Muscular Tissue Flashcards
is one of the four primary tissue types.
muscle
these are the largest soft tissues of the musculoskeletal system.
muscle
3 types of muscle tissue
• skeletal muscle
• cardiac muscle
• smooth muscle
three muscle types have some properties in common. what are these?
they all excitability as their plasma membranes change their electrical states (depolarisation).
a type of striated muscle found specifically in the heart or myocardium.
cardiac muscle
a structure specific to cardiac muscle formed from gap junctions and desmosomes that allow cardiac muscle cells to contract in a coordinated fashion
intercalated disc
the term for a muscle cell that applies to skeletal muscle, cardiac muscle, and smooth muscle
myofibers
tube like organelle present in skeletal muscle and cardiac muscle that coordinates contraction of the cell
myofibrils
modified cardiomyocytes that propagate electrical signals through the cardiac muscle of the myocardium allowing coordinated contraction
purkinje fibers
the basic functional unit of striated muscle that is composed of myofilaments.
sarcomere
the organelle that is responsible for the storage and release of calcium into the cytosol of the myofiber.
sarcoplasmic reticulum
a type of striated muscle responsible for voluntary movement
skeletal muscle
non-striated muscle that is responsible for involuntary movement within several organ systems.
smooth muscle
invaginations of the sarcolemma (cell membrane) into the cell that allows for the conduction of depolarization impulses from the outside of the cell to around the sarcomeres.
T tubules
which move bones and other structure (e.g the eyes)
skeletal muscle
which form most of the walls of the heart and adjacent great vessels such as the aorta
cardiac & smooth muscle
muscles are classified histologically into striated muscles and non-striated muscles based on the structural characteristics called
striations
skeletal and cardiac muscles are grouped as
striated muscles
visceral muscle are grouped as
non-striated
four main properties of muscle tissues
- excitability
- contractility
- extensibility
- elasticity
the ability to respond to stimuli
excitability
the ability to contract
contractility
the ability of the muscle to be stretched without tearing
extensibility
the ability to return to its normal shape
elasticity
both cardiac muscle and smooth muscle can respond to other stimuli such as,
catecholamines (epinephrine and norepinephrine)
are specialized types of epithelium and fibroblasts. that have contractile ability.
myoepithelium and myofibroblasts
often located in and around glands where extracellular product produced by the epithelial cells needs to be moved by contractile action towards the duct system.
myoepithelial cells
are often seen in healing wounds and assist in the maturation and contraction of the granulation tissue as it matures and contracts.
myofibroblasts
important functions of muscular system performs.
a. production of force and movement
b. support of the body, change of body posture
c. stability of joints
d. production of body heat
e. provision of form to the body
predominantly powered by the oxidation of fats and carbohydrates but anaerobic chemical reactions are also used.
muscles
are derived from mesenchyme
myoblasts
develop from local populations of mesenchymal cells (splanchnic mesoderm)
cardiac and smooth muscle tissues
develop from mesoderm within the somites
skeletal muscles
Functions of Skeletal Muscle
• contract and cause movement
• act not only to produce movement but also to stop movement
• constant small contractions
• prevent excess movement of the bones and joints
• maintaining skeletal stability
• preventing skeletal structure damage or deformation
• allows voluntary control of specific functions, such as swallowing, urination, and defecation
• protect internal organs
• acting as an external barrier
• shield to external trauma
• supporting the weight of the organs
• contribute to the generation of heat
consist of various integrated tissues. these tissues include;
a. skeletal muscle fibers
b. blood vessels
c. nerve fibers
d. connective tissue
skeletal muscle has three levels of connective tissue that enclose it.
a. epimysium
b. perimysium
c. endomysium
large muscle is wrapped in a sheath pf dense, irregular connective tissue
epimysium
holds muscle fascicles in a group and allows a muscle to contract while maintaining its structural integrity.
epimysium
this membranous envelope, or epimysium is impervious to the spread of fluid such as
pus
allows the muscle to move independently from other muscle groups and other types of tissue.
epimysium
term synonymous with muscle cell
muscle fiber
a cell with multiple peripherally located muclei that runs the ENTIRE length of the actual muscle.
muscle fiber
intermediate layer of connective tissue
perimysium
extremely thin connective tissue layer
endomysium
terminology associated with muscle fibers is rooted in the greek sarco which means
flesh
plasma membrane of muscle fibers
sarcolemma
specialized smooth endoplasmic reticulum that stores and controls the release of calcium ions
sarcoplasmic reticulum
individual sarcomeres sre joined together in a long chain
myofibril
bundled together within the sarcoplasm
myofibrilz
conveys the action potential from the sarcolemma into the cell in order to stimulate the myofibrils
T tubules
2 structures important in cardiac muscle contraction
gap junctions and desmosomes
this joining allowsthe quick transmission of action potentials and the coordinated contraction of the entire heart.
electric coupling
this network of electrically connected cardiac muscle cells creates a functional unit of contraction.
syncytium
a cell structure that anchors the ends of cardiac muscle fibers together
desmosome
controlled by specialized cardiac muscle cells. directly control heart rate
pacemaker cells
wave pf contraction that allows the heart to work as a unit
functional syncytium
group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called;
autorhythmicity
regulatory protein that facilitates contraction in smooth muscles
calmodulin
sarcoplasmic structure that attaches to the sarcolemma and shortens the muscle as thin filaments slide past thick filaments
dense body
process in which one cell splits to produce new cells
hyperplasia
subset of a cross-bridge in which actin and myosin remain locked together
latch-bridges
cell that triggers action potentials in smooth muscle
pacesetter cell
relaxation of smooth muscle tissue after being stretched
stress-relaxation response
enlargement of neurons that release neurotransmitter into synaptic clefts.
varicosity
smooth muscle found in the walls of visceral organs
visceral muscle
triggers for smooth muscle contraction
hormones
