Understanding Body Membranes & Skin Layers

2. Chapter 3: Membranes and the Integumentary System Lesson 3.1 Body Membranes

3. Body Membranes • Body membranes surround and help protect the body’s surfaces. • Epithelial membranes • mucous membranes • serous membranes • cutaneous membranes • Connective tissue membranes • synovial membranes

4. Epithelial Membranes • Mucous membranes • Line cavities open to the environment • These cavities include all the hollow organs of the respiratory, digestive, urinary, and reproductive tracts. • The mucous membranes are all moist • Mucus is a slippery solution that protectsthe mucous membranes and aids in transporting substances.

5. Epithelial Membranes • Serous membranes • Line cavities not open to environment • These include: • the pleura, which encloses the lungs; • the pericardium, which surrounds the heart; • the peritoneum, which lines the abdominal cavity. • Each serous membrane forms a double lining with an outer lining and an inner lining. • The outerlining of each body cavity is called the parietal layer. • The inner lining that covers each organ within a body cavity is called the visceral layer.

6. Epithelial Membranes • Serous membranes secrete a thin, clear fluid called serous fluid which serves as a lubricant between the parietal and visceral membranes to minimize friction and “wear and tear”

7. Mucous Membranes and Serous Membranes

8. Epithelial Membranes • Cutaneous membranes • Forms what we know as skin • The basic structure of skin is a keratinizing, stratified (layered) squamous epithelium over dense, fibrous connective tissue. • Although the skin contains sweat glands, it is a dry membrane when sweat is not present.

9. Connective Tissue Membranes • Synovial membrane • Is the only type of membrane in the body that is composed solely of connective tissue and includes no epithelial cells. • lines the capsules that surround synovial joints, such as the shoulder and knee. • Surrounds tendon sheath • Secretes synovial fluid which provides cushioning and reduces friction.

10. Chapter 3: Membranes and the Integumentary System Lesson 3.2 The Integumentary System

11. Functions of the Integumentary System • The skin forms a protective cover against • abrasion • chemical damage • drying out • UV radiation damage • The skin’s outermost layer contains keratin, a tough protein also found in hair and nails that adds structural strength.

12. Functions of the Integumentary System • Regulates body temperature due to the extensive array of tiny capillaries and sweat glands that lie near the surface of the skin. • When the body is overheated, the capillaries dilate, enabling body heat to dissipate. • When the environment is cold, the capillaries constrict, and blood flow moves to deeper vessels away from the skin to minimize heat loss.

13. Functions of the Integumentary System

14. Anatomy of the Skin • The skin has two layers • an outer epidermis • an underlying dermis • The epidermis and dermis are thick over areas such as the soles of the feet and thin in delicate areas such as the eyelids. • Beneath the dermis is the hypodermis, or subcutaneous fascia, which serves as a storage repository for fat.

15. Anatomy of the Skin • The hypodermis is not part of the skin, but it connects the skin to the underlying tissues. It also provides cushioningand insulation against extreme external temperatures.

16. Anatomy of the Skin • Epidermis • Dermis • Hypodermis

17. Layers of the Epidermis • Epidermis • Is the outer layer of skin that we see. • It contains five layers of tissue: from superficial to deep (the outside going in), • stratum corneum, • stratum lucidum, • stratum granulosum, • stratum spinosum, • stratum basale • All epidermal layers consist of cells, with no blood supply to provide nutrients to the skin.

18. Put together skin foldable • The Skin Foldable Color Code • A – Orange • B – Blue • C – Green • D – Purple • E - Yellow

19. Layers of the Epidermis • The innermost layer, the stratum Basale, absorbs nutrients from the adjacent, underlying dermis. • Stratum Basale: • Cells are constantly dividing. As new cells germinate, they are pushed toward the surface and away from nutrients. Eventually, they die. • Contains melanocytes, specialized cells that produce the pigment melanin. Melanin, which ranges in color from reddish yellow to brown and black, is primarily responsible for human skin color.

