Muscle Physiology Flashcards
composed of specialized cells called muscle fibers
muscles
predominant function is contractability that promotes movment
muscles
what kind of muscle are attached to bones
voluntary/involuntary
voluntary
muscles are responsible for the involuntary contraction and relaxation of longitudinal and circular muscles throughout the digestive tract,
peristalsis
function in posture and joint stability
muscles
percent of heat produced in muscle contraction
85%
is the ability of muscle cells to forcefully shorten.
contractility
muscles in blood vessels that helps promotes
circulation
present in the surface of epithelial cells; not muscle
cilia
present in sperm cells for locomotion
flagellum
sarco means
flesh
the only organ of the muscular system
skeletal muscle
composed of skeletal muscle tissue and also contains nervous tissue, blood vessels, and connective tissue
skeletal muscle
are not organs but mere tissues of the heart and visceral organs respectively
cardiac
smooth muscle
half of the body’s weight is ___ tissue
muscle
skeletal muscle accounts for what percent in males and females
40% males
32% females
what percent does the cardiac muscle account for in the human body
10%
function of muscles
generation of movement
stabilization of the position of the body
control of the volume of organs
motion of substances in the body
generation of body heat
what muscles are in control of the volume of organs
sphincters (smooth muscle)
what substance is moved by muscle
blood, lymph, urine, air, food and fluids, sperm
what kind of muscle generate body heat
voluntary and involuntary contractions of skeletal striatied muscle
ability of the skeletal muscle to respond to stimuli
electrical irritability/excitability
contracts as a result of nerve irritation
skeletal muscle
ability of contracton
contractility
ability to extend without tissue damage
extensibility
ability to return to the original shape of being extended
elasticity
is composed of specialized cells called muscle fibers.
muscular system
Their predominant function is
contractility
attached to bones or internal organs and blood vessels, are responsible for movement.
muscles
Nearly all movement in the body is the result of
muscle contraction
movement of some white blood cells.
what kind
ameboid
The integrated action of joints, bones, and skeletal muscles produces obvious movements such as
walking
running
also produce more subtle movements that result in various facial expressions, eye movements, and respiration.
skeletal muscles
such as sitting and standing, is maintained as a result of muscle contraction
posture
he tendons of many muscles extend over joints and in this way contribute to joint stability. This is particularly evident in what joints
knee
shoulder
is considered an organ of the muscular system.
skeletal muscle
muscle in the ear
stapedium
is a single cylindrical muscle cell.
skeletal muscle fiber
Each muscle is surrounded by a connective tissue sheath called the
epimysium
connective tissue outside the epimysium, surrounds and separates the muscles.
fascia
Each bundle of muscle fiber is called a
fasciculus
fasciculus is surrounded by a layer of connective tissue called the
perimysium
Within the fasciculus, each individual muscle cell, called a
muscle fiber
muscle fiber, is surrounded by connective tissue called the
endomysium
covering furnish support and protection for the delicate cells and allow them to withstand the forces of contraction.
connective tissue
fleshy part of the muscle,
belly
gaster
a thick ropelike tendon or a broad, flat sheet-like of muscle that extend beyond their gaster or belly
aponeurosis
form indirect attachments from muscles to the periosteum of bones or to the connective tissue of other muscles
aponeurosis
tendon
Typically a muscle spans a joint and is attached to bones by ____ at both ends
tendons
have an abundant supply of blood vessels and nerves. This is directly related to the primary function of contraction
skeletal muscle
Before a skeletal muscle fiber can contract, it has to receive an impulse from a
nerve cell
Generally, an artery and at least one vein accompany each nerve that penetrates the __ of a skeletal muscle
epimysium
Branches of the nerve and blood vessels follow the connective tissue components of the muscle of a nerve cell and with one or more minute blood vessels called
capillaries
if the muscle does not have a name, it is considered as a ___
tissue
bundle of muscle fibers in the muscle
fascicle
fascicle is comprised of smaller structures called
muscle fiber
muscle fiber = muscle ___
cell
multiple of this make up a muscle fiber
myofibril
structures beside the transverse tubule
terminal cisternae
structure of the sarcoplasmic reticulum
terminal cisternae
what makes up a triad
terminal cisterna
transverse tubule
significant in skeletal muscle
triad
two proteins in sarcomere
myosin
actin
surrounded by actin
myosin
state of muscle rigidity, that begins 3-4 hours after death and last approx.24
rigor mortis
after death, ___ ions leave the SR and enable the myosin heads to bond to the actin fiber
Ca2+
since the synthesis of ATP has ceased, ___ bridges don’t separate until the time when proteolytic enzymes start to eliminate the cells
actin
n the body, there are three types of muscle:
skeletal
smooth
cardiac
attached to bones, is responsible for skeletal movements.
