1. Function 2: Support, move, and cover itself
A. Skeletal System: supports the body, protects delicate organs, and helps move the body (Also makes blood cells and stores fat and minerals)
Important Terms and Parts:
Bones: 206 in adult body; bone cells surrounded by non-living materials (calcium, protein); marrow makes blood cells.
Cartilage: tissue that is more flexible than bone; keeps bones from grinding together in joints and gives shape to nose and ears (p. 397).
Joints: where bones meet (p. 398) Ex. Ball-and-Socket (shoulder), Hinge (elbow, knee), Gliding (wrist), Pivot (1st vertebra)
Ligaments: tissue that connects bones to other bones.
Tendons: tissue that connects bones to muscles.

2. Function 2: Support, move, and cover itself
B. Muscular System: moves bones and internal organs
Important Terms and Parts:
Voluntary: you can consciously control these muscles.
Involuntary: you can not consciously control these muscles.
Type 1: Skeletal Muscle Moves bones; they are attached to bones by tendons. Voluntary. **Usually come in pairs. Muscles can only pull; they never push.
Type 2: Smooth Muscle Lines internal organs such as esophagus, stomach, arteries; Keep your internal organs working. Involuntary.
Type 3: Cardiac Muscle Found only in heart; looks like skeletal muscle but acts like smooth muscle.

3. Function 2: Support, move, and cover itself
C. Skin: covers body and internal organs, protects the body from invaders, keeps in moisture, gets rid of some wastes, makes hair and nails, and senses the environment.
Important Terms and Parts:
Epidermis: upper layers of skin; makes new skin cells to replace dead cells that are constantly flaking off.
Dermis: lower layers of skin; very stretchy; contains many structures like blood vessels, oil and sweat glands, sense receptors, and hair follicles (p. 408).
Oil Glands: provide oil to keep skin and hair from drying out.
Sweat Glands: remove wastes like water, salts, urea, and excess heat as sweat.
Sense Receptors: nerve endings that can feel cold, hot, pain, pressure, and touch.