Physiology Terms from Human Physiology
Terms
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- Endocrine Glands
- Glands that secrete hormones into the bloodstream
- Target Cells
- Cells with receptor proteins for certain hormones
- Neurohormones
- Specialized neurons secrete these into the bloodstream
- What do hormones affect?
- The metabolism of the target cells
- Amine
-
Hormones from tyrosine, tryptophan:
NE, Epi, thyroxin, melatonin - Polypeptide/protein hormones
- AA chains: ADH, GH, Insulin, Oxytocin, Glucagon, ACTH, PTH
- Glycoprotein (hormones?)
- LH, FSH, TSH
- Steroids
- lipids from cholesterol: testosterone, estrogen, progesterone, aldosterone, cortisol
- lipids
- thyroid hormones, steriod hormones: can diffuse into target cells, have receptors in cytoplasm/nucleus
- hormones
- either proteins, steriods, (or thyroid?)
- prehormones
- inactive precursors of hormones (T4)
- how does tissue respond to hormones?
- more hormones=more response, usually
- synergistic hormones
- hormones work together to produce a bigger effect than alone (norep and eph: both raise HR)
- antagonistic hormones
- one hormone inhibits another (insulin=fat making & glucagon=fat breakdown)
- priming effect/upregulation
- All hormones CAN do this, aka increase # of receptor sites on target membrane, which increases the cell's response
- desensitization/downregulation
- after much POLYPEPTIDE HORMONE exposure, exposure creates a lesser response, there are less receptors on target membrane
- water soluble hormones
-
-receptors are on the surface of the target cell membrane
-mediated via 2nd msnger syst. - how do lipid hormones travel in the blood?
- attached to carrier proteins
- Nuclear Hormone Receptors
- where gene transcription is activated, mRNA is made
- HRE
- hormone response element, what binds to the target gene on the DNA
- what does the thyroid secrete?
- 80% T4, 10% T3
- T4
- has 2x 2 units attached to tyrosine (2 DIT)
- T3
-
has 1x 1 unit attached to tyrosine (1 MIT)
has 1x 2 units attached to tyrosine (1 DIT) - TBG
- Thyroid binding globulin: the carrier protein for T4 in the blood. Inside T4-->T3, T3 binds to a receptor protein in the nucleus.
- 2nd msngr syst
- carries signal from receptor to inside cell
- adenylate cyclase
- an enzyme in the membrane, which mediates the effects of polypeptide/glycoprotein hormones
- inhibitory protein kinase
- what cAMP binds to
- adenylate cyclase, cAMP
-
binds to g protein subunit
(=ATP-->cAMP) - when the inhibitory subunit breaks
- protein kinase is activated
- when protein kinase is activated
- enzymes are phosphorylated, hormones have their effects
- what inactivates cAMP?
- phosphodiesterase
- with the IP3 2nd msngr, step 1:
- hormone-->receptor, g-protein activated, which activates the Phospholipase C in the membrane
- phospholipase-c
- membrane phospholipid-->2 messengers: IP3 and DAG
- IP3
- to cytoplasm to ER=Ca 2+ channels open, in cytoplasm, bindss to&activates calmodulin
- Ca2+ and calmodulin
- activate protein kinases=phosphorylate enzymes=hormone's effects
- 2nd msnger that involves a surface receptor
- tyrosine kinase
- tyrosine consists of
- 2 inactive units, which, when bonding to insulin-->active dimer of tyrpsine kinase=phosphorylates molecules=hormone/growth effects
- effects of tyrosine kinase
- hormonal growth
- Location of pituitary gland
- under hypothalamus, base of forebrain
- structure of pituitary gland
- two lobes
- infundibulum
- what pituitary gland hangs from
- anterior pituitary
- gets a signal from the hypothalamus, and makes its own hormones
- posterior pituitary
- stores, releases hypothalamus' hormones: antidiuretic hormone (ADH) and oxytocin
- what do the anterior pituitary's 6 hormone's control?
- size of targets: hypertrophy/atrophy
- GH
-
a polypeptide/protein hormone
growth hormone
hypothal, ant. p, cells absorb AAs at muscle, bone, fat - GHRH
- from hypothalamus
- TSR
-
a glycoprotein hormone
thyroid stimulating hormone
thyroid makes lots of T4, and some T3 - TRH
- thyroid releasing hormone
- ACTH
- secretes cortisol, aldosterone
- LH
-
a glycoprotein hormone
Lutenizing hormone
causes estrogen/testost production - FSH
-
a glycoprotein hormone
Follicle stimulating hormone
egg and sperm production - PRL
- inhibited by PIH, released by PRH
- hypothalmic releasing&inhibiting factors, feedback from target hormone glands
- controll A. Pit. hormone release
- Short feedback loop
- bkwd flow of hormones from a.pit. to the hypothal.= inhibits the hormone release
- negative feedback
- GnRH ihibits secretion and responsiveness
- positive feedback
- more estrogen, more LH
- higher brain fxn
- controls hypothalamus
- Adrenal gland's medulla
- secretes amine hormones: epi and ne, and is controlled by the symp ns, the MEDulla MEDiates under stress
- when is the adrenal medulla activated?
