Flashcards in The final Deck (51):
what are the effects of the active form of Vit D. 1,25-dihydroxycholecalciferol?
1. increase calcium and phosphate absorption in the kidneys, intestine and bones. Increasing extracellular fluid concentration and forming a feedback regulation.
What domains are present on the Vit D receptors?
hormone binding and DNA binding domains
What is required for Vitamin D to induce DNA transcription?
must form a complex with retinoid-X receptor in order for both to bind to DNA and induce trasncription. used as a control check point.
Can vitamin cause activation of inhibition of DNA transcription when bound with the retinoid -X receptor?
Can induce activation and inhibition
Where are the majority of vitamin D receptors located?
1. most cells of the body in the nuclei of the cells
What is calbindin?
calcium binding protein which is expressed in intestinal cells to increase calsium reabsorption
Where does calbindin operate?
brush border of epithelial cells to move Calcium into the cell cytoplasm
How does absorbed calcium migrate through the cell?
facilitated diffusion through the basolateral membrane
WHat are characteristics of postganglionic sympathetic fibers?
1. pass through the gray rami
2. Type C
3. 8% of fibers in the average nerve
4. control blood vessel, piloerection, sweat glands
Waht are splanchnic nerves?
preganglionic fibers and visceral sensory fibers that supply the abdominal viscera when synapsed in the prevertebral ganglia.
Where do the greater, lesser and least splanchnic nerves arise from?
1. greater: T5-T9 synapse in celiac ganglion
2. lesser: T10-T11 synapse in superior mesenteric ganglion
3. least: T12 synapse in aorticorenal ganglion
How many parasympathetic fibers are in the vagus nerve?
75% of all parasympathetic nerves are located where?
in the vagus nerve
What are features of postganglionic parasympathetic fibers?
1. they locate in the wall of an organ
2. they use Ach as neurotransmitter
What is the funciton of the oculomotor nerve?
1. provides muscular innervation to 4 of the 6 extrinsic eye muscle and levator palpebra superioris.
What are the parasympathetic pathways of the ocuomotor nerve?
1. preganglionic: from edinger-westphal nucleus to the ciliary ganglion
2. postganglion: from ciliary ganglion to the sphincter pupillae muscle
What is the function of teh facial nerve?
1. facial expression
2. sensation from anterior 2/3 of tongue.
What are the pathways of the parasympathetics of the facial nerve?
1. pre: from superior salivatory/lacrimal nuclei to submandibular/sublingual ganglia
2. post: to the lacrimal gland, subandibular, sublingual, and mucous gland of mouth/nose
What are the function of the glossopharyngeal nerve?
1. carry general sensation and sensation of taste from the posterior 1/3 of teh tongue.
What are the parasympathetic pathways of teh glossopharyngeal nerve?
1. pre: from the inferior salivatory nucleus to the otic ganglion
2. post: from otic ganglion to parotid gland
What is the funciton of the vagus nerve?
1.muscle motor supply to 4th and 5th pharyngeal arches, swallowing and speaking.
What is the parasympathetic innervation of the vagus nerve?
1. pre: from dorsal motor nucleus
2. post: myenteric plexus of gut tube to left colic flexure.
3. provide parasympathetics to thoracic and abdominal organs
What is the entire course of the vagus nerve?
1. parallels and innervates teh esophagus.
2. posterior to each lung root
3. pierce diaphragm at T10
4. which point becomes gastric nerve
5. supplies thoracic cavity viscera
What is the entire process to form norepinephrine?
1. tyrosine hydroxylated to dopa
2. dopa decarboxylated to dopamine
3. dopamine hydroxylated to norepinephrine(occurs in vesicles)
How is epinephrine formed?
1. 80% of norepinephrine is methylated to produce epinephrine.
WHat are four methods that will remove norepinephrine?
3. monamine oxidase used to destroy at nerve endings
4. catechol-omethyl transferase present in all tissues
What is the reason circulating norepinephrine has a much longer half-life than the ones located within tissue?
circulation has no catechol-o-methyl transferase therefore has increased half-life, until it enters a tissue or liver.
Where are muscarininc acetylcholine receptors found?
1. found on all effector cells stimulated by postganglionic cholinergic neurons
Where are nicotinic Ach receptors found?
autonomic ganglia at synapse between preganglionic and postganglionic neurons. also at skeletal muscle neuromuscular junction
Alpha adrenergic receptors are generally excited by what NT?
alpha adrenergic receptor are stimulated by norepinephrine. beta receptors also at a lesser extent.
What NT excites alpha and beta adrenergic receptors with equal stimulation?
What are teh effects of activating alpha adrenergic receptors?
mostly contsticts. with pupil dilation.
Think of a fish, and pulling the tails in opposite direction, what happens to the "loop"
What are the effects of activating Beta 1 adrenergic receptors?
tachycardia, increased contraction, lipolysis
Equivalent to More ENERGY
What are the effects of Beta2 adrenergic receptor activation?
opposite of alpha 1. bronchdilation, glycogenolysis, uterus relaxation
What are the effects of beta 3 adrenergic receptor activation?
thermogenesis. increase heat production processes.
What are sympathomimetic drugs?
Which drugs are able to cause the release of norepinephrine?
ephedrine, tyramine, amphetamine
What drugs block the adrenergic activity?
reserpine, guanethidine, phenoxybenzamine, propranolol, metoprolol, hexamethonium
What are drugs that act on cholinergic effector organs?
parasympathomimetic drugs: pilocarpine/methacholine act directly on muscarinic receptors and are not rapidly destroyed
What drugs inhibit acetylcholinesterase?
neostigmine, pyridostigmine, ambenonium
What drugs block cholinergic activity?
atropine, homatropine, scopolamine
Where are sperm stored until ejaculation?
How long do sperm remain in epididymis until they gain motility?
Leydig cells produce what hormone?
When are leydig cells the most and least active?
1. most: newborn male, and adult males
2. least: during chidhood until puberty
How is testosterone transported after secreted?
1. bound to albumin of with beta globulin. it will be trasnferred to tissue or degraded into inactive subsequent products.
What is most testosterone converted to when it enters tissue?
dihydrotestosterone, with high concentration to prostate and external genitalia during development
What is the fate of testosterone that is not fixed int he liver?
1. converted to androsterone and dehydroepiandroesterone in the liver
2. conjugated as glucuronides or sulfate
3. excreted into gut as bile or urine
What are sertoli cells?
locate in seminiferous tubules, surround primary spermatocytes to mature sperm. help form estrogen from testosterone
What controls the number of cells of leydig and their secretions?
FSH and LH can control the spermatogenesis. both are from the ant.pituitary gland.