Let's Talk About It: To Disclose or Not to Disclose?
Introduction of muscle.pptx
1.
2. sustained contraction or alternating contraction
and relaxation, muscular tissue has four key
functions:
Produces body movements.
Stabilizes body positions.
Stores and moves substances within the
body.
Generates heat.
3. •Body movement
•Maintenance of posture
•Respiration
•Production of body heat
•Communication
•Constriction of organs and
vessels
•Heart beat
4. Muscular tissue has four special properties that
enable it to function and contribute to
homeostasis:
Electrical excitability
Contractility
Extensibility
Elasticity
5. Electrical excitability:
› a property of both muscle and nerve cells
to respond to certain stimuli by producing
electrical signals called action potentials
Contractility
› ability of muscular tissue to contract
forcefully when stimulated by an action
potential. When a muscle contracts, it
generates tension (force of contraction)
while pulling on its attachment points.
6. Extensibility
› ability of muscular tissue to stretch without
being damaged. Extensibility allows a
muscle to contract forcefully even if it is
already stretched.
Elasticity
› ability of muscular tissue to return to its
original length and shape after contraction
or extension
7. Muscles are classified by three different
methods, based on different factors:
› I. Depending upon the presence or absence of
striations
› II. Depending upon the control
› III. Depending upon the situation.
8. FEATURES SKELETAL CARDIAC SMOOTH
Location Attached with
bones
In heart In visceral organs
Shape cylindrical branched Spindle shaped
control voluntary involuntary involuntary
Nerve supply somatic autonomic autonomic
No. of nucleus multinucleated One nucleus One
Cross striations present present Absent
myofibrils present present Absent
Sarcomere, troponin Present present Present
Sarcotubular system Well developed Well developed Poorly developed
fatigue possible Not possible Not possible
Summation, tetanus possible Not possible possible
Speed of contraction fast intermediate Slow
Neuromuscular
junction
Well defined Not well
defined
Not well defined
Starling’s law applicable applicable Not applicable
9. Depending upon the presence or absence of
cross striations, the muscles are divided into
two groups:
› 1. Striated muscle
› 2. Non-striated muscle.
10. Striated Muscle
Striated muscle is the muscle
which has a large number of
cross-striations (transverse
lines).
› Examples are skeletal muscleand
cardiac muscles.
11. Non-striated Muscle
Muscle which does not have cross-
striations is called non-striated
muscle.
It is also called plain muscle or
smooth muscle.
It is found in the wall of the visceral
organs.
12. Depending upon control, the muscles are
classified into two types:
› 1. Voluntary muscle
› 2. Involuntary muscle.
13. 1. Voluntary Muscle
› Voluntary muscle is the muscle that is controlled
by our own will. Skeletal muscles are the
voluntary muscles.
› These muscles are innervated by somatic
nerves.
2. Involuntary Muscle
› Muscle that cannot be controlled by the will is
called involuntary muscle.
› Cardiac muscle and smooth muscle are
involuntary muscles
14. Depending upon situation, the
muscles are classified into three
types:
› 1. Skeletal muscle
› 2. Cardiac muscle
› 3. Smooth muscle.
15. 1. Skeletal Muscle
Skeletal muscle is situated in association
with bones forming the skeletal system.
form 40% to 50% of body mass and are
voluntary and striated.
Supplied by somatic nerves.
Fibers of the skeletal muscles are arranged
in parallel.
Muscle fibers are attached to tendons on
either end.
Skeletal muscles are anchored to the bones
by the tendons.
16. Description:
› Long, cylindrical, striated fibers with
many peripherally located nuclei;
voluntary control.
Location:
› Usually attached to bones by tendons.
Function:
› Motion, posture, heat production, and
protection.
20. MUSCLE MASS OR TISSUE
Muscle mass or muscle tissue is made up of
a large number of individual muscle cells or
myocytes.
The muscle cells are commonly called
muscle fibers because these cells are long
and slender in appearance.
Skeletal muscle fibers are multinucleated
and are arranged parallel to one another with
some connective tissue in between.
21. Muscle mass is separated from the
neighboring tissues by a thick fibrous tissue
layer known as fascia.
Beneath the fascia, muscle is covered by a
connective
tissue sheath called epimysium.
In the muscle, the muscle fibers are arranged
in various groups called bundles or fasciculi.
Connective tissue sheath that covers each
fasciculus is called perimysium.
Each muscle fiber is covered by a connective
tissue layer called the endomysium
24. 2. Cardiac Muscle
Cardiac muscle forms the
musculature of the heart.
These muscles are striated and
involuntary.
Cardiac muscles are supplied by
autonomic nerve fibers.
26. Description:
› Branched striated fibers with one or two centrally
located nuclei; contains intercalated discs;
involuntary control.
Location:
› Heart wall.
Function:
› Pumps blood to all parts of the body.
27. Description:
› Spindle-shaped (thickest in middle and tapering
at both ends), nonstriated fibers with one
centrally located nucleus; involuntary control.
Location:
› Iris of the eyes, walls of hollow internal structures
such as blood vessels, airways to the lungs,
stomach, intestines, gallbladder, urinary bladder,
and uterus.
Function:
› Motion (constriction of blood vessels and
airways, propulsion of foods through
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28. 3. Smooth Muscle
Smooth muscle is situated in association
with viscera.
It is also called visceral muscle.
It is different from skeletal and cardiac
muscles because of the absence of cross
striations.
Smooth muscle is supplied by autonomic
nerve fibers.
Smooth muscles form the main contractile
units of wall of the various visceral organs
E.g. stomach.
30. FEATURES SKELETAL CARDIAC SMOOTH
Location Attached with
bones
In heart In visceral organs
Shape cylindrical branched Spindle shaped
control voluntary involuntary involuntary
Nerve supply somatic autonomic autonomic
No. of nucleus multinucleated One nucleus One
Cross striations present present Absent
myofibrils present present Absent
Sarcomere, troponin Present present Present
Sarcotubular system Well developed Well developed Poorly developed
fatigue possible Not possible Not possible
Summation, tetanus possible Not possible possible
Speed of contraction fast intermediate Slow
Neuromuscular
junction
Well defined Not well
defined
Not well defined
Starling’s law applicable applicable Not applicable
