Adrenal Gland

Describe the Adrenal gland.

Important in governing bodily responses to stress, composed of two tissues that produce two classes of hormones.

Where is the adrenal steroidogenic tissue located?

Adrenal cortex.

Where is the adrenal chromaffin (center) tissue located?

Adrenal medulla.

The adrenal gland is located...

on top of the kidneys.

In what year did Meckel discover the gross anatomy of the adrenals?

1815

In what year did Ecker discover the histology and the microscopic anatomy of the adrenal medulla and cortex?

1846

In what year did Kölliker discover that the cortex and medulla were functionally different?

1854

In what year did Addison describe a disease involving degeneration of the adrenals (Addison's disease)?

1855

In what year did Brown-sequard study the effects of adrenalectomy? Glands are necessary for life.

1856

In what year did Baumann and colleagues discover that the adrenal cortex extracts as replacement therapy for adrenalectomized animals and patients with Addisons disease>

1928-1931

In what year did Long and colleges discover the adrenal cortex was important for CHO metabolism?

1940

In what year did scientists discover that there were at least 6 active and more than 20 inactive steroids extracted from the adrenal cortex. (greatest biological activity: 11-dehydrocoricosteron, corticosterone, cortisone, and hydrocortisone (cortisol)).

1945

In what year did scientists establish that cortisol is the major steroid hormone released to ACTH?

1951

Adrenal corticotropin is secreted from...

The anterior pituitary responds to being stimulated by CRH from the hypothalamus.

CRH binds to receptors on the corticotrophin cells...

secreted from the pituitary and causes synthesis and secretion from the adrenal cortex, causing the synthesis and secretion of cortisol.

Describe the adrenal gross/microscopic anatomy.

Located above the kidneys, it can be divided into the medulla and cortex. The medulla can be broken down from outside to inside: capsule --> zona glomerulosa--> zona fasciculata --> zona reticularis --> adrenal medulla.

The cells of the adrenal medulla are...

modified ganglion cells (respond to the peripheral nervous system).

Modifeed ganglion cells are referred to as...

"chromaffin tissue" because the fine granules stain with chromate salt.

Peripheral nervous system includes...

anything outside of the brain and the spinal cord.

Chromaffin cells (of the adrenal medulla) contain granules composed of...

catecholamines, ATP, proteins, and lipids. They serve to store things.

What are the Catecholamines?

The big picture class of hormones secreted from the adrenal medulla, include: Dopamine, Norepinephrine, Epinephrine

Describe the pathway of catecholamine Biosynthesis.

Tyrosine enters a cell, and an enzyme converts it into DOPA, which is then converted to dopamine. Dopamine enters a chromaffin granule; it is then converted to norepinephrine and transported out of the granule. It can then be converted to epinephrine and transported out of the cell.

What are the main adrenal medulla hormones?

Epinephrine, Norepinephrine, and Catecholamines.

What are the main differences between Epinephrine and Norepinephrine hormones?

The chemical difference is an additional methyl group on epinephrine. Hormone action is very rapid but brief.

What effect does epinephrine have on cardiac output (Increase or decrease)?

Increase

What effect does epinephrine have on Heart rate (Increase or decrease)?

Increase

What effect does epinephrine have on blood flow to the coronary artery (Increase or decrease)?

Increase

What effect does epinephrine have on blood flow to the skeletal muscle(Increase or decrease)?

Increase

What effect does epinephrine have on blood flow to the liver (Increase or decrease)?

Increase

What effect does epinephrine have on blood flow to the brain (Increase or decrease)?

Increase

What effect does epinephrine have on blood flow to the skin (Increase or decrease)?

Decrease

What effect does epinephrine have on blood flow to the kidney (Increase or decrease)?

Decrease

What effect does epinephrine have on bronchial tone (Increase or decrease)?

Decrease

What effect does epinephrine have on erectorpilae (Increase or decrease)?

Increase

What effect does epinephrine have on skeletal muscle (Increase or decrease)?

Increase

What effect does epinephrine have on intestinal sphincters (Increase or decrease)?

Increase

What effect does epinephrine have on Intestinal Wall (Increase or decrease)?

Decrease

What effect does epinephrine have on Blood sugar (Increase or decrease)?

Increase

What effect does epinephrine have on O2 Consumption (Increase or decrease)?

Increase

What effect does epinephrine have on Glycogenolysis (Increase or decrease)?

Increase

What effect does epinephrine have on Glycosuria (Increase or decrease)?

Increase

What effect does epinephrine have on Fatty Acid Release from Fat (Increase or decrease)?

Increase

What effect does epinephrine have on sweating (Increase or decrease)?

Increase

What effect does epinephrine have on contraction of spleen (Increase or decrease)?

Increase

What effect does epinephrine have on blood coagulation increase (Increase or decrease)?

Increase

What effect does epinephrine have on ACTH output increase (Increase or decrease)?

Increase

What effect does epinephrine have on Anxiety (Increase or decrease)?

Increase

What effect does norepinephrine have on heart rate (Increase or decrease)?

Increase and then decrease

What effect does norepinephrine have on blood flow to the coronary artery (Increase or decrease)?

Increase

What effect does norepinephrine have on blood flow to the brain (Increase or decrease)?

Decrease

What effect does norepinephrine have on blood flow to the skin (Increase or Decrease)?

