Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
43 Cards in this Set
- Front
- Back
exocrine glands
|
- release enzymes to external environment through ducts
- sudoriferous (sweat) glands - sebaceous (oil) glands - mucous glands - digestive glands - e.g. pancreas releases digestive enzymes through pancreatic duct |
|
endocrine glands
|
- release hormones directly into bodily fluids
- e.g. pancreas releases insulin & glucagon directly into blood |
|
How long can it take endocrine glands to produce their effects?
|
anywhere from seconds to days
|
|
What are the general effects of the endocrine system?
|
(1) alter metabolic activities
(2) regulate growth & development (3) guide reproduction |
|
What are the 3 basic types of hormones?
|
(1) peptide
(2) steroid (3) tyrosine derivatives |
|
peptide hormones (general characteristics)
|
- derived from peptides
- large or small - often include carbohydrate portions - cannot diffuse through membrane (b/c they are proteins), so they bind to membrane receptors & act through a second messenger - water-soluble, move freely through blood |
|
How are peptide hormones manufactured?
|
- manufactured in rough ER, usually as preprohormone
- preprohormone cleaved in ER lumen to prohormone & transported to Golgi - prohormone cleaved & sommetimes modified with carbohydrates in Golgi - final hormone packaged by Golgi into secretory vesicle and released via exocytosis upon stimulation by another hormone or nervous signal |
|
In what ways can a membrane-bound receptor react to a peptide hormone binding?
|
- act as ion channel & increase membrane permeability to specific ion
- activate or deactivate other intrinsic membrane proteins acting as ion channels - activate intracellular second messenger (cAMP, CGMP, calmodulin) to activate/deactivate enzymes and/or ion channels and create cascade of chemical reactions to amplify effect of hormone |
|
list of peptide hormones & sources
|
(1) anterior pituitary hormones
- FSH - LH - ACTH - hGH - TSH - prolactin (2) posterior pituitary hormones - ADH - oxytocin (3) parathyroid hormone - PTH (4) pancreatic hormones - glucagon - insulin |
|
steroid hormones (general characteristics)
|
- derived from/chemically similar to cholersterol
- formed from series of steps in smooth ER & mitochondria - lipids, so require protein transport molecule to dissolve into bloodstream - diffuse through cell membrane (lipid-soluble) - combine with a receptor in cytosol of cell, which transports steroid to nucleus where it acts at transcription level - typically increases certain membrane or cellular proteins w/in effector |
|
list of steroid hormones & sources
|
(1) glucocorticoids & mineral corticoids of adrenal cortex
- cortisol - aldosterone (2) gonadal hormones - estrogen* - progesterone* - testosterone *estrogen & progesterone also produced by placenta |
|
tyrosine derivatives (general characteristics)
|
- formed by enzymes in cytosol or on rough ER
- lipid soluble & carried in blood by plasma protein carriers - bind to receptors in nucleus - high affinity to binding proteins in plasma/nucleus causes latent period in response & increases duration of effect - increase transcription of many genes in almost all cells - epinephrine/norepinephrine are water-soluble & dissolve in blood; bind to receptors on target tissue & act mainly through second messenger cAMP |
|
list of tyrosine derivatives & sources
|
(1) thyroid hormones
- T3 (triiodothyronine, 3 iodine atoms) - T4 (thyroxine, 4 iodine atoms) (2) catecholamines from adrenal medulla - epinephrine - norepinephrine |
|
negative feedback
|
control point is conduct of effector, NOT concentration of hormone itself - so answer questions with how hormone RESPONDS!!!
[e.g. ADH holds water and increases blood pressure, so a question asking if a person with high blood pressure has high or low ADH should be answered with LOW ADH, since we are looking at how ADH output would respond to the body] |
|
hypothalamus
|
controls release of anterior pituitary hormones with releasing & inhibitory hormones (controlled by nervous signals) carried to capillary bed of anterior pituitary by small blood vessels
|
|
Where is the anterior pituitary located?
|
in brain, beneath the hypothalamus; releases peptide hormones
|
|
What are the 6 major hormones released by the anterior pituitary?
|
[all peptide hormones]
(1) human growth hormone (hGH) (2) adrenocorticotropin (ACTH) (3) thyroid stimulating hormone (TSH) (4) follicle-stimulating hormone (FSH) (5) leutinizing hormone (LH) (6) prolactin |
|
hGH
|
- human growth hormone (somatotropin)
- peptide - stimulates growth in almost all cells of the body - increases mitotic episodes, cell size, protein synthesis, & use of fatty acids for energy - mobilizes fat stores - decreases use of glucose - affects proteins by increasing amino acid transport across cell membrane, increasing translation & transcription & decreasing breakdown of proteins & amino acids |
|
ACTH
|
- adrenocorticotropic hormone
- peptide - stimulates adrenal cortex to release glucocorticoids via second messenger system using cAMP - release stimulated by many types of stress |
|
glucocorticoids
|
stress hormones
|
|
TSH
|
- thyroid-stimulating hormone (thyrotropin)
- peptide - stimulates thyroid to release T3 and T4 via second messenger system using cAMP - increases thyroid cell size, number & rate of T3/T4 secretion - T3/T4 have negative feedback effect on TSH release at anterior pituitary & hypothalamus |
|
prolactin
|
- peptide
- promotes lactation - progesterone & estrogen inhibit milk production before birth - hypothalamus mainly inhibits prolactin release, but suckling stimulates hypothalamus to stimulate anterior pituitary to release prolactin, which inhibits menstrual cycle |
|
posterior pituitary
|
- "neurophypophysis"
- composed mainly of support tissue for nerve endings extending from hypothalamus - releases oxytocin & ADH |
|
Where are oxytocin and ADH synthesized?
