muscular system😭🤢😵

synaptic cleft

A narrow space that separates the axon terminal of the neuron from opposing motor and plate/contains molecules of ACHe which breaks down ACH

ACh (acetylcholine)

A neurotransmitter/a chemical released by a neuron to change the permeability or other properties of another self is plasma membrane/contained with vesicles that are in the cytoplasm of an axon terminal/leads to excitation and the production of an action potential to the sarcolemma

tendons

At the end of each muscle the collagen fibers of the epimysium parimysium and epimysium come together to form either a bundle called a tendon or abroad she called an aponeurosis/usually attach skeletal muscles to bones/where they contact the bone the collagen fibers extending to the bone matrix providing a firm attachment/any contraction of the muscle will pull the bone

myofilaments

Bundles of protein filaments in a myofibril/constructed from proteins primarily actin and myosin/various arrangements of myofilaments create different muscles

A bands

Dark bands/Anisotropic/overlapping thick and thin filament/thick filaments are the center of each sarcomere/contain myosin

Trapezius

Elevates, depresses, retracts, and rotates the scapula; may elevate clavicle; may extend neck

Gastrocnemius

Extension (plantar flexion) at ankle; inversion of foot; flexion at knee

Thick filaments (myosin)

Protein filaments making up a myofilament/contains about 300 miles and molecules each made up of a pair of myosin subunits twisted around one another/has a free head projecting outward toward the nearest thin filament/all myosin molecules have tails pointing toward the m line (middle)/A bands

neuromuscular junction (NMJ)

this is the point where the axon terminal of the neuron lies near the motor end plate of the muscle fiber/each muscle fiber only has one neuromuscular junction/also myoneural junction

Deltoid

whole muscle-abduction at shoulder/anterior part- flexion and medial rotation/ posterior part- extension and lateral rotation

LADSNOR and muscle for each

•location of body-temporalis muscle of head •action-flexor carpi group •direction of fascicle organization-external oblique •shape-trapezius muscle •number of origins-quadriceps group •origins and insertion-sternocleidomastoid •relative size-peroneus longus

motor end plate

The large and complex terminal formation by which the axon of a motor neuron establishes synaptic contact with the striated muscle fiber/the particular synapse made between a spinal motor neuron and a skeletal muscle cell

Sternocleidomastoid

Together they flex the neck/alone one side flexes head toward shoulder and rotates face to the opposite side

vesicles

a small fluid filled sac within the body

gluteus medius

abduction and medial rotation at hip

go signal for muscle contractions

ach released-action potential reaches t tubule-sarcoplasmic reticulum releases Ca-active site exposure and cross bridge formation-contraction cycle begins

Z disc or Z line

bisect the I bands and mark the boundary between adjacent sarcomeres/in a sectional view it looks more like a disc with an open meshwork often called a z disc/this is the border that separates and link sarcomeres within a skeletal muscle

3 types of muscle tissue-how they are different from each other

cardiac- pumps blood through the cardiovascular system/found only in the heart/typically branched/contract without neural stimulation/contractions last 10 times as long as skeletal muscle contractions/protein(actin and myosin)are organized in sarcomeres making it a striated muscle smooth- pushes fluids and solids along the digestive tract and other internal organs and regulates the diameters of small arteries/ form sheets bundles sheaths around other tissues in almost every other organ/has a single centrally located nucleus in each cell/ lack myofibrils and sarcomeres/ non striated muscle/ many are not innervated by motor neurons/ not under voluntary control skeletal- moves the bodyBy pulling on our bones/attached to bones directly or indirectly/typically non-branched/proteins (actin and myosin) are organized and sarcomeres making it a striated muscle

orbicularis oculi

closes eye

transverse abdominus

compresses abdomen

external oblique

compresses abdomen, depresses ribs, flexes or bends spine

internal oblique

compresses abdomen, depresses ribs, flexes or bends spine

Buccinator

compresses cheek/moves food back across the teeth

orbicularis oris

constricts the mouth opening

rectus abdominis

depresses ribs, flexes vertebral column, compresses abdomen

Temporalis

elevates mandible

masseter

elevates mandible and closes jaw

difference between endomysium and fascicle

endomysium-delicate connective tissues that surrounds the individual skeletal muscle cells called muscle fibers/contains capillary networks that supply blood myosatellite cells(stem cells) that repair damaged tissue and nerve fibers that control the muscle/blends into the perimysium fascicle-a bundle of muscle fibers

