Muscle Tissue Lab Flashcards
________ the ability to shorten, is an inherent property of all cells
Contractility
these cells exhibit the greatest degree of contractility
muscle cells
it is composed of muscle cells that are supported and bound together by intercellular material that consists of connective tissue
muscle tissue
the basic tissue responsible for locomotion of the individual and movement of the various parts of the body because they are highly contractile
muscle tissue
_______ of muscle cells moves or restrains the movement of a body part
contraction
muscle cells are derived from ______
mesoderm
muscle cells in the iris of the eye arise from ______
ectoderm
Cell membrane of the muscle cells is known as
sarcolemma
Cytoplasm of the muscle cells is known as
sarcoplasm
smooth-surfaced endoplasmic reticulum of muscle cells is known as
sarcoplasmic reticulum
mitochondria of muscle cell is known as
sarcosomes
What are the 3 types of muscle cells?
skeletal, cardiac, smooth muscle cells
Skeletal and cardiac muscle fibers are referred to as ______ because they exhibit prominent alternating light and dark cross striations
striated
smooth muscle cells are _______ because they do not exhibit cross striations
nonstriated
a muscle tissue in the body that is organized to form mouse-shaped organs
skeletal muscle tissue
muscle is attached at either end by dense regular connective tissue called ________ to a part of skeletal system
tendon
numerous skeletal muscle fibers bunched in groups called
bundles or fascicles
the bundles or fascicles of skeletal muscle is enveloped by tough, dense, irregular connective tissue called ______ that keeps the fascicles together
epimysium
Within the muscle, each of the fascicles is likewise encased by connective tissue called
perimysium
this keeps the muscle fibers within the fascicle together
perimysium
Within the fascicle, each of the muscle fibers is individually wrapped and supported by a delicate connective tissue layer called
endomysium
extracellular fibers in the endomysium are mainly _____
reticular fibers
are long, tapering, cylindrical, and multinucleated cells that vary in length and diameter
skeletal muscle cells
muscle cell precursors of skeletal muscle is called
myoblasts
an oxygen-binding protein responsible for the brownish color of the muscle
myoglobin
the most noteworthy feature of the sarcoplasm is the presence of numerous long but thin filamentous elements called
myofibrils
there are roughly ________ to _______ myofibrils per muscle fiber, each of which spans the length of the cell
5,000 to 10,000
the light bands are called ________ because they do not alter polarized light
isotropic bands (I-bands)
the dark bands are called ________ because they display birefringence in polarized light
anisotropic bands (A-bands)
a fine dark transverse line is the _______, bisects the I-band
Z-line (Zwischenscheiben line)
The lighter mid-portion of the A-band is called
H-line (Heller band)
H-band is further bisected by a thin dark stripe called
M-line (Mittelscheible)
A myofibril is made up of numerous small contractile units called _____ that are laid end to end
sarcomeres
_______ refers to the region that spans two Z-lines and is about 1.5 to 2 micromillimeters long in a resting muscle
sarcomere
In high resolution electron microscopy, sarcomere has been shown to consist of a collection of thread-like structures called
filaments (myofilaments)
these filaments occupy the middle zone of a sarcomere
thick filaments
these filaments occupy the peripheral zones of a sarcomere
thin filaments
the filaments of skeletal muscle cells are made up mainly if four proteins:
actin, tropomyosin, troponin, and myosin
among the four proteins of skeletal muscle, ______ and _____ are the most abundant
actin and myosin
thin filaments consists of what skeletal proteins?
actin, tropomyosin, troponin
thick filaments consists of what skeletal protein?
myosin
the principal protein component of the thin filaments is
F-actin
these complexes play a role in the regulation of contraction
troponin-tropomyosin complexes
This theory states that when a muscle contracts, it shortens because the interaction of the actin and myosin molecules causes a thin and thick filaments to slide past each other, resulting in the shortening of sarcomeres.
