Med Phys Hormones

What are the primary hormones secreted by the pancreatic islets?

Insulin and glucagon

What is the role of insulin during the digestive phase?

Insulin promotes the utilization and storage of glucose, free fatty acids, and amino acids.

What triggers the release of insulin?

Increased glucose levels, nutrient supply, GI hormones, and certain neurotransmitters.

What is the effect of glucagon on blood glucose levels?

Glucagon increases plasma glucose levels through glycogenolysis and gluconeogenesis.

How does insulin affect liver metabolism?

Insulin enhances glucose uptake, promotes glycogen synthesis, and inhibits gluconeogenesis.

What is the primary action of glucagon in the liver?

To stimulate glycogenolysis and gluconeogenesis, raising blood glucose levels.

What is the insulin/glucagon ratio during normoglycemia?

Approximately 2:1

What happens to the insulin/glucagon ratio during stress?

The ratio declines, leading to increased glucose mobilization.

What are the symptoms of hyperglycemia in Type I diabetes?

Thirst, frequent urination, blurred vision, and weight loss.

What is the primary cause of Type II diabetes?

Resistance of target tissues to insulin, often related to obesity.

What is the role of somatostatin in insulin regulation?

Somatostatin inhibits insulin and glucagon secretion.

What is the effect of insulin on adipose tissue?

Insulin enhances storage of triglycerides and inhibits lipolysis.

What is the consequence of insulin deficiency?

Increased blood glucose levels and potential development of diabetic ketoacidosis.

What is the primary metabolic effect of glucagon on adipose tissue?

Glucagon has a minor effect on adipose tissue compared to its actions in the liver.

What is the typical treatment for Type I diabetes?

Insulin therapy

What is the role of GLP-1 in insulin secretion?

GLP-1 stimulates insulin secretion in response to food intake.

What is the primary metabolic pathway activated by insulin in muscle tissue?

Increased glucose uptake and amino acid flux.

What is the half-life of glucagon in circulation?

Approximately 6 minutes.

What is the impact of elevated free fatty acids (FFAs) on insulin secretion?

Elevated FFAs inhibit insulin secretion.

What is the significance of the Oral Glucose Tolerance Test (OGTT)?

It assesses glucose metabolism and can indicate diabetes or other metabolic disorders.

What are the consequences of hypoglycemia?

Symptoms include rapid heart rate, nervousness, sweating, and potential loss of consciousness.

What is the primary action of insulin on amino acids?

Insulin enhances the uptake and synthesis of proteins.

What is the effect of exercise on insulin levels?

Exercise can lower insulin levels and increase glucose utilization.

What is the role of adrenergic agonists in insulin secretion?

They stimulate insulin release via Gs protein and increased cAMP.

What is the effect of insulin on fatty acid oxidation?

Insulin inhibits the oxidation of fatty acids.

What is a common treatment for hypoglycemia caused by hyperinsulinism?

Removal of the insulin-secreting tumor or administration of diazoxide.

What type of hormone is prolactin?

Polypeptide

What is the half-life of prolactin?

20 minutes

What feedback mechanism does prolactin use?

Positive feedback

Where is prolactin produced?

Lactotropes in the anterior pituitary gland

What triggers the release of prolactin?

Suckling, parturition, infant's cry

What type of hormone is T3?

Tyrosine-derived hormone

What is the half-life of T3?

6-7 days

What feedback mechanism does T3 use?

Negative feedback

Where is T3 produced?

Follicular cells of the thyroid gland

What triggers the release of T3?

Cold, low T3/T4 levels

What type of hormone is aldosterone?

Cholesterol-derived hormone

What is the feedback mechanism for aldosterone?

Negative feedback

Where is aldosterone produced?

Zona glomerulosa of the adrenal cortex

What triggers the release of aldosterone?

Angiotensin II, elevated plasma [K+], decreased plasma [Na+]

What type of hormone is PTH (Parathyroid Hormone)?

Polypeptide

What is the feedback mechanism for PTH?

Negative feedback

Where is PTH produced?

Chief cells of the parathyroid gland

What triggers the release of PTH?

Decreased plasma Ca+2 levels

What type of hormone is cortisol?

Cholesterol-derived hormone

What is the feedback mechanism for cortisol?

Negative feedback

Where is cortisol produced?

Zona fasciculata of the adrenal cortex

What triggers the release of cortisol?

Stress, ACTH, surgery, burns, infection, fever

What type of hormone is oxytocin?

