tuWhat are of the integument? Protection, sensation, thermoregulation, excretion, vitamin D synthesis, immune defense What tissue makes up the epidermis? Keratinized stratified squamous epithelium What are the four cell types in the epidermis? Keratinocytes (keratin), melanocytes (melanin), Langerhans cells (immune), Merkel cells (touch) What are the two types of skin? Thick skin (palms/soles, 5 layers, no hair) and Thin skin (most of body, 4 layers, hair) What is the deepest layer of the epidermis and its function? Stratum basale – makes new cells, has melanocytes and Merkel cells Which epidermal layer gives skin strength and flexibility? Stratum spinosum Which epidermal layer waterproofs the skin? Stratum granulosum Which epidermal layer is only in thick skin? Stratum lucidum What is the outermost epidermal layer made of dead cells? Stratum corneum How long is the skin life cycle? About 4–6 weeks What 3 factors contribute to skin color? Melanin, carotene, hemoglobin Why do people near the equator tend to have darker skin? More melanin protects against intense UV radiation What are the benefits and harms of UV radiation? Benefits: Vitamin D; Harms: DNA damage, cancer, aging What are the 3 types of skin cancer? Basal cell carcinoma, squamous cell carcinoma, melanoma What are the two layers of the dermis? Papillary (capillaries, sensory) and Reticular (collagen, glands, follicles, vessels) What is the function of the dermis? Strength, elasticity, supports epidermis, houses structures How does the skin regulate body temperature? Sweat (cooling), vasodilation (heat loss), vasoconstriction (heat retention) What tissues make up the hypodermis? Adipose and areolar connective tissue What are the functions of the hypodermis? Energy storage, insulation, cushioning, anchors skin What are the accessory structures of the skin? Hair, nails, sebaceous glands, sweat glands What are the functions of hair? Protection, sensory role, reduces heat loss What are the two types of hair? Vellus (fine body hair) and Terminal (thick scalp, brows, pubic) What do sebaceous glands secrete and why? Sebum (oil) – lubricates skin/hair, antibacterial What are the two types of sweat glands? Apocrine (thick, odor; armpits/groin) and Merocrine/Eccrine (watery, cooling; all over) How does the skin age? Epidermis thins, less collagen/elasticity, drier, slower healing, gray hair What are the effects of aging on skin? Wrinkles, sagging, dryness, higher cancer risk What layer of skin does a first-degree burn affect? Epidermis only (redness, sunburn) What layers of skin does a second-degree burn affect? Epidermis and dermis (blisters, pain) What layers of skin does a third-degree burn affect? Epidermis, dermis, and hypodermis (charred, no sensation, grafts ne

Histology study guide

Anatomy