Chapter 8 Flashcards by Laneta Jones

what are the three varieties of muscle tissue

skeletal - striated - voluntary
cardiac - striated - involuntary - autorhythmic (create own rhythm)
smooth - non-striated - involuntary - lines digestive tract

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name the four functions of the muscle tissue (please stop staring pervert)

producing body movements
stabilizing body positions
storing and moving substances within the body
producing heat

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which variety of muscle moves blood and maintains blood pressure

cardiac

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which variety of muscle moves or stabilizes the skeleton; guards entrances and exits to the digestive, respiratory, and urinary tracts, generates heat, and protects internal organs

skeletal

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which variety of muscle moves food, urine, and reproductive tract secretions; controls diameter of respiratory passageways and regulates diameter of blood vessels

smooth

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which layer of connective tissue surrounds the entire muscle

epimysium

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which layer of connective tissue surrounds the bundle of muscle cells called a fascicle

perimysium

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which layer of connective tissue surrounds each individual muscle cell

endomysium

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when all three layers of muscle connective tissue converge at each end what do they form

a tendon

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surrounded by epimysium; contains muscle fascicles

muscle

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surrounded by perimysium; contains muscle fibers

fascicles

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surrounded by endomysium; contains myofibrils (also called muscle fibers)

muscle cells (muscle fibers)

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contains thick myofilaments and thin myofilaments

sarcomere

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consists of two kinds of proteins; filaments thin and thick

myofilaments

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what are the two kinds of filaments

actin - thin filament like beads on a string

myosin - thick filament, with a large golf-club like head

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arrange the following terms in order from largest to smallest
myofilaments
muscle cell
muscle
sarcomere
fascicle
myofibril

muscle
fascicle
muscle cell
myofibril
sarcomere
myofilament

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surrounded by sarcoplasmic reticulum consists of sarcomeres from z-line to z-line

myofibrils

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the name of the mechanism that represents a muscle contracts when actin slides along myosin shortening the sarcomere

sliding filament mechanism

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which step in the contraction cycle is this:

myosin head breaks an atp, and stores the energy released

step 1: cocking

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which step in the contraction cycle is this:

myosin binds actin

step 2: cross-bridge formation

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which step in the contraction cycle is this:

stored energy from ATP splitting causes myosin head to bend and pulls actin towards midline

step 3: powerstroke

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which step in the contraction cycle is this:

myosin releases from actin after binding a new ATP

step 4: release or binding ATP and detaching

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how is a muscle contraction initiated?

by a signal from a neuron which releases acetylcholine

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connection between a motor neuron and muscle cell is called what?

a neuromuscular junction

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where is acetylcholine released?

at the neuromuscular junction -

what happens when acetylcholine is released at the NMJ?

cell receptors bind to the acetylcholine and send an electrical impulse along the plasma membrane

what n the path the electrical impulse travels

travels along the membrane, down T-tubules, to the sarcoplasmic reticulum

what is stored in the sarcoplasmic reticulum that is activated

channels open and release calcium ions stored in the sarcoplasmic reticulum into the muscle cell

what do calcium ions bind to

troponin

what do the troponin do

troponin moves the tropomyosin exposing a myosin binding site

when the myosin binding site is opened what happens

the contracting cycle begins with the myosin head attaching to the actin and pulling it towards the midline

describe the 6 steps involved to release calcium and initiate a muscle contraction

1) the brain sends a message to a neuron to release acetylcholine at the neuromuscular junction (NMJ), muscle cell receptors bind to the acetylcholine and send the message down the muscle cell membrane to the sarcoplasmic reticulum 2) the sarcoplasmic reticulum releases calcium ions which bind to troponin and change the tropomyosin which causes it to move away from the myosin binding sites on actin. 3) ATP is converted to ADP and myosin stores the energy released by moving into a cocked position 4) cross bridges are formed when the cocked myosin head attaches and the exposed myosin binding site on the actin 5) the myosin then powerstrokes pulling the actin toward the midline of the sarcomere 6) a new ATP attached to the myosin which causes the myosin head to release from the actin and the whole cycle begins again

what makes up the neuromuscular junction

the synaptic end bulb and the motor end plate

what molecule does the calcium bind to

troponin

what molecule covers actin binding sites

tropomyosin

what are the four steps in relaxation

1) nerve impulse stops 2) acetylcholine is removed from NMJ 3) calcium is returned to the sarcoplasmic reticulum 4) tropomyosin returns to its original position (myosin cannot bind to actin, muscle relaxes)

an auto immune disorder caused by the immune system attacking the ACH receptors on the motor end plate causing a much weaker muscle contraction, the muscle receptors become more degraded as the disease progresses.

myasthenia gravis - symptoms are muscle fatigue and weakness and usually affects the facial muscles. Treatment - drugs to reduce the breakdown of acetylcholine.

what is botox

a form of botulism toxin

how does botox work

the toxin acts by blocking the release of acetylcholine s you get paralysis of the muscles.