skeletal muscle
The _____ portion of the central nervous system (CNS) controls the skeletal muscles.
peripheral
Thus, these muscles are under conscious, or voluntary, control. T
skeletal muscle
The basic unit is the muscle fiber with many/single nuclei
many
are striated (having transverse streaks) and each acts independently of neighboring muscle fibers
skeletal muscle
found in the walls of the hollow internal organs such as blood vessels, the gastrointestinal tract, bladder, and uterus, is under control of the autonomic nervous system.
smooth muscle
cannot be controlled consciously and thus acts involuntarily.
smooth msucle
The non-striated (smooth) muscle cell is what shaped
spindle
how many central nuclei does smooth muscle have
one
contracts slowly and rhythmically.
smooth msucle
found in the walls of the heart, is also under control of the autonomic nervous system.
cardiac muscle
has one central nucleus, like smooth muscle, but it also is striated, like skeletal muscle.
cardiac muscle
shape of cardiac muscle cell
rectangular
The contraction of ____muscle is involuntary, strong, and rhythmical.
cardiac
There are more than ____ muscles in the body, which together account for about ___percent of a person’s weight.
600
40
vastus
huge
maximus
large
longus
long
minimus
small
brevis
short
deltoid
what shape
triangular
ike a rhombus with equal and parallel sides
rhomboid
wide
latissimus
round
teres
like a trapezoid, a four-sided figure with two sides parallel
trapezius
straight
what fiber
rectus
across
what fiber
transverse
diagonally
what fiber
oblique
circular
what fiber
orbicularis
chest
what muscle
pectoralis
buttock or rump
what muscle
gluteus
brachii
what msucle
arm
supra-
location of muscle?
above
infra-
what location of muscle
below
sub-
location of muscle?
under or beneath
lateralis
what location of muscle
lateral
two heads
biceps
three heads)
triceps
four heads
quadriceps
origin on the sternum and clavicle, insertion on the mastoid process);
sternocleidomastoideus
origin on the brachium or arm, insertion on the radius
brachioradialis
(to abduct a structure)
abductor
to adduct a structure
adductor
o flex a structure
flexor
(to extend a structure);
extensor
(to lift or elevate a structure);
levator
(a chewer)
masseter
. Muscles of facial expression include (5)
frontalis
orbicularis oris
laris oculi
buccinator
zygomaticus
There are four pairs of muscles that are responsible for chewing movements or ___
mastication
All of these muscles connect to the ___ and they are some of the strongest muscles in the body.
mandible
There are numerous muscles associated with the throat, the hyoid bone and the vertebral column; only two of the more obvious and superficial neck muscles are identified in the illustration:
sternocleidomastoid
trapezius
temporal muscle, flat and fan shaped, located on the lateral side of the sun
O - temporal fossa
I - coronoid process of mandible
A- protrusion of mandible, elevation and retraction of mandible
innervated by the branches of the mandibular nerve of trigeminal nerve (CNV)
temporalis
most powerful muscle of mastication
rectangular muscle (composed of superficial and deep)
O - zygomatic arch
I - masseteric tuberosity (superficial) ramus of mandible (deep)
A - elevate mandible, protrusion of mandible
Innervated by masseteric nerve by the CNV (trigeminal)
Masseter
The muscles of the ___ include those that move the vertebral column, the muscles that form the thoracic and abdominal walls, and those that cover the pelvic outlet.
trunk
large muscle mass that extends from the sacrum to the skull.
what group of muscle
erector spinae
muscles that are primarily responsible for extending the vertebral column to maintain erect posture
erector spinae muscle group
occupy the space between the spinous and transverse processes of adjacent vertebrae.
deep back muscle
are involved primarily in the process of breathing
muscle in thoracic wall
are located in spaces between the ribs.
