(P) Lec 3.2: Muscular Tissue Flashcards
PPT-based
part of the cytoplasm
sarcoplasm
part of the cell membrane and external lamina
sarcolemma
part of the ribosomes
sarcosomes
part of the the smooth ER
Sarcoplasmic reticulum
All muscle cells are derived from
Mesoderm
cross-striations and cylindrical/elongated with blunt ends muscle cell with diameters of 10-100 μm.
Skeletal Muscle
T or F. The cardiac muscle is referred to as “fiber”
F (skeletal)
Large numbers of parallel skeletal muscle fibers are grouped into?
fascicles or bundles—arrangement
The nuclei (of skeletal muscle) are found at the periphery or eccentric under the?
sarcolemma (cell membrane surrounding a skeletal muscle fiber)
contraction is quick, forceful, and usually under voluntary control.
SKELETAL
external sheath of dense connective tissue that encloses the entire muscle
epimysium
A thin septa of dense connective tissue that immediately surrounds each bundle of muscle fibers termed a fascicle
Perimysium
Delicate layer of loose connective tissue (fibers and scattered fibroblasts) that surrounds the external lamina of individual muscle fibers; INSIDE THE FASCICLE
endomysium
the functional and structural unit of contraction in skeletal muscle; extends from Z disc to Z disc
Sarcomere
dark bands are called the
A band or anisotrophic bands
they are doubly refractile or birefringent under polarized light
A band or dark banks
they do not alter polarized light
light bands or I bands
center of the A band is a pale zone termed
H band
center of this H band is a narrow dark line, known as the
M band
depolarization of sarcoplasmic reticulum membrane, which results in the release of
Ca+++ ions
The depolarization of sarcoplasmic reticulum membrane is initiated at a?
specialized myoneuronal junction
To provide for a uniform contraction, skeletal muscles posses a system of?
transverse (T) tubules (fingerlike invaginations of the sarcolemma that form a complex anatomosing network of tubules that encircle both A-I junctions of each sarcomere in every myofibril)
end-to-end repetitive arrangement of sarcomeres
myofibrils
2 types of filaments of skeletal
myosin filaments and actin