Contractility Properties of Muscle Tissue Excitability Extensibility Elasticity Skeletal –...
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Transcript of Contractility Properties of Muscle Tissue Excitability Extensibility Elasticity Skeletal –...
• Contractility
Properties of Muscle Tissue
• Excitability
• Extensibility
• Elasticity
Skeletal – attached to bone
3 Types of Muscle Tissue
Cardiac – the heart
Smooth – internal organs blood vessels
Functions of Skeletal Muscle
• Movement of Body
• Heat Production
• Controls Entrances and Exits to Body
• Protection
Micro-Anatomy of Skeletal Muscle
• Muscle cell = muscle fiber
• Fascicle = bundle of muscle fibers
• Whole muscle = bundle of fascicles
Connective Tissue of Skeletal Muscle
• Endomysium => covers a muscle fiber
• Perimysium => covers fascicles
• Epimysium => covers whole muscle
Naming of Skeletal Muscle
• Size– Maximus
– Minimus
– Major
– Minor
– Longus
– Brevis
• Shape– Deltoid (triangle)
– Teres (round, cylinrical)
– Trapezius (trapezoidal)
– Rhomboideus (rhomboidal)
• Location– Abdominis
– Femoris
– Brachii
– Capitis
– Pectoralis
– Intercostal
– Digitorum
• Relative Position– Lateral
– Medial
– Internal
– External
– Superficialis
– Profundis
• Action– Abductor
– Adductor
– Flexor
– Extensor
– Pronator
– Supinator
– Levetor
– Depressor
• Number of Heads
– Biceps
– Triceps
– Quadriceps
• Orientation of Muscle
– Rectus
– Transversus
– Oblique
• Origin and Insertion
– sternocleidomastoid
– coracobrachialis
– Brachioradialis
Classification by Orientation of Fascicles
1) Circular:
2) Parallel:
3) Convergent:
b) Fusiform (Spindle-shaped):
a) Strap-like:
- e.g. orbicularis oris
- e.g. sartorius, rectus abdominis
- e.g. biceps brachii
- e.g. pectoralis major
4) Pennate Muscles:
a) Unipennate:
b) Bipennate:
c) Multipennate:
- e.g. extensor digitorum
- e.g. rectus femoris
- e.g. deltoid
Levers are rigid structures that
move on a fixed point,
called a fulcrum (F).
• Bones act as levers.
The role of levers is to Confer Advantage.
In the body:
• Joints act as the fulcrum.
• The Effort arm (E) is powered by muscular contraction.
• The Resistance (R) is the weight of the body
part being moved.
Also in the body:
• Each Lever System needs a:
Fulcrum, Effort arm and Resistance.
• Increase speed or distance of body part moved.
• Increase the force applied to the movement.
A Lever System can:
But never both!
OR
1st Class Lever: EFR
Effort Arm
E
E
E
E
2nd Class Lever: FRE
E
E
3rd Class Lever: FER
The Neuromuscular Junction
Motor Unit Recruitment