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BIPN 100
Lecture 15-18
65
Biology
Undergraduate 4
02/21/2010

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Term
Describe function and parts of a Muscle Spindle?
Definition
Parts:spindle shaped that contains stretch receptor

Function: to maintain muscle tone
Term
single synapse felex
Definition
afferent stimulus travels through sensory neuron to afferent neuron to create response.
Term
tonic activation of muscle spindle
Definition
afferent signal to spinals chord synapses onto alpha motor neuron to maintain tone in extrafusal fibers
Term
describe a knee-jerk reflex
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
Term
what could affect a reflex
Definition
inhibitory signals from brain, problems in sensory or motor neuron, problems in neuromuscular junction
Term
describe alpha-gamma coactivation
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.
Term
Describe the Golgi Tendon Reflex
Definition
excessive load/stretch in golgi tendon cause afferent signal to spinal chord. this signal inhibits motor neurons and release of contraction.
Term
give one example of a more detailed reflex
Definition
stepping on a nail. Primary afferent neuron diverges at the spinal chord
Term
path of motor coordination to brain
Definition
sensory information -> spinal chord, cerebellum -> brain stem -> thalamus -> sensory cortex
Term
Vestibular apparatus
Definition
connects directly to cerebellum, helps maintain balance and provides spatial orientation
Term
how does unconscious movement postural and spinal reflex) work?
Definition
occurs at level of cerebellum, brain stem, and spinal cord. no integration to the cortex.
Term
what happen when proprioceptor are damaged?
Definition
when hands are put out, eyes are closed, or head it tilt back balance can be lost
Term
explain sea sickness
Definition
there is a mismatch in visual information and vestibular apparatus ( eyes say your are still, but vestibular apparatus says otherwise.
Term
pattern generators and examples
Definition
neural circuits that when activated have a pattern.

playing instruments, respiratory pattern (located in medulla/pons), walking
Term
motor pathways are like what in the brain?
Definition
homonculus. size of brain proportion in brain for interpretation is not dependent of size but number of nerve endings.
Term
descent of a motor action
Definition
axon from the motor cortex -> midbbrain -> medulla ( where is crosses in the pyramids to the contrilateral side) -> descend down spinal chord
Term
name major organs and glands that release hormones
Definition
hypothalamus, pituitary (anterior & posterior), thyroid, parathyroid, adrenal glands, pancreas, gonads, heart, kidneys, GI, Liver, Adipose tissue
Term
name and describe the two basic hormone types?
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
Term
example of hydrophobic hormones
Definition
Steroid hormones - cortisol, aldosterone, androgens
Vitamin D, Thyroid hormones - T3 & T4,
Term
examples of hydrophilic hormones
Definition
hypothalamic hormones, pancreatic hormones, epo, GI hormones, catecholamines - Norepinephrine and Epinerphirne
Term
explain G(s & i) protein coupled pathway and their difference
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.
Term
what can the beta/gamma subunits of the g protein do
Definition
open ion channels as in muscarinic receptor
Term
what are the 4 ways a Gs protein coupled mechanism are turned off?
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
Term
what does Cholera do?
Definition
blocks GTPase activity of Alpha subunit of g protein
Term
how does viagra work?
Definition
inhibits cGMP phosphodiesterase which breaks down extending vasodilation in penis
Term
Describe tyrosine kinase
Definition
receptor with single tansmembrane segment that may dimerize and (cross)phosphorylation of a tyrosine residue happens that allows a phosphorylation cascade.
Term
describe Guanylyl cyclase
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.
Term
describe the Gq coupled receptor pathway
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
Term
how does one turn off the Gq protein receptor pathway
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
Term
describe the alpha adrenergic receptors
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
Term
describe adrenergic Beta receptors
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.
Term
one issue with early beta bockers
Definition
the blocked beta2 receptors which for some asthma patients prevented bronchioles from dilating.
Term
name two portions of the pituitary bland
Definition
anterior and posterior
Term
what does the posterior pituitary secrete
Definition
neuroendocrine cell in hypothalamus make and transport ADH and oxytocin to the posterior pituitary where they are released.
Term
ADH
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
Term
Oxytocin
Definition
casues conraction of smooth muscle in through positive feed back loop. examples the uterus during birth and the myoepithelial cells in milk letdown.
Term
what general types of hormones does the hypothalamus secrete to the anterior pituitary?
Definition
releasing and inhibiting
Term
name and describe the two hormones that affect organs released from the anterior pituitary
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.
Term
name the 4 trophic hormone released from the anterior pituitary and what other endocrine organ they effect?
Definition
TSH - Thyroid
ACTH - Adrenal Cortex
FSH/LH - Gonads
Term
two types of diabetes
Definition
Diabetes Mellitus - excess glucose in blood

Diabetes Insipidus - ADH deficiency
Term
what inhibits release of growth hormone
Definition
Somatostatin
Term
what increases release of growth hormone
Definition
GHRH - growth hormone releasing hormone
Term
how does growth hormone work
Definition
by binding directly on receptors on target cells
eg. stunulates liver to produce IGF-1 (Insulin-like growth factor)
Term
when is Growth hormone most important
Definition
childhood and "growth years"
Term
what can excess secretion of GH do before and after puberty?
Definition
before - gigantism
after - acromegaly(thickening of bones)
Term
if GH is deficient in childhood what could happen?
Definition
pituitary dwarfism
Term
if GH is deficient in childhood what could happen?
Definition
pituitary dwarfism
Term
give on example of negative feedback control on a trophic hormone?
Definition
T3 and T4 being inhibitory on TSH and TRH
Term
describe thyroid stimulating hormone.
Definition
stimulated by thyroid releasing hormone from hypothalamus and responsible for maintenance and growth thyroid gland. stimulates release of T3 and T4 in thyroid.
Term
what is more potent: T4 or T3
Definition
T3
Term
if thyroid malfunctions in childhood what are some possible results
Definition
mental retardation and no sexual maturation.
Term
what are some primary effects of thyroid hormones?
Definition
promote metabolism, promote adaptation to heat, increase heat production
Term
symptoms of hypothyroidism
Definition
gain weight, intolerant to cold
Term
what does the level of iodine have on thyroid levels
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
Term
what would be a secondary problem of the thyroid?
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)
Term
what is a goiter?
Definition
an increase in size of the thyroid gland. usually from over production.
Term
what is graves disease?
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.
Term
ACTH
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
Term
what does FSH do in males and females
Definition
males - stimulate sperm production
females - maturation of oocyte and eventually ovulation
Term
what does LH do in women and men?
Definition
women - stimulate production of estrogen and progesterones
males - production of androgens
Term
how does birth control work
Definition
add estrogen and pr0gesterone that inhibit FSH and LH, preventing ovulation
Term
glucagon
Definition
stimulate glycogen breakdown, increaes glucose, maintains levels of glucose in times of fasting
Term
insulin
Definition
elevated in response to rise in level of blood glucose and promotes intake and production of glycogen
Term
how is Ca2+ regulated
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
Term
name the three types of muscle?
Definition
Skeletel - attached to bones and tendons (striated)
Smooth muscle - not striated
Cardiac - striated
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