L3 MUSCLE TISSUE Flashcards
Describe muscle tissue?
One of the basic tissues of the body
Cells (Fibers) are long and narrow
Functions of muscle tissue?
Responsible for movements
Maintain posture
Transforms chemical energy into mechanical
energy, therefore, producing force
Stabilize joints
Thermogenesis
Increase muscle mass, increases immune system
Four properties of muscle tissue?
Excitability; respond to nerve cells by
generating electrical signals
• Contractility; get shorten and generate force
• Extensibility; can be stretched
• Elasticity; returning back to its original shape
What are three types of muscle tissue?
Skeletal muscle
Smooth muscle
Cardiac muscle
What is skeletal muscle?
These are most abundant, found
attached to skeleton
Exhibit cross striations under microscope
Respond quickly to stimuli
Are supplied by somatic nerves
Are under voluntary control
E.g., Muscles of the limbs and
body wall
Parts of a muscle?
Belly (fleshy part)
Tendons (fibrous part)
What is the belly of the muscle?
- highly vascular and
contractile part
What is the tendon?
part which is attached to the bones or cartilages made of collagen fibres, less vascular and non elastic
What is aponeurosis?
The fibrous part present in the flat muscles
What are the two attachments of muscles?
origin and insertion
What is the origin attachment of muscles?
Attachment of a muscle that remains relatively fixed during
muscular contraction
Generally the proximal part
What is the insertion attachment of muscles?
Attachment of a muscle that moves during muscular
contraction
Generally the distal part
What are the four muscle organization? (arrangement of muscle fibres?)
Parallel
Convergent
Pennate
Circular
What is the parallel arrangement of muscles?
What are the different types?
Example of each type and their location?
Muscle fibres run parallel to length of muscle
Most of the skeletal muscle are of this type
Different types – fusiform, strap, quadrilateral
• eg. biceps brachii, sartorius, pronator quadratus
What is the convergent arrangement of muscles?
Example and location?
Muscle fibres spread out like fan on one end and
converge to single point on other end
eg. Pectoralis major
What is the Pennate (feather like) arrangement of muscles?
Muscle fibres are arranged at an angle to tendon
What are the three types of pennate muscle arrangements?
Unipennate
Bipennate
Multipennate
What is the Unipennate arrangement of muscles?
Muscle fibres
angled on one side of tendon
(eg. palmar interossei)
What is the Bipennate arrangement of muscles?
Tendon in the
middle with angled muscle
fibres on each side (eg dorsal
interossei)
What is the multipennate arrangement of muscles?
Branched
tendon with muscle fibres
organised around each
branch (eg. Deltoid)
What is circular muscle arrangement?
Concentric arrangement of muscle fibres
Guard the openings and decrease the diameter of openings
eg. Orbicularis oculi, orbicularis oris
What are the eight Nomenclature of muscles?
shape, size, number of heads of origin, location, relative position, attachment, function, direction of fibres
What are the four actions of skeletal muscles?
Agonist
Antagonist
Synergist
Fixator
What is synergistic?
Muscle(s) that stabilises a
joint around which
movement is occurring,
which in turn helps the
agonist function effectively
n the biceps curl the synergist muscles are the brachioradialis and brachialis which assist the biceps to create the movement and stabilise the elbow joint
Fixator?
Stabilize the proximal joints to allow the movements at the distal joints
E.g. deltoid muscle during biceps curl
What is epimysium tissue?
A connective tissue that surrounds the muscle.
What are fascicles?
Also known as bundles.
Several cylindrical muscle
cells or muscle fibres that make up the muscle
What is perimysium tissue?
A connective tissue sheath that surrounds bundles or fascicles.
What is endomysium tissue?
A connective tissue sheath that surrounds muscle cell.
What does each muscle cell or fiber contain?
all of the organelles that we find in other cell types
multiple peripherally placed flat nuclei
Under the microscope, stripes called striations
What are T-Tubules?
Invaginations of sarcolemma at A Band and I Band junction (permit rapid transmission of the action potential into the cell)
What is Sarcolemma?
Plasma membrane of the
muscle cell
What is Sacroplasma?
Cytoplasm of the muscle
cell
What is Sarcoplasmic reticulum?
Contains?
the smooth endoplasmic
reticulum of the muscle cell
containing calcium
What are terminal cisternae?
Terminal cisternae are enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules- store calcium
What is a triad?
2 terminal cisterna
and 1 T-tubule
What is myoglobin?
red pigment that
stores oxygen within
muscle
What are glycosomes?
granules of
stored glycogen within the
muscle
Where are myofibrils found?
Muscle fiber or cell
What are myofibrils?
cylindrical bundle of contractile proteins
contains
several sarcomeres
What are sacromeres?
the functional or contractile units of muscle One sarcomere is separated from the other by the Z line
What do sacromeres of myofibrils contain?
Myofilaments
What are thin myofilaments composed of ?
Thin myofilaments are composed mainly of a protein
known as actin
What are thick myofilaments composed of?
composed mainly of the protein myosin
What does the striated
appearance (light and dark bands) of skeletal muscles result from?
the orderly overlapping of the actin and myosin
filaments
What is an I band?
I Band contains only thin (actin) myofilaments
isotropic; light band
What is an A band?
A Band
contains thick and thin (actin and myosin)
(anisotropic; not
isotropic; dark band)
What is H zone?
middle of A, only myosin
What is smooth muscle?
Where is it found?
Found in the walls of the hollow viscera (stomach) and
walls of blood vessels
• Muscle fiber is an elongated, spindle (fusiform) shaped cell
• Contains centrally placed spindle shaped nucleus
• Do not exhibit cross or transverse striations under
microscope, being plane and smooth in form
• Supplied by autonomic nerves, not under voluntary control
What is cardiac muscle?
Where is it found?
Striated (transverse) but involuntary muscle
Consists of short, cylindrical muscle fibers
It is present exclusively in the heart and is also
called myocardium of heart
Each muscle fiber contains many muscle cells
(cardiomyocytes) which are united by intercalated
discs
Each muscle cell contains centrally placed,
single oval or round nucleus
Muscle fibers branch
Functions of cardiac muscle
Automatic and rhythmic contractions
What do muscle fiber of cardiac muscle contain?
contains many muscle cells (cardiomyocytes) which are united by intercalated
discs
Muscle fibers branch and anastomose with the neighboring fibers
Each muscle cell contains centrally placed, single oval or round nucleus
Transverse striations are present
