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, 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 vessels  Nerves & nerve endings  hair follicles  sweat and oil glands  subcutaneous fat - various amounts of fat lie under the dermis

Functions of the Skin:  1. Thermoregulation – temperature control  2. Sensory organ – pressure, pain, temperature  3. Produces essential vitamins – Vitamin D  4. Protective layer – physical and chemical shield

The Skin Is 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 days Dead skin cells make up about 90% of household dust An average of 40 kilos of skin is shed during a lifetime Varies in thickness from 1mm on eyelids to 3mms on palms and soles Skin Facts !

Skin Injury and Healing  Epidermis 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 Facts Smallest bones are found in the ear. Longest bone in the body is the femur Bones are filled with a fatty substance called bone marrow In 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- 206  Two 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 fat  Storehouse – essential minerals, Ca Did you know that humans and giraffes have the same number of bones in their necks? Giraffe neck vertebrae are just much, much longer!

11/10/09  Did you know that humans and giraffes have the same number of bones in their necks?  Giraffe neck vertebrae are just much, much longer!

Bone Tissue  Bones 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 tissue  contains 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. Hinge  2. Ball & Socket  3. Gliding  4. 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 shoulder  Pivot - “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 muscle  ATP supplies muscles in aerobic and anaerobic exercises  Sliding filament theory - actin filaments within a sarcomere slider toward one another shortening the sarcomere and causing the muscle to contractcontract