Chapter 6 Section 2

catagen phase

a brief regression period where cell division ceases and the follicle undergoes involution

diffuse hair loss

a dramatic and distressing condition where hair is shed from all parts of the scalp

lanugo

a fine, unpigmented, downy hair that first appears on the fetus in the last trimester of development

hyponychium

a region of thickened stratum corneum over which the free nail edge projects

sebaceous glands

a small gland in the skin which secretes a lubricating oily matter into the hair follicles to lubricate the skin and hair

sweat glands

a small gland that secretes sweat, situated in the dermis of the skin

hair matrix

a structure immediately adjacent to the hair papilla in the hair bulb, houses keratinization

cerumen

a waterproof earwax secreted by ceruminous glands

eponychium

also know as the cuticle, a narrow band of epidermis extending from the margin of the nail wall onto the nail body

sweat pore

an indented region where there is an opening for the sweat gland on the epidermal surface

hair follicle

an oblique tube that surrounds the hair root

sebum

an oily, waxy secretion produced by sebaceous glands

male pattern baldness

causes loss of hair first from only the crown region of the scalp rather than uniformly

sweat

clear secretion released by exocytosis

cuticle

coats the hair, formed by a single cell layer around the cortex

apocrine sweat glands

coiled, tubular glands that release their secretion into hair follicles in the axillae, around the nipples, in the pubic region, and in the anal region

hair bulb

consists of epithelial cells and is a swelling at the base where the hair originates in the dermis

free edge

distal whitish part of the nail

hirsutism

excessive male pattern baldness in areas of the body that normally do not have terminal hair

nail folds

folds of skin that overlap the nail

hair

found almost everywhere on the body except the palms of the hands and palmar surfaces of the fingers, the sides and soles of the feet and toes, and portions of the external genitalia

cortex

hard structure that is formed by several layers of flattened cells closer to the outer surface of the developing hair

epidermal derivatives

includes the nails, hair, and exocrine glands of the skin, which are all derived from the epidermal epithelium

connective tissue root sheath

layer of a hair follicle that originates from the dermis

epithelial tissue root sheath

layer of a hair follicle that originates from the epidermis

nail bed

layer of epidermis which contains only the deeper, living cell layers of the epidermis

mammary glands

modified apocrine sweat glands

ceruminous glands

modified apocrine sweat glands located only in the external auditory meatus, where their secretion forms a waterproof earwax called cerumen

medulla

not found in all hair types, a remnant of the soft core of the matrix

nail body

pinkish part of the nail that covers a layer of epidermis that is called the nail bed

hair papilla

surrounded by epithelium at the base of the bulb, composed of a small amount of connective tissue containing tiny blood vessels and nerves

anagen phase

the active phase of growth where living cells of the hair bulb are rapidly growing, dividing, and transforming into hair

nail matrix

the actively growing part of the nail

merocrine sweat glands

the most numerous and widely distributed sweat glands

vellus

the primary human hair and is found on the upper and lower limbs

nail root

the proximal part of the nail embedded in the skin

thermoregulation

the regulation of body temperature by evaporation of fluid from the skin

telogen phase

the resting phase and is usually the phase where the hair is shed

shaft

the third portion of the hair that extends beyond the skin surface

lunula

the whitish semilunar area of the proximal end of the nail body

root

the zone of the hair extending from the bulb to the skin surface

arrector pili

thin ribbons of smooth muscle that extend from the hair follicle to the dermal papillae

alopecia

thinning of the hair

sweat gland duct

transports the secretion to the surface of the epidermis or into a hair follicle

terminal hair

usually coarser, pigmented, and longer than vellus