240 likes | 528 Views
MUSCULAR SYSTEM. anatomical terminology. ? Assume the anatomical position, what do these words mean? Inferior; superior Proximal; distal Medial; lateral Posterior; anterior. TYPES OF MUSCLES. SKELETAL : voluntary control striated appearance (alternating dark & light bands)
E N D
anatomical terminology ? Assume the anatomical position, what do these words mean? • Inferior; superior • Proximal; distal • Medial; lateral • Posterior; anterior
TYPES OF MUSCLES • SKELETAL: • voluntary control • striated appearance (alternating dark & light bands) • Tendons attach mostly to bone • Main function is movement
TYPES OF MUSCLE 2. CARDIAC: • Heart muscle, also striated • Involuntary control (contracts without thought)
TYPES OF MUSCLE 3. SMOOTH MUSCLE: • Lines the walls of blood vessels and hollow organs • eg. Stomach and intestines • Involuntary movement
MUSCLE FUNCTION • 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
MUSCLE FUNCTION • Postural muscles contract to stabilize and maintain body positions • Muscles can be active even when there is no movement at a joint
MUSCLE FUNCTION • When muscles contract voluntarily or involuntarily (as in shivering) they can generate up to 85% of body heat
MUSCLE PROPERTIES • 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.
MUSCLE PROPERTIES • EXTENSIBILITY: • The ability of a muscle to be stretched beyond its normal resting length
MUSCLE PROPERTIES • 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 tissuesurrounding 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
TENDONS • 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
MUSCLE FIBRE • 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
MUSCLE FIBRE • 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 THESE TERMS • Define and give an example for each of the following: • ATROPHY • HYPERTROPHY • ORIGIN • INSERTION