anat ch6 muscular system

muscle fibers

skeletal and smooth muscle cells

skeletal muscle

type of muscle that attach to the skeleton, have multinucleate cells, striated, and voluntary

endomysium

connective tissue sheath that wrap around each muscle fiber

perimysium

coarser fibrous membrane that wrap around several sheathed muscle fibers

fascicle

bundle of gibers, wrap around perimysium

epimysium

connective tissue that cound many fascicles together, covers the entire muscle

tendon

connective tissue that epimysium blend into, strong & cordlike, mostly tough collagenn fibers, can cross thru rough bony projections

aponeurosis

connective tissue that epimysium blend into, sheetlike, attach muscle indirectly to bones, cartilage, or connective tissue coverings

smooth muscle

type of muscle, no striations, involuntary, uninucleate, spindle-shaped muscle cell, found mainly in walls of hollow visceral organs

cardiac muscle

type of muscle that is only found in the heart, striated, uninucleate, involuntary, branching muscle cells

intercalated discs

special gap junctions found in cardiac muscle

sarcolemma

plasma membrane of skeletal muscle fibers

myofibrils

long ribbonlike organelles that push nuclei aside

I band

light band, contains only thin filaments, z band in the middle

A band

dark band, contains the entire thick filaments, has H zone in btwn, doesnt have any actin filaments

H zone

central area of A band

M line

in the center of H zone

sarcomeres

structural and functional units of skeletal muscle

myofilaments

threadlike protein that produce banding pattern

thick filaments

myosin, possess myosin heads that form cross bridges during contraction, contain ATPase enzymes

thin filaments

actin, anchored to the Z disc

sarcoplasmic reticulum (SR)

one of the muscle fiber organelle that is a specialized smooth endoplasmic reticulum, surround every myofibril and store and release Ca

graded responses

different degrees of shortening that generate diff amounts of force. produced by diff frequency and # of muscle stimulation

muscle fatigue

occurs when muscle is unable to contract even though it is still being stimulated.

isotonic contractions

contraction that myofilaments are able in sliding movements, muscle shortens, movement occurs

isometric contractions

contraction that the tension in the muscle keeps increasing but is unable to shorten or produce movement

eccentric

muscle contraction that lengthen muscle

concentric

muscle contraction that shorten muscle

muscle tone

state of continuous partial contraction, keeps muscles healthy and ready to react, result of diff motor units

insertion

one of the point that mucles attached to bone/connective tissue, attached to movable bone, moves toward the origin when contract

origin

one of the point that mucles attached to bone/connective tissue, attached to the immovable/less movable bone

flexion

movement that decreases the angle of the joint and brings two bones closer tgt

extension

movement that increases the angle between two bones or parts of the body

rotation

movement of a bone around its longitudinal axis

abduction

movement that moves limb away from the body

adduction

movement that moves limb toward the body

circumduction

movement that’s a combination of flexion, extension, abduction, and adduction

dorsiflexion

movement that’s lifting foot up

plantarflexion

movement that’s pointing toes down

inversion

movement that turn the sole medially

eversion

movements that turn the sole laterally

supination

movements that the dorearm rotates laterally, radius and ulna areparallel

pronation

movement that forearm ratates medially, radius across the ulna

opposition

movement that move thumb to touch the tips of the other fingers on the same hand