Endocrinology

What is the hypothalamus

Master homeostasis regulator, controls endocrine system by secreting to the pituitary gland.

What hormones are made and secreted by the hypothalamus?

ADH (antidiuretic hormone/vasopressin)

Oxytocin

TRH

CRH

GnRH

GHRH

Somatostatin

Dopamine

What does the posterior pituitary gland do?

Stores and releases ADH and oxytocin, does NOT synthesize any hormones

What does the anterior pituitary gland do?

Synthesizes, unlike posterior, and releases hormones into the bloodstream

What does TRH do?

TRH goes to the anterior pituitary and stimulates TSH

What does TSH do?

Stimulates thyroid to release T3, T4

What does CRH do?

stimulates anterior pituitary to release ACTH

What does ACTH do?

Stimulates adrenal cortex to release cortisol

What does GnRH do?

stimulates anterior pituitary to secrete FSH and LH

What does FSH do?

Stimulates spermatogenesis in males, ovarian follicle production in females

What does LH do?

Stimulates ovulation (more estrogen) and testosterone production

What does GHRH do?

Stimulates release of GH from anterior pituitary

What does GH do?

Growth hormone, some metabolism.

What does somatostatin do?

Inhibits GH and TSH as well as glucagon and insulin in the pancreas

What does dopamine do from the hypothalamus?

Decreases prolactin

What does ADH do?

Reaborption of water from kidneys

What does oxytocin do?

Milk letdown, uterine contractions

Where is the suprachiasmatic nucleus and what does it control?

Hypothalamus, circadian rhythms PER/CRY during the night, then they break down during the day due to negative feedback

What does ghrelin do?

Stimulates hunger

What does leptin do?

Stimulates satiety

Which area of the hypothalamus promotes hunger?

Lateral

Which area of the hypothalamus promotes satiety?

Ventromedial

What does the thyroid gland do?

Produces T3 and T4

What do T3 and T4 have to do with one another?

T4 is in the hypothalamus, but T3 is what it's converted to in order to do work.

Which element is essential for thyroid hormone synthesis?

Iodine, 3 for T3, 4 for T4

What do T3 and T4 do?

Increase metabolism, growth and development

What does hyperthyroidism do?

Everything speeds up! So you lose weight, too hot, etc.

What does hypothyroidism do?

Everything slows down, colder, fatter, etc.

What does goiter mean?

The thyroid is enlarged, can happen with any thyroid disease.

What does calcitonin do?

Lowers Ca2+ levels in blood, limits bone resporption

What is the difference between follicar and C cells in the thyroid?

Follicar does T3, T4

Parafollicar, C cells, does Calcitonin

What is primary hyperthyroidism?

TSH goes down, but T3/T4 up

What is primary hypothyroidism?

TSH goes up, but T3/T4 down

What is secondary hypothyroidism

TSH goes down and T3/T4 go down

Which disease causes hyperthyroidism?

Graves disease (starlight mog)

Which disease causes hypothyroidism

Hashimoto (work)

What causes a goiter during iodine deficiency?

Increased TSH because of low T3/T4 constantly makes the thyroid always need to be stronger and get bigger, so it does.

What does PTH do?

Increases blood calcium via increasing bone resorption and reasborption in the kidneys while letting loose phosphate that would otherwise bind calcium

What is the parathyroid?

Releases parathyroid hormone

What does an osteoblast do?

Builds bones

What does an osteoclast do?

Break down bone

What does calcitrol (vitamin D) do?

Increases absorption by the intestine of calcium

Why is Ca2+ important in the body?

Muscle contraction, neurotransmitter release (calcium channels), blood clotting, cell signalling, bone mineralization

What is hypoparathyroidism?

Too little PTH, causes things like tetany (sustained muscle contraction, increased excitability

What is hyperparathyroidism?

Too much PTH, increased Ca2+, less Pi, kidney stones, weak bones

Which is more imporatant, PTH or calcitonin?

PTH

What are the two adrenal regions?

Cortex and medulla

What does the adrenal cortex do, and where is it?

Outer, produces steroid hormones, like cortisol

What does the adrenal medulla do, and where is it?

Inner, produces catecholamines (fight or flight hormones), like adrenaline

What are the regions of the adrenal cortex?

Zona glomerulosa

Zona Fasciculata

Zona Reticularis

What does the zona glomerulosa make?

Aldosterone

What does the zona fasciculata make?

Cortisol

What does the zona reticularis make?

Androgens

What does aldosterone do?

Increases sodium and water retention, raising blood pressure, can be activated by high potassium, but never ACTH from the hypothalamus.

What are the steps of RAAS?

Renin -> angiotensinogen -> angiotensin 1 -> Angiotensin 2 via ACE -> Aldosterone

What is the function(s) of angiotensin ii?

Vasocompressor, increasing blood pressure, then also activating aldosterone

What does cortisol do?

Increases blood glucose via gluconeogenesis, suppresses immune system, increases responsiveness to catecholamines (dopamine, epinephrine, norepinephrine, etc)

What are the steps of the HPA axis?

Stress -> Hypothalamus acts -> CRH -> Anterior pituitary -> ACTH -> Adrenal cortex -> Cortisol

What do androgens do?

Sex hormone precursors, contribute to secondary sex characteristics, less important in adults

What does the adrenal medulla make and what system is it a part of?

Sympathetic nervous system, epinephrine (adrenaline), norepinephrine (noradrenaline)

What are the two functions of the pancreas?

Endocrine - Hormone release

Exocrine - Secretes digestive enzymes and bicarbonate into the small intestine

What are the parts of the islets of Langerhans?

Beta cells, alpha cells, delta cells

What do beta cells secrete?

Insulin

What do alpha cells secrete?

Glucagon

What do delta cells secrete?

Somatostatin

What does insulin do?

Lowers blood glucose via glycogenesis, decreases gluconeogenesis, increases fat storage

What does insulin do to GLUT4?

Allows glucose to enter skeletal muscle, adipose tissue

What does glucagon do?

Raises glucose levels via glycogenolysis, gluconeogenesis, causes lipolysis

How does insulin affect protein metabolism?

More insulin, more protein being made.

What is the difference between types 1 and 2 diabetes?

Type 1 is autoimmune, type 2 is acquired due to insulin resistance

What does somatostatin do?

Inhibits insulin, glucagon, and GH

Which digestive enzyme breaks down carbohydrates?

Amylase

Which digestive enzyme breaks down fats?

Lipase

Which digestive enzyme breaks down proteins?

Protease

Why does the pancreas secrete bicarbonate?

To neutralize stomach acid in small intenstine and adjust pH for pancreatic enzymes