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
nail matrix
thickened portion of bed responsible for nail growth
nail bed
epidermis underneath keratinized nail plate
nail fold
skin folds that overlap border of nail
What is the eponychium of the nail?
nail fold that projects onto surface of nail body; also referred to as the cuticle
What is the thick, white nail matrix called?
Lunule
What are the two types of sweat glands?
- Eccrine (or merocrine)
- Apocrine
Eccrine Sweat Glands
- Most numerous type
- Abundant on palms, soles, and forehead
- Ducts connect to pores
Apocrine Sweat Glands
- Confined to axillary and anogenital areas
- Secrete viscous milky or yellowish sweat that contains fatty substances and proteins
Two modified apocrine glands?
Ceruminous (earwax) and Mammary (lactation) glands
Sebaceous (Oil) Glands
Most develop from hair follicles and secrete into hair follicles; Widely distributed, except for thick skin of palms and soles
What do sebaceous glands secrete?
sebum: oily holocrine secretion, bacterial killing properties, softens hair and skin
the functions of the skin:
protection, body temp regulation, cutaneous sensations, metabolic functions, blood reservoir, excretion of wastes
Protection constitutes what three barriers?
chemical, physical, and biological
cutaneous sensory receptors are a part of what body system?
nervous system
insensible perspiration vs sensible perspiration
IP: under normal, resting body temperature, sweat glands produce about 500 ml/day of unnoticeable sweat
SP: if body temperature rises, dilation of dermal vessels can increase sweat gland activity to produce 12 L (3 gallons) of noticeable sweat
Pallor
blanching or pale skin caused by anemia, low blood pressure, fear, or anger
Erythema
redness of the skin due to fever, hypertension, inflammation, or allergy
Jaundice
yellow cast due to liver disorders
Bruises
Also referred to as ecchymoses or hematomas, are a result of clotted blood beneath skin
