Skeletal Muscular Integumentary The Support System shape & form basis for movement Chapter 36

Skeletal System –Bone, cartilage, tendons, & ligaments Provides protection for organs –Skull & vertebrae provide protection brain & spinal cord –Rib cage provides protection for the heart & lungs Provides point of attachment/anchor for muscles to pull against to provide movement Mineral reserves (Ca & P) Blood-cell formation happens here

Bone Mainly mineral deposits of calcium & phosphorus, but IS living tissue…. made of cells & can repair itself Bone marrow is within cavities of long bones –Yellow = contains blood vessels, nerves, fat –Red = production of red blood cells, white blood cells, platelets

Moving the Bones Two bones meet at a joint, cushioned by… –Cartilage =a dense, fibrous connective tissue –Able to develop into bone Bones are held together by ligaments Tendons-attach muscles to bone

Muscle Tendon Femur Patella Bursa Ligament Synovial fluid Cartilage Fat Fibula Tibia Knee Joint See cartilage cushion See ligament See tendon

Muscular System Tissue specialized to contract and pull on the bones of the skeleton to provide movement Makes up 40-50% of the mass of a human Found everywhere, not just along bones –Skeletal muscle-for movement –Smooth muscle- organs –Cardiac Muscle-heart

Skeletal Muscle Attached to bones Allow for voluntary movement (conscious) Also known as Striated Muscle –Looks like “bands” or striations (striped) –One muscle cell has more than one nucleus and can 30-60cm long –Cells also called muscle fibers for this reason

Muscles- attached to bone tendons Muscles work by contracting & relaxing, NOT extending work in pairs –One contracts, while the other relaxes

What causes a contraction? A nerve impulse –Motor neuron brings the “response” from the spinal cord or brain –The axon ends in a synapse, neurotransmitters are effecting the muscle cell (not another neuron in this case)

Skeletal Muscle Structure

Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin Muscle Contraction Label

Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin During Contraction, knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge. Muscle Contraction

Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge. Powered by ATP, the myosin cross- bridge changes shape and pulls the actin filament toward the center of the sarcomere. Muscle Contraction

Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomere Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin During muscle contraction, knoblike head of myosin attaches to a actin, forming a cross-bridge. Powered by ATP, the myosin cross-bridge pulls the actin filament toward the center cross- bridge is broken, myosin binds to actin, and the cycle begins again. Muscle Contraction

Movement Biceps (relaxed) Triceps (contracted) Biceps (contracted) Triceps (relaxed) Opposing Muscle Pairs

Smooth Muscle NOT under voluntary control Found in many organs & blood vessels –(can’t consciously control stomach or kidneys!) Smooth muscle

Cardiac Muscle Found only in the heart Striated, but unlike skeletal are NOT voluntary & only 1 nucleus

FYI Skeletal Muscle-regular striped Cardiac Muscle-irregular striped Smooth- no stripes

Integumentary System- Largest organ in the body Comprised of skin, hair, nails, and glands Surrounds & protects (like a cell membrane) –Barrier to infection & injury to internal structures –Regulates body temp (helps) –Removes wastes (urea) –UV protection (melanin) –Sensory organ (contains nerves)

The Structure of Skin

Different nerves