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)