Polypeptide

What is the feedback mechanism for oxytocin?

Positive feedback

Where is oxytocin produced?

Paraventricular nucleus of the hypothalamus

What triggers the release of oxytocin?

Suckling, parturition, infant's cry

What type of hormone is testosterone?

Cholesterol-derived hormone

What is the feedback mechanism for testosterone?

Negative feedback

Where is testosterone produced?

Leydig cells in the testes

What triggers the release of testosterone?

GnRH, LH stimulation

What is the chemical make-up of PTH?

Polypeptide

What is the chemical make-up of progesterone?

Cholesterol

What is the chemical make-up of testosterone?

Cholesterol

What is the chemical make-up of aldosterone?

Cholesterol

Which hormones are classified as non-lipid soluble (NLS)?

PTH

Which hormones are classified as lipid soluble (LS)?

Progesterone, Testosterone, Aldosterone

What is the half-life of PTH?

Long half-life

What is the carrier protein for PTH?

SSBG, albumin

What is the carrier protein for progesterone?

TBG, SSBG

What is the carrier protein for testosterone?

Transcortin

What is the primary source of PTH?

Chief cells of parathyroid

What is the primary source of progesterone?

Granulosa / theca cells

What is the primary source of testosterone?

Leydig cells

What is the primary source of aldosterone?

Zona glomerulosa

What stimulates the release of PTH?

↓plasma Ca+2

What stimulates the release of progesterone?

GnRH and FSH

What stimulates the release of testosterone?

GnRH, LH

What stimulates the release of aldosterone?

ACTH, Hyperkalemia, Hypotension, Hyponatremia, Acidosis, Hypovolemia, dehydration

What inhibits the release of PTH?

↑ plasma Ca+2

What inhibits the release of progesterone?

Dopamine, CRH, stress

What inhibits the release of testosterone?

Dopamine, CRH, stress

What inhibits the release of aldosterone?

Hypokalemia, Hypertension, Hypernatremia, Alkalosis, hypervolemia

What is the target cell/tissue for PTH?

Bones, kidney, GI

What is the target cell/tissue for progesterone?

Uterus myometrium, endometrium

What is the target cell/tissue for testosterone?

Bones, muscle, kidney, reproductive organs

What is the target cell/tissue for aldosterone?

Principal cells of late DCT/CT; Intercalated cells of late DCT/CT

What is the overall target response of PTH?

↑plasma Ca+2

What is the overall target response of progesterone?

Stimulates secretory phase of endometrium after ovulation

What is the overall target response of testosterone?

Differentiation and growth of genitalia; stimulates growth of long bones and muscle

What is the overall target response of aldosterone?

Increase blood volume and pressure; decrease urine output

What is the effect of insulin on carbohydrate metabolism?

Insulin promotes glycogenesis, decreasing plasma glucose levels.

What is the effect of glucagon on carbohydrate metabolism?

Glucagon promotes glycogenolysis and gluconeogenesis, increasing plasma glucose levels.

How does insulin affect protein metabolism?

Insulin promotes proteogenesis, decreasing plasma amino acid levels.

What is the effect of glucagon on fat metabolism?

Glucagon promotes lipolysis and ketogenesis, increasing plasma fatty acids and ketoacids.

What type of signaling cascade is involved in insulin signaling?

Insulin signaling involves a membrane signaling cascade with receptor tyrosine kinase (TK).

What is the role of ANP in the body?

ANP (Atrial Natriuretic Peptide) regulates blood pressure and volume by promoting sodium excretion.

What triggers the release of Angiotensin II?

Angiotensin II is triggered by hypovolemia.

What is the chemical make-up of estrogen?

Estrogen is a lipid-soluble (LS) hormone.

What is the primary source of cortisol?

Cortisol is produced in the adrenal cortex.

What is the feedback mechanism for estrogen?

Estrogen has both negative and positive feedback mechanisms.

What is the target tissue for aldosterone?

Aldosterone primarily targets the principal cells of the late distal convoluted tubule (DCT) and collecting duct (CD).

What is the overall impact of glucagon on blood volume and pressure?

Glucagon decreases blood volume and pressure through osmotic diuresis.

What is the overall impact of insulin on urine volume?

Insulin generally decreases urine volume.

What is the effect of cortisol on carbohydrate metabolism?

Cortisol has a hyperglycemic effect, promoting gluconeogenesis.