2. • Muscles ( Musculus) It is a
Latin term refers to little
mouse
• Muscles are of three types in
vertebrates
• Striped or voluntary -skeleton
• Unstriped or involuntary -
present in the gut
• Cardiac muscle - present in the
heart
• Skeletal muscles are covered
by epimysium, perimysium, and
endomysium.
3.
4. • General remarks
• They are developed from mesoderm except
erector pilorum ,muscles of the iris and
myoepithelial cells of the salivary , sweat and
lacrimal gland which are derived from ectoderm.
• Voluntary muscles constitutes 42% of the total
body weight and are used for movements of the
body, and the remaining are used for production
of heat.
• The voluntary muscles are having two parts,
fleshy part which is contractile in nature
• The fibrous part may be in the form of
aponeurosis and tendon, they are non elastic less
vascular and resistant to friction.
5. The site where the tendons are
under the friction there we see
the bursa or a synovial sheath.
Tendon--- contracts muscles.
Tendon ---may be twisted or
plaited.
Every muscle has origin and
insertion, they may be multiple in
numbers
All the skeletal muscle fibers do not
undergo contraction simultaneously
Types of insertion
Insertion at the proximal end, distal
end or middle of the shaft of bone.
Ex-Biceps brachii, Brachioradialis,
corachobrachialis, respectively.
6.
7. Classification according to colour
Red muscles
• Less striated and contains
more sarcoplasm
• Its contraction is slow and
sustained
• Having high density of
mitochondria ,enzymes and
capillary network
• Helps in postural
movements
• Found in deeper and
deeper aspects of
superficial muscles
• Examples; muscles of trunk,
soleus muscles etc.
White muscle
• contains more cross
striations and less
cytoplasm
• Contractions are rapid
• Contains high levels of
glycogen and glycolytic
enzymes and few
mitochondria
• They are used in sudden
stressful action
• Found in superficial muscles
• Examples; hamstring and
gastrocnemius muscles
8. According to direction of muscle fibres
Parallel-Strap, quadrate, fusiform
Pennate muscles-Uni,Bi,Multi,Circumpinnate
Spiral muscles
Cruciate muscles
According to force of action
Spurt and shunt muscles
12. Classification on the basis of their
action
• 1) Prime movers- Desired movements
• 2) antagonists- Oppose the desired movements
• 3) Fixation muscles- stabilizes the proximal
joints
• 4) synergists- stabilizes the intermediate joints
13. • They acts like levers
• Fulcrum
• Efforts
• Resistance
14. • Nerve supply of voluntary
muscles
• They are supplied by mixed
nerves consists of 60% motor
and 40% sensory fibres.
• Motor supply- Alpha neurons
supply extra fusal fibres
produce movements.The gama
fibres supply inta fusal fibres of
muscle spndle maintain the
tone of the muscle.
• Sensory supply They convey
pain sensation from free nerve
endings.
• Annulo spiral they regulate the
muscle tone
15. • Motor point
• Motor unit;
• Large motor unit- Triceps
• Small motor unit-Eye ball
muscles
• Growth and regeneration
16. Motor end plate – motor axons break up into a number
of branches, each of which terminate on an individual
muscle fiber in the form of specialized structure.
Muscle tone – During the resting stage every skeletal
muscle is in a partial state of contraction. This condition
is called muscle tone. A few muscle fibers within a
muscle are fully contracted all the time.
To bring muscle tone and to avoid fatigue, different
groups of motor units contract alternately.
Muscle tone depends on the integrity of a simple
monosynaptic reflex arc composed of two neurons.
If the afferent or efferent pathways of the simple reflex
arc are cut the muscle would lose its tone and become
flaccid. It quickly atrophies and become reduced in
volume
17. Active insufficiency – The muscle cannot contract to less
than a certain minimum length.
Passive insufficiency – The muscle cannot be stretched
beyond certain length without injury.
18. • The blood supply and
lymphatic drainage of the
muscle
• Blood supply through the
neurovascular hilum
• In some it is at the end of
the muscle or in some at
the beginning .
• The vessels will undergo
ramification into small
arterioles and go along the
epimysium ,perimycsum
and endomysium.
• The lymphatics also go
along the connective tissue
fibres to the deeper part of
the muscle except the
endomycium.
