Chapter 10 - Muscular Tissue Flashcards
(101 cards)
Four main functions of muscle tissue
Producing body movements, stabilizing body positions, storing and moving substances within the body, generating heat
Shivering
Involuntary contractions that increase rate of heat production (contraction=heat)
Four properties of muscle tissue that contribute to homeostasis
Electrical excitability (action potentials respond to stimuli)
Contractility
Elasticity
Extensibility (stretch)
Fascia
dense sheet or broad band of irregular connective tissue that lines the body wall and limbs and supports and surrounds muscles and other organs of the body.
Fascia allows free movement of muscles; carries nerves, blood vessels, and lymphatic vessels; and fills spaces between muscles.
Epimysium
is the outer layer, encircling the entire muscle. It consists of dense irregular connective tissue.
Perimysium
is also a layer of dense irregular connective tissue, but it surrounds groups of 10 to 100 or more muscle fibers, separating them into bundles called fascicles
Fascicles
The grainy look of meat, bundles of muscle fibers.
Endomysium
penetrates the interior of each fascicle and separates individual muscle fibers from one another. The endomysium is mostly reticular fibers.
Aponeurosis
When the connective tissue elements extend as a broad, flat sheet,
Nerve and blood supply
Generally, an artery and one or two veins accompany each nerve that penetrates a skeletal muscle.
Somatic motor neuron
neurons that stimulate skeletal muscle to contract threadlike axon that extends from the brain or spinal cord to a group of skeletal muscle fibers
Sarcolemma
plasma membrane of a muscle cell
Transverse tubules
Thousands of tiny invaginations of the sarcolemma, tunnel in from the surface toward the center of each muscle fiber.
Sarcoplasm
cytoplasm of a muscle fiber.
Myoglobin
This protein, found only in muscle, binds oxygen molecules that diffuse into muscle fibers from interstitial fluid. and releases when mitochondria need it
Myofibrils
Look like little threads, contractile organelles of skeletal muscle.
Sarcoplasmic reticulum
Fluid-filled system of membranous sacs
Terminal cisterns
Dilated end sacs of the sarcoplasmic reticulum butt against t tubule from both sides.
Triad
A transverse tubule and the two terminal cisterns
Muscular hypertrophy
muscle growth that occurs after birth occurs by enlargement of existing muscle fibers
Fibrosis
the number of new skeletal muscle fibers that can be formed by satellite cells is not enough to compensate for significant skeletal muscle damage or degeneration, the muscular tissue undergoes fibrosis, the replacement of muscle fibers by fibrous scar tissue.
Muscular atrophy
decrease in size of individual muscle fibers as a result of progressive loss of myofibrils.
Thin filament
are 8 nm in diameter and 1–2 m long* and composed mostly of the protein actin,
Thick filament
16 nm in diameter and 1–2 m long and composed mostly of the protein myosin