Unit 10 The Human Body Ch. 36 Skeletal, Muscular, & Integumentary System

The Skeleton The skeleton supports the body, protects internal organs, provides for movement, stores mineral reserves, & provides a site for blood cell formation Bones provide a system of levers on which muscles act to produce movement

The Skeleton The skeleton supports the body The human skeleton is divided into 2 parts: the axial skeleton, & the appendicular skeleton

Structure of Bones Bones are a solid network of living cells & protein fibers that are surrounded by deposits of calcium salts Periosteum - tough layer of connective tissue that surrounds bone

Structure of Bones Haversian canals - found in dense, compact bone, contains blood vessels & nerves Bone marrow - soft tissue found in bone cavities Yellow marrow - made of fat cells Red marrow - produces red blood cells, some white blood cells, & platelets

Development of Bones Cartilage - type of connective tissue that does not have blood vessels, it is dense & fibrous & therefore, can support weight Ossification - process when cartilage is replaced by bone

Types of Joints Joint - a place where 1 bone attaches to another bone They permit bones to move without damaging each other Depending on its type of movement, a joint is classified as immovable, slightly moveable, or freely moveable

Types of Joints Freely movable joints are classified by the type of movement they permit

Structure of Joints Cartilage covers the surfaces where 2 bones come together Ligaments - link bone-to- bone in a joint Tendons - tie muscle-to- bone in a joint

Skeletal System Disorders Excessive strain on a joint may produce inflammation, where excess fluid causes swelling, pain, heat, & redness Arthritis is inflammation of the joint itself Osteoporosis is a loss of calcium in the bones, can cause serious fractures, typically occurs in older women

Types of Muscle Tissue There are 3 different types of muscle tissue: skeletal, smooth, & cardiac Skeletal muscles have stripes, & many nuclei Smooth muscle cells are spindle- shaped & have 1 nucleus

Types of Muscle Tissue Cardiac muscle cells have stripes & only 1 nucleus

Skeletal Muscle Structure

How Muscles & Bones Interact Tendons are attached so they pull on the bones when the muscles contract Most skeletal muscles work in opposing pairs, when 1 contracts, the other relaxes

Exercise & Health Regular exercise is important in maintaining muscular strength & flexibility Aerobic exercises cause the body’s systems to become more efficient Resistance exercises increase muscle size & strength

The Integumentary System The integumentary system serves as a barrier against infection & injury, helps regulate body temp., removes waste products from the body, & provides protection against UV radiation from the sun

The Skin The largest component of the integumentary system is the skin It contains many sensory receptors, therefore, it serves as gateway through which sensations like pressure, heat, cold, & pain, are transmitted to the nervous system

The Skin After strenuous exercise, the skin produces sweat, which decreases the temperature of the body & rids the body of wastes

Structure of The Skin

The Skin Epidermis - the outer layer of skin Melanin - a dark brown pigment, it helps protect the skin from damage by absorbing UV rays from the sun Dermis - the inner layer of the skin, contains blood vessels, nerve endings, glands, sensory receptors, smooth muscles, & hair follicles

The Skin Excessive exposure to UV radiation can produce skin cancer, an abnormal growth of cells in the skin Protect yourself by wearing a hat, sunglasses, & sunscreen

Hair & Nails The basic structure of human hair & nails is keratin, which is a protein Hair covers almost every exposed surface of the body, it serves as protection from the sun (head), & from dirt, viruses, & bacteria, from entering the body (nostrils, external ear canals, & eyelashes)

Hair & Nails Nails grow at an average rate of 3mm/month, with fingernails growing 4 times more rapidly than toenails Nails protect the tips of fingers and toes (digits)