Decrease

What effect does norepinephrine have on blood flow to the kidney (Increase or decrease)?

Decrease

What effect does norepinephrine have on Bronchiole tone (Increase or Decrease)?

Decrease

What effect does norepinephrine have on The Intestinal wall (Increase or Decrease)?

Decrease

Hypothalamus is stimulated and signals to the sympathetic nervous system which stimulates the adrenal medulla releasing....

epinephrine/norepinephrine.

What are the different Adrenergic receptors?

alpha 1, alpha 2, beta 1, beta 2 (G protein receptors which are the target of epinephrine and norepinephrine).

What is the antagonist for the alpha 1 receptor?

Epinephrine.

What is the target tissue of the alpha 1 receptor?

Vascular smooth muscle, liver, GI smooth muscle, and the Heart.

What is the response of the alpha 1 receptor?

Contraction, Glycogenolysis, Hyperpolarization, and relaxation, increased contractile force/arrhythmias.

What is the antagonist of the alpha 2 receptor?

Epinephrine

What is the target tissue of the alpha 2 receptor?

Pancreatic Islates, Platelets, Nerve terminals, and Vascular smooth muscle.

What is the response of the alpha 2 receptor?

Decreased insulin secretion, aggregation, decreased release of NE, contraction.

What is the agonist of Beta 1 receptor?

Epinephrine and Norepinephrine are equal

What is the target tissue of the beta 1 receptor?

Juxtaglomerular cells and the heart.

What is the response to the beta 1 receptor?

increased renin secretion and increased force and rate of contractility.

What is the agonist of Beta 2 receptors?

Epinephrine

What is the target tissue of Beta 2 receptors?

Smooth muscle and Skeletal muscle

What is the response to stimulation of Beta 2 receptors?

Relaxation and Glycogenolysis (uptake of potassium).

What is the agonist of Beta 3 receptors?

Norepeineprhine

What is the target tissue of Beta 3 receptors?

Adipose tissue.

What is the response to stimulation from beta 3 receptors?

Lipolysis.

What two enzymes catabolize catecholamines?

Catecholamine-O-methyltransferase (COMT) and Monoamine oxidase (MAO).

What are the the three main layers of the Adrenal Cortex?

Zona glomerulosa, Zona Fasciculata, and Zona reticularis. All contained within the capsule.

The adrenal cortex produces...

steroid hormones.

The steroidogenic cells of the three layers of the adrenal cortex are filled with...

lipid droplets containing cholesterol.

All steroid hormones contain a...

cyclopentanoperhydrophenanthrene nucleus.

Adrenal cholesterol comes from...

plasma circulation. LDL is a major cholesterol transport complex. Cholesterol is packaged with apolipoproteins and, upon ACTH stimulation, binds to LDL receptors on adrenal cells.

What is the major cholesterol transport complex?

LDL.

Cholesterol is packaged with apoliproteins and, upon ACTH stimulation...

binds to LDL receptors on adrenal cells.

What are the different classifications of steroid hormones?

Glucocorticoids, Mineralocorticoids, and Sex Hormones.

How are steroid hormones classified?

According to their principal effects.

Describe Glucocorticoids.

Type of corticosteroids effective at reducing inflammation and suppressing the immune system.

Describe Mineralocorticoids.

A class of corticosteroids that influences salt and water balances (electrolyte and fluid balances).

Describe Sex Hormones.

A class of Gonadocorticoids that influence gonadal and reproductive tissue function.

What are the Glucocorticoids?

Cortisone, Cortisol (Hydrocortisone), and Corticosterone.

What are the Mineralocorticoids?

Aldosterone and Deoxycorticosterone.

What are the Sex Hormones?

Testosterone, Estradiol, and Progesterone.

Provide an example of what Glucocorticoids do to the Pancreas.

Decrease glucose phosphorylation.

Provide an example of what Glucocorticoids do to the Bones.

Decrease bone formation.

Provide an example of what Glucocorticoids do to the Liver.

Increase lipogenesis.

Provide an example of what Glucocorticoids do to the Skeletal muscle.

Decrease glycogen synthesis.

Provide an example of what Glucocorticoids do to the White adipose tissue.

Increase lipolysis

Of the Mineralocorticoids, which is the most important?

Aldosterone. Activate the reabsorption of Na, water, and CL in kidney canaliculi, promoting the excretion of potassium ions via the kidneys, skin, and saliva.

What hormones affect the Zona glomerulosa? What is its regulation of secretion and function?

Mineralocorticoids are stimulated by angiotensin II. Regulates salt and water balance in the blood by increasing sodium and water absorption and potassium secretion by the distal convoluted tubules in the kidneys.

What hormones affect the zona fasciculata? What is its regulation of secretion and function?

Glucocorticoids are stimulated by ACTH. Suppresses immune response and regulates carbohydrate metabolism.

What hormones affect the zona reticularis? What is its regulation of secretion and function?

Weak androgens are stimulated by ACTH. Precursor for testosterone production.

What hormone affect Chromaffin cells? What is its regulation of secretion and function?

Catecholamines, preganglionic sympathetic neuron. Increases heart rate, respiration, and blood pressure. Constricts vessels to reduce blood flow to the GI tract.

What happens to individuals affected by Addisons disease?

Adrenal glands do not produce enough cortisol.

What happens to individuals affected by Cushing's disease?

Adrenal glands produce excess cortisol.