Ch. 4 Skin and Body Membranes Part 2 Mrs. Barnes A & P

Skin Color 3 Pigment Contributors O The amount and kind of Melanin in the epidermis O The amount of Carotene O The amount of oxygen-rich hemoglobin in the dermal blood vessels

Hemoglobin O A condition when hemoglobin is poorly oxygenated and both the blood and skin of Caucasians appears blue, is known as Cyanosis. O Heart failure O Severe breathing problems What do you think happens in African Americans?

Emotions and Skin O Redness or Erythema O Pallor or blanching O Jaundice or a yellow cast O Bruises or black-and-blue marks O What’s another name for bruises? Use page 119

Skin Appendages O Cutaneous glands O Hair O Hair follicles O Nails Each of these arises from the epidermis and plays a part in maintaining body homeostasis.

Cutaneous Glands O Exocrine Glands- release secretions to the skin surface via ducts Two Groups- O Sebaceous Glands O Sweat Glands

Sebaceous Glands O Oils glands O Found all over skin (except palms and soles) O Empty into a hair follicle O Produces Sebum (mixture of oily substances and fragmented cell) O These glands become very active in adolescence

Sebum O Acts as a lubricant and keeps skin soft and moist O Prevents the hair from becoming brittle O Contains chemicals that kill bacteria

Acne O Ducts are blocked by sebum- Whiteheads O Material oxidizes and dries- Blackheads O Acne is an active infection of the sebaceous glands. O Can have mild to extreme cases.

Sweat Glands O Sudoriferous glands O 2.5 million per person Two types O Eccrine glands O Apocrine glands

Eccrine Glands O Most numerous and found all over body O Produce sweat (clear secretion) p 121 O Sweat is acidic pH 4 to 6

Apocrine Glands O Confined to Axillary and Genital areas O Larger than eccrine glands O These secretions contain fatty acids and proteins O Milky or yellow color O The secretion is odorless; bacteria that feed on the fatty acids and proteins are what cause the odor.

Hair and Hair Follicles O Millions of hairs all over the body O Hair is produced by a hair follicle O Hair enclosed by the follicle is the root O Hair projecting from the surface of the scalp or skin is called the shaft

Hair and Hair Follicles O The bulk of the hair shaft is dead material and almost entirely protein O Hair’s central core is called the medulla. Surrounded by the bulky cortex layer. O The cuticle wraps around the cortex layer

Split Ends O The cuticle is what gives the hair its strength and keeps the inner layers tightly compacted. O The cuticle tends to wear away at the tip because its most subject to abrasion. O The hair begins to frizz out and this is called “split ends”

Hair Shapes O Oval shaft- hair is smooth and silky; wavy hair O Flat shaft- curly or kinky hair O Round- hair is straight and tends to be coarse

Hair Follicles O Structures: O Epidermal Sheath O Dermal Sheath O Papilla O Arrector Pili

Nails O Scale-like modification of the epidermis O Made up of: O Free edge O A body O A root

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Burns O Tissue damage and cell death caused by intense heat, electricity, UV radiation (sunburn), or certain chemicals

Burns O Rule of Nines- divides the body into 11 areas O Infection becomes the most important threat and is the leading cause of death in burn victims. O Burned skin is sterile for 24 hours.

Types of Burns O First-degree burns- only the epidermis is damaged. Area becomes red and swollen. Heals in 2-3 days (ex. Sunburn)

Types of Burns O Second-degree burns- damage to epidermis and the upper region of the dermis. Skin is red and painful, blisters appear. Regrowth does occur. O Called a partial thickness burn.

Types of Burns O Third-degree burns- destroy the entire thickness of the skin. Area appears gray- white or blackened. Nerve endings are destroyed. Area is not painful and regeneration is not possible. O Called full thickness burns.

Rule of Nines Burns are Critical if: O Over 25% of the body has second-degree burns O Over 10% of the body has third-degree burns O There are third-degree burns of the face, hands, or feet.

Rule of Nines Totals– 100 % O Anterior and Posterior Head and Neck- 9 % O Anterior and Posterior Upper Limbs- 18 % O Anterior and Posterior Trunk- 36 % O Anterior and Posterior Lower Limbs- 36 % O Perineum 1 %