Term
| Describe function and parts of a Muscle Spindle? |
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Definition
Parts:spindle shaped that contains stretch receptor
Function: to maintain muscle tone |
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Term
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Definition
| afferent stimulus travels through sensory neuron to afferent neuron to create response. |
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Term
| tonic activation of muscle spindle |
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Definition
| afferent signal to spinals chord synapses onto alpha motor neuron to maintain tone in extrafusal fibers |
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Term
| describe a knee-jerk reflex |
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Definition
| a stretch of knee causes efferent signals from to spinal chord which cause somatic motor neuron of the quadriceps muscle to fire and a twitch to occur |
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Term
| what could affect a reflex |
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Definition
| inhibitory signals from brain, problems in sensory or motor neuron, problems in neuromuscular junction |
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Term
| describe alpha-gamma coactivation |
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Definition
alpha motor neurons innervate intrafusal muscle units
gamma motor neuron: innervate intrafusal fibers of muscle spindle.
as alpha motor neurons fire the muscle fiber contracts and gamma motor neurons fire at the same rate to keep stretch receptor in intrafusal fiber taut.
w/o gamma motor neurons the contraction of muscles of shorten the stretch receptor and cause loss of contraction. |
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Term
| Describe the Golgi Tendon Reflex |
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Definition
| excessive load/stretch in golgi tendon cause afferent signal to spinal chord. this signal inhibits motor neurons and release of contraction. |
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Term
| give one example of a more detailed reflex |
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Definition
| stepping on a nail. Primary afferent neuron diverges at the spinal chord |
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Term
| path of motor coordination to brain |
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Definition
| sensory information -> spinal chord, cerebellum -> brain stem -> thalamus -> sensory cortex |
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Term
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Definition
| connects directly to cerebellum, helps maintain balance and provides spatial orientation |
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Term
| how does unconscious movement postural and spinal reflex) work? |
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Definition
| occurs at level of cerebellum, brain stem, and spinal cord. no integration to the cortex. |
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Term
| what happen when proprioceptor are damaged? |
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Definition
| when hands are put out, eyes are closed, or head it tilt back balance can be lost |
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Term
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Definition
| there is a mismatch in visual information and vestibular apparatus ( eyes say your are still, but vestibular apparatus says otherwise. |
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Term
| pattern generators and examples |
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Definition
neural circuits that when activated have a pattern.
playing instruments, respiratory pattern (located in medulla/pons), walking |
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Term
| motor pathways are like what in the brain? |
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Definition
| homonculus. size of brain proportion in brain for interpretation is not dependent of size but number of nerve endings. |
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Term
| descent of a motor action |
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Definition
| axon from the motor cortex -> midbbrain -> medulla ( where is crosses in the pyramids to the contrilateral side) -> descend down spinal chord |
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Term
| name major organs and glands that release hormones |
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Definition
| hypothalamus, pituitary (anterior & posterior), thyroid, parathyroid, adrenal glands, pancreas, gonads, heart, kidneys, GI, Liver, Adipose tissue |
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Term
| name and describe the two basic hormone types? |
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Definition
hydrophobic - low water solubility, carried by carrier proteins, able to pass through lipid bilayer, receptors usually in cytoplasm, slow and long lasting
Hydrophilic - water soluble, proteins or peptides, receptor usually on cell surface, fast and short lasting |
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Term
| example of hydrophobic hormones |
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Definition
Steroid hormones - cortisol, aldosterone, androgens
Vitamin D, Thyroid hormones - T3 & T4, |
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Term
| examples of hydrophilic hormones |
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Definition
| hypothalamic hormones, pancreatic hormones, epo, GI hormones, catecholamines - Norepinephrine and Epinerphirne |
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Term
| explain G(s & i) protein coupled pathway and their difference |
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Definition
| hormone binds and causes conformational change in 7 transmembrane helix receptor. the causes the alpha subunit to exchange a GDP for GTP and the beta/gamma subunits to disassociate. the alpha subunit then activates or inactivates adenylyl cylase that in the case of activation converts ATP to cAMP. cAMP activates protein kinase A that activated more downstream target. |
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Term
| what can the beta/gamma subunits of the g protein do |
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Definition
| open ion channels as in muscarinic receptor |
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Term
| what are the 4 ways a Gs protein coupled mechanism are turned off? |
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Definition
| remove hormone from receptor, alpha subunit has intinsic GTPase properties so once GTP is hydrolyzed to GDP the beta/gamma subunit can reassociate, activating cAMP phosphodiesterase converting cAMP -> AMP, Phosphotases to dephosphorylate proteins downstream |
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Term
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Definition
| blocks GTPase activity of Alpha subunit of g protein |
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Term
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Definition
| inhibits cGMP phosphodiesterase which breaks down extending vasodilation in penis |
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Term
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Definition
| receptor with single tansmembrane segment that may dimerize and (cross)phosphorylation of a tyrosine residue happens that allows a phosphorylation cascade. |
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Term
| describe Guanylyl cyclase |
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Definition
| receptor can be in the cell or on the cell, they have guanylyl cyclase activity which produces cGMP from GTP. this goes on to activate more proteins. |
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Term
| describe the Gq coupled receptor pathway |
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Definition
| hormone binds and the receptor had a conformational change, the alpha subunit then replaces GDP for GTP and the beta/gamma subunit disassociate. alpha subunit activates phospholipase C. this break up PIP3 to IP3 and DAG. soluble IP3 then cause release of Ca2+ from ER and DAG cuses activation of Protein kinase C which then phosphotylate other proteins |
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Term
| how does one turn off the Gq protein receptor pathway |
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Definition
| remove hormone from receptor, GTPase of alpha subunit, IP3 can be broken down metabolically thus redeucing release of Ca2+ in cell, phosphotases deposhphorylate down stream proteins |
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Term
| describe the alpha adrenergic receptors |
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Definition
alpha 1 -> Gq, more responsive to norepinephrine than epinephrine,
functions: secretion, contraction of smooth muscle causing vasoconstriction
Alpha 2:Gi, more responsive to norepinephrine than epinephrine, funtion: inhibitory |