intercostal muscles
They contract during forced expiration.
intercostal muscle
contract to elevate the ribs during the inspiration phase of breathing.
internal/external intercostal muscle?
external
is a dome-shaped muscle that forms a partition between the thorax and the abdomen
diaphragm
has three openings in it for structures that have to pass from the thorax to the abdomen
diaphragm
unlike the thorax and pelvis, has no bony reinforcements or protection.
abdomen
The wall consists entirely of four muscle pairs, arranged in layers, and the fascia that envelops them.
abdomnal wall
is formed by two muscular sheets and their associated fascia.
pelvic outlet
made up of the pectoralis major and pectoralis minor
pectoralis muscle
large, fan shaped muscle of the shoulder joint
O - medial half of clavicle, sternum, anterior layer of rectus sheath
I - crest of greater tuberosity of humerus
A - adduction of the humerus, anteversion, assist in respiration
innervated by C5 to T1 (brachial plexus)
pectoralis major
include those that attach the scapula to the thorax and generally move the scapula, those that attach the humerus to the scapula and generally move the arm, and those that are located in the arm or forearm that move the forearm, wrist, and hand.
muscle of upper extremity
Muscles that move the shoulder and arm include the
trapezius
serratus anterior
muscles connect to the humerus and move the arm.
pectoralis major
latissimus dorsi
deltoid
rotator cuff
The muscles that move the ____ are located along the humerus, which include the triceps brachii, biceps brachii, brachialis, and brachioradialis.
forearm
The 20 or more muscles that cause most wrist, hand, and finger movements are located along the
forearm
what side of the arm
coracobravhialis
brachialis
biceps brachii
anterior
what side of the arm
anconeus
triceps brachii
posterior
two heads, short head medially, lateral long head
O - scapula
I - radius
biceps brachii
O - ant. surface of humerus
I - ulna
brachialis
have their origins on some part of the pelvic girdle and their insertions on the femur.
thigh muscle
he largest muscle mass belongs to the posterior group, the ____ muscles, which, as a group, adduct the thigh.
gluteal
an anterior muscle, flexes the thigh.
iliopsoas
muscle group straightens the leg at the knee.
quadriceps femoris
antagonists to the quadriceps femoris muscle group, which are used to flex the leg at the knee
hamstrings
which dorsiflexes the foot, is antagonistic to the gastrocnemius and soleus muscles
tibialis anteriror
which plantar flex the foot.
gastronemius
soleus
innervated by femoral nerve
flexor of hip joint
iliopsoas
40 50% of total body weight voluntary
Mostly movement of bone & body parts
Stabilizing body positions
skeletal muscle
only in heart involuntary
Heart only
Develops pressure for arterial blood flow
cardiac
grouped in walls of hollow organs
Sphincters regulate flow in tubes
Maintain diameter of tubes
Move material in GI tract and reproductive organs
smooth muscle
skeletal muscle that has no direct attachment to the bone
tongue
what shape of skeletal muscle occupies the anal sphincter
circular
main objective is to accomplish work in conjunction with bones (skeletal muscle)
muscle
The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch.
muscle tonicity
two principal substances that msucle store
glycogen and calcium
act of shivering caused by a cold environment
anatomical or molecular?