|
neural cell bodies of hypothalamus (transported to posterior pituitary down axons)
|
|
oxytocin
|
- peptide hormone (small polypeptide)
- increases uterine contractions during pregnancy - causes milk to be ejected from the breasts |
|
ADH
|
- antidiuretic hormone (vasopressin)
- peptide hormone (small polypeptide) - causes collecting ducts of kidney to become permeable to water, reducing amount of/concentrating urine - increases blood pressure since fluid is reabsorbed - coffee/alcohol block ADH & therefore increase urine volume |
|
adrenal glands
|
- located on top of kidneys
- separated into adrenal cortex & adrenal medulla |
|
adrenal cortex
|
- outside portion of adrenal gland
- only secretes steroid hormones (mineral corticoids & glucocorticoids) ***also secretes small amount of sex hormones, only significant in females*** |
|
mineral corticoids
|
- affect electrolyte balance in blood stream
- aldosterone is major mineral corticoid |
|
glucocorticoids
|
- increase blood glucose concentration
- have greater effect on fat & protein metabolism - cortisol is major glucocorticoid |
|
aldosterone
|
- steroid hormone
- mineral corticoid - acts in distal convoluted tubule & collecting duct - increases Na+ & Cl- reabsorption - increases K+ & H+ secretion - creates net gain in plasma particles, increasing BP - same effect (to lesser extent) on sweat glands, salivary glands & intestines |
|
cortisol
|
- steroid hormone
- glucocorticoid - increases blood glucose by stimulating gluconeogenesis in liver - degrades adipose tissue to fatty acids for cellular energy - causes moderate decreases in glucose use by cells - causes degradation of nonhepatic proteins, decreases of nonhepatic amino acids & increases liver/plasma proteins & amino acids - stress hormone (anti-inflammatory properties, diminishes immune system capacity) |
|
gluconeogenesis
|
creation of glucose & glycogen, mainly in liver, from amino acids, glycerol, and/or lactic acid
|
|
catecholamines
|
- tyrosine derivatives synthesized in adrenal medulla
- epinephrine & norepinephrine = vasoconstrictors of internal organs/skin, but vasodilators of skeletal muscle - effects on target tissues last longer than effects in sympathetic NS - stress hormones |
|
thyroid
|
located along trachea in front of larynx; hormones include T3, T4 & calcitonin
|
|
T3 & T4
|
- T3 = triiodothyronine
- T4 = thyroxine - lipid soluble tyrosine derivatives that diffuse through lipid bilayer - act in nucleus of effector cells - increase basal metabolic rate - secretion regulated by TSH |
|
calcitonin
|
- large peptide hormone released by thyroid gland
- slightly decreases blood calcium by decreasing osteoclast activity & number - can still control calcium levels without it in humans |
|
pancreas
|
- acts as both and endocrine & exocrine gland
- Islets of Langerhans - releases peptide hormones insulin & glucagon into blood - delta-cells release somatostatin |
|
somatostatin
|
- released by delta-cells of pancreas
- inhibits both insulin & glucagon - function may be to extend period of time over which nutrients are absorbed |
|
insulin
|
- peptide hormone
- released by beta-cells of pancreas - released during high blood levels of carbs/proteins - affects carb, fat & protein metabolism - causes carbs to be stored as glycogen in liver & muscles, fat to be stored in adipose tissue & amino acids to be taken up by cells and made into proteins - binds to membrane receptor & starts reaction cascade, causing cells t o become highly permeable to glucose (except for neurons in brain & a few other cells) - insulin receptor not a glucose carrier itself - also increases membrane permeability to amino acids - activates intracellular metabolic enzymes - affects transcription & translation rates - NET EFFECT: lower blood glucose levels |
|
glucagon
|
- peptide hormone
- released by alpha-cells of pancreas - essentially opposite effects to insulin - stimulates glycogenolysis & gluconeogensis in liver - acts via second messenger system of cAMP - breaks down adipose tissue in higher concentrations (increases fatty acid level in blood) - NET EFFECT: raise blood glucose levels |
|
parathyroid glands
|
- four small glands attached to back of thyroid
- release parathyroid hormone |
|
PTH
|
- parathyroid hormone
- peptide hormone - increases blood calcium - increases osteocyte absorption of calcium & phosphate from the bone - stimulates osteoclast proliferation - increases renal calcium reabsorption & renal phosphate excretion - increases calcium phosphate uptake from gut by increasing renal production of a steroid derived from vitamin D - secretion regulated by calcium ion plasma concentration (parathyroid glands shrink/grow accordingly) |