THE SKELETAL SYSTEM

Functions of the Skeletal System

1. Movement: Muscles work on the foundation of the bones to allow for movement.

2. Support: The backbone is the main support center for the upper body.

3. Protection: The bones of your skull protect the brain.

4. Storage: Bones store minerals, such as calcium, for use by the body.

5. Blood Cell Formation: Red and white blood cells are formed by marrow.

Two Major Parts of Skeletal System Axial: supports the

central axis of the body; includes skull, vertebral column, ribcage.

Appendicular: consists of the bones of the arms, legs, pelvis, shoulder area

*THERE ARE 206 BONES IN AN ADULT SKELETON

Appendicular/Axial Skeleton Labeling

Appendicular Skeleton Labeling

What are bones? Bones: solid network of living cells and

protein fibers that are surrounded by deposits of calcium salts.

Bone Structure Periosteum: tough layer of connective tissue

surrounding bone Compact bone: thick, dense layer of bone

containing Haversian canals – containing blood vessels

Spongy bone: strong layer found inside compact bone

Bone Marrow: soft tissue located inside bone cavities

Types of Bone Marrow• Yellow Marrow – made up primarily of fat

cells• Red Marrow – produces red blood cells,

some white blood cells, and platelets

Development of Bones The skeleton of an embryo is composed

almost entirely of cartilage Cartilage: connective tissues with cells that

are scattered in a network of protein fibers including collagen and elastin

Ossification: process of cartilage being replaced by bone

During adolescence/early adulthood, cartilage in growth plates are replaced by bone – stopping growth!

Joints Joint: place where one bone attaches to

another Depending on its type of movement, a

joint is classified as immovable, slightly movable, or freely movable

Types of Joints Immovable: allow for no

movementEx. Skull

Slightly Movable: small amount of restricted movementEx. joint between

adjacent vertebrae

Types of Joints Ball-and-Socket: Round end of one

bone fits snuggly into another Ex. Shoulder and Hip

Types of Joints Hinge Joint: movement at joint occurs in

one direction, like a door Ex. Knee and Elbow

Types of Joints Pivot Joint: bone resting atop another

bone permitting free movement Ex. Neck, Wrist, Ankle

Types of Joints Saddle Joints: permit one bone to slide

in two directions Ex. knuckles

Structure of Joints Ligaments: tough

connective tissue that connects bone to bone

Synovial Fluid: a substance that enables joints to slide over each other smoothly

Skeletal System Disorders Arthritis: Inflamed/stiff

joints Osteoporosis: weakening of

bones, especially in women

THE MUSCULAR SYSTEM

Muscular System More than 40% of the mass of a human

is muscle Muscular system includes large muscles

displayed by some athletes Muscular system also includes many

tiny muscles used to help regulate blood pressure, move food, and power every movement of the body

Types of Muscle Tissue: Skeletal Usually attached to bones Responsible for voluntary movements:

dancing, walking, typing Referred to as striated muscle Controlled by the central nervous

system Consists of muscle fibers, connective

tissue, blood vessels, and nerves

Skeletal Muscles Labeling

Types of Muscle Tissue: Smooth Usually not under voluntary control Found in walls of hallow structures:

stomach, blood vessels, intestines Can function without nervous system

stimulation

Types of Muscle Tissue: Cardiac Found in the heart ONLY! Cells may have up to two nuclei Is not under control of the central

nervous system

Muscle Tissue Makeup Myofibril: smaller structures that make

up a muscle; composed of two filamentsMyosin: the name of the protein that

composes the thick filamentActin: the name of the protein that

composes the thin filament

Muscle Contraction A muscle contracts when the thin

filaments in the muscle fiber slide over the thick filaments

ATP is used to power muscle contractions

Large amounts of ATP are needed!

Muscle and Bone Interactions Tendon: attaches bone

to muscle Origin: attachment of

muscle to immovable bone

Insertion: attachment to bone that moves when muscle contraction

Muscles move from insertion point to origin

Exercise and Health Muscle tone: result of skeletal muscles

remaining in a state of partial contraction Regular exercise is important in

maintaining muscular strength Aerobic exercise causes the body

systems to become more efficient

Muscle Pain Sprain: wrenching,

twisting, stretching injury to a ligament

Strain: injury to muscle or tendon – often caused by overuse

Muscle Pain

Shin splints is pain resulting from damage to the muscles along the shin. Pain is felt in different areas, depending on which muscles are affected.

Shin splints

Shin splints represent an "overuse injury" and occur most commonly in runners.

THE INTEGUMENTARY SYSTEM

Integumentary System Functions Barrier against infection and injury Regulates body temperature Removes waste products from the body Provides protection against ultraviolet

radiation from the sun

Skin Serves as a gateway through which

sensations such as pressure, heat, cold, and pain are transmitted to the nervous system

Two main layers: epidermis, dermis Below the dermis is a layer of fat and

connective tissue to insulate the body

Structure of Skin

Skin: Epidermis Epidermis has two parts: outside portion is

made of dead cells, inside portion is made of living cells

As cells move from the inner layer towards the outer layer, they create keratin – a fibrous protein

Eventually the cells die and form a waterproof coating – skin

The outer layer of cells is shed every 4-5 weeks

Skin: Epidermis Epidermis contains melanocytes – cells

that produce melanin Melanin protects skin from the damage

of UV rays Differences in skin color are due to the

differences in the amount of melanin produced

Skin: Dermis Dermis contains collagen, blood

vessels, nerve endings, glands, smooth muscle, hair follicles

The vessels in the dermis help control body temperature: contracting and widening as needed

Skin: Dermis Dermis contains two types of glands:

Sweat glands: produce perspiration; sweat contains salts, water, and other compounds; sweat helps get rid of waste

Sebaceous glands: produce an oily secretion called sebum; sebum helps keep the epidermis flexible and waterproof

Skin Cancer Skin cancer = abnormal growth of cells

in the skin Excessive sun exposure can produce

skin cancer SPF 15 should be the minimum!!!

Hair and Nails Keratin forms the basic structure Hair

Functions: protect surface of the body from UV; prevent dirt/particles from entering body

Hair Follicles: tubelike pockets of epidermal cells that produce hair

NailsNail root: area of rapidly dividing

cells from which nails growGrow at a rate of 3mm per month