muscle contractions require a vast amount of what

ATP or energy

what are the three ways our muscles get ATP

1) ATP is stored in the muscle cells (gone in 6 seconds) 2) Aerobic respiration - (oxygen) used for prolonged exercise 3) Anaerobic respiration - (no oxygen) - causes build up of lactic acid which causes muscle fatigue

a nerve and all the muscle fibers it stimulates is called what

a motor unit

what kind of motor units provide precise movements but not a lot of power

small motor units

what kind of motor units provide a lot of power but less precise movements

large motor units

using more and more and more motor units stimulating greater force is known as what

motor recruitment

the quick shortening nd relaxing of a muscle from single action potential is known as what

a muscle twitch

what are the three phases of a muscle twitch

1) latent period 2) contraction period 3) relaxation period

the period after stimulus, but before contraction

latent period

the period during which muscle contracts

contraction period

the period during which muscle relaxes

relaxation period

if another stimulus occurs before the muscle relaxes, repeatedly this is called what

wave summation

if you have repeated muscle twitches without any relaxation period between the contractions what is this called

unfused tetanus

if you have a sustained contraction (holding the contraction for the maximum amount of time) what is this called

fused tetanus

when you have held a muscle in fused tetanus for as long as possible it results in what

muscle fatigue

what are the three types of skeletal muscle cells

slow oxidative fast glycolytic fast oxidative-glycolytic

this type of skeletal muscle cell is extremely fatigue resistant and does not tire out. It is red. It creates ATP with the presence of oxygen, and is found in the postural muscles of the back and neck

slow oxidative - red creates atp with the presence of oxygen found in the postural muscles of back and neck

this type of skeletal muscle cell makes ATP quickly but also fatigues easily, it is used for quick bursts of energy, It is white. It creates ATP without the presence of oxygen and is found in big muscles like quads. It can also be strengthened through training to increase the size and strength

``` fast glycolytic white creates atp without oxygen found in large muscles like quads can be trained to increase strength and size ```

this type of skeletal muscle cell are flexible and can create ATP with or without oxygen and is found everywhere in the body. It is also red.

fast oxidative-glycolytic red creates atp with or without oxygen found everywhere in the body

attachment of a tendon to the stationary or non-moving bone

origin

attachment of a tendon to the movable bone

insertion

main movements that occur during contraction - pulling on different bones

action

the muscle that creates the action (bicep contracts pulling the forearm up)

prime mover

helps the prime mover by contracting at the same time (biceps and brachioradialis)

synergistic muscles

the muscle that opposes or has an opposite action - produces movement when one relaxes and the other contracts (most muscles, biceps & triceps, hamstrings & quads)

antagonistic muscles

muscle that points toe

gastrocnemius

muscle that opens eyes

orbicularis oculi

muscle that elevates scapula

trapezius

muscle that extends leg at knee joint (straightens knee)

quadriceps

muscle that opens mouth

orbicularis oris

muscle that moves thigh away from body

gluteus medius

muscle that moves arm toward body

pectoralis major

muscle that raises corners of the mouth (smiling)

zygomaticus

muscle that extends forearm

triceps brachii

muscle that flexes leg and knee joint (bends knee)

hamstrings

muscle that flexes forearm

biceps brachii

muscle that extends thigh

gluteus maximus

muscle that moves arm away from body

deltoid

``` The space between an axon terminal and the sarcolemma is the a - synaptic vesicle. b - motor end plate. c - motor unit. d - synaptic cleft. e - neuromuscular junction. ```

d - synaptic cleft.

``` Match the stage of the sliding filament mechanism to its events. Cocking Crossbridge formation Powerstroke Detaching ```

Cocking - ATP is split and myosin heads reorient Crossbridge formation - myosin binding sites on actin are bound by the myosin heads Powerstroke - ADP is released and crossbridges move towards the center of the sarcomere Detaching - ATP binds to the myosin head and myosin releases actin

``` The pigmented protein in the muscle fibers that stores oxygen is a - melanin. b - carotene. c - hemoglobin. d - myoglobin. e - glycogen. ```

d - myoglobin.

``` The neurotransmitter at the neuromuscular junction is a - calcium. b - acetylcholine. c - adrenaline. d - norepinephrine. e - glycine. ```

b - acetylcholine.

``` Which skeletal muscle structure is largest? a - Sarcomere b - Fascicle c - Myofibril d - Myofilament ```

b - Fascicle

``` Which of the following is/are striated and involuntary? a - skeletal muscle b - skeletal muscle and smooth muscle c - skeletal muscle and cardiac muscle d - cardiac muscle e - smooth muscle ```

d - cardiac muscle

Put these events in order: ``` Tropomyosin changes shape The sarcoplasmic reticulum releases calcium Myosin binding sites on actin are exposed Troponin binds to calcium a - 2, 4, 1, 3 b - 1, 3, 2, 4 c - 1, 2, 3, 4 d - 2, 3, 4, 1 ```

a - 2, 4, 1, 3

``` In ________, muscle force is increased when the contraction period overlaps the relaxation period. a - latency b - recruitment c - wave summation d - unfused tetanus ```

c - wave summation

``` Match the muscle with its description or action. Closes the eyes Flexes the trunk Extends the forearm Extend the leg at the knee Points the toe ```

``` Closes the eyes - orbicularis oculi Flexes the trunk - rectus abdominis Extends the forearm - triceps brachii Extend the leg at the knee - rectus femoris Points the toe - gastrocnemius ```