Skeletal Muscular and Integumentary System Chapter 32 Skeletal

Skeletal, Muscular, and Integumentary System Chapter 32

Skeletal System • Skeleton has two main parts – Axial Skeleton: • The skull, spine, ribs and sternum • The axis of the skeleton – Appendicular Skeleton: • Shoulder and arm bones, hip and leg bones • All the bones of the limbs (appendages) – Scapula, Clavicle, Humerus, Ulna, Radius, Carpals, Phalanges – Pelvis, Femur, Patella, Tibia, Fibula, Tarsals, Phalanges

Structure of Bone • Periosteum: – Outer lining of bone • Compact Bone: – Hard dense bone • Spongy Bone: – Hard, holey bone • Bone Marrow: – Soft center where blood cells are produced • Haversian Canal: – Tubes which contain blood vessels and nerves • Osteocytes: – Living bone cells found in compact bone

Structure of Bone Cont.

Joints Fasten Bones Together • Three main types of joints – Immovable – Slightly moveable – Freely moveable • Joint: – A place where two or more bones meet. • Cartilage: – Covers the ends of bones at joints and provides a cushion • Ligaments: – Strong connective tissue that holds a bone to another bone, while being flexible enough to allow movement

Muscular System • Functions of the Muscular System – Allow for voluntary movement • Ex. Walking and Talking – Allow for involuntary movement • Ex. Blood flow, heart beat, and food digestion • 3 Type of Muscle – Smooth: • Lines the walls of blood vessels and intestines and is controlled unconsciously – Cardiac: • Found only in the heart and is controlled unconsciously. – Skeletal: • Connected to bones and allows for voluntary movement.

Muscle Contraction • Muscles work in opposing pairs. – When one muscle contracts, the other relaxes. • Each muscle fiber is made of small cylindrical structures called • Myofibrils: • Segments that come together are called – Sarcomeres: » Composed of 2 proteins • Myosin: • Thick protein filaments • Actin: • Thin protein filaments Fiber

Steps of Muscle Contraction 1. Nerve impulse is sent to the muscle 2. Myosin attaches to actin – Need calcium 3. Myosin head rotates, causing actin to slide past myosin. 4. ATP is used to detach myosin head from actin. – It will then reset itself to normal position. 5. If calcium is still present, the myosin will bind to actin again.

Muscle Contraction Cont. • Sliding filament theory: – When signaled, actin filaments slide toward one another, shortening the sarcomere

Skin, Hair, and Nails • Skin has 2 distinct layers – Epidermis: • Outer layer of skin – Exterior layer » Dead skin cells that contain keratin, which protect the living skin underneath. – Interior layer » Living skins cells that continually die and replace the exterior layer above. • Contains melanin, which gives skin its color and helps protect the body from solar radiation. – Dermis: • Thick layer of living skin. Contains blood vessels, hair follicles, nerves, sweat and oil glands.

Skin, Hair, Nails Cont. • Hair - Provides protection and insulation • Grow from bulb • Dead cells (shaft) pushed out • Serves to retain body heat • Nails – Provide protection • Grow from nail bed (lunula) • Fill with keratin (protein for hardening) • Dead cells pushed out