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35 Cards in this Set
- Front
- Back
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_____ and _____ are the 2 main systems for coordinating the fxns of various body organs and they are functionally integrated
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endocrine and nervous sys
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What are 'MUSCARINIC RECEPTOR STIMULANTS' used for in medicine?
(*THERE ARE 4 USES) |
1. STIMULATE INTESTINES
2. STIMULATE URINARY BLADDER 3. DILATE PERIPHERAL BLOOD VESSELS 4. TREAT 'MYASTHENIA GRAVIS' |
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contrast the fxns of the endocrine system and the nervous system.
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Major roles of nervous system
- coordination of muscle motility - regulation of exocrine glands - the residency and coordination of intellect maj role of endocrine sys - predominant regulator of the rate and quality of metabolic reactions Nervous sys response - ultra-fast as well as localized responses Endocrine responses - response to endo regulation is slow - the metabolic respones to these hormones is broad how the nervous sys works - by establishing direct "wiring' connections between a center and cells within the effector organ Endocrine sys works - bathes all body cells with hormones dissolved in fluid surrounding the cells - non-specific anatomical space for routing - allows for infinite interactions in a reduced space Nervous sys signals - electrical Endocrine sys signals - chemical messengers recognized by specific hormone receptors in cells level of response to nerve stim - directly correlated with the frequency of pulses and # of nerve fibers involved effect of hormones - associated with the dosse of hormone and time of exposure |
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1. hormones are (traditional definition)
2. why isn't it an accurate definition? 3. Why are CO2 and prostaglandins not considered hormones |
1. hormones are
- chemical agents - synthesized and secreted by curcumscribed and specialized glands - circulated by blood to another part of the body - to stimulate specific tissues 2. not accurate b/c - the source of hormones isn't always a well defined gland (ie. cells in intestine secrete hormones) - hormones not always carried by the blood to target cells b/c they sometimes diffuse to nearby tissues through ECF - they can be stimulatory or inhibitory of a given process 3. not hormones b/c specific cells do not produce them |
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paracrine regulation
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hormones reach nearby target cells by diffusion through the extracellular fluid (not blood stream)
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autocrine regulation
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chemical feedback action of a given hormone to its own secreting cells
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pheromones
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substances produced by animals that specifically serve as a stimulus to other animals of the same species for one or more behavioral responses.
impt smell signals to finding a sexual partner during the estrous cycle |
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neurohormones
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secreted by neurons (nervous tissue)
often enter bloodstream and act on distant organs that are not part of the nervous sys (oxytocin/ ADH/ vasopressin/ hypothalamic releasing hormones) |
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neurotransmitters
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chemicals released by nerve endings into the synaptic cleft where they are inactivated w/o release of the neurotransmitter inot the blood (norepi)
however norepi can be released directly into the blood from the adrenal medulla, in which case it is a hormone |
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neuroendocrine reflex
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physiological mechanism in which the nervous and endocrine systems are part of a chain that often synchronizes interactions b/w 2 individuals (male & female/ mother & offspring)
- in reflex ovulation, vaginal stimulation during coitus (cat and rabbit) activates the afferent nerves to teh hypothalamus which causes the release of GnRH in to the pituitary gland - GnRH stimulates the release of LH into the bloodstream from the pituitary gland - LH causes ovulation w/in 12-24 hrs - milk ejection reflex - cervical reflex of the uterus |
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the endocrine sys is composed of ____
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9 well-defined endocrine glands
- pineal - hypothalamus - pituitary - thyroid - parathyroid - pancreas - adrenals - testis - ovary 4 organs in which endocrine secretions are a secondary fxn - heart - intestine - kidney - placenta |
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What does each abbreviation stand for?
1) TRH 2) GH 3) P4 4) DHT 5) GnRH 6) TRH 7) GHRH 8) GHIH 9) PIH 10) CRH 11) MSH(s) 12) T3 13) T4 |
1) Thyrotropin- releasing hormone
2) Growth hormone (somatotropin) 3) Dihydrotestosterone 4) Progesterone 5) gonadotropin releasing hormone 6) thyrotropin-releasing hormone 7) growth hormone releasing hormone (somatomedin) 8) growth hormone inhibiting hormone (somatostatin) 9) prolactin inhibiting hormone (dopamine) 10) Corticotropin releasing hormone 11) menocyte stimulating hormone 12) Triiodthyronine 13) thyroxine |
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what 4 organs have an endocrine function? What hormones do they secrete?
