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

cavitiesYellow marrow - made of fat cellsRed 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)