Support and Locomotion Chapter 36 1

Skin The body’s protection 2

Epidermis  the outer layer Exterior layer  layers of dead, flattened cells –Constantly being shed –Keratin  protective protein (elasticity) Interior layer  living cells continually dividing –Melanin  protective skin pigment 3

Epidermis cont. Epidermal ridges Fingers and palms Toes and soles Good for gripping  give increased friction 4

Dermis  the inner layer Blood vessels, nerves, nerve endings, hair follicles, sweat and oil glands Layer of fat underneath  insulation and protection 5

This picture shows a false-colored SEM of human skin. The lower portion is the living epidermis. As those cells die, they flake off and become the stratum corneum, which does most of the work creating a barrier between the body and the outside world. 6

Functions of the skin Regulate body temperature Sense organ Vitamin D production Physical barrier against damage and microbial invasion 7

Aging Drier  glands decrease production Skin loses it’s elasticity  wrinkles Accelerated by prolonged exposure to UV rays 8

The Skeletal System 9

Axial skeleton Includes the skull, vertebral column, ribs, and sternum 10

Appendicular skeleton Includes the bones of the arms and legs, and associated structures 11

Joints Places where bones are connected 12

Ball-and-socket joint Allows for rotational movement Hips and shoulders 13

Hinge joint Allows for back-and- forth movement Elbows, knees, fingers, and toes 14

Pivot joint Allows bones to twist around each other Neck and elbows 15

Gliding joint Allows bones to slide past each other Wrists and ankles 16

Fixed joint Also called a fused joint Allows for no motion Skull 17

Cartilage Bones are cushioned by a thin layer of cartilage Flexible, elastic tissue Nose, ears, trachea, between each vertebrae 18

Bursae Fluid-filled sacs between bones Absorb shock 19

Arthritis Inflammation of the joints Wearing down of cartilage Bone spurs  splinters Causes  infections, aging, injury, genetic 20

Connective tissue Ligaments  connect bone to bone –Sprain  torn or stretched ligament Tendons  connect muscles to bones –Tendonitis  inflammation of the tendon 21

Bone Structure 22

Compact bone Very dense and strong Outside of ends and along shafts Osteocytes  bone cells 23

Osteon systems (Haversian canals) –Openings which allow blood vessels and nerves through bone 24

Spongy bone Less dense, porous Ends of bones 25

Periosteum Outer covering of bone shafts 26

Osteoblasts  potential bone cells Secrete a protein called collagen Deposition of minerals turns them into osteocytes  ossification 27

Osteoporosis  loss of bone mass Growth –Length: cartilage plates at ends –Width: outer surface After growth  repair and maintenance 28

Marrow  found at the center of bones Red marrow Long bones only –Production of blood cells Yellow marrow Most bones –Stored fat 29

Functions of the skeletal system Protects internal organs Framework for body tissues Attachment for muscles Production of blood cells Mineral storage 30

Skeletal system 31

Muscles 3 types 32

Smooth muscle Sheets of cells Walls of internal organs and blood vessels Function  squeezing (pressure) Involuntary  not under conscious control 33

Smooth muscle tissue 34

Cardiac muscle Found in your heart Interconnected bands of muscle fibers  striated Adapted to generate and conduct electrical impulses Involuntary 35

Cardiac muscle tissue 36

Skeletal muscle Attached to bones Controls movement Work in opposing pairs  1 bends a limb and the other extends the limb Striated in appearance Voluntary 37

Skeletal muscle tissue 38

Muscle and nerves 39

Skeletal muscle contraction 40

Muscle strength The number of muscle fibers you have is fixed before birth Muscle fibers get bigger and more fibers contract as you increase your strength 41

Muscle fatigue  when muscles hurt after use Due to decreased available oxygen Cells switch from aerobic to anaerobic Lactic acid buildup  toxic, causes pain Cure  rest Not resting can result in permanent muscle damage 42

Comparative anatomy 43

Amoeba Pseudopods  “false feet” Extensions of the cell membrane that can reach in any direction Locomotion 44

Amoeba with pseudopods 45

Paramecium Have cilia to propel them through the water Locomotion 46

Paramecium with cilia 47

Hydra Pull with tentacles Glide on base Somersaulting Movement 48

Hydra with tentacles 49

Earthworm Setae  bristles used as anchors Longitudinal muscles  shorten body Circular muscles  lengthen body 50

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Grasshopper Jointed appendages Walking legs and jumping legs 2 sets of wings Exoskeleton made of chitin –Attachment site for muscles 52

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