Muscle Physiology Flashcards by Franchez Cassandra Escander

composed of specialized cells called muscle fibers

muscles

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predominant function is contractability that promotes movment

muscles

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what kind of muscle are attached to bones

voluntary/involuntary

voluntary

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muscles are responsible for the involuntary contraction and relaxation of longitudinal and circular muscles throughout the digestive tract,

peristalsis

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function in posture and joint stability

muscles

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percent of heat produced in muscle contraction

85%

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is the ability of muscle cells to forcefully shorten.

contractility

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muscles in blood vessels that helps promotes

circulation

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present in the surface of epithelial cells; not muscle

cilia

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present in sperm cells for locomotion

flagellum

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sarco means

flesh

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the only organ of the muscular system

skeletal muscle

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composed of skeletal muscle tissue and also contains nervous tissue, blood vessels, and connective tissue

skeletal muscle

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are not organs but mere tissues of the heart and visceral organs respectively

cardiac
smooth muscle

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half of the body’s weight is ___ tissue

muscle

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skeletal muscle accounts for what percent in males and females

40% males
32% females

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what percent does the cardiac muscle account for in the human body

10%

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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

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what muscles are in control of the volume of organs

sphincters (smooth muscle)

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what substance is moved by muscle

blood, lymph, urine, air, food and fluids, sperm

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what kind of muscle generate body heat

voluntary and involuntary contractions of skeletal striatied muscle

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ability of the skeletal muscle to respond to stimuli

electrical irritability/excitability

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contracts as a result of nerve irritation

skeletal muscle

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ability of contracton

contractility

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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

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)

throughout sarcoplasm is this that stores calcium ions

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

1. release of ACh (diffusion) 2. activation of ACh receptors 3. generation of muscle action potential (repeats with each neuronal action potential) 4. 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

◼ 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