Chapter 30- How Animals Move

• Aerobic exercise• Anaerobic exercise• Appendicular skeleton• Axial skeleton• Ball-and-socket joint• Endoskeleton• Exoskeleton• Hinge joint• Hydrostatic skeleton• Ligaments• Locomotion• Motor units

• Myofibrils• Neuromuscular junctions• Osteoporosis• Pivot joint• Red bone marrow• Sarcomeres• Skeletal muscle• Sliding-filament model• Tendons• Thick filament• Thin filament• Yellow bone marrow

Locomotion

• Movement from 1 place to another– Requires E to overcome friction and gravity– All ways animals move have similarities but

have adapted to an environment

Types of skeletons• Exoskeleton- rigid external skeleton

– Muscles attach to inner surface, move jointed body parts

– Insects, arthropods

Types of skeletons

• Hydrostatic skeleton- fluid under pressure in closed body compartment– Earthworms, jellies– Protects (cushions body parts from shock)

Types of skeletons

• Endoskeleton- hard/leathery supportive elements inside body

Human skeleton

• Axial- supports trunk- skull, backbone, ribs

• Appendicular- supports appendages

• Bipedal vs. quadrapedal:– 2-legged vs. 4-legged

walking

Joints

• Ball and socket- enables movement in several planes • Hinge- permits movement in single plane• Pivot- enables rotation

Skeletal disorders• Arthritis- inflammation of joints

– Rheumatoid- autoimmune disease• Osteoporosis- bones become thinner, porous and easily

broken– Many contributing factors, there is treatment and

prevention

Bones • Made of CT, cartilage and bone matrix• Bone matrix- flexible protein collagen embedded in hard Ca salts• Shaft- compact bone• Ends of bone- spongy bone• Yellow bone marrow- stored fat brought into bone by blood• Red bone marrow- produces blood cells• Haversian canals- where blood vessels run, transport nutrients and

wastes and hormones• Can absorb force up to certain extent, then break• Interact with muscles to perform movement

– Tendons- connect muscle to bone– Muscles are antagonistic- pairs that

work opposite each other to produce movement by contraction and relaxation

Skeletal muscle• Consists of bundles of fibers- each fiber being a single cell with

many nuclei• Each fiber is many myofibrils consisting of repeating units-

sarcomeres• Sarcomeres- contractile mechanism in a myofibril

– Z line to Z line – each is made up of an actin (thin) and a myosin (thick) filament

• Thin filament sliding across the thick filament is a sarcomere contraction

• Contraction is an E consuming interaction between actin and myosin

• Stimulated by contact with motor neurons– 1 neuron can stimulate many fibers b/c a motor unit controls a

few fibers– Axons release acetylcholine-which diffuses into muscle fiber

making them contract– More neurons controlling a fiber = stronger contraction– Eye- 1 neuron/fiber (for precision)

Aerobic vs. Anaerobic exercise

• Aerobic exercise- increases efficiency and fatigue resistance of muscles– Endurance sports- increases size and # of mitochondria

• Anaerobic exercise- building larger muscles that generate greater power– Increases size of muscle fibers

• Cross-training = both

• Movement- structure allows function