Muscular system for UNC EXSS 175
Perimysium
covering of fascicles
Bipennate
fascicles are arranged on both sides of centrally positioned tendons
parallel muscles
terminate at either end of the muscle in flat tendons
myosin
thick filaments in muscles, the heads attach to the thin filaments
Functions of Muscle tissue
Producing body movements, stabilizing body positions, regulating organ volumes, movement of substances within the body, producing heat
isotonic
a load is moved
Eccentric contractions
a muscle lengthens while maintaining force and movement
Concentric contraction
a muscle shortens to produce force and movement
Elasticity
ability of muscle to return to its original length and shape after contraction or extension
Extensibility
ability of muscle to stretch, within reason, without being damaged.
contractility
ability of muscular tissue to contract forcefully when stimulated by action potential
Electrical excitability
ability to respond to certain stimuli by producing electrical signals called action potentials, found in nerves also
skeletal muscle
attaches to bone, skin, or fascia, striated with light and dark bands, voluntary control of contraction and relaxation, easily repaired
Muscles that regulate organ volumes
bands of smooth muscles called sphincters
Substances in body moved by muscles
blood, lymph, urine, air, food and fluids, sperm
3 types of muscle tissue
cardiac, smooth, skeletal
sphincters
circular muscles
Endomysium
covers each muscle fiber
Sacroplasm
cytoplasm of muscle fiber
Fascia
epimysium that covers muscle
Unipennate
fascicles arranged on one side of tendon
multipennate
fascicles attach from many directions to several tendons
Triangular muscles
fascicles spread over broad area and converge at a thick central tendon, pectoralis major
Smooth muscles
found on walls of hollow internal structures, found under skin, attached to hair follicles, no sitrations
Sacromere
functional unit of muscle
Motor unit
functional unit of skeletal muscle, has a single motor neuron and muscle fibers that it innervates
Shivering
involuntary contractions of skeletal muscle
Greatest at physiologic resting length
isometric: complete overlap between actin and mayosin maximal cross bridges are generated
fulcrum
joint moving
actin
little balls that make up the thin filaments
Myofibril
little threads that are the contractile organelles of skeletal muscles, contractile elements of the muscle
Fascicles
many bundles of muscle fibers
order of largest to smallest
muscle bundles, muscle fascilces, muscle fibers, myorfibril, sacromere
fusiform
muscle gets wider at belly and is similar to parallel in that it ends at both sides with tendons
Regulation of smooth and cardiac muscle
neurons from autonomic system and hormones released by endocrine glands
isometric
no movement occurs
Ratio of muscle cells to nerves
one muscle cell to one nerve
Z discs
one z line to the other is a sacromere
Sacrolemma
pasma membrane in the muscle
Muscle subject to greatest amount of stretching
smooth muscle
Cardiac muscle
striated in appearance, involuntary in control, autorhythmic because of built in pacemaker, has striations
Effort
the action of the muscle
Thin filaments
the small ropes connected by heads of myosin
Load
weight of the object plus area moving