20. Work of Brazilian Photographer Angelica Daas: Humanae Project

21. Layers of the Epidermis • Stratum spinosum / granulosum • Moving up through the stratum spinosum and granulosum, cells become progressively flatter and more filled with keratin, which makes them tough and water resistant. • Stratum Lucidum • This is a clear layer of thick skin cells found only on the palms of the hands, fingers, soles of the feet, and toes. • Stratum Corneum • This outermost layer of the epidermis, consists of dead cells that are completely filled with keratin and are continually shedding. • The epidermis completely replaces itself every 25 to 45 days.

22. Layers of the Epidermis • The epidermis contains specialized cells: • Epidermal dendritic cells respond to the presence of foreign bacteria or viruses. • Merkel cells, located in the stratum basale, function as touch receptors.

23. Layers of the Epidermis Dendritic cells Merkel cells

24. Layers of the Dermis • The dermis, or “true skin,” is a dense, fibrous connective tissue composed of collagenand elastic fibers. • The collagen fibers provide toughness and also bind with water molecules to helpkeep the inner skin moist. • The elastic fibers are what keep the skin looking young, without wrinkles or sagging 

25. Layers of the Dermis • The outer layer of the dermis is the papillary layer. • Some of the dermal papillae contain capillaries that supply nutrients to the epidermis. Other dermal papillae contain nerve endings involved in sensing touch and pain. • These papillae form genetically determined, ridged patterns on the palms of the hands, fingers, toes, and soles of the feet. These papillae patterns on the fingers determine each person’s unique fingerprints.

26. Layers of the Dermis • Underneath the papillary layer lies the reticular layer of the dermis. The reticular layer includes: • blood and lymphatic vessels, • sweat and oil glands, • involuntary muscles, • hair follicles, • nerve endings.

27. SKIN FOLDABLE • Use your notes or textbook to write one fact about the following layers: • Stratum Corneum • Stratum lucidum • Stratum granulosum • Stratum spinosum • Stratum basale • Epidermis • Dermis • Get your stamp when done

28. Layers of the Hypodermis • The hypodermis, or subcutaneous fascia, includes fibrous connective tissue and adipose (fatty) tissue. • It is within the hypodermis that lipocytes or fat cells, reside. • Some amount of body fat is important for padding and insulating the interior of the body. • Fat also serves as a source of energy.

29. Dermis • Dense, fibrous connective tissue • Papillary layer • forms fingerprints • Reticular layer

30. Appendages of the Skin • Sudoriferous (sweat) glands • Eccrine: major sweat glands of the body • Apocrine: larger than Eccrine glands, located in the genital and axilla (armpit) areas • Sebaceous glands • Produce an oily substance called sebum • Hair • Nails

31. Chapter 3: Membranes and the Integumentary System Lesson 3.3 Injuries and Disorders of the Skin

32. Injuries of the Skin • Decubitus ulcers • These are commonly known as bedsores • They are caused by an area of localized pressure that restricts blood flow to one or more areas of the body. • Without the normal blood supply to provide nutrients and oxygen, the skin cells die. • Proper nutrition is an important factor in both the prevention and healing of bedsores.

33. Injuries of the Skin • Burns • These are injuries that can arise from exposure to excessive heat, corrosive chemicals, electricity, or ultraviolet radiation. • Vary in severity: • First-degree burns: • affect only the epidermal layer of skin, • involve reddening of the skin and mild pain, • tend to heal in less than a week. • Most types of sunburn are first-degree burns. Suzanne Tucker/Shutterstock.com, JTeffects/Shutterstock.com, Naiyyer/Shutterstock.com

34. Injuries of the Skin • Second-degree burns: • Involve damage to both the epidermis and the upper portion of the underlying dermis. • characterized by blisters, fluid-filled pockets that form between the epidermal and dermal layers. • painful and take longer to heal than first-degree burns.

35. Injuries of the Skin • Third-degree burns • the most serious type of skin burn • destroy the entire thickness of the skin, • initially not painful because the nerve endings in the skin have been destroyed. Later, scarring and pain will occur. • cannot heal on its own because the stratum Basale, which generates new skin cells, has been destroyed. Treatment involves grafting skin over the damaged area.

36. Injuries of the Skin • Clinicians use the rule of nines to estimate the extent of burned tissue. The percentage of total body surface area covered by burns is approximated as follows: • 9% for both the anterior (front) and posterior (back) of the head and neck; • 18% for the anterior and 18% for the posterior of the torso; • 9% for both the anterior and posterior of each arm; • 18% for both the anterior and posterior of each leg; • 1% for the genital region.