difference between epimysium and muscle fibers

epimysium- outermost layer and surrounds the entire skeletal muscle/separates the muscle from nearby tissues and organs muscle fibers- individual skeletal muscle cels found within the fascicle

rectus femoris

extends leg, flexes hip

gluteus maximus

extension and lateral rotation at hip

latissimus dorsi

extension, adduction, and medial rotation at shoulder

biceps brachii

flexion at elbow the shoulder/ supination

Sartorius

flexion at knee, flexion and lateral rotation at hip

pectoralis major

flexion, adduction, and medial rotation at shoulder

sarcoplasmic reticulum

found in skeletal muscle fibers and is a membrane complex/it forms a tubular network around each individual myofibril fitting over it like a lacy shirt sleeve/they combine with a t tubule(transverse tubule)

difference between insertion and origin

insertion- the one end of a skeletal muscle the moves/this end will move toward the fixed end origin- the one end of a skeletal muscle that is usually fixed in position during a contraction

difference between isotonic and isometric

isotonic- when tension increases and the skeletal muscles length changes/lifting and object off a desk walking and running are examples isometric- if neither end of the myofibril can move thick and thin filament interactions consume energy and generate tension but sliding cannot occur/ tension is developed without contraction of the muscle/ the muscle as a whole does not change length and the tension produced never exceeds the load

triceps brachii

lateral head- extension at elbow/ long head- extension at the elbow extension and adduction at the shoulder

I bands

light bands/isotropic/contains then filaments but no thick filaments/extends from A band of one sarcomere to the a band of the next sarcomere/on each side of a Z line

What is the interaction between actin and myosin

muscle contractions results from an interaction between actin and myosin filaments that generates their movement relative to one another/myosin binds to actin filaments allowing myosin to function as a motor that drives filament sliding

difference between perimysium and myofibril

perimysium- connective tissue fibers separating the fascicles dividing into a series of compartments/contains blood vessels and nerves that supply the muscles fibers within the fascicle/blends into the emdomysium myofibril- hundreds to thousands of cylindrical structures contained within a muscle fiber/the active shortening of a myofibril is a responsible for skeletal muscle fiber contraction/contain thin and thick filaments/anchored to the inner surface of the sarcolemma at each end of the skeletal muscle fibers

functions of the muscular system

produce skeletal movement maintain posture and body position support soft tissues guard body entrances and exits maintain body temp store nutrients

Thin filaments (actin)

protein filaments making of a mile filament/contains 4 proteins- F-actin (filamentous actin), nebulin/tropomyosin and troponin/connected to Z discs of the striated muscle/I bands

Frontalis

raises eyebrows, wrinkles forehead

sarcomere

repeating functional units of myofilaments/smallest function unit of a muscle fiber/interactions between thick and thin filaments within sarcomeres are responsible for muscle contraction as they slide past one another/1 myofibril has approximately 10,000 sarcomeres end to end

Zygomaticus

retracts and elevates upper lip and corner of mouth

what is muscle tone

the resting tension in a skeletal muscle/in any skeletal muscle some motor units are always active even when the entire muscle is not contracting; but they do not produce enough tension to cause movement/ this is when the muscle is tense and firm

what creates skeletal muscle striations

the sarcomere which is made up of myofibrils composed of actin and myosin filaments/the sarcomeres are repeated in units

crossbridges

When the myosin heads interact with thin filaments during a contraction/connection between the head and a tail functions as a hinge that lets the head pivot/the head swings toward or away from the M line

ATP (adenosine triphosphate)

Scattered among the myofibrils our mitochondria and granules of glysocen(Storage from glucose)The mitochondrial activity in glucose break down by glycolosis provide this energy for a short duration maximum intensity muscular contraction