anatomical
generation of heat in molecular level
ATP breakdown
anything that bears an anatomical name
muscle group
surrounding a bundle of muscle fibers
perimysium
surrounding an entire muscle
epimysium
around individual muscle fiers
endomysium
wrapped by the perimysium, bundle of fibers
fascicle
surrounded by endomysium
fiber
where does blood vessel and nerves pass through in skeletal muscle tissue
connective tissue
surrounds fiber bundles called fascicles
perimysium
surround each individual fiber
endomysium
convergence of the three types of tissue make up the ____
tendon
muscle injection sites should be rich/poor with blood vessels
rich
consist of neuron, axon, or any individual axon fiber and the muscle fiber it innervate
motor unit
make up the muscle fiber
myofibril
make up the myofibril
myofilament
myofilament is made up of
actin
myosin
Elongated cylindrical cells = m
muscle fibers
Plasma membrane =
sarcolemma
s tunnel from surface to
center of each fiber
transverse tubule
Cytoplasm
sarcoplasm
◼ Multiple nuclei lie near/away surface of ce
near
how many triad does cardiac muscle have
1 triad
how many triad does skeletal muscle have
2 triad
have no triads
smooth muscle
shows its relative proximity to the sarcomere
triad
part of sacroplasmic reticulum adjacent to transverse tubules
terminal cisterns
will only happen when nerve impulses travel the inside of the muscle fiber
contraction
where the nerve impulse enters to get inside
T tubule openings
can be found in the myofibril
structural and functional unit of muscle tissue
have the necessary component in order for muscle contraction to happen
sarcomere
measured in nanometers
can be viewed in electron microscope
sarcomere
cell membrane of the muscle fiber
sarcolemma
does not work similarly to ER, function in calcium reservoir, releases calcium and storage of calcium
sarcoplasmic reticulum
behaves like a vaccuum pump when on (relaxation happens) when off (contraction happens)
SR
throughout sarcoplasm is this that stores calcium ions
SR
contains myoglobin
sarcoplasm
Red pigmented protein related to Hemoglobin that
carries oxygen
myoglobin
Along entire length are
myofibrils
made of protein filaments
myofibrils
happens because of the calcium in the sarcoplasmic reticulum
(pump turns off permanently causing the muscle to contract), happens by the duration
of 24 hours
rigor mortis
> decomposition happens after 24 hours
softening due to pancreatic enzymes (responsible for accelerated decomposition)
rigor mortis
first removed when embalming
pancreas
bisects the A band, H
zone, and sarcomere
M line
space between the
thick filaments to allow
the thin filaments to slide
H zone
“stands for Zigzag’
> intermediate filament makes up the Z line
> bisects the I band
z disc
dark bond, stand for ‘anisotropic’ lack
of light
H zone
stands for ‘Isotropic’ only thin filaments
even distribution of light
two bands are located
I band
Unit structure is called s
sarcomere
sarcomere is separated by
Z disc
Darker area = ___ band associated with
thick filaments
A band
has no thin filaments
H zone
has thin filaments no thick
filaments
I band
bends, allowing it to move towards the thin
filaments to attach itself for contraction
pivot point
ingular protein that resembles a golf club
myosin
> two/three myosin make up a twisted myosin protein
two
principal protein, spherical/globular protein with a
structure that looks like an eye (myosin binding site)
actin
wisted with each other (helical strand)
what strand
actin
cover the myosin binding site, preventing the myosin
head (state of relaxation)
tropomyosin
attached to the tropomyosin, changes it shape in the presence of calcium (exposing the myosing binding site_
troponin
affect troponin
calcium
attach by mere chemotaxis (attraction of two chemicals together)
myosin head
has moveable
heads (like “heads” of golf clubs)
thick filament
are anchored to Z
discs
thin filament
❑ Contain myosin binding sites for myosin head
❑ Also contain tropomyosin & troponin
thin filament
blocks myosin binding site
when muscle is at rest
tropomyosin
universally accepted concept of muscle
contraction
sliding filament mechanism
During contraction myosin heads bind to
actin site
pull and slide actin molecules (and Z
discs) toward H zone
myosins
become more narrow
what zones
I bands
H zones
generates force and shortens
sarcomeres and thus fibers
sliding
opened when electrical impulse carry over to T tubules
calcium gated channels
- entering the axon terminal to
stimulate synaptic vesicle
calcium
contains ACh
synaptic vesicle
still part of the neuron, aligns with the synaptic vesicle
presynaptic terminal
have receptors that
detect ACh to change the chemical impulse back to an electrical impulse
