1. INTRODUCTION TO BODY STRUCTURE

2. BODY ORGANIZATION 1. The levels of organization of the body: cells- individual unit tissues- Similar cells that work together to perform a common function. organs- Combination of 2 or more tissues that work together to perform a common function organ system- Group of organs that work together to perform a specific function.

3. BODY ORGANIZATION Maintaining homeostasis requires: 1. Body’s organs functioning together. 2. Temperature regulation (endotherms) 3. Adjusting metabolism 4. Detecting and responding to stimuli 5. Maintaining water and mineral balances

4. Integumentary System Consists of: Skin, Hair, & Nails

5. Skin The largest organ in your body. Yes, skin is an organ. Functions of the Skin Protective barrier against pathogens Prevents water loss Offers body protection Regulates body temperature through sweating

6. Four Tissues of the Integumentary System Epithelial- covers body surfaces Connective- provides support and protection Muscle – body movement Nerve- forms body ’ s communication network

7. 3 layers of skin 1. Epidermis: Top layer Constantly makes new skin cells to replace dead ones Contains keratin, which as a waterproof barrier Also contains melanin, a brown pigment that helps protect you from UV rays. (This is why people tan)

8. 3 layers of skin 2. Dermis: The 2 nd layer of skin Contains hair follicles (each follicle contains 1 hair) Contains the sebaceous glands which produce an oil called sebum. This lubricates the skin and hair. Contains sweat glands. These release water and some wastes to cool the body and maintain homeostasis

9. 3 layers of skin 3. Subcutaneous tissue: The 3 rd layer Composed of fat cells This is used for insulation and an energy supply

10. SKIN LAYER DIAGRAM HAIR FOLLICLE SWEAT GLAND SEBACEOUS GLAND EPIDERMIS DERMIS SUBCUTANEOUS TISSUE

11. SKELETAL SYSTEM Functions of the skeleton: 1. Support the body 2. Provide protection for the internal organs 3. Enables movement

12. SKELETAL SYSTEM There are 206 bones in the skeleton. The skeleton is divided into 2 parts: 1. axial- includes the skull, spine, ribs, and sternum 2. appendicular- includes shoulders, arms, hips, and legs

14. SKELETAL SYSTEM Bone is made of hard compact bone surrounding porous bone.

15. BONE MARROW RED – makes all blood cells for body (RBC, WBC, & platelets) YELLOW = stores fat tissue

16. SKELETAL SYSTEM Early in development, the skeleton is made mostly of hyaline cartilage. Bones hardens as calcium, phosphate and other mineral deposits build up. Osteoblasts make bone tissue. Bones thicken and elongate as development continues.

17. SKELETAL SYSTEM JOINT = where 2 bones meet. Three types of joints: 1. Immovable permits little or no movement. ex. skull joined by sutures. 2. Slightly moveable ex. Spine and ribs 3. Freely moveable joints (see table 2 p. 854) ex. knee

18. SKELETAL SYSTEM 1. Ligament: Connects bone to bone 2. Tendon: Connects muscle to bone

19. Osteogenesis Imperfecta

20. MUSCULAR SYSTEM Functions Include: Movement in body Generate Heat for Body Temperature

21. MUSCLES Involuntary muscles – not under conscious control. 1. Smooth muscles – line internal organs & blood vessels. a. Function of smooth muscle is to contract. b. Smooth muscle contractions are slow.

22. MUSCLE 2. Cardiac muscle – heart muscle. Adapted to conduct electrical impulse.

23. MUSCLE Voluntary muscles – under conscious control skeletal system. 3. Skeletal muscles – attached to the bones & skeletal system. a. Majority of muscles are skeletal b. Contractions are short & strong

24. MUSCLE Page skeletal muscle structure 1. Skeletal muscle are made up of bundles of muscle fibers. 2. Each muscle fiber is made up of myofibrils.

25. MUSCLE 3. Myofibrils are made up of smaller proteins filaments. a. Myofibrils are striated or divided into sections called sarcomeres which are the functional units of the muscle

26. MUSCLE 4. Two types of filaments a. Thick filaments are made up myosin. b. Thin filaments are made up of actin.

28. MUSCLES Sliding Filament Theory 1. during contractions, actin filaments move towards one another from the pulls of myosin heads

29. Muscular Dystrophy

30. NERVOUS The function of the nervous system is allow an organism to think, learn, perceive, move, and express emotion. Neurons are specialized cells that transmit information thought the body by conducting electrical signals called nerve impulses.

31. NERVOUS Structure of Neurons: (see p. 944) 1. Dendrites – receive information from other cells. 2. Cell body – collects information from the dendrites, relays the information, and maintains the neuron. 3. Axon – conducts nerve impulses. 4. Axon terminals – Where neuron communicate with other cells. 5. Nerves- bundles of axons

32. NERVOUS Myelin sheath is a layer of insulation found on some neurons. Myelin sheaths causes nerve impulses to travel faster down the axon. Nodes of Ranvier – gaps between the myelin sheath.

33. NERVOUS - see p. 948 Synapse – where a neuron meets another cell. Neurotransmitters – a chemical that transmits the electrical impulse across the synapse.

34. NERVOUS The central nervous system consists of the brain and spinal cord controls the body responds to stimuli from the environment

35. NERVOUS Peripheral nervous system contains: Sensory neurons – send information from sense organs to the CNS. Motor neurons – send commands from the CNS to muscles and other organs.