MUSCLE TISSUE (Lecture 6) Flashcards
3 types of muscle
skeletal
cardiac
smooth
function of muscle fibers
produce force, contraction / movement, heat
muscle fibers are surrounded by __________ matrix
connective tissue matrix, bound by external lamina
sarcolemma aka ?
plasma membrane
sarcoplasm aka ?
cytoplasm
what causes contraction in muscle fibers
the interaction of cytoplasmic protein chains (myofilaments)
interactions of cytoplasmic protein chains are called?
myofilaments
what muscle cells are striated?
skeletal and cardiac
what muscle cells are non-striated?
smooth muscle
the cell diameter of a muscle cell is proportional to its _____ production
force production
skeletal muscle is usually attached to ____ or other muscles
bone
what are triads composed of and where are they located
triad = 2 terminal cisternae + 1 T tubule
located: junction of A and I bands
what is a motor unit composed of
motor neuron + muscle fibers it innervates
skeletal muscle has a rich blood supply that comes from _____?
surrounding connective tissue
term for a bundle of muscle fibers
Fascicle
term for single muscle fiber
myocyte
term for long rows of myofilaments
myofibrils
the dark bands are ____ bands
A
the light bands are ____ bands
I
the dark line in the I band is called the ____ disk/line
Z disk/line
what causes striations in skeletal muscle
the overlapping myofilament arrangement
a sarcomere is ?
smallest contractile unit
a sarcomere spands from ____ disk to ___ disk
Z disk to Z disk
An ‘I’ band is ______ myofilament
thin only
An ‘H’ band is ____ myofilament
thick only
muscle fiber aka _____ aka ______
muscle fiber = muscle cell = myocyte
Skeletal muscle has an abundance of what
- mitochondria
- glycogen (E source inside muscles)
- myoglobin (like hemoglobin but has more O2)
sarcoplasmic reticulum (SR) aka
the muscle term for…
smooth ER
what ion is needed for muscle contraction to occur
Calcium
CT that surrounds muscle fibers
endomysium: made of type IV, III collagen
similar function to the basal lamina, reticular lamina
CT that surrounds fascicles
perimysium: type I collagen
CT that surrounds the entire muscle
Epimysium: type I collagen
What is the sliding filament theory
the Z lines get closer together as the myofilaments slide past eachother
what are t tubules (transverse tubules)
extensions of the sarcolemma
sarcolemma = muscular plasma membrane
the sarcolemma of the myocyte has ______ folds and ______ receptors
junctional folds and ACh receptors
explain why rigor mortis occurs
lack of ATP prevents the dissociation of action and myosin = no muscle movement
where is smooth muscle found?
- hollow organs, blood vessels, dermis, respiratory passages
smooth muscle characteristics
- often in perpendicular layers
- produce their own “CT matrix”
-fusiform shape - single and centrally located nucleus
- not striated
- NO t-tubules
- barely any SR
- have caveolae
where does smooth muscle get a majority of its Calcium?
Ca2+ source is mainly extracellular
role of caveolae in smooth muscle?
caveolae are membrane invaginations that facilitate the INTAKE of Ca2+
type of muscle tissue that has a crisscross pattern of myofilaments
- the crisscross pattern facilitates contraction of the fusiform shape
smooth muscle
type of muscle tissue with a “corkscrew” nucleus
smooth muscle
smooth muscle cells can be relaxed or _______
relaxed or contracted
