SKIN APPENDAGES — HAIR & HAIR FOLLICLES

Hair

A structure made mostly of keratin that grows from hair follicles.

Hair follicle

A tube-like structure in the skin where hair grows.

Hair bulb

The enlarged base of a hair follicle where hair growth begins.

Root

The part of the hair below the skin's surface.

Shaft

The part of the hair that extends above the skin's surface.

Arrector pili

Tiny muscles attached to hair follicles that pull the hair upright, causing goosebumps.