13.2 Flashcards
Where are the adrenal glands located?
Where are the adrenal medulla and adrenal cortex found?
on top of the kidneys.
Adrenal medulla- inner adrenal gland
adrenal cortex- outer adrenal gland
What does adrenal medulla secrete compared to adrenal cortex?
adrenal medulla: epinephrine and norepinephrine
adrenal cortex: cortisol[glucocorticoid] and aldosterone[mineralcorticoid]
What are Catecholamines?
-derived from tyrosine: epinephrine and norepinephrine
-made by the adrenal medulla
-secreted in response to the synpathetic system
Explain the receptors that epinephrine binds to
Explain overall function
-epinephrine can bind to α receptors on the smooth muscle of blood vessels, can contract vessels and reduce blood glow to peripheral regions like skin
-epinephrine can bind to β1 on heart cells, can contract and increase blood flow
-epinephrine can bind to β2 on liver cells and can stimulate glycogen to glucose
Function: increase energy
Besides those receptors of epinephrine what other function does it have?
-reduce blood flow to kidneys and reduce water loss
-Inhibits smooth muscle contraction in intestine and slows digestive system
Norepinephrine can bind to what receptors in the heart muscle?
In the heart muscle, the receptors for norepinephrine are β andrenergic receptors.
What are the hormones of the adrenal cortex?
-glucocorticoids
-mineralocorticoids
-androgens
-cortisol
Explain the function of glucocorticoids
-type of hormones of the adrenal cortex
-maintain normal blood glucose levels
-stimulated glucose synthesis from fats + proteins
-inhibition of glucose intake
-breakdown of fats + protein as energy source instead of glucose
Explain function of mineralocorticoids
–type of hormones of the adrenal cortex
-regulate Na+ and extracellular fluid volume
ex: aldosterone
Example: Aldosterone
What is the function of aldosterone?
-increase Na+ absorption and release K into the kidney
-part of renin-angiotensin system
-result: increase in blood volume and bp
What is the renin-angiotensin system
Renin: enzyme that converts a protein to angiotensin
Angiotensin: peptide hormone that raises blood pressure by constricting blood vessels and stimulating the release of aldosterone.
Renin-angiotensin system
If there is low blood volume, what does the kidney secrete?
renin becomes-> angiotensin I -> angiotensin II-> aldosterone secreted from adrenal cortex
Result: increased water absorption, increase volume of fluid
Angiotensin II ->blood vessels to constrict ->increased blood pressure
What are androgens?
–type of hormones of the adrenal cortex
-control male characteristics
What is cortisol
-type of hormone of the adrenal cortex
-type of glucocorticoid, increase bp
ACTH
ACTH stimulates the adrenal cortex (the outer part of the adrenal glands) to produce and release glucocorticoids, such as cortisol.
Explain the feedback mechanism involving the adrenal cortex
1)Either low glucose levels or epinephrine release
2) + feedback on hypothalamus
3) The hypothalamus releases corticotropin-releasing hormone
4) + feedback on anterior pituitary
5) release of ACTH to the adrenal cortex, + feedback
6) The adrenal cortex releases glucorticoids which has negative feedback on everything
Islets of Langerhans
(in pancreas)
release what two hormones
Insulin: secreted by beta cells, lowers blood glucose levels by stimulating the storage of glucose as glycogen in the liver and muscle.
Glucagon: secreted by alpha cells, raised blood glucose by degrading other sources like fat + protein
Function: regulate blood glucose levels
Diabetes mellitus
Results because of low insulin
Symptoms:
-frequent urination
-Increase in thirst
-Increase appetite
Difference in type I and II of diabetes mellitus
Type 1: autoimmune disease that destroys pancreatic beta cells aka insulin, need insulin injections
Type II: cells less receptive to insulin, can’t properly take it up
neurogenic DI,
caused by a deficiency of antidiuretic hormone (ADH) + an insensitivity of the kidneys to ADH