Sliding filament theory
The __________ of straited muscle cells forms tubular invaginations that penetrate the muscle fiber and create anastomosing systems of tubes that surround the sarcomeres of the myofibrils at the junction of the A- and I-bands
sarcolemma
These tubes, whose lumens are continuous with the extracellular space, are called
transverse tubules (T-tubules)
in the area of the myofibrils in between the T-tubules, the ________________ creates an intricate and complex system of membrane-bound channels whose functions is to capture and store calcium ions needed for muscle contraction.
sarcoplasmic reticulum
A T-tubule and the pair of terminal cisternae associated with it are collectively referred to as
triad
The signal for the sarcoplasmic reticulum to depolarize comes from the _____________ on the surface of the muscle cells
motor endplate
an axon terminal sheds its myelin and settles into a depression on the surface of the muscle fiber called
synaptic trough or primary synaptic cleft
The sarcolemma in the primary synaptic cleft forms numerous deep folds called
junctional folds
What are the three types of skeletal muscle fibers that vary morphologically and functionally?
red, white, and intermediate
____ muscle fibers are smaller and have a richer blood supply than white muscle fibers
red muscle fibers
Red muscle fibers are also called
slow twitch muscle fibers
Red muscle fibers are called slow twitch muscle fibers because they contract at a _______
slower rate
White muscle fibers are also called
fast twitch muscle fibers
White muscle fibers are called fast twitch muscle fibers because they contract at a ________
faster rate
These muscle fibers have morphological and physiological characteristics that are in-between those of red and white muscle fibers
Intermediate muscle fibers
are receptors whose collective function is proprioception, i.e., the monitoring of the position of the limbs and state of contraction of the muscles
Proprioceptors
these spindles are embedded in the endomysium and perimysium and are present in all skeletal muscles
Neuromuscular spindles
Two kinds of intrafusal fibers:
nuclear bag and nuclear chain
It is a kind of intrafusal fibers that possess a dilated central area that contains a bunch of nuclei
Nuclear bag fibers
It is a kind of intrafusal fibers that do not manifest any dilatation and their nuclei are set in a single row
nuclear chain fibers
The intrafusal fibers are provided with two types of sensory nerve endings:
1.) annulospiral ending
2.) flower-spray ending
A sensory nerve ending that consists of the unmyelinated terminations of sensory neurons that are spirally wrapped around the central portion of the intrafusal fibers.
Annulospiral ending
A sensory nerve ending that consists of smaller nerve endings that innervate the peripheral portions of the intrafusal fibers.
flower-spray ending
is a stretch receptor that detects the degree and velocity of stretch applied to a muscle
Neuromuscular spindle
are small, one-mm-long structures located in the tendons that attach skeletal muscles to their insertions and origins
Golgi tendon organs
consists of collagen fibers enclosed by a thin, cone-shaped connective tissue capsule, supplied by a single afferent nerve fiber that discards its myelin and breaks into branches as it enters the capsule
Golgi tendon organs
are sensitive to muscle contraction rather than stretch and evidently measure the tension that is generated by muscle contraction
Golgi tendon organs
this muscle tissue occurs only in the heart and sometimes, in small areas in the wall of some of the big blood vessels attached to the heart
Cardiac muscle tissue
are cylindrical cells that are much shorter than skeletal muscle cells and as broad as many skeletal muscle cells
Cardiac muscle cells
True or False: Cardiac muscle cells contain only one to two nuclei
True
True or False: Skeletal muscle cells are multinucleated
True
True or False: the pale-staining nuclei of cardiac muscle cells are centrally located
True
True or False: Sarcoplasm of a cardiac muscle cell is filled with myofibrils
True
True or False: The sarcoplasmic reticulum of cardiac muscle is well developed
False
Cardiac muscle cells’ terminal branches are attached end-to-end to the terminal branches of their neighbors via specialized junctional complexes called
Intercalated discs
the impulse that initiates cardiac muscle contraction is generated by the
sinoatrial node (SA node)
a small structure in the heart that consists of Purkinje fibers
sinoatrial node
are modified cardiac muscle cells, non-contractile cells that are specialized to comprise the impulse conducting system of the heart which generates and propagates the electrical impulse that initiates cardiac contraction
Purkinje fibers
are fusiform cells that are broad in the middle and tapering at both ends
Smooth muscle cells
________ breakdown releases energy that enables the myosin molecule to interact with actin molecules
ATP
True or False: Skeletal muscle tissue is capable of some degree of regeneration
True
The source of new muscle cells is a small residual population of myoblast-like stem cells called
satellite cells
