Chapter 17: Structure and Chapter 17: Structure and MovementMovement

Aim: What are the 5 Aim: What are the 5 functions of the skeletal functions of the skeletal systems?systems?

Skeletal SystemSkeletal SystemAll the bones in your body make up

the skeletal systemIt is the framework of your body5 major functions:Copy from pg 484

Aim: What are the Aim: What are the characteristics of our characteristics of our

bones?bones?

Characteristics of Characteristics of BonesBonesDifferent sizes and shapesHave bumps, edges, round ends,

rough spots, pits and holesMuscles and ligaments attach to

many of the pitsBlood vessels and nerves enter

and leave through the holes

Parts of the BoneParts of the Bone1. Periosteum Is a tough, tight fitting membrane

that covers the bone’s surface Small vessels carry blood into the

bone cells that aid in growth and repair

of the bone are present2. Compact Bone Directly under the periosteum Hard, strong layer

Contain calcium phosphate, which makes the bones hard

Bone cells and blood vessels found here

Keeps bones from being brittle3.Spongy BoneLocated towards the end of boneHas many small, open spaces,

which makes bones light weightCavities filled with marrowRed marrow produces blood cells

4. Cartilage Cover the end of bones Is a smooth, slippery and thick

layer of tissue Is flexible and important to joints Makes movement easier by

reducing friction Damaged cartilage causes pain

Aim: What is the difference Aim: What is the difference between movable and between movable and

immovable joints?immovable joints?

JointsJointsA joint is any place where two or

more bones come togetherCartilage keeps bones from

rubbing togetherLigaments hold bones in place2 types of jointsI. Immovable JointsAllows little or no movement Ex: bones in skull and pelvis

II. Movable Joints All movements require movable joins 4 types of movable joints:

i. Pivot: One bone rotates in a ring of another bone that does not move

◦ Ex: turning your head

ii. Ball and socket: Consists of a bone w/ a rounded end that fits into a cuplike cavity of another bone

◦ Allows a wide variety of motions◦ Can be easily dislocated◦ Ex: movement of legs and arms

iv. Hinge Joint Has a back and forth movement Ex: elbows, knees and fingersv. Gliding Joint one part of a bone slides over

another bone Found in wrists and ankles Are used the most in your body

Aim: What is the major Aim: What is the major function of the muscular function of the muscular

system?system?

Muscular SystemMuscular SystemMuscles help make all your

movements possibleA muscle is an organ Muscles do 3 things:1.Relax2.Contract3.Provide force to move your bodyMore than 600 muscles in your

body

2 types of muscles:1.Voluntary muscles:Muscles that you can controlExs: face, legs, hand and arm

muscles2.Involuntary muscles:Muscles you can’t controlWork all day, everydayEx: heart, stomach

Aim: What are the types of Aim: What are the types of muscles?muscles?

Types of MusclesTypes of Muscles3 types:1.Skeletal MusclesAttached to bones by tendonsMost common typeThey are striated (looks striped)Voluntary muscles2.Cardiac Musclefound only in the heartStriatedContracts about 70 times per

minute

3. Smooth Muscles Found in intestines, bladder,

blood vessels and other internal organs

They are nonstriated They are involuntary Slowly contract and relax Internal organs are made up of

several layers of smooth muscle

Aim: How does muscle action Aim: How does muscle action result in the movement of result in the movement of body parts? body parts?

Aim: What are the layers of Aim: What are the layers of the skin?the skin?

Skin StructuresSkin StructuresThe skin is made up of 3 layers of

tissue1.Epidermis-outer, thinnest layerThe cells are dead and water repellantCells produce melanin, which protects

your skin and gives it colorDifferent amounts of melanin result in

different skin colorsWhen exposed to UV rays more

melanin is produced and your skin gets darker

2. Dermis Is thicker than the epidermis Contains blood vessels, nerves,

muscles, oil and sweat glands

3. Fatty Layer Insulates the body This is where fat is deposited

when someone gains weight

Aim: What are the functions Aim: What are the functions of the skin?of the skin?

Functions of the SkinFunctions of the SkinSkin is the largest organ of your

body1.The most important function is

protectionIt helps prevent physical and

chemical injuryGlands in the skin secrete fluids

that help kill certain bacteriaAs long as the skin is not open,

bacteria can not enter

2. Nerve cells in the skin make it a sensory organ too

3. Vitamin D also forms in the skin Vitamin D helps the body absorb

calcium into your body from food4. The skin also helps regulate your

body temperature Blood vessel help hold or release

heat5. Sweat glands help excrete wastes

and regulate your body temperature

Perspiration removes heat from your body and helps it cool

Sweat glands releases wastes such as, water, and salt

It is important to stay hydrated during periods of sweating and extreme heat, to keep yourself from fainting

Aim: How does the skin heal Aim: How does the skin heal itself?itself?

Skin Injuries and Skin Injuries and RepairRepair1. Bruises A bruise occurs when the tiny blood

vessels under your skin have burst The blood releases hemoglobin,

which breaks down in the tissue into pigments

The pigments cause your skin to turn different colors

When the bruise starts to turn yellow, it is beginning to heal

The yellow color comes from the breakdown of pigment in red blood cells

2. Cuts A cut is any tear in the skin Blood flows out until it clots A scab forms to prevent bacteria

from entering The skin cells under the scab

grow to fill the part that was injured

When the new skin has fully formed, the scab falls off

3. Skin Grafts Are used when the skin has been

severely burned or injured Pieces of skin are cut from one

part of the body and moved to replace the injured skin

It is kept alive by blood vessels and becomes part of the surrounding skin

They can also be made from a cadaver or a victim’s healthy skin