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55 Cards in this Set
- Front
- Back
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sarcomere |
functional unit of muscle portion of myofibril between zdiscs |
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sliding filament mechanism |
contraction results from the sliding action of interdigitating actin and myosin filaments |
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tropomyosin |
covers actin active sites |
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troponin |
binds Ca2+ moving the troponin-tropomyosin complex to allow myosin and actin to bind |
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power stroke |
myosin attaches to actin, ratchets forward, and binds ATP to release |
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motor unit |
muscle fibers innervated by a single nerve fiber |
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small motor unit |
larynx, extraocular 10 fibers/unit precise control and rapid reaction |
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large motor unit |
quadriceps 1000 fibers/unit coarse control and slower reaction |
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multiple fiber summation |
increase in the number of motor units contracting simultaneously |
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frequency summation |
as frequency of stimulation increases the contractions happen so rapidly that one starts before the previous one could fully relax strength of contraction increases as frequency does |
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tetanization |
at critical frequency contractions become so rapid that they fuse together and muscle contraction looks smooth and continuous |
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muscle hypertrophy |
increase in mass of muscle due to loaded muscle during contraction |
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muscle atrophy |
decrease in muscle mass due to inactivity |
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myasthenia gravis |
muscle weakness due to loss of nicotinic receptors autoimmune - Ab attack N receptors |
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excitation-contraction coupling |
an AP causes the muscle cell to release Ca2+ causing a contraction |
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acetylcholinesterase |
enzyme that breaks down Ach into acetyl and choline acetyl is metabolized and choline is taken back up by neuron |
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curare |
an antagonist, it blocks Ach from binding to N receptors, preventing muscle contraction |
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antagonist |
a substance that binds to a receptor and does not cause an effect |
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agonist |
a substance that binds to a receptor and causes an effect |
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botulinum toxin |
blocks release of Ach from the neuron causes paralysis |
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muscular dystrophy |
dystrophin, the protein that connects actin the the cell membrane doesnt work causes muscle weakness and degeneration, heart problems |
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amyotrophic lateral sclerosis |
death of neurons that control voluntary movement destroys smooth movement |
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multiple sclerosis |
demyelinating disorder |
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venom |
blocks Ca2+ channels on neuron so that Ach cannot be released |
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visceral smooth muscle |
unitary smooth muscle, all acts as one |
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coronary vessels |
supply the heart with blood |
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gap junctions |
connections between smooth muscle cells that allow an AP to travel through them as a unit NOT electrically isolated |
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atrial muscle |
causes right atrium to depolarize |
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anterior interatrial band |
passes the impulse from SA node to the left atrium causing it to depolarize |
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internodal pathway |
brings impulse from SA to AV node |
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atrioventricular node (AV node) |
delays passage of impulse from atria to ventricles allows atria to contract before ventricles |
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SA node intrinsic pace |
70-160 |
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AV node intrinsic pace |
40-60 |
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Bundle branches and Purkinje intrinsic pace |
20-40 |
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vagus nerve |
parasympathetic NS DOES NOT innervate ventricles, only SA and AV node long pre-ganglionic fiber |
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sympathetic chain |
structure adjacent to spinal cord where the sympathetic nerves synapse - short pre-ganglionic fibers |
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mitral valve |
valve between left atrium and ventricle |
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tricuspid valve |
valve between right atrium and ventricle |
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aortic valve |
valve between left ventricle and aorta |
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pulmonary valve |
valve between right ventricle and pulmonary artery |
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papillary muscle |
keeps AV valves from bulging up intro atria |
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diastole |
the pause in the heart beat when ventricles are relaxed and filling with blood |
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systole |
when ventricles contract and blood is pushed through the body |
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stroke volume |
EDV-ESV amount of blood ejected into aorta during each beat |
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ejection fraction |
percentage of EDV ejected in each heart beat 55% and higher = normal |
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cardiac output |
amount of blood the heart pumps in one min SV x heart rate = CO |
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stenosis |
narrowing of a valve that causes a murmur when it is open - narrowing causes turbulence |
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regurgitation |
murmur occurs when valve is closed due to blood flowing backwards through the faulty valve |
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contractility |
strength of contraction of ventricles |
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lead |
each different angle or pair of electrodes has a - and + electrode |
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extracellular fluid % |
20% of body weight |
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intracellular fluid % |
40% of body weight |
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negative feedback |
feedback system that promotes stability ex. arterial BP regulation |
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positive feedback |
feedback system that promotes a change in one direction ex. clotting and AP *rare mechanism |
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osmotic pressure |
the amount of pressure required to counter osmosis higher conc of osmotic particles = higher osmotic pressure |
