The Integumentary System: The Skin

1. The Integumentary System:The Skin

2. The Integumentary System • Integument is skin • Skin and its appendages make up the integumentary system • A fatty layer (hypodermis) lies deep to it • Two distinct regions • Epidermis • Dermis

3. Skin Your skin is your largest organ It is your first line of defense against disease and damage It is made of several layers

4. Functions of skin • Protection • Cushions and insulates and is waterproof • Protects from chemicals, heat, cold, bacteria • Screens UV • Synthesizes vitamin D with UV • Regulates body heat • Prevents unnecessary water loss • Sensory reception (nerve endings)

5. Layers of Skin • Epidermis • Uppermost layer of skin • Contains dead and living cells • New cells are replaced daily old ones slough off (they shed) • Dermis- • Inner thicker layer of skin • Contains: • Blood vessels • Nerve receptors • Hair follicles • Sebaceous glands • Sweat glands • Oil glands • Wax glands

6. Remember… • Four basic types of tissue • Epithelium – epidermis just discussed • Connective tissue - dermis • Muscle tissue • Nervous tissue

7. Dermis • Strong, flexible connective tissue: your “hide” • Rich supply of nerves and vessels • Critical role in temperature regulation (the vessels) • Two layers (see next slides) • Papillary – includes dermal papillae- makes fingerprints • Reticular – “reticulum” (network) of collagen and reticular fibers

8. Skin Layers • Subcutaneous Layer- lies below the dermis layer, not really a skin layer • Contains • Fat cells • Fibers used to attach skin to muscle

9. *Dermal papillae *Dermis layers * *

10. Skin Color • Skin pigments • Melanin- dark skin pigment (causes human skin colors) • Where there are darker colors on the skin there is a higher concentration of melanin in that area • Freckles • Moles • birthmarks

11. Skin color • Three skin pigments • Melanin: the most important • Carotene: from carrots and yellow vegies • Hemoglobin: the pink of light skin • Melanin • Variations in color • Protection from UV light by producing vitamin D

12. How does our skin protect us? • Forming • callus- a thickened area of epidermis caused by rubbing or pressure • Blisters- area of skin when the layers of skin separate due to excessive friction or intense heat • Melanin produces vitamin D- “natural sunblock”

13. Sweat glands • Prevent overheating • 500 cc to 12 Liters/day! (is mostly water) • Humans most efficient (only mammals have) • Produced in response to stress as well as heat

14. Fingerprints, palmprints, footprints • Dermal papillae lie atop dermal ridges • Elevate the overlying epidermis into epidermal ridges • Are “sweat films” because of sweat pores • Genetically determined Flexion creases • Deep dermis, from continual folding Fibers • Collagen: strength and resilience • Elastic fibers: stretch-recoil • Striae: stretch marks • Tension lines (or lines of cleavage) • The direction the bundles of fibers are directed The dermis is the receptive site for the pigment of tattoos

15. Disorders of the integumentary system • Burns • Threat to life • Catastrophic loss of body fluids • Dehydration and fatal circulatory shock • Infection • Types • First degree – epidermis: redness (e.g. sunburn) • Second degree – epidermis and upper dermis: blister • Third degree - full thickness • Infections • Skin cancer

17. Burns First-degree (epidermis only; redness) Second-degree (epidermis and dermis, with blistering) Third-degree (full thickness, destroying epidermis, dermis, often part of hypodermis)

18. SKELETAL SYSTEMBONES & JOINTS

20. Functions of the Bones Support Protection Movement Storage (minerals like calcium and phosphorous) Hematopoiesis (makes new blood cells in the bone marrow)

21. Fig. 6.21

22. Bones The adult human skeleton has 206 bones Bones store minerals (calcium) and make blood cells (in the center of the bone, bone marrow) Are made of mineral deposits of calcium and phosphorous There small spaces that contain blood vessels (veins, arteries, and capillaries) The blood vessels and surrounding bone materials makes up an osteon (bone cell)

24. Broken Bones • A broken bone is a fractured bone: • Bones can break in many ways: • Incomplete fracture- when there is only a crack, but not a break • Complete fracture- when the bone breaks completely in two • Comminuted fracture- fractures that splinter the bone

