increase dulls the hunger sensation

the adrenal cortex is divided into three layers and manufactures

three kinds of steroid hormones (corticosteroids)

T/F in response to stress, the cortex and medulla are often both activated

true

cortisol promotes

use of fat for energy production in our bodies (rather than glucose)

symptoms of cushing's disease

weight gain, buffalo hump, central obesity, moon face, purple striae, infection