endocrine system (E3)

What are the roles of the endocrine system?

Regulating mood, growth, development, tissue function, metabolism, s3xual function, and reproductive processes.

What does the anatomy of the endocrine system consist of?

Consists of glands (glandular tissue) throughout the body that works with the nervous system.

What does the physiology of the endocrine system consist of?

Glands secrete different hormones that bind to and affect cells; these hormones can be target or non-target hormones.

What are target hormones?

Hormones that target specific tissues and cells of the body.

What are non-target hormones?

Hormones that impact many cells of the body instead of one specific type.

What are the two main groups of hormones?

Steroid and protein.

What are steroid hormones?

Cholesterol based and include sex hormones; non-polar and hydrophobic = lipid soluble/membrane permeable and blood insoluble.

What are protein hormones?

Hormones containing chains of amino acids, such as insulin and growth hormones; polar and hydrophilic = membrane impermeable and blood soluble.

How do steroid hormones bind?

Diffuse from capillaries into the interstitial fluid then the target cell; combine with receptor molecules in the cytoplasm (pass through lipid membrane).

How do protein hormones bind?

Can travel through blood without a carrier protein but require receptor proteins on target cell; combine with receptors on cell membranes at very specific sites.

What is the pituitary gland?

“Master gland;” exercises control over other endocrine glands, as well as produces and stores several hormones.

Where is the pituitary gland located?

Connected to the hypothalamus, by which it is controlled, and has two lobes; the posterior and the anterior lobe.

How do the pituitary gland and hypothalumus work together?

Hormones travel by way of specialized nerve cells from the hypothalamus to the pituitary gland, where it releases them into the blood when necessary.

What are the hormones secreted by the anterior pituitary?

TSH, ACTH, STH/GH, FSH, LH, prolactin.

What are the hormones secreted by the posterior pituitary?

Oxytocin and ADH.

What is the function of the thyroid-stimulating hormone (TSH)?

Targets the thyroid gland, stimulating the release of thyroxine which regulates cell metabolism.

What is the function of the adrenocorticotropic hormone (ACTH)?

Targets the adrenal cortex and stimulates the release of hormones involved in stress response.

What is the function of somatotropin (STH) or growth hormone (GH)?

Targets most cells and promotes growth and cell division.

What is the function of the follicle-stimulating hormone (FSH)?

Targets the ovaries/testes; stimulates follicle development in ovaries or promotes development of sperm cells in testes.

What is the function of the luteinizing hormone (LH)?

Targets the ovaries/testes; stimulates ovulation and formation of the corpus luteum in females, stimulates the production of testosterone in males.

What is the function of prolactin?

Targets the mammary glands; stimulates and maintains milk production in lactating females.

What is the function of oxytocin?

Targets the uterus and mammary glands; initiates strong contractions for childbirth and triggers milk release.

What is the function of the antidiuretic hormone (ADH)?

Targets the kidneys by increasing water reabsorption by the kidneys.

What are the four main human hormones?

Hormones that regulate blood sugar levels, hormones that respond to stress, reproductive hormones, hormones affecting metabolism.

Where are blood sugar regulating hormones produced?

Cells producing hormones in the pancreas are located in structures called the islets of Langerhans; the beta cells produce insulin and the alpha cells produce glucagon.

What are the affects of the two hormones secreted by the pancreas, insulin and glucagon?

Antagonistic hormones; insulin responds to high blood glucose and glucagon responds to low blood glucose.

How do insulin and glucagon regulate blood glucose levels?

Insulin stimulates the conversion of glucose (active form) to glycogen (storage/inactive form); glucagon stimulates the breaking down of glycogen to glucose.

How does diabetes affect an individual’s affect to maintain blood glucose levels?

Diabetes mellitus prevents the body from producing enough insulin; insulin deficiency causes hyperglycemia.

What are the symptoms associated with hyperglycemia?

Glucose in urine, dehydration caused by glucose in the nephron which draws out water, low energy levels due to less glucose burned and less ATP made.

What are the three types of diabetes?

Type 1 (juvenile onset), Type 2 (adult onset), and gestational (occurs in pregnant women).

What do the adrenal glands produce and where are they found?

Produce stress hormones that trigger the release of sugar into the blood; located above each kidney containing an outer cortex and inner medulla.

What does the medulla of the adrenal gland release?

Releases epinephrine (adrenalin) and norepinephrine, which respond to short-term stress.

What does the adrenal medulla respond to versus the adrenal cortex?

The adrenal medulla responds to short term stress; the adrenal cortex responds to long term stress.

How does the body respond to short-term stress/what are the physiological responses?

Epinephrine and norepinephrine are released by adrenal medulla when signals are sent from the hypothalamus; blood sugar level, heart rate, breathing rate, and cell metabolism increase, while blood vessels and irises dilate.

How does the body respond to long-term stress?

Cortisol and aldosterone are released by adrenal cortex; the hypothalamus sends a releasing hormones to the anterior pituitary which releases ACTH, a hormone that stimulates the adrenal cortex to release cortisol (glucocorticoids) and mineralocorticoids (aldosterone).

What are the physiological responses of long-term stress?

Cortisol causes proteins and fats to break down and the liver to convert amino and fatty acids to glucose, raising blood sugar; aldosterone increases sodium retention and water reabsorption, blood pressure, and partial suppression of immune system.

What are reproductive hormones?

Hormones that control the development of reproductive systems during growth and when sexually mature.

What are male reproductive hormones called?

Androgens; the main androgen is testosterone.

What is testosterone?

Manufactured by interstitial cells of the testes; increased secretion at puberty responsible for development of secondary sexual characteristics and production of sperm.

What hormone does the hypothalamus release at puberty (males)?

Releases gonadotropin-releasing hormone (GnRH).

What role does GnRH have in male reproduction?

Activates the anterior pituitary gland to secrete and release FSH and LH.

What does FSH act on?

Acts on sertoli cells; activating function is the release of ABP which binds to testosterone and stimulates sperm formation.

What does LH acts on?

Acts on leydig cells; activating function is releasing testosterone to start sperm formation.

How are FSH and LH part of a negative feedback loop?

Inhibin is released to signal the anterior pituitary gland to stop the release of FSH and LH; when testosterone is very high, LH acts as negative feedback to stop release of FSH and LH.

What are the main structures of the male reproductive system?

Testes, seminiferous tubules, epididymis.

What is the function of the testes?

Where testosterone manufacturing occurs.

What is the function of the seminiferous tubules?

Where spermatogenesis occurs; lined with sertoli cells (provide structural and nutritional support to developing sperm) and germ cells (spermatogonia); leydig cells are the interstitial tissue between.

What is the main female reproductive hormone?

Estrogen.

What are the main structures of the female reproductive system?

Uterus, ovaries, follicles.

What is the function of the uterus?