Chapter 34 - Protection, Support

and Locomotion34.1 - Skin: The Body’s Protection

Structure and Function of the skin

4 tissue types in the body:________ - covers the surface of the body_________ - tough and flexible protein fibers, acts like

an organic glue______ - Interacts with hairs to respond to stimuli such

as cold and fright_______ - Allows us to detect external stimuli (pain,

pressure etc)

2 layers:EpidermisDermis

Structure and Function of the skin

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Epidermis: Outer layer

Exterior portion25 - 30 layers of dead

flattened cellsContains ______: protects and

gives elasticity

Interior portionLiving cells that replace

the dead cellsSome contain ______ - colors

the skin. Protects cells from damage

Takes about 28 days

Dermis: Inner layer

Thicker than the Epidermis

Thickness varied in different parts of the body

Contains blood vessels, _____, nerve endings, hair follicles, ______ glands and oil glands.

Oil glandsPrevents hair from drying out.

Keeps skin soft. Inhibits ______ growth

Dermis: Inner layer

Hair _______Narrow cavities out of which

hair grows

Sweat GlandsAverage human looses ______

of sweat/day

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Skin Functions

Regulates internal body ___________

Sweat is released in response to elevated body temperature

As sweat evaporates, the body cools

Functions as a _______ ________

Nerve cells receive stimuli from outside and relays information on the inside

Skin Functions

Produces ________Vitamin D - when exposed to light.

Helps the blood absorb Calcium

_________ the underlying tissues

Skin Injury and Healing

Repair stages (in response to injury):

_______ flows to the wound until a clot forms

_____ develops (barrier between bacteria and underlying tissues

New skin cells repair the wound from beneath

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Chapter 34 - Protection, Support

and Locomotion34.2 - Bones: The Body’s Support

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Skeletal System Structure

The adult human skeleton contains approximately ____ bones

2 main parts:The _____ Skeleton:

The skull and the bones that support it (vertebral column, ribs, sternum)

The __________ SkeletonBones of the arms and legs and

structures and structures associated with them

Joints

Where two or more ______ meet

Usually facilitate movement of bones in relation to one another (not the joints of the skull)

Held together and enclosed by ________

Tough band of connective tissue

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Compact and Spongy Bone

Two types of bone tissue_______ bone: layer of hard

bone that surrounds every bone

Composed of osteon systemsOsteocytes: living bone cells.Receive O2 and nutrients from small

blood vessels within osteon system

Nerves conduct impulses to and from each cell

_______ bone: less dense bone, filled with holes and spaces

Formation of Bone

In embryo, the vertebrate skeleton is made of _________

By week 9, bone begins to replace the cartilage

Blood vessels penetrate the cartilage and the cells become __________ (potential bone cells)

Formation of Bone

Osteoblasts secrete the protein _________

Deposits minerals (i.e. calcium) in the bloodstream

Calcium salts and other ions cause the osteoblasts to harden and become osteocytes

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Bone Growth

Growth in Length:Occurs at the ends of bones in ____________Growth in Diameter (thickness)Occurs at the _______ surface of the boneAccelerated by Sex hormones during

teen years.

Skeletal System Functions

Provides __________ for the tissues in our bodies

_________ internal organsProduce ______ cellsRed marrow: produces red blood cells, white blood cells

and cell fragments for clottingYellow marrow: Stores fatStores ________, including calcium and

phosphatesNeeded to form strong, healthy bones.

Bone injury and disease

__________Loss of bone volumeBones become more porous and

brittleBroken bonesShown by X-ray imagesBones are moved back into

position and immobilized so the bone can regrow

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Chapter 34 - Protection, Support

and Locomotion34.3 - Muscles for Locomotion

In This Section . . .

The 3 Types of MusclesHow Muscles WorkMuscles during Exercise

3 Types of Muscles

______________Found in the walls of internal organs (i.e.

organs of the digestive tract) and blood vessels

Also called involuntary muscle (not under conscious control)

______________Found ONLY in the heartInterconnected to form a network to help

muscle cells contract efficientlyAdapted to generate and conduct electrical

impulses_______________Attached to and moves bonesAlso called voluntary muscle (under

conscious control)

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Skeletal Muscle

The majority of skeletal muscles work in ________ pairs

Skeletal Muscle

Muscle tissue is made up of muscle fibers (long fused muscle cells)

Each fiber is made up of myofibrils (2 kinds):Thick filament (_______)Thin filament (_____)

Appears striated (striped)

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Skeletal Muscle

__________: functional unit of contractionMuscles contract according to the sliding

filament theory______ heads pull against the ______ filaments and

actin filaments slide toward one anotherSarcomere shortens

Image by: David Richfield

Excercise

The number of muscle cells are _____ at time of birth

Working out makes you stronger, but you donʼt get more muscle

Muscle fibers increase in ________ in response to regular exercise

Muscle contraction required ____

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Excercise

During exercise, muscles use oxygen (_________ respiration)

This eventually shifts to anaerobic respiration and lactic acid is produced

_________ builds up. As you catch your breath, more oxygen is delivered and lactic acid is broken down

Regular exercise results in improved performance of muscles

In Review . . .

The 3 Types of MusclesHow Muscles WorkMuscles during Exercise

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