Muscular Tissues Part 1 Flashcards
Muscle tissue is composed of cells that optimize the universal cell property of
contractility
in these specialized cells, movement is generated by interaction of the proteins
actin & myosin
important component of certain secretory glands, where they function to expel secretions from glandular acini
myoepithelial cells
smooth muscle-like cells that surround blood vessels
pericytes
cells that have a contractile role in addition to being able to secrete collagen
myofibroblasts
this type of cell is not readily seen in normal tissues but becomes essential following tissue damages during the process of healing and repair, leading to formation of a scar
myofibroblasts
contains bundles of very long, multinucleated cells with cross-striations.
skeletal muscle
their contraction is quick, forceful, and usually under voluntary control
skeletal muscle
also has cross-striations and is composed of elongated, often branched cells attached to one another called intercalated discs
cardiac muscles
the contraction of cardiac muscle are (3)
involuntary, vigorous, rhythmic
type of muscle that consists of disinformation cells that lack striations and have solos involuntary contractions
smooth muscle
cytoplasm of muscle cells
sarcoplasm
surrounding cell membrane or plasmalemma
sarcolemma
smooth endoplasmic reticulum
sarcoplasmic reticulum
muscle cells of all three types are surrounded by
external lamina
external lamina binds
individual muscle cells into single functional mass
muscular tissue consists of elongated muscle cells called
muscle fibers or myocytes
muscular tissue is specialized for contraction by the sliding interaction of myosin filaments along actin filaments, a process known as the
sliding filament mechanism
Walking and running, localized movements like holding a pencil, writing, or nodding the head due to muscular contractions rely on the integrated functions of skeletal muscles, bones and joints.
producing body movements
Skeletal muscle contractions stabilize joints and help maintain body positions like standing or sitting.
stabilizing body positions
Postural muscles contract continuously when you are awake: for example, sustained contractions of your neck muscles hold your head upright when you are listening intently to your teacher talk about the muscular tissue.
stabilizing body positions
is done by sustained contractions of ringlike bands of smooth muscle called sphincters.
storing and moving substances within the body
prevent oufflow of the contents of a hollow organ (temporary storage of urine in the urinary bladder or storage of food in the stomach).
sphincters
the process of producing heat
thermogenesis
Muscular tissues produce heat during contraction.
generating heat
Most of the heat generated by the muscle is used to maintain
normal body temp
the involuntary contractions of skeletal muscle, which can increase the rate of heat production
shivering
usually attached to bones by tendons
skeletal muscle tissue
Long cylindrical fiber with many peripherally located nuclei; unbranched; striated with alternating light and dark bands seen by microscopy
skeletal muscle tissue
Arise from the fusion of a hundred or more small mesodermal cells called
myoblasts
Part of the myoblast population does not fuse and differentiate but remains as a group of mesenchymal cells called muscle
satellite cells
proliferate and produce new muscle fibers following muscle injury
satellite cells
length of skeletal muscle
from few centimeters or 30-40 in the longest muscles
diameter of skeletal muscle fibers
very large (10-100um)
long, finger-like invaginations of the sarcolemma that penetrate into the sarcoplasm
transverse tubules
aligned with each A-I band junctions
transverse tubules
filled with interstitial fluid
transverse tubules
number of nuclei of skeletal muscle
100 or more in each skeletal muscle fiber
found just beneath the sarcolemma
nuclei
large molecule composed of many glucose molecules
glycogen
can be used for ATP synthesis
glycogen
red-colored protein, found only in muscle
myoglobin
binds oxygen molecules that diffuse into muscle fibers from interstitial fluid and releases oxygen when it is needed by the mitochondria for ATP Production
myoglobin
lie in rows throughout the muscle fiber, strategically close to the contractile muscle proteins that use ATP during contraction so that ATP can be produced quickly as needed
mitochondria
fluid-filled system of membranous sacs that encircles each myofibril
sarcoplasmic reticulum
dilated end sacs of the SR called terminal cisterns butt against the T tubule from both sides
sarcoplasmic reticulum
in a relaxed muscle fiber, this stores calcium ions. release of ca++ from the terminal cisterns of this triggers muscle contraction
sarcoplasmic reticulum
contractile organelles of skeletal muscle
myofibrils
About 2um in diameter and extend the entire length of muscle fiber
myofibrils
containing thin and thick filaments (myofilaments) whose overlapping organization produces staining differences that cause striations
myofibrils
consists of long series of sarcomere s separated by z discus and containing thick and thin filaments that overlap in certain regions
myofibrils
basic functional contractile unit of myofibril
sarcomere
narrow, okay/shaped regions of dense material that separate one sarcomere from the next
z discs
dark, middle part of sarcomere that extends entire length of thick filaments and includes those parts of thin filaments that overlap thick filament
a band
lighter, less dense area of sarcomere that contains remained of thin filaments but no thick filaments
I band
Narrow region in center of each A band that contains thick filaments but no thin filaments
H zone
Region in center of H zone that contains proteins that hold thick filaments together at center of sarcomere
M line
the outer layer, encircling the entire muscle
epimysium