post synaptic membrane
calcium is used in two ways
synaptic vescile stimulation
bind to troponin
triggers muscle action potential
nerve signal
Delivered by motor neuron
nerve signal
can trigger 1 or more fibers at
the same time
one neuron
Neuron plus triggered fibers =
motor unit
Neuronal ending to muscle fiber =
neuromuscular junction
Muscular area =
muscular area
action at NMJ
- release of ACh (diffusion)
- activation of ACh receptors
- generation of muscle action potential (repeats with each neuronal action potential)
- breakdown of ACh
contraction trigger
◼ Muscle action potential → Ca2+ release from
Sacroplasmic Reticulum (SR)
◼ Ca2+ binds to troponin →
◼ Moves tropomyosin off actin sites →
◼ Myosin binds & starts cycle
binds to actin & releases phosphate
group (forming crossbridges)
myosin
◼ Crossbridge swivels releasing ADP and
shortening sarcomere
powerstroke
- characterized by depletion of ATP
fatigue
powerstroke is not completed (myosin head is still attached)
cramp
attachment of myosin heads
> caused by the exposure of myosin binding site
> myosin shaft should be flexible (pivot point)
> chemotaxis should occur
crossbridge
binds to the myosin head
ATP
energy is expended for powerstroke
1st ATP
needed to detach the myosin head
2nd ATP
Breakdown of ACh to stop muscle action
potentials
muscle relaxation
ions transported back into SR lowering
concentration →
❑ This takes ATP
Ca2+
covers actin binding sites
tropomyosin
Even at rest some motor neuron activity
occurs
muscle tone
if nerves are cut fiber becomes
flaccid
is the main high-energy, phosphate-storage molecule of muscle, short lived about 15 secs
creatine phosphate
Break down glucose to 2 pyruvates getting 2
ATP
glycolysis
If insufficient mitochondria or oxygen,
pyruvate →
lactic acid
Get about 30–40 seconds more activity
maximally
glycolysis
end product of glycolysis > pyruvic acid > (possible if there is oxygen)
acetyl-CoA
end product of glycolysis > pyruvic acid > ____ (oxygen debt, fermentation happens)
lactic acid
causes muscle pain (replenish your oxygen debtt
lactic acid
◼ Production of ATP in mitochondria
◼ Requires oxygen and carbon substrate
◼ Produces CO2 and H2O and heat.
aerobic cellular respiration
Inability to contract forcefully after prolonged
activit
fatigue
Limiting factors can include:
❑ Ca2+
❑ Creatine Phosphate
❑ Oxygen
❑ Build up of acid
❑ Neuronal failure
fatigue
◼Convert lactic acid back to glucose in liver
◼ Resynthesize creatine phosphate and ATP
◼ Replace oxygen removed from myoglobin
what after exercise
oxygen
→ twitch
❑ Smaller than maximum muscle force
single action potential
Total tension of ___ depends on
frequency of APs (number/second)
fiber
Total tension of ___ depends on
number of fibers contracting in unison
muscle
small diameter and red
❑ Large amounts of myoglobin and mitochondria
❑ ATP production primarily oxidative
❑ Fatigue resistant
what kind of fiber
slow oxidative
glycolytic (FOG)
❑ Large diameter = many myofibrils
❑ Many mitochondria and high glycolytic capacity
fast oxidative
White, fast & powerful and fast fatiguing
❑ For strong, short term use
fast glycolytic fibers
Muscle contractions only use the fibers
required for the work
motor unit recruitment
what is used for sprinters
high FG
what is used for marathoners
SO
◼ Endurance exercise gives
FG -> FOG
increases size and
strength of FG fibers
strength exercise
involuntary muscle found only in heart wall
Striated, branched short fibers with single,
central nucleus in each fiber
cardiac muscle
thickened cell membranes that connects cardiac muscle fibers
intercalated discs
Gap junctions that allow spread of action
potentials
cardiac muscle
generated by abundant mitochondria
and by lactic acid when cells lack oxygen
ATP
Does not require nerve stimulation nerve
cardiac muscle
as its own intrinsic pacemaker (and conduction
system within cardiac muscle) that initiates cardiac
contraction known as
autorhythmicity
Intercalated discs with gap junctions transmit
action potentials from ne muscle cell to the
next
what muscle
cardiac muscle
◼ Involuntary
◼ Found in internal organs such as stomach,
bladder, walls of arteries
smooth msucle
◼ Structure
❑ Tapered cells each with single nucleus
❑ Filaments not regular so tissue does not appear
striated
smooth muscle
type of smooth muscle
visceral
multi-unit type
◼ As with bone there is a slow progressive loss
of skeletal muscle mass
◼ Relative number of SO fibers tends to
increase
aging
Muscles move one bone relative to another
around one or more joint(s
movement
most stationary end
❑ Location where the tendon attaches
origin
most mobile end
❑ Location where tendon inserts
insertion
→ the motion or function of the
muscle
action
