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