MOD2 hair + nails p3

hair covers the body except:

palms, side of hands and fingers

sides and soles of feet

lips

portions of external genitalia

functions of hair:

protect and insulate

sensory receptors

guard openings

explain hair follicles:

extend deep into dermis

wrapped in connective tissue

base surrounded by sensory nerves

what do hair follicles do:

produce non-living hairs

explain arrestor pili muscle:

involuntary smooth muscle

causes hair to stand up

produces goose bumps

explain hair root:

portion that anchors it into skin

explain hair shaft:

upper part of hair

name & explain 3 parts of hair structure:

medulla:

• central core

cortex:

• intermediate layer

cuticle:

• surface layer

name 3 layers of the follicle:

internal root sheath

external root sheath

glassy membrane

explain internal root sheath:

surrounds hair root

explain external root sheath:

extends from skin surface to hair matrix

explain glassy membrane:

clear layer wrapped in connective tissue sheath

explain hair production at hair follicles:

connective tissue containing capillaries and nerves surrounds hair papilla

explain hair production at hair bulb:

epithelial cells form hair matrix

hair is produced

cells divide and hair pushes out of skin

how is hair colour produced and determined:

produced by melanocytes

determined by genes

explain the nail body:

visible portion of nail

covers nail bed

explain the nail sides:

lie in lateral nail grooves

surrounded by lateral nail folds

name the skin beneath edge of nail:

hyponychium

where does nail production occur:

in epidermal fold called the nail root

lies close to bone

name the visible nail that emerges from under the nail root:

eponhychium the cuticle

explain blood vessels near nail root:

obscured producing pale lunula

name 3 types of skin cancer

basal cell carcionoma

squamous cell carcinoma

malignant melanoma

explain basal cell carcinoma:

least dangerous

forms from cells in stratum basale

small shiny bump with central depression and beaded edges

explain squamous cell carcinoma:

arise from stratum spinosum

scalp, ears, lower lip

raised reddened scar, later concave

explain malignant melanoma:

arise from melanocytes

can be removed if caught early

in men, read heads and sunburn from early childhood