WorksheetsMuscle System
Total questions: 74
Worksheet time: 39mins
what are the functions of muscle tissue?
movement
posture
protection
power
shape
what are the functions of muscle tissue?
contraction
sphincters
storage
heat
energy
how many different muscles we have?
how much is the muscle body mass?
40-50%
50-60%
below 30%
long cylindrical multinucleated, striated cells
Skeletal
Smooth
Cardiac
attach to bone, skin, fascia
Skeletal
Smooth
Cardiac
responsible for voluntary control
activated by reflexes
very fast contraction
fatigues quickly
Skeletal
Smooth
Cardiac
short, branched, striated cells
Skeletal
Smooth
Cardiac
cells joined by intercalated disks
*allows conduction of heart impulse
Skeletal
Smooth
Cardiac
responsible for involuntary control
slower contraction
e.g. in heart walls
Skeletal
Smooth
Cardiac
function to pump blood to all parts of the body
Skeletal
Smooth
Cardiac
spindle-shaped, tapered ends
no striations
Skeletal
Smooth
Cardiac
lines walls of blood vessels & hollow organs
involuntary control
contracts slowest
Skeletal
Smooth
Cardiac
mainly function in motion
Skeletal
Smooth
Cardiac
also called myocytes
elongated cell
looks long cylinder
muscle fiber
endomysium
fascicles
perimysium
epimysium
means "within"
a connective tissue
surrounding each muscle fiber
muscle fiber
endomysium
fascicles
perimysium
epimysium
bundle of muscle fibers
about 10 to 100 fibers
muscle fiber
endomysium
fascicles
perimysium
epimysium
a connective tissue surrounding each fascicle
separates fascicle
muscle fiber
endomysium
fascicles
perimysium
epimysium
attaches to periosteum of bone
outer layer
strong connective tissue surrounding many fascicle
muscle fiber
endomysium
fascicles
perimysium
epimysium
supplied by a nerve, artery, and vein
muscle
muscle fiber
motor neuron
supplied by a motor neuron and 1 to 2 capillaries (located in endomysium)
muscle
muscle fiber
motor neuron
innervates (supply nerve) several muscles cells via action potential
muscle
muscle fiber
motor neuron
rope formation of epimysium
attaches muscle to bone
built to withstand tension
Tendons
Aponeurosis
Achilles Tendon
dense regular connective tissue
limited blood & nervous supply
Tendons
Aponeurosis
Achilles Tendon
dense regular connective tissue
limited blood & nervous supply
flatter & thinner
Tendons
Aponeurosis
Achilles Tendon
thickest and strongest tendon of the body
Tendons
Aponeurosis
Achilles Tendon
flat sheet of epimysium that attach flat muscle to bone or muscle to muscle
separate muscle
Tendons
Aponeurosis
Achilles Tendon
surround muscle fiber
cell membrane
found under endomysium
sarcolemma
sarcoplasm
Transverse Tubules
sarcoplasmic reticulum
Skeletal Muscle Fibers
cytoplasm of a muscle fiber
has glycogen for ATP
consist myoglobin & myofibril
sarcolemma
sarcoplasm
Transverse Tubules
sarcoplasmic reticulum
Skeletal Muscle Fibers
invagination of sarcolemma
carry signals to contract
deep into sarcoplasm
sarcolemma
sarcoplasm
Transverse Tubules
sarcoplasmic reticulum
Skeletal Muscle Fibers
smooth endoplasmic reticulum that surrounds each myofibril
stores calcium (needed for contraction)
sarcolemma
sarcoplasm
Transverse Tubules
sarcoplasmic reticulum
Skeletal Muscle Fibers
muscles are full of the following organelles:
myofibrils
mitochondria
sarcoplasmic reticulum
myosin
actin
red-coloured protein found in sarcoplasm
myofibril
myoglobin
myosin & actin
regulatory proteins
structural proteins
small structure, occupying 80% of cytoplasm
long-tube like organelles of skeletal muscle
myofibril
myoglobin
myosin & actin
regulatory proteins
structural proteins
alternating dark regions that gives muscle striped appearance
myofibril
myoglobin
myosin & actin
regulatory proteins
structural proteins
contraction proteins
myofibril
myoglobin
myosin & actin
regulatory proteins
structural proteins
troponin or tropomyosin
turn contraction on and off
myofibril
myoglobin
myosin & actin
regulatory proteins
structural proteins
titin or dystrophin
provide proper alignment, elasticity, & extensibility
myofibril
myoglobin
myosin & actin
regulatory proteins
structural proteins
thick filaments composed
myosin
actin
troponin & tropomysin
resembles 2 golf clubs twisted
myosin heads extend towards thin filaments
thick filaments
thin filaments
myosin binding site on each actin molecules
covered by tropomyosin supported by troponin
thick filaments
thin filaments
components of sarcomere
Z discs
A band
I Band
H zone
M line
narrow, plate-shaped regions
separate one sarcomere from the next
Z discs
A band
I Band
H zone
M line
dark, middle part of sarcomere
extends entire length of thick filament
Z discs
A band
I Band
H zone
M line
lighter, less dense area of sarcomere
contains remainder of thin filament but no thick filament
Z discs
A band
I Band
H zone
M line
where Z disc passes through
Z discs
A band
I Band
H zone
M line
narrow region in center of each "A band"
that contains thick filaments but no thin filaments
Z discs
A band
I Band
H zone
M line
region in center of "H zone" that contains proteins
hold thick filaments together at center of sarcomere
Z discs
A band
I Band
H zone
M line
what is the association site if of nerve and muscle
(a)
what is the neurotransmitter for skeletal msucle?
