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Assume the anatomical position, what do these words mean?
• Inferior; superior
• Proximal; distal
• Medial; lateral
• Posterior; anterior

1. SKELETAL:
• voluntary control
• striated appearance
(alternating dark & light bands)
• Tendons attach mostly to bone
• Main function is movement

2. CARDIAC:
• Heart muscle, also striated
• Involuntary control (contracts without thought)

3.
SMOOTH MUSCLE:
• Lines the walls of blood vessels and hollow organs
• eg. Stomach and intestines
• Involuntary movement

• Interaction of bones, skeletal muscles
& joints = MOVEMENT
• Muscles move substances within the body eg. Smooth muscles move food through the intestines; cardiac muscle moves blood; skeletal muscle helps venous blood return to the heart

• Postural muscles contract to stabilize and maintain body positions
• Muscles can be active even when there is no movement at a joint

• When muscles contract voluntarily or involuntarily (as in shivering) they can generate up to 85% of body heat

• CONTRACTILITY:
– Ability of muscle to contract and generate force when stimulated by a nerve
– Only muscle tissue can do this
– Muscles are usually in pairs: when one contracts the other is stretched.

• EXTENSIBILITY:
– The ability of a muscle to be stretched beyond its normal resting length

• ELASTICITY:
– The muscles’ ability to return to its original resting length after the stretch is removed
?
Give an example
Using contractility, extensibility & elasticity together…

SKELTAL MUSCLE STRUCTURE
• FASCIA:
– Connective tissue surrounding tissues (as in bones & muscles)
– Made of fibrous tissue, adipose tissue (fat)
& fluid
– Superficial or deep
– Skeletal muscles mostly work in groups
– Each group (compartment) is surrounded by fascia

SKELTAL MUSCLE STRUCTURE
• 3 layers of Fascia in each individual muscle.
• EPIMYSIUM: the outer layer covering the entire muscle
• PERIMYSIUM: surrounds bundles of muscle fibres or fascicles
• ENDOMYSIUM: surrounds the individual muscle fibres

SKELTAL MUSCLE STRUCTURE

• Layers of Fascia continue beyond muscle to form TENDONS.
– Strong, flexible bands of fibrous connective tissue connecting muscle to bone
– Various forms: rounded cord or flat sheet
– Tendons can be grouped together in a tendon sheath. These contain synovial fluid
?
Why?
– They play an important role in muscle contraction & joint movement

• Muscles contain thousands of long, cylindrical fibres lying parallel to each other
• Inside are small structures called myofibrils – light & dark bands
• They are arranged into units called
Sarcomeres.
• Sarcomeres contain contractile proteins called Actin & Myosin

• Muscles have a good nerve & blood supply.
• Motor neurons send messages from
CNS to the muscle
• Neurons release neurostransmitters into the blood which stimulate the muscle to contract & produce force
• Muscles have a rich network of capillaries = good damage repair

• Define and give an example for each of the following:
• ATROPHY
• HYPERTROPHY
• ORIGIN
• INSERTION