Endocrine Flashcards
What is the Pituitary gland AKA
Master Gland
What does the Pituitary gland do?
functions as an intermediary, receives input from the hypothalamus and peripheral endocrine glands.
Pancreas – 2 key hormones
insulin and glucagon with some digestive enzymes
Thyroid – Produces 3 hormones
1) thyroxine, or T4
2) triiodothyronine, or T3
3) thyrocalcitonin, or calcitonin
What secretes Thyrotropin-releasing factor?
The hypothalamus
What does Thyrotropin-releasing factor do?
Stimulates the anterior pituitary gland to release TSH (thyroid stimulating hormone) which stimulates the release of thyroxine and triiodothyronine.
Also stimulates the release of Prolactin from the anterior pituitary gland which stimulates breast development during pregnancy and milk production postpartum. Suppresses ovarian function during breastfeeding
What secretes Gonadotropin-releasing factor
The hypothalamus
What does Gonadotropin-releasing factor do?
It stimulates the anterior pituitary gland to release FSH and LH which stimulates gamete production and hormone production by the gonads.
What secretes Corticotropin releasing factor?
The hypothalamus
What does Corticotropin releasing factor do?
stimulates anterior pituitary gland to release ACTH (adrenocorticotropic hormone) to stimulate secretion of hormones by the adrenal cortex, esp glucocorticoids
What secretes Growth hormone releasing factor?
Thy hypothalamus
What does the Growth hormone releasing factor do?
Stimulates the anterior pituitary gland to release Growth Hormone that stimulates cell growth and fat breakdown. Primary targets are muscle and bone, where GH stimulates amino acid uptake and protein synthesis.
What secretes Somatostatin?
The hypothalamus
The pancreas
What does Somatostatin do?
to inhibit release of growth hormone in the anterior pituitary gland. Inhibits the releases of TSH in the anterior pituitary gland
in the pancreas regulates insulin, glucagon, and pancreatic peptide by inhibiting their secretion
What secretes Substance P?
Hypothalamus
What does Substance P do?
stimulates secretion of growth hormone in the anterior pituitary gland. Inhibits synthesis and release of ACTH. Stimulates secretion of FSH and LH. Stimulates secretion of Prolactin.
What secretes Prolactin-releasing factors?
Hypothalamus
What does Prolactin-releasing factors do?
Stimulates secretion of Prolactin
What secretes Dopamine?
Hypothalamus
What does Dopamine do?
inhibits synthesis and secretion of prolactin
What secretes Adrenocorticotropic hormone?
Anterior Pituitary gland
What does Adrenocorticotropic hormone do?
Stimulates secretion of hormones by the adrenal cortex, especially glucocorticoids.
What secretes Melanocyte-stimulating hormone?
Posterior Pituitary gland
What does Melanocyte-stimulating hormone do?
Has a function in promoting secretion of melanin (darkens skin).
Also stimulates water reabsorption by nephrons of the kidney.
What secretes Growth Hormone?
anterior pituitary gland
What does Growth hormone do?
Stimulates cell growth and fat breakdown. Primary targets are muscle and bone where GH stimulates amino acid uptake and protein synthesis.
What secretes prolactin?
anterior pituitary gland
What does prolactin do?
Stimulates breast development during pregnancy and milk production postpartum. Suppresses ovarian function during breastfeeding.
What produces Triiodothronine (aka T3)
10% is produced by the Thyroid, the rest is converted from T4 to T3 in the tissues)
The thyroid hormones remain attached to what until they are released?
a protein known as thyroglobulin
What is required to synthesize the T3 and T4?
Iodine
What produces Thyroxine (T4)?
Thyroid
Where is Parathyroid hormone produced
Parathyroid
Where is Calcitonin produced
Thyroid
Where are glucocoricoids synthesized
middle region of the adrenal cortex
where is Aldosterone produced
the outer most region of the adrenal cortex
What is aldosterone?
principle mineral corticoid - lipid soluable
Where is Estrogen produced?
inner most region of the adrenal cortex usually masked by the amounts produced by the ovaries
Where is Epinephrine produced?
some produced in medulla during times of stress
What is epinephrine used for
sympathetic NS fight or flight
Where is Norepinephrine produced?
some produced in medulla during times of stress
What is Norepinephrine used for?
sympathetic NS fight or flight
Where is Lutenizing hormone produced? (LH)
Anterior Pituitary gland
What does Lutenizing hormone do?
stimulates gamete production and hormone production in the gonads
Where is Follicle stimulating hormone produced
anterior pituitary gland
What does Follicle stimulating hormone do?
stimulates gamete production and hormone production in the gonads
Where is Thyroid stimulating hormone Produced?
Anterior pituitary gland
What does Thyroid stimulating hormone do?
Stimulates release of thyroxine and triiodothyronine
What happens when Serum glucose levels fall, insulin levels fall or glucose needs increase (ie- in exercise)?
Glucagon released ->This stimulates glycogen breakdown into glucose (in the liver) which raises the serum glucose levels.
Glucagon also decreases uptake of glucose in the skeletal muscle and fat and promotes the release of amino acids and fatty acids
What is Gluconeogenesis?
glucagon stimulates liver and to a small amount the kidneys
the formation of glucose from various chemicals such as pyruvate, and conversely glycolysis is the breakdown of glucose to pyruvate.
What happens to serum glucose levels when High blood sugar inhibits glucagon release.
Serum glucose levels elevated -> insulin released ->stimulates cellular uptake of glucose which decreases serum glucose levels
Amylin stimulation and glucose
Amylin stimulation results in glucose control by suppressing glucagon, delaying gastric emptying, and increasing satiety (feeling of fullness)
What is glycogenolysis
the breakdown of glycogen to glucose – occurs in the muscle and liver
What regulates Serum Calcium levels?
Calcitonin and PTH
What happens when serum Ca levels drop?
-> PTH is secreted ->increases osteoclasts ->releases Ca from bone and Increased Ca absorption in GI and kidneys. PTH then decreases serum phosphate levels. PTH stimulates Vit D and together they increase calcium and phosphate absorption in the kidneys.
What is the inner portion of the adrenal gland called
Medulla
What is the outer portion of the adrenal gland called
Cortex
What feedback regulates the adrenal cortex?
Negative feedback loop
The outermost region of the adrenal cortex produces what type of hormones? What is the principle hormone?
Mineralocorticoids – principle one being Aldosterone (acts to conserve Na and in turn H2O in the body).
What type of hormones does the middle region of the adrenal cortex produce? What is the principle hormone secreted?
glucocorticoids(released during stress) – principle one is cortisol.
Cortisol
increases serum glucose levels. Cortisol is released in a diurnal (circadian) pattern. Just before you awaken, your cortisol levels begin to rise. Throughout the day, the cortisol levels slowly decline.
What type of hormones does the inner most region of the adrenal cortex produce?
gonadocorticoids (sex hormones). Male hormone (androgen) and Female hormone (estrogen) These are secreted at minimum amounts as opposed to the testes and ovaries.
Adrenal medulla is regulated by nerve impulses from
the hypothalamus – produces epinephrine and norepinephrine during times of stress mediating the fight or flight of the sympathetic nervous system
