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Eastham's chapter 6
| Question | Answer |
|---|---|
| muscle cell | muscle fiber |
| contractility | the ability of skeletal muscle to shorten with force |
| Excitability | the capacity of skeletal muscle to respond to a stimulus |
| extensibility | the ability to be stretched |
| elasticity | ability to recoil to their original resting length after they have been stretched |
| Epimysium | each skeletal muscle is surrounded by a connective tissue sheath |
| Fascia | connective tissue located outside the epimysium |
| The fasciculi are composed of single muscle cells | fibers |
| each fiber is surrounded by a connective tissue sheath called | endomysium |
| The cytoplasm of each fiber is filled with___ a threadlike structure that extends from one end of a fiber to another | myofibrils |
| actin myofilaments | thin myofilamen> resemble 2 minute strands of pearls twisted together |
| myosin myofilaments | thick myofilaments. Resemble bundles of minute golf clubs |
| Actin and myosin myfilaments form highly ordered units called___ which are joined end to end to form the myofibril | sarcomeres |
| The charge difference across the membrane | resting membrane potential |
| The brief reversal back of the charge | action potential |
| motor neurons | nerve cells that carry action potentials to skeletal muscle fibers |
| ___enter the muscles and branch | axons |
| each branch form what? | neuromusclular junction |
| single motor neuron and all skeletal muscle fibers | motor unit |
| What is formed by an enlarged nerve terminal resting in an indentation of the muscle cell membrane | neuromusclular junction |
| enlarged nerve terminal | presynaptic terminal |
| each presynaptic terminal contains | synaptic vesicles |
| synaptic vesicles secrete a neurotransmitter called what? | acetylcholine |
| the acetylcholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by an enzymes | acetylcholinesterase |
| occurs as actin and myosin | muscle contraction |
| actin and myosin myofilaments slide past one another causing___to shorten | sarcomeres |
| when sarcomeres shorten it causes muscle to___ | shorten |
| the sliding during contraction is called what? | sliding filament mechanism |
| What bands shorten? | H and I |
| What bands do not change length? | A |
| a contraction of an entire muscle in response to a stimulus that causes the action potential | muscle twitch |
| muscle fiber will not respond to stimulus until that stimulus reaches a level called what? | threshold |
| this phenomenon is called | all-or-none response |
| time between application of a stimulus to a motor neuron and the beginning of a contraction | lag phase |
| what is time of contraction? | contraction phase |
| what is the time which the muscle relaxes | relaxation phase |
| where the muscle remains contracted without relaxing | tetany |
| the increase in number of motor units being activated | recruitments |
| ATP | adenosine triphosphate |
| ATP is needed for what? | energy for muscle contractions |
| ATP is produced in what? | mitochondria |
| ATP is short-lived and what? | unstable |
| It degenerates to more stable___plus phosphates | ADP |
| ADP | adenosine diphosphate |
| muscle cells must constantly produce | ATP |
| at rest they can't stockpile ATP but store another high-energy molecule | creatine phoshate |
| anaerobic respiration | without oxygen |
| aerobic respiration | with oxygen |
| what is the amount of oxygen needed in chemical reactions to convert lactic acid to glucose | oxygen debt |
| what results when ATP is used during muscle contraction faster than it can be produced in muscle cells | muscle fatigue |
| What are two types of muscle contractions | isometric, isotonic |
| (equal distance)the length of the muscle does not change | isometric |
| (equal tension)the amount of tension produced by the muscle is constant during contraction | isotonic |
| what refers to constant tension produced by muscle of the body for long periods of time | muscle tone |
| contracts quickly and fatigue quickly | fast-twitch fibers |
| contract more slowly and are more resistant to fatigue | slow-twitch fibers |
| what are the points of attachment of each muscle? | origin and insertion |
| At these attachment points the muscle is connected to what?and by what? | bone by a tendon |
| origin | head |
| insertion | end of the muscle undergoing the greatest movement |
| belly | the muscle between the origin and the insertion |
| Muscles that work together to accomplish specific movements | synergists |
| Muscles that work in opposition to one another | antagonists |
| If one muscle plays the major role in accomplishing the desired movement | prime mover |
| some muscles have multiple what? | origins and heads |
| What has no striations and is involuntary | smooth muscle |
| What is found in only one place in the body? | cardiac muscle |
| Muscle plays four important roles in the body | produces movement, maintains posture, stabilizes joints, generates heat |
| produces movement | just about all movements of the human body are a result of muscle contractions |
| What are different types of exercise for the muscles? | aerobic, endurance |
| a movement, generally in the sagittal plane | flexion |
| is the opposite of flexion | extension |
| the movement of a bone around its longitudinal axis | rotation |
| moving a limb away | abduction |
| moving a limb toward the body midline | adduction |
| a combination of flexion, extension,abduction, and adduction | circumduction |
Created by:
chrisrailey
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