Protection, Support & Locomotion

Chapter 34

Skin has 4 types of tissues:

1. Epithelial - covers surface of body

2. Connective - tough and flexible protein fibers, holds the body together

3. Muscle – interact with hairs on the skin to respond to stimuli

4. Nervous – helps detect external stimuli as pain or pressure

Skin composed of 2 layers: 1. Epidermis –

outermost layer, 25-30 layers of dead cells,

keratin : a protein called which protects and gives elasticity

melanin : inner layer contains – pigment that colors skin and protects from sun

Skin composed of 2 layers:2. Dermis – inner, thicker

portion of the skin which contains:

blood vesselsNerves & nerve endingshair folliclessweat and oil glandssubcutaneous fat - various

amounts of fat lie under the dermis

Functions of the Skin:1. Thermoregulation –

temperature control2. Sensory organ –

pressure, pain, temperature

3. Produces essential vitamins – Vitamin D

4. Protective layer –physical and chemical shield

The SkinIs the body’s largest organ

Makes up about 16% of our total body weight Every 24 hours, the surface of the skin sheds a layer of dead cells, constantly renewing about every 28 daysDead skin cells make up about 90% of household dustAn average of 40 kilos of skin is shed during a lifetimeVaries in thickness from 1mm on eyelids to 3mms on palms and soles

Skin Facts!

Skin Injury and HealingEpidermis injury – fills

with deeper epidermal cells through cell division

Dermis Injury – bleeding occurs, clots form, scab covers site, WBC invade the area to clean up the mess

Scaring occurs due to connective tissue being laid down on severe damage/gaps to skin

BURNS

Amazing Skeleton FactsSmallest bones are found in the ear.  Longest bone in the body is the femurBones are filled with a fatty substance called bone marrowIn Bone marrow, red and white blood cells are manufactured and then released into the bloodstream.    Over half the body's bones are in the hands and feet The only jointless bone in your body is the hyoid bone in your throat.

Skeletal System- 206Two systems:1. Axial (green)

skull, vertebrae, ribs and the sternum

2. Appendicular(Purple) - arms,

legs, shoulder and hip

Joints - point where 2 bones meet

Ligament - fibrous structure that connects bone to bone

Tendon - connective tissue that connects muscle to bone

Bursae - fluid filled sacs to protect bones/tendons

Functions of the skeleton –

Protect – internal organs & Support -Move – muscular attachments, levers

Cells - produce blood cells, store fatStorehouse – essential minerals, CaDid you know that humans and giraffes

have the same number of bonesin their necks? Giraffe neck vertebrae are just much, much longer!

11/10/09Did you know that humans and giraffes have the same number of bones in their necks?

Giraffe neck vertebrae are just much, much longer!

Bone TissueBones are porous, these pores contain

living cells and channels for blood vessels that supply the cells with nutrients. The pores make bones lighter.

2 Types:1. Spongy or Cancellous bone tissue

contains many large spaces filled with marrow (storage for marrow)

2. Compact or Dense bone tissuecontains few spaces, it is deposited in a

layer over the spongy bone tissue

Diaphysis- Shaft or long main portion,

hollow, covered in compact bone

Epiphysis Extremities or ends of the

bones, bulbous in shape to provide muscle attachment

Metaphysis growing portion of the

bone Articular Cartilage

Thin layer of hyaline cartilage covering the epiphysis (cushions and protects)

Types of Joints

Go to page 931 in your book

Draw and give an example of the 4 types of joints

1. Hinge2. Ball & Socket3. Gliding4. Pivot

Types of Joints Gliding - (arthrodia), flat articulating surfaces

side to side and back and forth movements

(Flex/Ext and Ab/ad) 2 planes - biaxial Ex: carpal, tarsal bones,

sternum, clavicle, scapula Hinge -(ginglymus) -

convex surface fits into the concave surface

single plane motion (monaxial) flex/ext

Ex: elbow, knee, ankle & interphalangeal joints

Ball and Socket - (spheroid) ball like surface fits into a cup like depression

(triaxial)moves in 3 planes flex/ext, ab/ad and rotation

Ex: hip and shoulderPivot - “twist” on each other, C1-C2, radio-

ulnar joint

Weird Muscle Facts!Flea's can jump 130 times higher

than their own height. In human terms this is equal to a 6ft. person jumping 780 ft. into the air

Hummingbirds are the only animals able to fly backwards

A cat has 32 muscles in each ear

Muscular >600 Three Types of muscle

fibers: 1. Smooth muscle -

involuntary, non-striated, blood vessels, digestive and reproductive tract

2. Cardiac muscle - involuntary, striated, has own electrical conduction system, heart

3. Skeletal muscle - voluntary, striated, muscles for movement

muscle fibers - myofibrils - smaller protein filaments either: actin - thinner filaments myosin- thicker filaments sarcomeres - sections of the functional units of

muscleATP supplies muscles in aerobic and

anaerobic exercisesSliding filament theory - actin filaments

within a sarcomere slider toward one another shortening the sarcomere and causing the muscle to contract