Unit 7: The Human Body!

1. Unit 7:The Human Body!

2. Chapter 19: Skin, Skeletal System, and Muscular System

3. 19.1 Human Body Organization • Cells => Tissues => Organs => Organ systems => Organism

4. Review parts of the cell: the basic unit of life

5. Tissue: a group of cells that work together to perform a specific function. • There are 4 main types of tissue in the human body: • Epithelial tissue • Connective tissue • Muscle tissue • Nervous tissue

6. Epithelial tissue • Covers the outside of the body and lines structures inside the body. • Cells are closely packed to provide a protective barrier for the body.

7. Connective tissue • Tendons, ligaments, bones, and blood. • Holds together other tissues. • Cells are loosely packed.

8. Muscle tissue • Muscles around bones and in organs. • Allows movement.

9. Nervous tissue • Gathers and transmits information throughout the body (senses and responds).

10. Organ • A group of tissues working together to perform a specific function.

11. Organ system • A group of organs that work together to carry out one or more body functions.

12. Circulatory system • Pumps blood through the body, brings nutrients to cells, carries wastes away from cells.

13. Skeletal system • Supports the body and gives it shape.

14. Muscular system • Enables the body to move.

15. Respiratory system • Takes in oxygen from the air and gives off carbon dioxide.

16. Digestive system • Takes in food and breaks it down into usable energy.

17. Urinary system • Rids the body of liquid and dissolved wastes and helps balance salts and water in the body.

18. Nervous system • Takes in and responds to information in the environment.

19. Endocrine system • Helps regulate the body’s functions

20. Immune system • Helps the body fight disease.

21. Reproductive system • Allows the production of offspring.

22. 19.2 Skin

23. Skin: also known as the integumentary system. • Largest organ of the body (2 square meters). • Sense organ. • Covers body and protects it from injury. • Regulates body temperature. • Rids body of wastes. • Prevents water and blood loss. • Protects body from disease.

24. The skin is made of three layers: • Epidermis: Outer layer. • Dermis: Middle layer. • Subcutaneous tissue: Deepest layer.

25. Epidermis: • The outermost layer. Replaced every 28 days. • Made of cells called keratinocytes that produce keratin, a protein that makes the skin tough. • Hair, nails, feathers, claws, and horns are also made of keratin. • Keratinocytes protect deeper cells from damage and drying out, and keep out microorganisms.

27. The cells in the epidermis are in layers. • Old keratinocytes fill up with keratin and get pushed up by new keratinocytes, which are produced by the innermost layer of the epidermis. • As the cells get pushed away, they are away from the blood supply and die. • These cells then flake off (and become dust, EWW!)

29. Other cells in the epidermis: • Melanocytes: Produce melanin. • Melanin: The chemical responsible for skin color. • More melanin = darker skin. • Melanin is released when the skin is exposed to the sun (causes a tan). Protects skin from sun damage. • Langerhan’s cells: Immune cells.

30. Dermis: the thick middle layer of the skin. • Contains many different items: • Nerve endings: Sense of touch. • Blood vessels: Control body temperature. • Expand to release heat, contract to keep heat. • Sweat glands: Control body temperature. • Sweat evaporates to cool body off. • Sweat also removes some wastes from the body.

31. More items in the dermis: • Connective tissue • Collagen and elastin fibers: Elasticity. • Hair follicles • Oil glands: Keep skin smooth and waterproof and keep hair from getting brittle.

33. Subcutaneous tissue • The innermost layer of the skin. • Contains connective tissue and fat cells. • Fat cells insulate the body and conserve heat.

34. Burns: • First degree: Just the epidermis. Pain. • Second degree: Epidermis and dermis. Pain. • Third degree: All three layers of skin. No pain because the nerve endings are destroyed.

35. Skin Cancer: Warning Signs: The ABCDEs of Melanoma • Asymmetry If you draw a line through this mole, the two halves will not match. • Border The borders of an early melanoma tend to be uneven. The edges may be scalloped or notched. • Color Having a variety of colors is another warning signal. A number of different shades of brown, tan or black could appear. A melanoma may also become red, blue or some other color. • Diameter Melanomas usually are larger in diameter than the size of the eraser on your pencil (1/4 inch or 6 mm), but they may sometimes be smaller when first detected. • Evolving Any change — in size, shape, color, elevation, or another trait, or any new symptom such as bleeding, itching or crusting — points to danger. http://www.skincancer.org/melanoma/Page-3.html

36. Nails: • Modified skin. • Mostly keratin. • Protect the soft tissue at the tips of the fingers.

37. Hair: • Covers the entire body (except for palms, soles, and lips) • Mostly keratin. • Protects eyes and nose from dust. • Keeps body warm. Insulates head. Goose bumps. • Hair follicles: Tiny, saclike structures in dermis from which hair grows.

38. 19.3 The Skeletal System

39. There are 206 bones in the skeletal system. • Gives the body shape. • Supports the body. • Protects organs. • Allows movement. • Stores nutrients. • Produces blood cells.

40. The skeleton is divided into two main sections: • Axial skeleton: Bones of the head, neck, and trunk (in green). • Appendicular skeleton: Bones of the limbs (in purple).

41. Bones to know: • Skull • Hyoid • Sternum • Ribs • Vertebrae • Sacrum • Coccyx

42. Bones to know: • Clavicle • Scapula • Humerus • Radius • Ulna • Carpal bones • Metacarpal bones • Phalanges

43. Bones to know: • Pelvic girdle • Femur • Patella • Tibia • Fibula • Tarsal bones • Metatarsal bones • Phalanges

44. A bone’s shape relates to its function: • Long bones: In arms and legs, for example. • Short bones: In fingers and toes, for example. • Flat bones: In skull and pelvis, for example. • Irregular bones: In backbone and ears, for example.

45. Composition of a bone: • A bone is made of three layers: • Periosteum • Compact bone • Spongy bone • (plus bone marrow in the middle of long bones)

46. Periosteum: Thin layer that covers the bone. Contains blood vessels. • Compact bone: Dense layer underneath the periosteum. Contains blood vessels, nerve cells, osteocytes, and minerals (calcium and phosphorous). • Spongy bone: Strong but lightweight.

47. Bone marrow: Found in the cavity in the middle of long bones. • Red bone marrow: Produces red blood cells and some white blood cells. • Yellow bone marrow: Contains mostly fat cells, which store energy.

48. Bone growth and repair are allowed by two types of cells: • Osteoblasts: Produce bone. • Osteoclasts: Break down bone.

49. Bone tissue

50. Formation of bone: • Bones start out as cartilage in the fetus. • Cartilage: Soft, flexible connective tissue. • The cartilage gradually changes to bone through a process called ossification. • At birth, a person has over 300 bones. • As we develop, some of these bones fuse, so we end up with 208 bones.