Ch. 5 Text Flashcards
What are the three main layers of the skin?
- Epidermis (outermost protective layer),
- Dermis (middle layer with blood vessels and glands),
- Hypodermis (deepest layer with fat and connective tissue).
What are the five layers of the epidermis (in thick skin) from deep to superficial?
- Stratum basale (new cell production).
- Stratum spinosum (keratin production).
- Stratum granulosum (cells flatten and toughen).
- Stratum lucidum (only in thick skin, adds strength).
Stratum corneum (outermost, dead keratinized cells that shed).
“Base Spinning Grants Lucid Corn”
What are the main cell types in the epidermis and their functions?
- Keratinocytes (produce keratin for strength).
- Melanocytes (produce melanin for pigmentation and UV protection).
- Merkel cells (detect touch).
- Langerhans cells (immune defense).
What are the two layers of the dermis and their functions?
- Papillary layer (loose connective tissue, contains dermal papillae, touch receptors, and blood vessels).
- Reticular layer (dense connective tissue with collagen and elastin fibers for strength and elasticity).
What structures are found in the dermis?
Blood vessels, lymph vessels, nerves, sweat glands, sebaceous (oil) glands, hair follicles, collagen and elastin fibers.
What is the function of the hypodermis?
Stores fat for insulation and energy, connects skin to muscles and bones, absorbs shock to protect underlying structures.
How do thick and thin skin differ?
Thick skin (palms, soles, five epidermal layers, includes stratum lucidum), Thin skin (most of the body, four layers, lacks stratum lucidum).
What are the four main accessory structures of the skin?
- Hair (protection, sensory input, thermoregulation).
- Nails (protect fingertips, enhance grip).
- Sweat glands (regulate body temperature).
- Sebaceous (oil) glands (moisturize skin and hair).
What are the three main parts of a hair strand?
- Hair Shaft (visible part).
- Hair Root (anchored below skin)
- Hair Bulb (base, contains mitotically active basal cells).
What are the three layers of a hair strand?
- Medulla (soft inner core).
- Cortex (thickest layer with keratin).
- Cuticle (tough outer protective layer).
What are the main structures of the nail?
- Nail Body (hardened visible part).
- Nail Root (growth center).
- Lunula (crescent-shaped base).
- Cuticle (protects root).
- Hyponychium (thickened skin under free edge).
What are the two types of sweat glands and their functions?
- Eccrine glands (all over body, watery sweat for thermoregulation, antimicrobial peptides).
- Apocrine glands (armpits/genitals, thick sweat causing body odor, influenced by hormones).
What is the function of sebaceous (oil) glands?
Produce sebum to moisturize skin and hair, provide antibacterial protection, and prevent water loss; increase activity during puberty (causes acne).
What are the four main functions of the skin?
- Protection (barrier against dehydration, infection, and injury).
- Sensory Function (detects touch, pain, and temperature).
- Thermoregulation (regulates body heat through sweat and blood vessels).
- Vitamin D Synthesis (produces vitamin D for bone and immune health).
How does the skin protect the body?
The stratum corneum acts as a physical barrier, keratin and glycolipids prevent water loss, sweat contains antimicrobial peptides, and immune cells patrol for invaders.
How does the skin regulate body temperature?
Sweat glands release sweat to cool the body; vasodilation increases blood flow to release heat; vasoconstriction reduces blood flow to conserve heat in cold environments.
How does the hypodermis aid in thermoregulation and protection?
Stores fat for insulation, cushions against impacts, and helps regulate body temperature.