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HEART
- atrial natriuetic peptide (ANP) INTESTINE - cholecystokinin (CCK) - gastrin - gastrin inhibitory peptide (GIP) - Secretin Vasoactive intestinal peptide (VIP) - Somatostatin (GHIH) - motilin - neurotensin KIDNEY - 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) - erythropoietin PLACENTA - hypothalamic and pituitary hormones - human chorionic gonadotropin (hCG - pregnant mare serum gonadotropin (equine chorionic gonadotropin) (PMSG, eCG) - estrogens - progestins - androgens - inhibin - relaxin |
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a leydig cell is an example of what kind of
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autocrine
to tubule = paracrine to blood = endocrine |
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give an example of a neurohormone
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oxytocin
ADH releasing hormones |
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give an example of a neurotransmitter that can also be a neurohormone
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norepi
serotonin |
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what tissues do not respond to T4
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brain
spleen testis |
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T4 stimulates what tissues the most?
the least? not at all? |
most
- heart - gastric mucosa least - skeletal muscle - diaphragm not at all - spleen - testis - brain |
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Parts of the pituitary and what hormones they secrete
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pars distalis
- 2/3 of the hypophysis - 50% chromophilic - acidophilic (40% GH and Pr secreting) - basophilic (10% TSH, LH, FSH, ACTH, beta-lipotropin secreting) - 50% chromophobic (inactive states of acidophilic and basophilic cells following degranulation) pars intermedia - less than 5% of the hypophysis - cells migrate into the pars distalis and constitute the ACTH and B-LPH - cells secrete MSH and small quantities of ACTH Neurohypophysis - posterior lobe - consists of cells, pituicytes, and unmyelinated nerve fibers derived from neurosecretory neurons in the hypothalamus - nerve fibers contain oxytocin and ADH in transit nad are secreted into the systemic circulation |
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describe the 2 major hormones secreted by the pituitary (pars distalis)
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TSH
- stimulates thyroid gland - alpha subunit = 92 ar, beta subunit = 112, CHO= 16% Prolactin - stimulates mammary gland - 199 ar - S-S (3) |
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what hormones come from the adrenal gland
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cortisol
j- antistress aldosterone - Na+/K+ regulation norepi/ epi - stim HR & blood glucose |
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what areas of the hypothalamus have an endocrine fxn?
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paraventricular nucleus
supraoptic nucleus arcuate nucleus preoptic area |
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if you have a tumor in supraoptic nucleus of hypothalamus, what symptoms do you get?
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ADH hormone symptoms
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if the pituitary gl is enlarged, it may press on
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optic chiasma
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1) what happens if you inject estrogen into the hypothalamus?
2) put lesion in hypothalamus? |
1) get heat behavior
2) block heat behavior but don't affect ovarian cycle |
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_________ lesions can result in continuing heats despite spay
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hypothalamic
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hypothalamus pituitary dependent loops
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adrenals
thyroid ovary testis growth hormone prolactin |
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the primary capillary plexus is located where?
secondary plexus? |
primary
- hypothalamus secondary - adenohypophysis |
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frequent places of endocrine feedback failure
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The primary gland
The secondary gland Ectopic secretion First messenger (chemical structure) Receptor Second messenger |
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1) proportional mode
2) integral mode 3) derivative mode |
1) proportional to demand
no overshooting/ no cycling Causes offset: deviation from setpoint by change in load (insulin needs when eat big) 2) eliminates offset in proportional mode measures error signal many times until set point (summing) small corrective actions (hemithyroidectomy) 3) Measures rate of change of error signal (not absolute value) Anticipates magnitude of future error i.e. large load of glucose in the intestine = large secretion of insulin |
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what are the advantages/ disadvantages of on/off control
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advantage: simplicity
disadvantage: cycling |
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what happens when you inject aldosterone (what do you expect to see)
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Lot of K+ in urine
Low Na+ in urine Lots of Na+ in blood |
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what happens if you have low calcium?
high calcium? what does calcium do? |
< Ca = >excitability by facilitating Na/K to cause action potential
>Ca = < excitability bc stabilizes membrane calcium fxns: 2nd messenger, activate enzymes, proteins |
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parathyroid hormone vs calcitonin
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Parathyroid hormone induces osteoclasts to break down bone and liberate Ca2+
Calcitonin prevents calcium liberation so not too much ca2+ in blood |
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regulation of calcium tests (suppression or stimulation)
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Inject calcium and measure PTH (suppression test)
- PTH should go down Inject calcitonin and measure calcium (should go down) Stim test - Inject parathyroid hormone and calcium should go up - Or inject PTH and calcium should go up |
