Anatomy and Physiology - Integumentary System

Skin functions

protects your body against infection and extreme temperatures, maintains your balance of fluids and synthesizes vitamin d

integumentary system

Consists of the skin, mucous membranes, hair, and nail

Epidermis

Outer layer of skin

dermis

middle layer of skin

hypodermis

loose connective tissue layer of skin below the dermis

Epidermis is made up of

keratinized stratified squamous epithelium

Keratinocytes

the building blocks of the tough fibrous protein keratin

Melanocytes

cells that produce melanin

langerhans cells

epidermal macrophages that help activate the immune system, located on epidermis

Merkel cells

combine with nerve endings to create a sensory receptor for touch

thick skin

Covers the palms of the hands and soles of the feet

Has five layers of keratinocytes

think skin

covers rest of the body

possesses hair follicles, sebaceous glands and sweat glands

stratum corneum

outermost layer of epidermis

stratum lucidum

a layer of the epidermis found only in the thick skin of the fingers, palms, and soles

stratum granulosum

a layer of the epidermis that marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata

stratum spinosum

a layer of the epidermis that provides strength and flexibility to the skin

stratum basale

deepest layer of epidermis

papillary layer

outer layer of the dermis, directly beneath the epidermis

dermal papillae

a fingerlike projection of the dermis that may contain blood capillaries or Meissner corpuscles (of touch)

Friction ridges

the markings on the fingertips that leave oily fingerprints on surfaces we touch

reticular layer

Deeper layer of the dermis that supplies the skin with oxygen and nutrients

Hypodermis contains

adipose tissue

dermis contains

Blood vessels, sensory neurons, sweat glands, sebaceous glands, hair follicles, smooth muscle

Cutaneous sensory receptors

Receptors located throughout the skin that respond to stimuli arising outside the body; part of the nervous system.

corpuscles

living cells capable of moving about in a liquid

tactile corpuscles

small epidermal structures with nerve endings that are sensitive to touch and pressure

Lamellar corpuscles

deep pressure receptors

insensible perspiration

interstitial fluid lost by evaporation through the stratum corneum

sensible perspiration

produced by active sweat glands

hair cuticle

Outermost layer of hair; consisting of a single, overlapping layer of transparent, scale-like cells that look like shingles on a roof.

Hair shaft

The portion of hair that projects above the epidermis, keratinization is complete

Hair root

The part of the hair located below the surface of the epidermis, where keratinization is still happening

Eccrine sweat glands

Secreting glands, are far more numerous and are abundant on palms, soles of feet and forehead.

apocrine sweat glands

Found in armpits, around nipples, and groin; Secrete products into hair follicles; Produce sticky, cloudy secretions; Break down and cause odors;

Mammary glands

specialized sweat glands that secrete milk

Ceruminous glands

produce ear wax

sebaceous glands

secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis

sebum

oily substance secreted by sebaceous glands