Muscle 1 Flashcards
Origin of muscle
more stationary and proximal attachment of muscle to a bone
Insertion of muscle
the distal attachment of a muscle to bone
Tendon
connective tissue that forms the attachment of muscle to bone
Antagonistic pair
muscle pairs that act to move muscle in opposite directions, example: biceps-triceps, one flexes, one extends
Skeletal muscle classification
cross striations, voluntary, CNS
Cardiac muscle
cross striations, functional syncytium (contraction driven by pacemaker cells)
Smooth muscle (visceral)
Lacks cross striations (smooth structure), Involuntary: driven by ANS
T/F Skeletal muscles can push and pull.
FALSE. Can only pull
Epimysium
connective tissue surrounding entire muscle
Perimysium
connective tissue surrounding muscle fascicle
Endomysium
connective tissue surrounding muscle fiber
Sarcolemma
membrane surrounding muscle cell (neuron)
T/F Skeletal muscle fibers are multinucleated
TRUE
How are myofibrils arranged within a muscle
PARALLEL
Myofibrils contain few or many sarcomeres
MANY
When a muscle contracts, what pulls closer together?
the Z-lines get close (the I band disappears)
Triad region in skeletal muscle
2 terminal cisternae and one t-tubule
What stores calcium in the skeletal muscle
sarcoplasmic reticulum
How does the Ca++ get into the sarcolemma
Through the t-tubules (invaginate in from within the sarcolemma)
Sarcomere
the basic functional and anatomical unit of the contractile machinery of skeletal muscle
How long are myofibrils
they run the entire length of the muscle
What are the 2 internal membrane structures and what do they do?
Transverse tubules: extend inward from the sarcolemma
Sarcoplasmic reticulum: runs length of sarcomeres, right angles to t-tubules, site of Ca++ storage
Z-line
boundary of the sarcomere; connects the ends of the thin filaments; z-line moves closer together during contractions
A-band
composed of thick filaments arranged side by side (width remains constant during contraction)
M-line
runs down the center of the A-band
I-band
portion of thin filaments where there is no overlap with thick filaments; width narrows during contraction
H-zone
region of the A-band into which thin filaments do not extend
Thin filaments
Actin
Thick filaments
Myosin
Troponin/Tropomyosin complex
TnC binds Ca++ and allows the tropomyosin molecule to shift in the groove creating a situations where actin and myosin can interact
Titin
cytoskeletal protein; large elastic protein that extends from the Z-line to the center of the sarcomere
What does the Titin do?
Helps maintain the myosin interaction with actin
Nebulin
structure of the actin molecules (organization and connection of actin to the Z-line)
Myosin contains ___.
ATP and actin binding sites that project out in spiral fashion
A-band
Overlap of thin and thick filaments
