Epidermis or Dermis?
Composed of epithelial cells; is the outermost protective shield of the body.
Epidermis
Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. See occasional melanocytes and dendritic cells.
Stratum basale
The thin, superficial layer made up of areolar connective tissue.
Papillary layer
Flexible strands produced by hair follicles and consist largely of dead, keratinized cells.
Hairs or pili
______ (with a few exceptions) are distributed over the entire body surface. Their primary function is thermoregulation. They are simple coiled tubular glands that secrete a salt solution containing small amounts of other solutes. Official name for "sweat" glands.
Eccrine glands
Subcutaneous tissue just deep to the skin.
Hypodermis
Most superficial layer; 20-30 layers of dead cells, essentially flat membranous sacs filled with keratin.
Stratum corneum
Deeper layer; accounting for 80% of the thickness of the dermis.
Reticular
Hairs can be classified as _____ or ______.
Vellus or terminal
______ glands occur all over the body surface except for the palms and soles. They are simple alveolar glands; their oily holocrine secretion is called sebum. ______ gland ducts usually empty into hair follicles.
Sebaceous glands
Makes up the bulk of the skin; is a tough, leathery layer composed mostly of dense connective tissue.
Dermis
Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin.
Stratum spinosum
Collectively, skin ridges are referred to as?
Friction ridges
_______ fold down from the epidermal surface into the dermis.
Hair follicles
______ lubricates the skin and hair; prevents water loss from the skin, and acts as a bactericidal agent. Sebaceous glands are activated (at puberty) and controlled by androgens.
Sebum
Another name for the hypodermis.
Superficial fascia
Typically 1-5 layers of flattened cells, organelles deteriorating; cytoplasm full of lamellar granules (release lipids) and keratohyaline granules.
Stratum granulosum
Peglike projections (papillary layer) called _______ indent the overlying epidermis.
Dermal papillae
The deep end of the follicle, located about 4mm below the skin surface expands to from ________.
Hair bulb
Apocrine sweat glands
Only the _____ is vascularized.
Dermis
The epidermis consists of how many distinct cell types arranged in how many distinct layers?
Four; and four-five.
Network of blood vessels that nourishes the reticular layer that lies between the reticular layer and the hypodermis is known as:
Cutaneous plexus
Associated with each hair follicle is a bundle of smooth muscle cells called an ____________.
Arrector pili
You have up to _____ million sweat glands per person.
3