37. Burn Video

38. Infections of the Skin and Membranes • Viral infections • Produce small, painful, blister-like sores. • Once a herpes infection is present, it lasts for the rest of a person’s life. • Fortunately, herpes infections tend to stay dormant most of the time, • herpes varicella (chicken pox): childhood disease, highly contagious • herpes zoster (shingles): painful blistering rash, fever, and feeling of unwellness • herpes simplex virus • type 1 (common cold) • type 2 (genital herpes) Maksym Bondarchuk/Shutterstock.com

39. Infections of the Skin and Membranes • Human papillomavirus (HPV) • Common warts – skin blemish on hands and fingers • Plantar warts – warts that develop on the soles of feet growing inwards

40. Infections of the Skin and Membranes • Fungal infections • Occur in areas of the body that are moist. • They tend to be more prevalent during warm weather, • They are more common in individuals whose work or sporting activities involve frequent periods of sweating. • Athlete’s foot (Tinea pedis) • characterized by cracked, flaky skin between the toes or on the side of the foot. • Jock itch (Tinea cruris) • primarily affects males around the groin and scrotum.

41. Infections of the Skin and Membranes • Ringworm (Tinea corporis) • does not involve any type of worm. • red ring-shaped rash with a pale center somewhat resembles the shape of a worm. • Toenail fungus (Tinea unguium) • infection under the nails of the fingers or toes. • It causes discoloration and thickening of the infected nail.

42. Infections of the Skin and Membranes • Bacterial infections • Impetigo • Highly contagious staphylococcus infection common in elementary school children. • Its symptoms are pink, blister-like bumps, usually on the face around the mouth and nose, that develop a yellowish crust before they rupture. • Cellulitis • Staphylococcus infection, is characterized by an inflamed area of skin that is red, swollen, and painful. • The origin of cellulitis often is an open wound or ulceration.

43. Inflammatory Conditions of the Skin and Membranes • Inflammation is a general response of bodily tissue to any injury or disease that damages cells. • It is a protective response that involves increased blood flow to the distressed area, along with specialized cells that attack infectious agents and destroy dead tissue. • Pleurisy • Inflammation of the pleura, the membrane that lines the thoracic cavity and lungs. • It can be caused by an infection, such as pneumonia or tuberculosis. • makes smooth surface of pleura rough. Kenxro/Shutterstock.com

44. Inflammatory Conditions of the Skin and Membranes • Peritonitis • Infection of peritoneum • The membrane that lines the inner wall of the abdomen and covers the abdominal organs. • Caused by the accumulation of blood, bodily fluids, or pus in the abdomen. • Psoriasis • Common skin disorder that involves redness and irritation • The condition is characterized by regions of thick, red skin with flaky, silver-white patches called scales that itch, burn, crack, and sometimes bleed

45. Cancers of the Skin • Basal cell carcinoma • the most common form of skin cancer • It is caused by overproduction of cells in the stratum Basale that push upward, forming dome-shaped bumps. • squamous cell carcinoma • caused by overproduction of cells in the stratum spinosum layer of the epidermis. • Appear as a scaly, reddened patch that progresses to an ulcer-like mass with a raised border. Librakv/Shutterstock.com

46. Cancers of the Skin • malignant melanoma • The most serious form of cancer • Cancer of the melanocytes.

47. Cancers of the Skin • ABCD rule • The American Cancer Society advocates the ABCD rule for determining the presence of melanoma: • Asymmetry: • The shape of the mole is irregular. • Border irregularity: • The outside borders are not smooth. • Color: • More than one color is present. Melanomas may contain different shades of black and brown, blues, reds, or pinks. • Diameter: • The mole size is larger than about one-quarter of an inch in diameter, or larger than the diameter of a pencil.

48. Review and Assessment True or False? 1. Herpes zoster causes decubitus ulcers. 2. Peritonitis is an infection of the skin. 3. Impetigo is caused by a fungus. 4. Warts are caused by a virus. 5. Ringworm is caused by a fungus. FALSE FALSE FALSE TRUE TRUE