Locomotion and Support By Charlene, Coco, Bryan

Locomotion Act, ability, or power of moving The musculoskeletal system gives animals the ability to move Provides form, support, stability, and movement to eh body

Bones Made of collagen and calcium salts Bones change shape when osteoblasts (bone-building cells) and osteoclasts (bone-breaking cells) remodel them. Joints are held together by ligaments The connective tissue that attach muscles to bones are tendons.

Exoskeleton Encloses the bodies of arthropods Supports the important internal organs and protects them from being damaged Insects shed their exoskeleton to increase in size

Endoskeleton Found in all vertebrates Made up of phosphate and calcium Important to maintain the body shape, supports the soft- body tissues and protects the internal organs from getting injured Certain parts store minerals

Hydrostatic Consists of internal body fluids in the confined body cavity The fluid is held under pressure in compartments and surrounded by muscles This ensures the shape of soft-bodied organisms like earthworms and sea anemones.

Human Skeleton

Axial Skeleton Is the part of the skeleton that forms an imaginary line down the back bone of the body Is made out of -skull -vertebral column -sternum and ribs

Appendicular Skeleton Scapula- flat, triangular-shaped bone that forms the basis of the shoulder Humerus- articulates with the scapula to form a ball-end socket joint at the shoulder Ulna- longer bone of the forearm that articulates with the humerus Radius- flattened, slightly curved bone in the hand Pelvic Girdle- provides connection between the axial skeleton and hind limbs Femur- largest bone in the human body. Forms a hind joint at the knee Fibula- shorter and smaller bone, giving support to the leg

Muscular System An organ system consisting of skeletal, smooth, and cardiac muscles It permits movement of the body, maintains posture, and circulates blood throughout the body Muscle cells (fibers) move by lengthening and contracting, a process that generates much of the body heat needed for survival

Muscle Three Types of Muscle Skeletal Muscle Smooth or Visceral Muscle Cardiac Muscle

Skeletal Muscle Striated voluntary muscles Attached to bones by dense, fibrous connective tissue called tendons Important in maintaining posture, providing support and allowing for movement

Organization of Skeletal muscle Muscles are made up of muscle bundles, which subdivide into muscle fascicles Within each muscle fascicle are units called muscle fiber cells Within each muscle fiber are contractile fibrils called myofibrils A single myofibril is subdivided intro sarcomomeres or contractile units

Sarcomere The functional unit in a muscle cell Inside a sarcomere, there are two protein filaments Actin: thin filament Myosin: thick filament Interaction of both proteins cause muscle contractions

Cardiac Muscle Found in the heart Its action is beyond conscious control When the skeletal muscles are exercised, they send signals to the heart via nerve cells to provide more oxygen

Smooth Muscle Found throughout the body (in the walls of blood vessels, the digestive tract, and internal organs) Involuntary They respond to demands for increased oxygen from the skeletal muscles by narrowing or widening blood vessels

Ligaments Tendons are tough bands of fibrous connective tissue that usually connect muscle to bone Ligaments refer to fibrous tissue that connect bones to other bones Ex: head and neck, wrist, thorax, pelvis, knee

How does a muscle contract? A nerve impulse is sent to a skeletal muscle. The neuron sending the impulse releases a neurotransmitter onto the muscle cell. The muscle depolarizes. Depolarization causes the sarcoplasmic reticulum to release calcium ions. These calcium ions cause the actin and myosin filaments to slide past each other. The muscle contracts.

Invertebrates Sponges Cnidarians Nematodes Flatworms Annelids

Hydrostatic Skeleton Many invertebrates have these skeletons. As mentioned earlier, three types of skeletons: exoskeleton, endoskeleton, and hydrostatic skeleton.

How it Works Exterior muscles contract along the body of the organism, causing the fluid filled chamber inside to move. Similar to peristalsis in the human intestine.

Nematodes Locomotion in nematodes Roundworms Important: Nematodes and annelids have a one way digestive track although they are invertebrates

Annelids Earthworms are annelids Have better locomotion than nematodes because they are segmented, so they can control their peristaltic waves of motion better.