Chapter 5 pt. 2 Flashcards
What 3 pigments contribute to skin color?
- Melanin
- Carotene
- Hemoglobin
What is Melanin?
only pigment made in skin; made by melanocytes but packaged by keratinocytes
What is Carotene?
yellow to orange pigment in the skin; carrots can produce carotene
What is Hemoglobin?
a pinkish hue of fair skin due to lower levels of melanin
Cyanosis
blue skin color due to low oxygenation of hemoglobin
What does hair consist of?
dead keratinized cells (contains hard keratin, which is tougher and more durable)
Three parts of hair shaft:
medulla (central core), cortex (layers surrounding medulla), and cuticle (outer layers)
What are hair pigments made of?
melanocytes in hair follicles (red hair has additional pheomelanin pigment)
hair matrix
actively dividing the area of the bulb that produces hair cells
- as new cells are made, older cells are pushed upward
Arrector Pili
small band of smooth muscle attached to follicle
- responsible for “goose bumps”
hair papilla
Dermal tissue containing a knot of capillaries that supplies nutrients to growing hair
Hair follicle receptor
sensory nerve endings that wrap-around bulb
types of hair
vellus (pale, fine) and terminal (coarse)
Homeostatic Imbalance (hair)
- hirsutism: excessive hairiness due to abnormally large amounts of androgens
- alopecia: hair thinning after 40y/o
- true baldness: genetically determined and sex-influenced
- baldness in males caused by follicular response to DHT (dihydrotestosterone)
What do nails consist of?
hard keratin, free edge, nail plate, and root