- during fight/flight response
- adrenal cortex
- controlled by ACTH adrenocorticotrophic hormone, secretes STERIOD hormones: cortisol, aldosterone, can secrete prehormones
- cortisol
- steriod that inhibits glucose using, and promotes gluconeogenesis. MINOR sug. mech, from long term stress on body
- aldosterone
- kidneys reabsorb Na+, secrete K+ (MAIN mechanism for K+, from nephron to urine)
- GAS
- general adaptation syndrom, causes acth and cortisol release from adrenal cortex
- Addison's disease
-
poor secretion of cortex (steriods, perhaps adrenal gland doesn't fxn, or adrenal gland is resistant to acth.)
low blood glucose
weak b/c of poor glucose useage
bad Na+ & K+ balance - Cushings
-
high ACTH secretion from cortex, (excess stimulation of adrenal gland or adrenal over pumps)
opposite Na K imbalance
high blood glucose=high bp
fat redistributed - Thyroid gland's location
- below larynx
- thyroid gland's fxn
- secrete TH (T3, T4) and change the BMR
- outer thyroid
- follicle cells
- inner layer
- protein rich colloid (fluid)
- thyroglobulin
- attaches to oxidized iodide (iodine), stores TH, and stimulates TH hydrolysis, secretion
- tyrosines
- also bond to iodine
- Goiter
- absent dietary iodide, TH can't be made=negative feedback=TSH levels up. TSH=trophic, so thyroid gland grows
- hypothyroid
- low TH, synthroid, more in women, low CO, cold, lethargic, low BMR, wt gain, lowered immune syst
- Hyperthyroid
- high TH, lose weight, high temp, high HR, sleeplessness
- results of thyroid probs
- antibodies chew at thyroid, and then it has more holes and allows mass amounts of hormones out-->autoimmune problem
- grave's disease
- autoimmune disese: antibodies act like TSH. gland oversecretes, trophic problem=goiter-like growth.
- parathyroid glands
- secrete PTH (a polypeptide protein hormone) MAIN mech for Ca2+ level control
- PTH
- released if low blood Ca, bones, kidneys, intenstines increase Ca levels
- parathyroid hormone
-
on kidney: ca reabsorp
on bone: dissolves crystals - calcitonin
- stores ca, does opp of parathyroid hormone
- islets of langerhans
- endocrine cells in pancreas w/ alpha and beta cells
- alpha cells
-
like eating alphabet soup when hungry
secrete glucagon, stimulate glycogenolysis and lipolysis, when blood glucose is low - gluconeogenesis
- forms glucose from non-carbs
- gylcogenolysis
- glycogen split-->glucose
- beta cells
- secrete insulin when blood glucose is high, glucose goes into cells, glucose is turned into glycogen, fat for storage, lowers blood glucose
- when cells have enough glucose, and more uptake is needed
- enough glycogen will create fat
- Thymus
- below thyroid, produces t cells of immune system, and their stimulating hormones, produces prostaglandins
- gonads
- secrete steroid hormones: test, est, progest
- placenta
- secretes est, progest, hCG, somatomammotrophin
- prostaglandins
-
(wbc-->injury)
eicosanoid family - prostaglandin fxn
-
antagonistic to tissues
change permiability
vaso constrict/dilate
blood vessle maintenance
change infmammation
clotting/not
musc contract/relax
ovulation
gastric secretion - MR
- metabolic rate= O2 consumption/min
- BMR
- MR of awake, relaxed not eating person
- what increases BMR?
-
maleness/testosterone
youth
fat vs muscle
surface area
exercise - PPARgamma
- activated receptors of adipocytes that secrete regulatory fxns--> muscle responds more to insulin
- adipocyte hormones
- TNF alpha, resistin, leptin, reduce the sensitivit of muscle to insulin
- leptin
- tells body that it is full, esp when fat is stored more. more leptin = more adiposity
- glucagon
- maintains blood glucose, stimulates glyconeolysis in liver, gluconeogenesis, liploysis, ketogenesis at other places
- insulin
- anabolic, but adrenal, thyroid and ant. pit. antagonize it
- normal fasting glucose
- 65-105
- max glucose
- 107 afer meal, or glucose dumping in urin occurs
- min glucose
- 50 b/w meals
- diabetes mellitus
- chronic high blood glucose
- Type 1
- insulin dependant: not enough beta cells, glucose can't enter cells, ketoacidosis, high glucagon levels=glycogenolysis in liver
- type 2
- more common, insulin resistant, happens in overwt ppl, treated w/ diet, exercise
- gestational diabetes
- preggers
- cortisol changes metabolism
- lipolysis, ketogenesis, protein breakdown
- protein breakdown
- aa's for liver to gluconeogenesis
- protein synthesis from
- insulin, thyroxine, and GH
- somatostatin
- from hypothal, inhibs GH
- circadian pattern
- lots of GH at night, not during day
- high blood glucose
- stops GH secretion
- excess growth hormone
- excess before epiphyseal discs stop growing, or after
- dwarfism
- lack of GH during childhood
- acromegaly
- excess GH in adults, weird pics