Exercise 7- The Integumentary System

Thick skin of the epidermis contains ___ layers.

5

stratum basale

A single row of cells immediately above the dermis. Its cells are constantly undergoing mitosis to form new cells. Some 10-25% of the cells in this layer are melanocytes. Occasional tactile cells are also present in this layer.

stratum granulosum

A thin layer (1-5 layers) of flattened cells named for the abundant granules its cells contain. At the upper boundary of this layer, the cells are beginning to die.

dendritic cells

AKA Langerhans cells play a role in immunity by performing phagocytosis

Bedsores

AKA decubitus ulcers occur in bedridden patients who are not turned regularly enough the weight of the body puts pressure on the skin, especially over bony projections, which leads to restriction of the blood supply and tissue death

eccrine sweat gland

AKA merocrine sweat glands; distributed all over the body and produce clear perspiration consisting primarily of water, salt, and urea

cutaneous plexus

It supplies the fatty tissue of the hypodermis, and the deeper parts of the dermis, including the capillaries for hair follicles, deep sebaceous glands and sweat glands

stratum corneum

Most superficial layer; 20-30 layers of dead, scalelike keratinocytes. They are constantly being exfoliated and replaced by the division of deeper cells. Glycolipids in extracellular space.

stratum lucidum

Present only in thick skin. Very thin transparent band of flattened, dead keratinocytes with indistinct boundaries.

stratum spinosum

Several layers of cells that contain thick, weblike bundles of intermediate filaments made of pre-keratin protein. The cells in this layer appear spiky because when the tissue is prepared, the cells shrink, but their desmosomes hold tight to adjacent cells. Cells in this layer and the basal layer are the only ones to receive adequate nourishment from diffusion of nutrients from the dermis.

melanocytes

Spidery black cells that produce the brown-to-black pigment called melanin.

keratinocytes

The most abundant epidermal cells, their main function is to produce keratin fibrils. They are tightly connected to each other by desmosomes.

keratin

a fibrous protein that gives the epidermis its durability and protective capabilities

hair matrix

a layer of actively dividing epithelial cells located on top of the hair papilla

hair follicle

a structure formed from both epidermal and dermal cells

acne

and active infection of sebaceous glands

hair root

beneath the surface of the skin, embedded within the hair follicle

Which gland plays a major role in the body's heat-regulating apparatus?

eccrine sweat glands

nail bed

extension of the stratum basale beneath the nail

granules in the stratum granulosum

lamellar granules and keratohyaline granulest

subpapillary plexus

lies just beneath the dermal papillae, and supplies the capillaries in the dermal papillae

What system controls eccrine sweat glands?

nervous system

tactile (merkel) cells

occasional spiny hemispheres that in combination with sensory nerve endings, form sensitive touch receptors located in the epidermal-dermal junction

sensory nerve fiber with free nerve endings

pain receptor

hair shaft

part of the hair coming out of the epidermis

lamellar corpuscle

pressure receptor

sebum

product of sebaceous glands mixture of oily substances and fragmented cells that acts as a lubricant to keep the skin soft and moist and keeps hair from becoming brittle

eponychium

projection of the thick proximal nail fold commonly called the cuticle

hair follicle receptor

receptor when hair moves

sweat pore

releases sweat

The ducts of ___ glands usually empty into a hair follicle but may also open directly on the skin surface.

sebaceous

The most superficial layer of the epidermis is the:

stratum corneum

What are the five layers of the epidermis?

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

papillary layer

the more superficial dermal layer composed of areolar connective tissue

nail root

the part that is embedded in the skin and adheres to an epithelial nail bed

free edge of nail

the portion of the nail that grows out away from the body

phagocytosis

the process by which a cell—often a phagocyte or a protist—engulfs a solid particle to form an internal compartment known as a phagosome

lunule

the proximal region of the thickened nail matrix, which appears as a white crescent moon

hyponychium

the region beneath the free edge of the nail

nail matrix

the thickened proximal part of the nail bed containing germinal cells responsible for nail growth

apocrine sweat glands

found predominantly in the axillary and genital areas these glands secrete the basic components of eccrine sweat plus proteins and fat-rich substances

keratohyaline granules

help to form keratin in the more superficial layers

The portion of the hair that projects from the surface of the skin is known as the:

shaft

All of the following are functions of the skin except: excretion of body wastes insulation protection from mechanical damage site of vitamin A synthesis

site of vitamin A synthesis

blackheads

accumulation of dried sebum, bacteria, and melanin from epithelial cells in the oil duct

___ sweat glands are found primarily in the genital and axillary areas.

apocrine

dermal papillae

attaches to the epidermis and papillary layer; supplies the fatty tissue of the hypodermis, and the deeper parts of the dermis, including the capillaries for hair follicles, deep sebaceous glands and sweat glands

___ is the yellow-orange pigment found in stratum corneum and the hypodermis.

carotene

hair bulb

collection of well-nourished epithelial cells at the base of the hair follicle

lamellar granules

contain waterproofing glycolipid that is secreted into the extracellular space

The skin has two distinct regions. The superficial layer is the ___, and the underlying connective tissue is the ___.

epidermis, dermis

adipose tissue

fat underneath skin

sebaceous (oil) gland

found all over skin except on palms of hands and soles of feet

These cells produce a brown-to-black pigment that colors the skin and protects DNA from ultraviolet radiation damage. These cells are called:

melanocytes

nail folds

skin folds that overlap the borders of the nail

arrector pili muscle

small bands of smooth muscle cells that connect each hair follicle to the papillary layer of the dermis; hair stands up when these muscles are contracted

hair papilla

small nipple of dermal tissue that protrudes into the hair bulb from the peripheral connective tissue sheath and provides nutrition to the growing hair

hypodermis

subcutaneous tissue that is not part of the skin

dermis

the bottom layer of skin that is divided into two different layers: papillary layer and reticular layer

reticular layer

the deepest skin layer composed of dense irregular connective tissue and contains arteries, veins, sweat glands, sebaceous glands, and pressure receptors

nail body

the visible attached portion

epidermis

top layer of skin that is further divided into five different layers

tactile corpuscle

touch receptor

True or False: Nails originate from the epidermis.

true