1. Chapter 5 The Integumentary System

2. Functions of Skin protection prevention of water loss temperature regulation metabolic regulation immune defense sensory reception excretion

4. The Integument The skin that covers your body. Skin is also known as the cutaneous membrane. Integumentary system consists of the skin and its derivatives—nails, hair, sweat glands, and sebaceous glands.

5. The Integument Is the body’s largest organ. Its surface is covered by an epithelium that protects underlying body layers. The connective tissues contain blood vessels that provide nutrients and provide strength and resilience to the skin. Smooth muscle controls both blood vessel diameter and hair position. Neural tissue supports and monitors sensory receptors in the skin

6. 3 Distinct Layers A layer of stratified squamous epithelium called the epidermis. A deeper layer of dense irregular connective tissue called the dermis. deep to the dermis is a layer of areolar and adipose connective tissue called the subcutaneous layer, or hypodermis

9. Thick Skin Thick epidermis is found on the palms of the hands, the soles of the feet, and corresponding surfaces of the fingers and toes. All five epidermal strata occur in thick skin.

10. Thin Skin Thin epidermis covers most of the body. Lacks the stratum lucidum Has only four specific layers. Contains the following accessories: hair follicles, sebaceous glands, and sweat glands.

11. Skin Color ` Melanin is a pigment produced and stored in cells called melanocytes. the two types of melanin occur in various yellow, reddish, tan, brown, and black shades Carotene comes primarily from diet. - Skin produces/ synthesizes vitamin D

12. Nails Scalelike modifications of the epidermis that form on the dorsal surfaces of the tips of the fingers and toes. Protect the exposed distal tips and prevent damage or distortion during jumping, kicking, catching, or grasping. Hard derivatives formed from the stratum corneum layer of the epidermis.

14. Hair Found almost everywhere on the body except the palms of the hands, the sides and soles of the feet, the lips, the sides of the fingers and toes, and portions of the external genitalia. Most of the hairs on the human body are on the general body surface rather than the head.

16. Functions of Hair Protection Heat retention Prevents the loss of conducted heat from the scalp to the surrounding air Facial expression Sensory reception Visual identification Chemical signal dispersal

17. Hair Color Result of the synthesis of melanin in the matrix adjacent to the papillae. Variations in hair color reflect genetically determined differences in the structure of the melanin. Environmental and hormonal factors Age Gray hair

18. Exocrine Glands of the Skin Sweat (sudoriferous) glands produce a watery solution that performs several specific functions. merocrine (eccrine) sweat glands- most numerous. Palms and soles have the highest number (99% water). apocrine sweat glands- most active during puberty. Sebaceous glands produce an oily material that coats hair shafts and the epidermal surface.

19. Burns Major cause of accidental death, primarily as a result of their effects on the skin. Usually caused by heat, radiation, harmful chemicals, sunlight, or electrical shock. The immediate threat to life results primarily from fluid loss, infection, and the effects of burned, dead tissue. Burns are classified according to the depth of tissue involvement.

20. Classification of Burns First- and second-degree burns are called partial-thickness burns. Third-degree burns are called full-thickness burns. first-degree burns involve only the epidermis and are characterized by redness, pain, and slight edema an example is sunburn

22. Classification of Burns Second-degree burns involve the epidermis and part of the dermis. The skin appears red, tan, or white, and is blistered and painful. An example is a scald.

24. Classification of Burns Third-degree burns involve the epidermis, dermis, and subcutaneous layer, which are often destroyed. Regeneration may occur from the edge only, due to the absence of dermis. Skin grafting is required to prevent abnormal connective tissue fibrosis and disfigurement. Dehydration is a major concern because the entire portion of skin has been lost, and water cannot be retained. Must be aggressively treated for dehydration.

26. Aging of the Integument Skin repair processes take longer due to reduced number and activity of stem cells. Skin forms wrinkles and becomes less resilient. Skin’s immune responsiveness is diminished. Skin becomes drier due to decreased sebaceous gland activity. Altered skin and hair pigmentation.

27. Aging of the Integument Sweat production diminishes. Blood supply to the dermis is reduced leading to impaired thermoregulation. Hair thinning and loss. Integumentary production of vitamin D3 diminishes. Development of skin cancers.