Question | Answer |
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 |
What do muscles do? | help produce heat essential for maintenance of normal body temperature |
epimysium | skeletal muscle that is surrounded by connective tissue sheath |
fascia | another connective tissue located outside the epimysium and it surrounds and separates muscle |
perimysium | loose connective tissue |
muscle cells | muscle fibers |
endomysium | the outer connective tissue that surrounds each fiber |
myofibrils | threadlike structure that extends from one end of the fiber to the other |
What are the 2 major types of protein fibers? | actin and myosin myofilaments |
actin myofilaments | thin myofilaments: 2 minute strands of pearls twisted together |
myosin myofilaments | thick myofilaments: bundles of minute golf clubs |
sarcomeres | highly ordered units joined end to end to form the myofibril |
resting membrane potential | the change difference across a membrane |
action potential | the brief reversal back of the charge |
motor neutrons | are nerve cells that carry action potential to skeletal muscle fibers |
neuromusclular junction or synapse | where each branch that connects to the muscle |
motor unit | they form a single muscle and they are a single motor neuron and all the skeletal muscle fibers it innervates |
presynaptic terminal | the enlarged nerve terminal |
synaptic cleft | the space between the presynaptic terminal and the muscle cell membrane |
postsynaptic terminal | muscle fiber in between the muscle cell and terminal |
How does synaptic vesicles work with the acetylcholine? | it diffuses across the synaptic cleft and blinds to the postsynaptic terminal causing a change in the postsynaptic cell |
acetylcholinesterase | the acetylcholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by an enzymes |
sliding filament mechanism | the sliding of actin myofilaments during contraction |
muscle twitch | is a contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers |
threshold | a level: at which point the muscle fiber will contract maximally |
What is this whole process called? | all-or-none response |
lag phase | time between application of a stimulus to a motor neuron and beginning of a contraction |
contraction phase | the time during contraction |
relaxation phase | the time during which the muscle relaxes |
tetany | where the muscle remains contracted without relaxing |
recruitment | the increase in number of motor units being activated |
What is ATP needed for? | it is needed for energy for muscle contraction |
What does ATP stand for? | Adenosine triphosphate |
How is ATP produced? | it is produced in the mitochondria |
ATP is short-lived and unstable? | true |
What does ADP stand for? | Adenosine diphosphate |
It is not necessary for muscle cells to constantly produce ATP? | False |
creatine phosphate | high energy molecule |
anaerobic respiration | without oxygen |
aerobic respiration | with oxygen |
oxygen debt | is the amount of oxygen needed in chemical reaction to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells |
muscle fatigue | is the result when ATP is used during muscle contraction faster than it can be produced in the muscle cells |
What are the 2 types of muscle contractions? | isometric and isotonic |
isometric | equal distance |
isotonic | equal tension |
muscle tone | constant tension produced by muscle of the body for long periods of time |
fast twitch fibers | contract quickly and fatigue quickly |
slow twitch fibers | contract more slowly and are more resistant to fatigue |
origin | is the most stationary end of the muscle |
insertion | is the end of the muscle undergoing the greatest movement |
belly | the portion of the muscle between the origin and the insertion |
synergists | muscles that work together to accomplish specific movements |
antagonists | muscles that work in opposition to one another |
prime mover | when one muscle plays a major role |
Where is the H Zone located? | its located between the A Bands |
What is the line in between the H Zone? | M line |
occipitofrontalis | raises the eyebrows |
orbicularis oculi | closes the eyelids |
orbicularis oris | puckers the lips |
What are the two kissing muscles? | orbicularis oris and buccinator |
buccinator | flattens the cheeks |
zygomaticus | smiling |
levator labi superioris | sneering |
depressor anguli oris | frowning |
What is another word for chewing? | mastication |
Name the two major muscles in mastication. | masseter and temporalis |
tongue and swallowing muscle | is important in speech and mastication |
What are the two types of tongue muscles? | extrinstic and instrinstic |
extrinstic tongue muscle | moves the tongue |
instrinstic tongue muscle | changes the shape of the tongue |
What is the neck muscle? | sternocleidomastoid |
sternocleidomastoid | rotates the neck |
What is the band located on the outer part near the Z Line? | I Band |
What does the A Band do? | extends the length of the myosin |
Each Z Line is an attachment site for actin. | True |
What are the four major functional characteristics? | contractibility, excitability, extensibility, and elasticity |
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