What event allows the muscle fiber to return to a relaxed state after contraction?
Continuous release of ACh
Breakdown of ACh and reabsorption of calcium into the SR
More calcium being released from the SR
Constant depolarization of the sarcolemma
What is the main purpose of releasing calcium during muscle contraction?
To depolarize the muscle fiber
To expose binding sites on actin so myosin can attach
To break down acetylcholine
To repolarize the muscle membrane
Which step happens immediately after acetylcholine (ACh) is released into the neuromuscular junction?
Calcium is released from the sarcoplasmic reticulum
The muscle fiber depolarizes
ACh is broken down by acetylcholinesterase
The muscle relaxes
Which of the following correctly represents the sequence of events in skeletal muscle contraction?
Nerve signal → ACh release → Muscle depolarization → Action potential travels → Calcium released → Muscle contraction → ACh breakdown → Relaxation
ACh release → Nerve signal → Calcium release → Muscle depolarization → Relaxation
ACh breakdown → Nerve signal → Muscle depolarization → Calcium released → Muscle contraction
Calcium release → Nerve signal → ACh breakdown → Muscle contraction → Relaxation
Which ions does sarcolemma becomes permeable to?
Na+
K+
Ca2+
in relaxed muscle, ____ is unable to bind to actin,
myosin
troponin
tropomysoin
Step 1 in initiation of Muscle Contraction
Calcium binds to troponin
Step 2 in initiation of Muscle Contraction
Troponin-Tropomyosin complex moves to free up binding site
First Event during Contraction Cycle
Myosin Heads activated by ATP
Second Event during Contraction Cycle
Third Event during Contraction Cycle
Last Event during Contraction Cycle
Myosin heads bind ATP & Crossbridge detach
Muscle Contraction is continuous as long as ____ & _____ are available:
which are NOT shortened during contraction?
Which of the following correctly describes the sequence of events during muscle relaxation?
Calcium pumped back to SR → Muscle AP ends → ACh broken down → Troponin–tropomyosin covers actin → Muscle relaxe
ACh broken down → Muscle AP ends → Calcium channels close → Calcium pumped back to SR → Troponin–tropomyosin covers actin → Muscle relaxes
Muscle AP ends → ACh broken down → Troponin–tropomyosin covers actin → Calcium released → Muscle contracts
Troponin–tropomyosin covers actin → ACh broken down → Calcium pumped back to SR → Muscle AP starts → Muscle contracts
Which of the following events occur during muscle relaxation? Select all that apply.
Acetylcholine (ACh) is broken down by enzymes in the synaptic cleft
Calcium is pumped back into the sarcoplasmic reticulum (SR)
Troponin–tropomyosin complex covers the binding sites on actin
Myosin heads perform the power stroke
Muscle action potential continues to propagate along the sarcolemma
What causes troponin-tropomyosin complex to cover myosisn-binding site on actin?
brief contraction of all fibers in a motor unit in response to a single action
20-200 Milliseconds
Isometric Contraction
Twitch Contraction
Concentric Isotonic
Eccentric Isotonic
Isotonic Contraction
contractions allow movement of muscle and shorten joint angles
Isometric Contraction
Twitch Contraction
Concentric Isotonic
Eccentric Isotonic
Isotonic Contraction
contraction control the lengthening of a muscle that previously shortened (contracted)
Isometric Contraction
Twitch Contraction
Concentric Isotonic
Eccentric Isotonic
Isotonic Contraction
muscle length changes
e.g. dumbbell exercise
Isometric Contraction
Twitch Contraction
Concentric Isotonic
Eccentric Isotonic
Isotonic Contraction
muscle length doesn't change
e.g. holding a book
Isometric Contraction
Twitch Contraction
Concentric Isotonic
Eccentric Isotonic
Isotonic Contraction
muscle fibers obey "all or nothing" law but contraction of muscle can be graded by:
Changing the number of fibers stimulated
occurs when second ACTION POTENTIAL is applied before muscle is completely relaxed
calcium ions remain in the cell
"second contraction is stronger"
Wave summation
Graded Action Potential
Muscle Metabolism
