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