26. J O I N T S

27. JOINTS = a site where 2 or more bones come together with or without movement

28. JOINTS 1. Hinge joints = bend in only one direction, like a door hinge flexion & extension movements possible e.g.: elbow, knee 2. Gliding Joints- = allows bones to slide across one another, and allows some twisting movement Like the bones between the vertebrae 3. Ball & socket joints = ball – shaped head of one bone fits into a socket – like concavity of another = free movements possible: e.g. shoulder and hip

29. 4. Pivot Joint- =allows for some circular movement e.g. The two bones of the forearm near the elbow 5. Fused Joints- = do not allow any movement They become permanently fused together e.g. Bones of the skull Joints

30. Muscles

31. My muscles are important because they… • Hold my organs in place • Hold my bones together so that I can move • Help me chew my food • Open and close my eyelids • Pump my blood • Allow me to run and play • Help me to smile!

32. Muscles & the Skeleton • Skeletal muscles cause the skeleton to move at joints • They are attached to skeleton by tendons. • Tendons transmit muscle force to the bone. • Tendons are made of collagen fibres & are very strong & stiff

33. Functions of the Muscular System • The characteristics of muscle tissue enable it to perform some important functions, including: • Movement – both voluntary & involuntary • Maintaining posture • Supporting soft tissues within body cavities • Guarding entrances & exits of the body • Maintaining body temperature

34. Muscular System • This system is responsible for movement of the body: • But it cannot do this alone. Help is required from the nerves, joints, and bones. • –They work together as an orchestra, each playing their part in perfect harmony • Muscles work by pulling never pushing

35. Muscular System • Muscles are responsible for all types of body movement • 3 basic muscle types are found in the body • Skeletal muscle • Cardiac muscle • Smooth muscle

36. Types of Muscles • Voluntary: muscles you can control, they are subject to one’s will • Skeletal muscles- move your skeleton/bones • Have striations- they have a banded pattern, appears layered

37. Characteristics of the Skeletal Muscles Most are attached by tendons to bones Striated – have visible banding Voluntary – subject to conscious control

38. Anatomy of skeletal muscles epimysium tendon perimysium Muscle Fascicle Surrounded byperimysium endomysium Skeletal muscle Skeletal muscle fiber (cell) Surrounded by epimysium Surrounded by endomysium Play IP Anatomy of Skeletal muscles (IP p. 4-6)

39. Characteristics of Cardiac Muscle • Similar to skeletal muscle cardiac muscle has striations • These striations are not as pronounced in cardiac muscles as in skeletal muscle • It is the only involuntary muscle that is striated • Found only in the heart

40. Smooth Muscle Characteristics • Has no striations • Involuntary – no conscious control • Found mainly in the walls of hollow organs • Stomach, intestines, blood vessels, and other internal organs • The heart is involuntary, but not smooth muscle • Slow, sustained and tireless • They are constantly in motion and do not tire as do skeletal muscles

41. Smooth Muscle

42. Comparison of Muscle Tissue

43. How Muscles Work • Skeletal muscles work in pairs • When your bicep contracts your triceps relax • When the triceps contract your bicep relaxes • Many skeletal muscles extend across at least one joint to 2 different bones • The Sartorius (longest muscle in body) attaches to the top of the hip bone and extends across the hip and knee connecting to the tibia

44. How Muscles Work • Some muscles do not extend across joints but rather movement in skin or other muscles • Tongue and throat muscles do not extend over joints but they move to allow swallowing

45. Frontal Obicularis oculi Temporalis Obicularis oris Masseter Sternoclediomastoid

46. Functions of Muscles • Muscles keep you warm by contracting • When you are cold your body shivers in an attempt to warm you up by increasing muscle contractions and thereby producing heat • They keep your body erect (standing up) • Even when you are still, standing or sitting, your muscles are working and thereby can keep your body warm • This is why yoga is so effective in working muscles, prolonged muscle contractions

47. More Muscle Functions • When muscles in your skin contract making the hair follicles stand upright your skin around the hair follicle also stands up and causes… • Goose bumps

48. Goose Bumps

49. How Muscles Work • Muscles need energy to function, so where does that energy come from • Energy is stored in the body as glucose (sugar) • It is carried by the blood to the muscles where the muscles break down the glucose into usable energy • In order to break down glucose the body needs oxygen

50. How Muscles Work • When the muscles break down sugar, with the use of oxygen, it is aerobic respiration • The oxygen comes to the muscles from the lungs via arteries so that they muscles can break the sugar down into usable energy for the body