Chapter 8 Flashcards
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
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
which variety of muscle moves blood and maintains blood pressure
cardiac
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
which variety of muscle moves food, urine, and reproductive tract secretions; controls diameter of respiratory passageways and regulates diameter of blood vessels
smooth
which layer of connective tissue surrounds the entire muscle
epimysium
which layer of connective tissue surrounds the bundle of muscle cells called a fascicle
perimysium
which layer of connective tissue surrounds each individual muscle cell
endomysium
when all three layers of muscle connective tissue converge at each end what do they form
a tendon
surrounded by epimysium; contains muscle fascicles
muscle
surrounded by perimysium; contains muscle fibers
fascicles
surrounded by endomysium; contains myofibrils (also called muscle fibers)
muscle cells (muscle fibers)
contains thick myofilaments and thin myofilaments
sarcomere
consists of two kinds of proteins; filaments thin and thick
myofilaments
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
arrange the following terms in order from largest to smallest myofilaments muscle cell muscle sarcomere fascicle myofibril
muscle fascicle muscle cell myofibril sarcomere myofilament
surrounded by sarcoplasmic reticulum consists of sarcomeres from z-line to z-line
myofibrils
the name of the mechanism that represents a muscle contracts when actin slides along myosin shortening the sarcomere
sliding filament mechanism
which step in the contraction cycle is this:
myosin head breaks an atp, and stores the energy released
step 1: cocking
which step in the contraction cycle is this:
myosin binds actin
step 2: cross-bridge formation
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
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
how is a muscle contraction initiated?
by a signal from a neuron which releases acetylcholine
connection between a motor neuron and muscle cell is called what?
a neuromuscular junction
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
