Unit 8 (LT 1-4) - Endocrine System

Hypothalamus

Controls everything and highest level of endocrine function

What activities does the hypothalamus integrate?

nervous and endocrine system

What does the pituitary gland consist of?

Anterior lobe and posterior lobe

How many hormones does the anterior lobe secrete?

7 - called tropic because they "activate" other glands

How many hormones does the posterior lobe secrete?

2 - from hypothalamic axons - ADH and OXT

TSH

thyroid stimulating hormone

What does TSH do?

stimulates secretion of thyroid hormones (thyroid gland)

ACTH

adrenocorticotropic hormone

What does ACTH do?

stimulates secretion of glucocorticoids (steroid hormone) - from adrenal gland (cortex)

FSH

follicle-stimulating hormone

What does FSH do?

control reproductive system - ovaries & testes

LH

luteinizing hormone

What does Lh do?

control reproductive system - ovaries & testes

GH

growth hormone

What does GH do?

promote growth, control of protein, lipid, and carbohydrate metabolism.

What does prolactin do?

Milk production - mammary gland

MSH

melanocyte-stimulating hormone (skin)

What does MSH do?

increase melanin production

ADH

antidiuretic hormone - kidney

What does ADH do?

Helps with conservation of body water

What does OXT do?

stimulates milk ejection and uterine contractions (uterus and mammary glands)

What is the hormone secretion in the hypothalamus and pituitary gland controlled by?

Negative feedback

What are the two hormones produced by the thyroid?

thyroxine (T4) and triiodothyronine (T3)

What is the primary responsibility of the thyroid gland?

regulation of metabolism

What chemical is important for thyroid production? Why?

Iodine - a deficiency leads to decreased production of T3 and T4 which causes goiter

- a rise in blood pressure

- Elevated rates of oxygen and energy consumption

- increase sensitivity to sympathetic stimulation

-Enhance O2 delivery

- Higher turnover of minerals in bone

Effects of thyroid hormones

What are the two cell populations of the parathyroid gland?

Oxyphil cells and parathyroid cells (produce PTH)

What is the main function of parathyroid glands?

Mobilize calcium from bones

Where are the adrenal glands?

on top of the kidneys - pyramid shaped

Adrenal cortex

produces 24 steroid hormones (corticosteroids)

Adrenal medulla

produces epinephrine and norepinephrine

Glucocorticoids (cortisol and corticosterone)

Increase rates of liver glucose and glycogen formation

Stimulate release of :

- amino acids from skeletal muscles

- lipids from adipose tissue

- promote lipid metabolism

- can have an anti-inflammatory effect

Glucocorticoids

- increase cardiac activity, bld. pressure, glycogen breakdown, and blood glucose

epinephrine and norepinephrine

What do pineal glands contain?

neurons, neuroglia, and secretory cells (pinealocytes)

What do pinealocytes do?

produce and release melatonin

What are the two regions of the pancreas?

exocrine pancreas and endocrine pancreas

What does the exocrine pancreas do?

secrete pancreatic fluid and enzymes with digestive function (99% volume)

What does the endocrine pancreas do?

secrete hormones (have clusters called pancreatic islets)

Alpha cells (pancreas cell)

secrete glucagon - rasies blood glucose by increasing liver glycogen breakdown

Beta cells (pancreas cells)

secrete insulin - lowers blood glucose by increasing glucose uptake