Muscular System (Chapter 8) Flashcards
What are the three types of muscle tissue
skeletal, smooth, and cardiac
How many skeletal muscles are in the body?
600 +
fascia
layers of dense connective tissue surrounding and separating each muscle
tendons
connective tissue extending beyond muscle ends
aponeuroses
broad sheets of connective tissue connecting muscles
epimysium
connective tissue around skeletal muscles (blending with fascia)
perimysium
surrounds bundles of skeletal muscle fibers (fascicles) within each muscle. Extends inwards from epimysium.
fascicles
bundles of skeletal muscle fibers
endomysium
connective tissue layer covering each individual muscle cell (fiber)
muscle fiber
single, long, cylindrical muscle cell
How do fibers respond to stimulation?
by contracting
sacrolemma
cell membrane of muscle fiber
sacroplasm
cytoplasm of muscle cell containing mitochondria and nuclei
myofibrils
active in muscle contraction inside sacroplasm. Can be thick or thin filaments.
thick filaments
contain protein myosin
thin filaments
mainly composed of protien actin, also contain troponin and tropomyosin
striations
organization of thick and thin myofibril filaments
sacromeres
make up myofibrils
Where do sacromeres extend?
From one z line to the next
What do striations consist of?
Alternating patterns of light and dark bands
I bands (light bands)
made of actin filaments, anchored to z lines
A bands (dark bands)
made of overlapping thin and thick filaments
H-zone
located in the center of A band consisting of myosin filaments ONLY
M line
in center of H-zone, consisting of proteins holding filaments in place
sacroplasmic reticulum (SR)
network of membrane channels
transverse tubules
invagnations of sacrolemma, between 2 cisternae of SR
What do the SR and T tubules activate?
muscle contraction mechanism
When do skeletal muscles contract?
When stimulated by motor neuron
