Chapter 17

Structure and Movement

Section 1- The Skeletal System• All the bones in your body make up your

skeletal system.

• 5 Major Functions.– 1. Gives shape and support to your body.– 2. Protects your internal organs. Ex. Skull

encloses the brain.– 3. Major muscle are attached to bone and help

them move.– 4. Blood cell formation– 5. Stores minerals

Bone Structure• Periosteum

– Tight-fitting membrane that makes up outer covering of bone.

– Under the periosteum are compact and spongy bone.

• Compact bone– Directly underneath periosteum– Gives bones strength

• Spongy bone– Found on the ends of bone– Makes bone lightweight

• Cartilage– Flexible tissue without blood cells that cushions ends

of bones.

Bone Formation• Osteoblasts- build up bone.

• Osteoclasts- breaks down bone tissue.

• Marrow– Substance that produces red and white

blood cells inside bones.

Joints• Joint

– Where two or more bones meet.

• The bones are held in place at these joints by a tough band of tissue called a ligament.

• Immovable Joint– Allows little or no movement– Ex. Skull and Pelvis

• Movable Joint– Joint that allows range of movement.– Ex. Ball and socket, pivot, hinge– Ball and socket- attaches your arm and shoulder.– http://glencoe.mcgraw-hill.com/sites/0078617022/student_

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Section 2- The Muscular System• Muscle

– Organ that contracts and relaxes. Makes all your daily movements possible.

• MORE THAN 600 MUSCLES MAKE MOVEMENT POSSIBLE!!!!!

• Tendons– Thick bands of tissue that attach muscle to bone.

• Voluntary Muscles– Muscles that you are able to control– Ex. Arm, Hand, and Leg

• Involuntary Muscles– Muscles you can’t control consciously– Blood moves through blood vessels– Food is moved through your digestive system

Classification of Muscle Tissue• Three types of Muscle:

– 1. Skeletal– 2. Smooth– 3. Cardiac

• Skeletal– Muscles that look striped and are used to move

bones. Always work in pairs. When on contracts the other relaxes.

• Smooth– Involuntary muscles that have NO striations

• Cardiac– Involuntary muscles with straitions in your heart.

Section 3- The Skin• The LARGEST organ in your body!!!!• Epidermis

– Outermost layer of your skin. (thinnest)– Cells of the epidermis are constantly rubbing off,

being replaced, and dying off.

• What pigment gives the skin color??

– Melanin!– Exposure to ultraviolet rays, increases melanin production.

• Dermis– Layer of tissue under the epidermis.– Contains blood vessels, nerves, muscles, oil and

sweat glands.

Skin Functions• Skin Protects Your Body:

– 1. Prevents internal damage (injury)

– 2. Prevents excess water loss from body tissues

– 3. Glands secrete fluids that destroy bacteria– 4. Formation of vitamin D. – 5. Regulates body temperature

• Sweat glands help rid the body of wastes by releasing water and salt.

• Skin Grafts– pieces of skin that are cut from one part of a

person’s body and then moved to the injured or burned area where there is no skin.