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Term
| describe adrenergic Beta receptors |
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Definition
Beta 1: Gs, responsive to epinephrine more than norepihephrine,function: increased Ca2+ ion channel conductivity, increased contractility of heart and heart rate
Beta 2: Gs, more responsive to Epinephrine that norepinephrine, function: increase vasodilation, especially sketetal muscle, increase bronchodilation
Beta 3: Gs, more responsive to epinephrine that norepinephrine, Function: work in adipocytes to increase fat breakdown. |
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Term
| one issue with early beta bockers |
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Definition
| the blocked beta2 receptors which for some asthma patients prevented bronchioles from dilating. |
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Term
| name two portions of the pituitary bland |
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Definition
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Term
| what does the posterior pituitary secrete |
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Definition
| neuroendocrine cell in hypothalamus make and transport ADH and oxytocin to the posterior pituitary where they are released. |
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Term
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Definition
| antidiuretic hormone or vasopressin, controls osmoregulation and blood pressure, when secreted it causes the reabsorption of water in the kidney by inserting aquaporin, Alcohol inhibits ADH |
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Term
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Definition
| casues conraction of smooth muscle in through positive feed back loop. examples the uterus during birth and the myoepithelial cells in milk letdown. |
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Term
| what general types of hormones does the hypothalamus secrete to the anterior pituitary? |
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Definition
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Term
| name and describe the two hormones that affect organs released from the anterior pituitary |
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Definition
Growth hormone - promotes growth in muscle, bone, and other tissues
Prolactin - targets breast in women to create milk, inhibit LH and FSH, is inhibited by dopamine. |
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Term
| name the 4 trophic hormone released from the anterior pituitary and what other endocrine organ they effect? |
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Definition
TSH - Thyroid
ACTH - Adrenal Cortex
FSH/LH - Gonads |
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Term
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Definition
Diabetes Mellitus - excess glucose in blood
Diabetes Insipidus - ADH deficiency |
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Term
| what inhibits release of growth hormone |
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Definition
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Term
| what increases release of growth hormone |
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Definition
| GHRH - growth hormone releasing hormone |
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Term
| how does growth hormone work |
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Definition
by binding directly on receptors on target cells
eg. stunulates liver to produce IGF-1 (Insulin-like growth factor) |
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Term
| when is Growth hormone most important |
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Definition
| childhood and "growth years" |
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Term
| what can excess secretion of GH do before and after puberty? |
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Definition
before - gigantism
after - acromegaly(thickening of bones) |
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Term
| if GH is deficient in childhood what could happen? |
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Definition
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Term
| if GH is deficient in childhood what could happen? |
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Definition
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Term
| give on example of negative feedback control on a trophic hormone? |
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Definition
| T3 and T4 being inhibitory on TSH and TRH |
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Term
| describe thyroid stimulating hormone. |
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Definition
| stimulated by thyroid releasing hormone from hypothalamus and responsible for maintenance and growth thyroid gland. stimulates release of T3 and T4 in thyroid. |
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Term
| what is more potent: T4 or T3 |
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Definition
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Term
| if thyroid malfunctions in childhood what are some possible results |
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Definition
| mental retardation and no sexual maturation. |
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Term
| what are some primary effects of thyroid hormones? |
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Definition
| promote metabolism, promote adaptation to heat, increase heat production |
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Term
| symptoms of hypothyroidism |
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Definition
| gain weight, intolerant to cold |
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Term
| what does the level of iodine have on thyroid levels |
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Definition
| since thyroid hormone need to be iodided if not enough is available them the hormone may not be able to be produced and effects of hypothyroidism maybe seen.but high levels of TRH and TSH |
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Term
| what would be a secondary problem of the thyroid? |
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Definition
| a tumor on the pituitary that causes higher than need amount of TSH to be secreted. thus higher T3 and T4, but lower TRH.symptons maybe intolernat to heat and weight loss (tachichardia) |
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Term
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Definition
| an increase in size of the thyroid gland. usually from over production. |
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Term
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Definition
| antibodies of the body activate TSH receptor so T3 and T4 are over produced and TSH and TRH level are low. one symptom is bulging eyes. |
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Term
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Definition
| relaesed by anterior pituitary but CRH from stimulates pituitary. stimulate adrenal cortex to secrete cortisol. funtions: anti-inflammatory. over does of exogenous cortisol can lead to atrophy of adrenal cortex. rounding of face and central obesity |
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Term
| what does FSH do in males and females |
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Definition
males - stimulate sperm production
females - maturation of oocyte and eventually ovulation |
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Term
| what does LH do in women and men? |
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Definition
women - stimulate production of estrogen and progesterones
males - production of androgens |
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Term
| how does birth control work |
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Definition
| add estrogen and pr0gesterone that inhibit FSH and LH, preventing ovulation |
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Term
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Definition
| stimulate glycogen breakdown, increaes glucose, maintains levels of glucose in times of fasting |
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Term
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Definition
| elevated in response to rise in level of blood glucose and promotes intake and production of glycogen |
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Term
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Definition
Parathyroid hormone - when extracellular Ca2+ is lowered parathyroid hormone is released and causes bone to break down.
when Ca2+ increase it is inhibited and calcium is lost in urine and feces |
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Term
| name the three types of muscle? |
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Definition
Skeletel - attached to bones and tendons (striated)
Smooth muscle - not striated
Cardiac - striated |
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