Muscle Tissue & Neural Tissue (quiz 3) Flashcards
Muscle tissue is composed of cells that optimize the universal cell property of…
contractility
Actin microfilaments and associated proteins generate the forces necessary for ____________ contraction. This drives movement within organ systems, or blood, and of the body as a whole.
muscle
Muscle cells are of ____________ origin and differentiate by a gradual process of cell lengthening
mesodermal
The 3 types of muscle tissue can be distinguished on the basis of morphologic and functional characteristics. What are the 3 types?
-skeletal
-smooth
-cardiac
Are skeletal muscles voluntary or involuntary?
voluntary
Skeletal/striated muscle consists of muscle fibers, which are long cylindrical, __________________ cells/fibers
multinucleated
During muscle development, myoblasts fuse forming __________ with many nuclei
myotubes
What is the stem cell of muscle tissue?
satellite cell (helps form new muscle fibers as needed)
Thin layers of _____________ tissue surround and organize the contractile fibers in skeletal muscle
connective
An entire skeletal muscle is enclosed within a thick layer of dense CT called the ___________ that is continuous with fascia and the tendon binding muscle to bone
epimysium
epi- = outside
Large muscles contain several fascicles (bundles of fibers/cells) of muscle tissue, each wrapped in a thin but dense CT layer called the _____________
perimysium
peri- = around
Within fascicles, individual muscle fibers (elongated multinuclear cells) are surrounded by a delicate connective tissue layer, the ________________
endomysium
endo- = inner/inside
The epimysium is an external sheath of dense irregular CT, surrounding the entire muscle. __________ of this tissue extends inward, carrying the larger nerves, blood vessels, and lymphatics of the muscle
Septa
The perimysium is a thin CT layer that immediately surrounds each bundle of muscle fibers termed a…
fascicle
Within fascicles, there is a very thin, delicate layer of reticular fibers and scattered fibroblasts, the _________________ surrounds the external lamina of individual muscle fibers
endomysium
Skeletal muscle fibers (cells) are composed mainly of….
myofibrils
Each myofibril extends the length of the fiber and is surrounded by parts of the sarcoplasmic reticulum (ER). What is stored here?
calcium
The membrane of myofibrils is called the sarcolemma and it extends into the cytoplasm as….
T-tubules
What is the organization of skeletal muscle from largest to smallest?
-epimysium
-perimysium
-fascicle
-endomysium
-fibril = cytoskeleton (also known as myofibril)
Longitudinally sectioned skeletal muscle fibers show ____________ of alternating light and dark bands
striations
The sarcoplasm is highly organized, containing primarily long cylindrical filament bundles called ____________ that run parallel to the long axis of the fiber. Mitochondria and sarcoplasmic reticulum are found between myofibrils
myofibrils
(myofibrils consist of an end-to end repetitive arrangement of sarcomeres)
Each muscle fiber contains several parallel bundles called….
myofibrils
Each myofibril consists of a long series of sarcomeres, separated by…..
Z discs
Thin filaments are __________ filaments. Thick filaments are __________ filaments
actin, myosin
The sarcomere produces staining differences which cause the dark and light staining bands to be seen by light microscopy and is therefore termed…..
striated
What is the sliding filament theory?
during contraction, neither thick or thin filaments change their length. Contraction occurs as the overlapping thin and thick filaments of each sarcomere slide past one another
There are different types of skeletal muscle fibers. The different fibers can be identified on the basis of…
1) their maximal rate of contraction (fast or slow fibers)
2) their major pathway for ATP synthesis (oxidative phosphorylation or glycolysis)
Ex: skeletal muscles such as those that move the eyes and eyelids need to contract rapidly, while those for bodily posture must maintain tension for longer periods while resisting fatigue
Slow oxidative (SO) or _____________ fibers have high levels of acidic ATPase activity and stain the darkest
type 1
Fast glycolytic (FG) or _____________ fibers stain the lightest
type 2b
Fast oxidative-glycolytic (FOG) or __________ fibers are intermediate between type 1/2b
type 2a
________________________ muscle fibers are adapted for slow contractions over long periods without fatigue, having many mitochondria, surrounding capillaries, and myoglobin, all these features that make fresh tissue rich in these fibers dark or red in color
Slow oxidative
________________ fibers are specialized for rapid, short-term contraction, having few mitochondria or capillaries and depending largely on anaerobic metabolism of glucose derived from stored glycogens, features which make such fibers appear white. Rapid contractions lead to rapid fatigue as lactic acid produced by glycolysis accumulates
Fast glycolytic
_____________________ fibers have physiological and histological features intermediate between those of slow oxidative and fast glycolytic fibers
Fast oxidative-glycolytic
What is another name for mature cardiac muscle cells?
cardiomyocytes
Mature cardiac muscle cells have a striated banding pattern comparable to that of skeletal muscle. Unlike skeletal muscle, each cardiac muscle cell usually only has _______________.
1 nucleus
Cardiac muscle is surrounded in delicate sheath of __________________ with a rich capillary network (densely innervated w/ blood supply)
endomysium
A unique characteristic of cardiac muscle is the presence of transverse lines that cross the fibers where the myocardial cells join. These are called _____________________ and consist of many junctional complexes. The discs are full of ________________ and fascia adherens junctions which together provide strong intercellular adhesion. There are also gap junctions, which provide ionic continuity between the cells (a syncytium)
intercalated discs, desmosomes
Cardiac muscle cells within one fiber often branch and join with cells in ____________ fibers. The tightly knit bundles of cells are interwoven in spiraling layers that give a wave of contraction that squeezes the ventricles
adjacent