Muscle Tissue Flashcards
Skeletal Muscle
(S, F, L)
Structure: composed of long, striated multinucleated muscle fibers; limited ability to renew
Function: production of major movements of the body
Location: all over the body; most are attached to bones
Cardiac muscle
(S, F, L)
Structure: composed of short, striated, uninucleate cardiomyocytes with branched cytoplasm, firmly attached to each other via intercalated discs; inability to renew, contains glycogen storage
Function: coordinated contraction and relaxation fills and pumps blood; glycogen stores for energy
Location: heart
Smooth muscle
(S, F, L)
Structure: composed of short, fusiform, uninucleate smooth muscle cells staggered in parallel; able to renew continually; homogenous eosinophilic cytoplasm (no striations or bands)
Function: coordinated contraction of the visceral organs
Location: visceral organs; gastrointestinal tract (GI blood vessels, exocrine glands, etc.)
Regeneration in skeletal muscle
Satellite cells in skeletal muscles have limited ability to proliferate and differentiate into skeletal muscle cells; as a result, extensive injury and destruction of muscle tissues cannot be fully repaired; muscle building exercises causes muscle fibers to grow, not to increase in number
Skeletal muscle fiber
(S, F, L)
Structure: striated, multinucleated muscle cell
Function: individual contractile cell
Location: throughout the muscle
Endomysium
(S, F, L)
Structure: thin reticular fibers
Function: structural support for each cell and delivery of small vessels and nerves
Location: surrounds each muscle fiber
Fascicle
(S, F, L)
Structure: A bundle of muscle fibers
Function: functional unit that works together
Location: throughout the muscle
Perimysium
(S, F, L)
Structure: connective tissue
Function: bind together fascicles and help it function as a unit, deliver larger vessels and nerves
Location: surround each fascicle
Named muscles
(S, F, L)
Structure: formed from a collection of fascicles
Function: work in a coordinated manner to create movements
Location: throughout the body
Epimysium
(S, F, L)
Structure: dense connective tissue
Function: sheath the muscle, help transmit contractile force of the muscle, deliver major vessels and nerves
Location: surround each muscle
Myofibril
(S, F, L)
Structure: thin and long bundles that fill the muscle fiber
Function: contractile structure as long as the muscle cell
Location: throughout sarcoplasm
Sarcomere
(S, F, L)
Structure: contractile unit of the myofibril
Function: line up back to back to form a myofibril
Location: length of the myofibril
Myofilaments
(S, F, L)
Structure: strands of protein polymers; myosin (thick filaments) and actin (thin filaments)
Function: Interaction between thick and thin filaments produces contraction; overlap between the two filaments creates a banding pattern (striations)
Location: within each sarcomere
Sarcoplasmic reticulum
(S, F, L)
Structure: network of specialized sER surrounds each myofibril. Terminal cisternae are dilated portions of the sarcoplasmic reticulum
Function: store, release, and reuptake Ca++
Location: throughout the sarcoplasm surrounding each myofibril; terminal cisternae are located between A and I bands
Transverse tubules (T-tubules)
(S, F, L)
Structure: invagination of the sarcoplasmic reticulum (sarcoplasm??)
Function: Transmit membrane depolarization throughout the sarcoplasm; trigger Ca++ release from terminal cisternae
Location: travel through the muscle fiber at A and I junctions