A&P – Flashcards

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endoysium
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the sheath that surrounds muscle fiber
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epimysium
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the sheath that surrounds the whole muscle
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perirmysium
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the sheath that surrounds a fascice
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complete tetanus
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continuous fused contraction of muscles
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Sequence the events that take place when a motor neuron's action potential triggers a muscle contraction.
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motor neuron action potential arrives at the nueromuscular junction. 1. ACH arrives at muscle fiber's plasma membrane causing depolarization 2. the action potential moves through the muscle fiber along transverse (T) tubules. 3.the sacroplamismic reticulum becomes more permeable in response cause a release of CA ions 4.when the tropomyosin shifts positions as calcium ions bind to troponin, actin binding sires are exposed 5.myosin cross bridges attach to actin fibers 6.sarcomeres within the muscle fibers contract
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Why would calcium deficiency limit muscle contractions?
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Calcium binds to the troponin-tropomyosin complex, exposing actin's myosin-binding sites.
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Place the events of excitation-contraction coupling in the sequence they occur.
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1. an action potential is produced in the sarcolemma 2. the action potential enter the T tubules 3. calcium channels in the sacroplasmic reticulum open 4. calcium ions flow into the sarcoplasm. 5. calcium ions bind to troponin 6.troponin changes shape 7. tropomyosin moves 8. active sites are exposed on the thin filament 9. the thin and thick filaments bind
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Which of the following statements best describes the sliding filament model of contraction?
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Myosin binding to actin through cross bridges causes thin filaments to slide past thick filaments.
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Select the statement that describes recruitment in muscle contraction.
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More motor neurons and larger motor units are activated to stimulate a greater number of muscle fibers for a stronger muscle contraction.
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z disc
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section of actinin that connects adjacent sacromeres
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i band
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region of a sarcomere that contains only thin filaments
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h zone
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region of a sarcomere that contains only thick filaments
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m line
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section of proteins that connect central points of thick filaments
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a band
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section of a sarcomere that is as long as a thick filament
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Place the events of neuromuscular junction (NMJ) excitation in order of occurrence.
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1. action potential arrives at axon terminal 2. opening of voltage gated calcium channels 3. influx of calcium ions 4. release of ACH from vesicles into synaptic cleft 5. binding of ACH to cholinergic receptors in muscle cells 6. opening of sodium channels causing influx of sodium ions 7. end plate potential in muscle cell
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elasticity
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ability to regain shape after stretching or contracting
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extensibility
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ability to lengthen and stretch
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contractility
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ability to shorten and increase in width
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excitability
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ability to respond to a stimulus
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conductivity
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ability to transmit electrical signal
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action potential/ graded potential
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-changes in the cells membrane potential - Hyperpolarization - depolarization
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Which of the following statements describes saltatory conduction?
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Conduction occurs exclusively at nodes of Ranvier.
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how to increase likelihood of an action potential in a postsynaptic neuron
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EPSP (excitatory postsynaptic potential spatial summation synaptic potentiation
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how to decrease likelihood of an action potential in a postsynaptic neuron
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IPSP (inhibitory postsynaptic potential) presynaptic inhibition
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Action potential
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-all or none potential - initiated by voltage- gated channels -irreversible - nondecremental - long distance
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graded potential
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-potentials summate - initiated by lion-gated channels - reversible -decremental - size varies -short distance
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What is spatial summation?
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combination of postsynaptic potentials due to the simultaneous stimulation of multiple synapses
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Place the events of synaptic transmission in order.
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1. action potential is generated in the presynaptic neuron 2. action potential arrives at the axon terminal 3. voltage-gated ca2+ channels in the axon terminal open and ca2+ flows inward down the concentration gradient 4. cytosolic ca2+ stimulates synaptic vesicles to release neurotransmitter via exocytosis 5. neurotransmitters diffuses across the synaptic cleft 6. binding of nuerotransmitter opens ion channels and causes a change in membrane potential 7. neurotransmitter effects are terminated
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Action potentials in neurons involve opening and closing of voltage-gated Na and K ion channels. Place the events of an action potential in order, starting and ending with a cell at its resting membrane potential.
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1. resting state 2. graded potential brings the membrane to threshold potential 3. fast Na+ and slow K+ channels are activated 4 Na+ ruses into cell causing membrane depolarization 5. K+ channels fully open and Na+ channel inactivation gates close 6. K+ ruses out of the cell, causing repolarization 7. return to n
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Which of the following describes how neurons use neurotransmitters to communicate with one another?
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At synapses, axons release neurotransmitters that are recognized by proteins on dendrites.
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Which statement best describes the function of the nervous system?
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The nervous system senses stimuli, integrates information, and generates a response.
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