MUSCLE - Coggle Diagram
- The muscle cell, like the neuron, is an excitable tissue,
i.e. an action potential is generated when it is stimulated either chemically,electrically or mechanically.
- Further, the muscle is a contractile tissue with a chemically stored energy which can be transformed into mechanical energy.
All three muscle tissues
have some properties in common;
- they all exhibit a quality called excitability
-as their plasma membranes can change their electrical states (from polarized to depolarized)
-and send an electrical wave called an action potential along the entire length of the membrane.
- skeletal muscles completely depends on signaling frm the NS to work properly
- in cardiac n smooth muscle
can influence the the excitability
to some degree
- both cardiac n smooth muscles
can respond to other stimuli
such as hormones n other stimuli
- Skeletal muscle is made up of
many long thin cells called
muscle cells or muscle fibers.
They are contained in connective tissue sheets and form - bundles of fibers.
These are then bound in further connective tissue to
form the whole muscle.
- Muscles begin (origin) and end (insertion) in the tendons and muscle
fibers are arranged in parallel
between tendinous ends so that the force
of contraction of the 'unit' is additive.
- Each muscle fiber is
-1-40 mm long,
-cylindrical in shape,
-50 to 100 μm diameter
-and surrounded by a cell membrane,
-There are no syncytial bridges
between the cells.
The muscle fibers are made up of
many fibrils called Myofibrils.
Each myofibril is 1-2 μm in diameter,
lies parallel to one another
and are striated.
The fibrils are divisible into
made up of the contractile proteins:
tropomyosin and troponin.
is the cytoplasm in the muscle fibers,
- numerous mitochondria (sarcosomes)
- smooth surface endoplasmic reticulum
called (sarcoplasmic reticulum)
- and rich in glycogen.
Structurally, the skeletal muscle consists of a
large number of muscle fibres and a
connective tissue framework organized as:
Each muscle fibre is surrounded by delicate
connective tissue called endomysium which
contains large quantity of elastic tissue
- At the junction of the muscle with its
tendon, the fibres of endomysium,
perimysium and epimysium become
continuous with the fibres of the tendon.
- Tendons are fibrous terminal ends of the
muscles made up of collagen fibres.
a highly specialized system
made up of:
- The sarcolemma
- n the sarcoplasmic reticulum
- plays an important role in the internal
conduction of depolarization
within the muscle fibre.
under E microscope - appears as vesicles and tubules
is primarily formed by:
- a transverse tubular system (T- system)
- and a longitudinal sarcoplasmic reticulum.
- is more than a cell membrane
- has a Lipid bilayer,
n associated basement membrane.
- has Specialized adaptations for
physiological requirements of
skeletal muscle fibers.