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Exam 3
n/a
69
Physiology
Undergraduate 3
04/25/2010

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Term
functional atrophy
Definition
when the muscles you use for everyday function deplete because you don't use them anymore
Term
muscles affected by functional atrophy
Definition
gluteal muscles, extensor muscles of the neck and back, muscles of the trunk and lower extremities (muscles used for gravity)
Term
effect of spaceflight on muscles
Definition
increased breakdown of muscel proteins, decreased muscle volume, strength, mass, endurance, muscle nitrogen
Term
intervention techniques for atrophy in spaceflight
Definition
diet and exercise techniques (still doesn't eliminate atrophy)
Term
black widow spider venom
Definition
causes explosive release of ACh
-prolonged depolarization leads to respiratory paralysis=death
-blocks voltage-gated na+ channels and they are trapped in an inactivated state and are not capable of opening
-prohibits new action potential from firing
Term
botulinum toxin
Definition
blocks release of ACh from terminal button in response to a motor neuron action potential
-food poisoning
-prevents muscles from responding to nerve impulses, leads to respiratory failure (diaphragm cant contract)=death
-most lethal poison known
Term
curare
Definition
blocks action of ACh at receptor-channels on the motor end plate
-binds to receptors preventing ACh from receptors resulting in paralysis
-when enough bind the person dies due to inability to contract diaphragm
Term
organophosphates
Definition
irreversibly prevents inactivation of ACh
-death due to respiratory failure because diaphragm cant repolarize, return to resting state, and then contract again
-used in pesticides and military gases
Term
myasthenia gravis
Definition
an autoimmune disease that causes severe muscle weakness
-causes the destruction of ACh before it can be used
-treat it by administering a drug that prolongs the existence of ACh long enough to stimulate a sufficient action potential
Term
anabolic androgenic steroid
Definition
"build up of tissue"
"male producing"
"hormone"
Term
Effects of steroids on reproductive system
Definition
male: testes dont get enough stimulation from anterior pituitary gland and shrink, testosterone secretion and sperm production decrease
females: suppresses hormonal output, failure to ovulate, menstrual irregularities, deminishes breast size, lowers voice, increases facial hair
Term
effects of steroids on cardiovascular system
Definition
induces artherosclerosis, reduces HDL, elevates blood pressure, damages heart mscle
Term
effects of steroids on liver
Definition
creates liver dysfunction, increases risk of cancer
Term
liver dysfunction
Definition
liver is overloaded by the excess of steroid intake and cant inactivate them and prepare them for urine
Term
effects of steroids on behavior
Definition
agressive, hostile (controversial effects)
Term
addictive effects of steroids
Definition
risks are worse when you use steroids longer, many people are addicted, $1 billion in black market for selling steroids
Term
gene doping
Definition
gene therapy aimed at improving athletic performance, like promoting production of naturally occuring muscle-building chemicals
Term
complete heart block
Definition
when the conducting tissue between atria and ventricles is damaged and becomes nonfunctional
Term
pacemakers and speeds
Definition
normal-SA node=70bpm
abnormal
-AV node=50 bpm
-purkinje fibers=30 bpm (comatose)
Term
artificial pacemaker
Definition
inserted if you have an abnormally low hr, and it gives of rhythmic pulses to create a heart rate of 70 bpm
Term
ectopic focus
Definition
when the purkinje fibers are overly excited and initiate a premature action potential before the SA node initiates a normal one
-associated with anxiety, lack of sleep, caffeine, nicotine, or alcohol
Term
premature ventricular contraction (PVC)
Definition
produced by occasional abnormal impulses from a ventricular ectopic focus
Term
tachycardia
Definition
100 bpm or more, fast heart rate
Term
bradycardia
Definition
60 bpm or less, slow heart rate
Term
arrhythmia
Definition
variation from normal rhythym of the heart
Term
atrial flutter
Definition
rapid but regular sequence of atrial depolarizations at rates between 200 and 380 bpm, one out of every two or three atrial impulses passes to the ventricles (2:1, 3:1 rhythm)
-ventricles cant keep up because they cant fill that fast, if they did=death because of not enough blood flow to brain
Term
atrial fibrillation
Definition
rapid irregular uncoordinated depolarizations of the atria with no definite P waves=results in occasional lack of blood ejection from ventricles because not enough time to fill completely
Term
pulse deficit
Definition
difference in heart rate and pulse rate
-caused by not being able to palpate the heart rate in the wrist because not enough blood was pumped out of the ventricles
Term
ventricular fibrillation
Definition
very serious abnormality, the ventricular musculature exhibits uncoordinated, chaotic contractions, ineffectual pumps,if no rhythm is established in four minutes, irreversible brain damage occurs and possible death
Term
heart block
Definition
the atria still beat regularly but the ventricles occasionally fail to be stimulated and thus do not follow an atrial contraction, only every ssecond or third impulse will pass to the ventricles (2:1 or 3:1 block)
Term
cardiac myopathies
Definition
damage of heart muscles
Term
myocardial ischemia
Definition
inadequate delivery of oxigenated blood to the heart tissue
Term
necrosis
Definition
actual death of heart muscle cells due to blocked or ruptured blood vessels that supply that area of the heart
Term
acute myocardial infarction
Definition
"heart attack"
-when the heart muscle becomes necrotic
Term
Somatic motor neuron
-location of cell body
-# of neurons in pathway from spine to effector organ
-effector organ
-neurostransmitter
Definition
-cell body lies in spinal cord
-one single motor neuron
-skeletal muscle
-acytlcholine (ACh)
Term
acetylcholinesterase (AChE)
Definition
an enzyme located in the motor end-plate membrane that inactivates ACh
Term
motor end-plate
Definition
the specialized underlying potrion of the muscle cell membrane that the entire axon terminal ending fits into
Term
botox
Definition
-botulinum toxin put to use as a cosmetic tool
-helps to relax overly contracted muscles in the body, whether a disease or wrinkles, it wears off in 3-6 months and needs to be repeated
-doses aren't enough to cause food poisoning or complete paralysis of the muscles
Term
How to get muscle relaxation
Definition
prevent the release of ACh, thats what starts the excitation process, preventing its release will relax the muscle
Term
organization of skeletal muscle
Definition
whole muscle (organ)-muscle fiber (cell)-myofibril (intracellular structure)-thick and thin filaments (cytoskeleton elements)-myosin and actin (protein molecules)
Term
muscle fiber
Definition
a single skeletal muscle cell
Term
myofibril
Definition
structural contractile feature of a muscle fiber
Term
sarcomere
Definition
the functional unit of a skeletal muscle, the area between two Z lines
Term
thick and thin filaments
Definition
highly organized cytoskeletal elements-thick filaments assemblies of myosin, thin filaments assemplies of actin
Term
I band
Definition
consists of the remaining portion of the thin filaments that do not project into the A band, with a Z line right in the middle of it
Term
A band
Definition
made up of a stacked set of thick filaments along with the portions of the thin filaments that overlap on both ends of the thick filaments
Term
H zone
Definition
the lighter area within the A band in which the thin filaments do not reach
Term
Z line
Definition
Visible in the middle of each I band and on the ends of each sarcomere
Term
sarcolemma
Definition
plasma membrane of a muscle cell
Term
sarcoplasmic reticulum
Definition
modified endoplasmic reticulum that consists of a fine network of interconnected membrane encloded compartments surrounding each myofibril like a sleeve
Term
striations
Definition
dark and light bands like stripes that are visible when you look at the muscle tissue, caused by the z lines that separate the sarcomeres
Term
sliding filament theory
Definition
as all the sarcomeres throughout the muscle fiber's length shorten simultaneously, the entire muscle fiber shortens-the thin filaments slide together shortening the A band and bringing the Z lines closer together
Term
rigor mortis
Definition
"stiffness of death" a generalized locking in place of the skeletal muscles that begins 3 to 4 hours after death and completes in about 12 hours
-Ca comes into cell causing actin and myosin to bind and they stay bound
Term
pulmonary circuit
Definition
blood circulation between heart and lungs
Term
systemic circuit
Definition
blood circulation between heart and the rest of the body
Term
bicuspid valve
Definition
separates the left atrium from the left ventricle
Term
tricuspid valve
Definition
separates the right atrium from the right ventricle
Term
pulmonary valve
Definition
prevents blood traveling to lungs through the pulmonary veins from going back into the right ventricle
Term
aortic valve
Definition
prevents blood traveling to the aorta from going back into the left ventricle
Term
chordae tendinae
Definition
thin, fibrous cords of tendinous-type tissue that prevent atrioventricular valves from being everted
Term
papillary muscles
Definition
attachment sites of chordae tendinae; when ventricles contract, papillary muscles contract pulling downward on the chordae tendinae sealing the valves shut
Term
intercalated disks
Definition
made of gap junctions and desmosomes, gap junctions allow for action potential to spread from cardiac cell to cardiac cell, desmosomes hold the cells together
Term
defibrillation
Definition
use of electric shock to depolarize heart cells and bring heart rhythm back to normal rhythm
Term
PR segment
Definition
AV nodal delay after stimulation from SA node
Term
ST interval
Definition
time during which ventricles are contracting and emptying
Term
TP interval
Definition
time during which ventricles are relaxing and filling
Term
P wave
Definition
atrial depolarization
Term
QRS complex
Definition
ventricular depolarization (atria repolarization simultaneously)
Term
T wave
Definition
ventricular repolarization
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