Anatomy and Physiology CH. 5 and 6

tension lines

(lines of cleavage) in the skin indicate the predominant direction of underlying collagen fibers

nevus

A round, flat, or raised area that represents a benign localized growth of melanocytes and usually develops in childhood or adolescence is called a _____, or a mole

hemoglobin

Dark-skinned individuals have large amounts of melanin in the epidermis, so their skin color ranges from yellow to reddish-brown or black. Light-skinned individuals have little melanin in the epidermis. Thus, the epidermis appears translucent, and skin color ranges from pink to red depending on the oxygen content of the blood moving through capillaries in the dermis. The red color is due to ______, the oxygen-carrying pigment in red blood cells

epidermal ridges

Theses ______ ridges are produced during the third month of fetal development as downward projections of the epidermis into the dermis between the dermal papillae of the papillary region

nails

____ are plates of tightly packed, hard, dead, keratinized epidermal cells that form a clear, solid covering over the dorsal surfaces of the distal portions of the digits

tattooing

____ is a permanent coloration of the skin in which a foreign pigment is deposited with a needle into the dermis. It is believed that the practice originated in ancient Egypt between 4000 and 2000 B.C.

albinism

____ is the inherited inability of an individual to produce melanin

body piercing

_____ ____, the insertion of jewelry through an artificial opening, is also an ancient practice employed by Egyptian pharaohs and Roman soldiers, and a current tradition among many Americans.

carotene

_____ is a yellow-orange pigment that gives egg yolks and carrots their skin color

reticular region

_____ region, which is attached to the subcutaneous layer, contains bundles of thick collagen fibers, scattered fibroblasts, and various wandering cells. collagen fibers arranged in the the reticular region are arranged in a net like manner and have a more regular arrangement than those is the capillary region

jaundice

______ is due to a buildup of yellowish appearance to the skin and the shites of the eye, and usually indicates liver disease

pallor

______, or paleness of the skin, may occur in conditions such as shock and anemia.

erythema

______, redness of the skin, is caused by engorgement of capillaries in the dermis with blood due to skin injury, exposure of heat, infection, inflammation, or allergic reactions

depilatory

a substance that removes hair

melanocytes

about 8% of epidermal cells; develop from the ectoderm of a developing embryo and produce the pigment melanin. Their long slender projections extend between the keratinocytes and transfer melanin granules to them

keratinocytes

about 90% of epidermal cells; are arranged in four or five layers and produce the protein keratin

stratum granulosum

about the middle os the epidermis, consist of three to five layers of flattened keratinocytes that are undergoing apoptosis. A distinct feature of cells in this layer is the presence of darkly staining granules of a protein called keratohyalin, which assembles keratin intermediate filaments into keratin

resting stage

after the regression stage, the hair follicle enters a ____ Stage.

intraepidermal macrophages

also known as Langerhans cells arise from red bone marrow and migrate to the epidermis, where they constitute a small fraction of epidermal cells

tactile epithelial cells

also known as Merkel cells are the least numerous of the epidermal cells. The are located in the deepest layer of the epidermis, where they cnatact the flattened process of a sensory neuron (nerve cell), a structure called a tactile disc or merkel disc.

skin

also known as the cutaneous membrane, covers the external surface of the body and is the largest organ of the body in weight. Is about 7% of total body weight

subcutaneous layer

also known as the hypodermis, deep beneath the dermis, consists of areolar and adipose tissue

callus

an abnormal thickening of the stratum corneum

electrolysis

an electric current is used to destroy the hair matrix so the hair cannot regrow

dandruff

an excessive amount of keratinized cells shed from the skin of the scalp

apocrine sweat glands

are also simple, coiled tubular glands but have larger ducts and lumens that eccrine glands. mainly found in the skin of the axilla (armpit), groin, areolae of the breasts, and bearded regions of the face in adult males

eccrine sweat glands

are simple, coiled tubular glands that are much more common than apocrine sweat glands. they are distributed throughout the skin of most regions of the body, especially in the skin of the forehead, palms and soles.

fingerprints

because the ducts of sweat glands open on the tops of the epidermal ridges as sweat pores, the sweat and ridges form fingerprints (or footprints) on touching a smooth object. The epidermal ridges pattern is in part genetically determined and is unique for each individual.

hyponychium

beneath the free edge is a thickened region of stratum corner called the ____, which secures the nail of the fingertip

epidermis

composed primarily of keratinized stratified squamous epithelium. Has 4 main types of cells: keratinocytes, melanocytes, intraepidermal macrophages, and tactile epithelial

stratum corneum

consists on average of 25 to 30 layers of flattened dead keratinocytes, but can range in thickness from a few cells in thin skin to 50 or more cell layers in thick skin. cells are extremely thin, flat, plasma membrane-enclosed packages of keratin that no longer contain a nucleus or any internal organelles. they are the final product of the differentiation process of there keratinocytes.

Integumentary System

contributes to homeostasis by protecting the body and helping regulate body temperature. It also allows you to sense pleasurable, painful, and other stimuli in your external environment.

stratum basale

deepest layer in the epidermis, composed of a single row of cuboidal or columnar keratinocytes. contains stem cells that undergo cell division to continually produce new keratinocytes. also known as the stratum germinatvium to indicate its role in forming new cells

free nerve endings

dendrites that lack any apparent structural specialization. different free nerve endings initiate signals that give rise to sensations of warmth, coolness, pain, tickling and itching

lanugo

downy hairs that cover the body of the fetus

growth stage

each hair follicle goes through a growth systole, which consists of a growth stage, a regression stage, and a resting stage. During the ____ ___, cells of the hair matrix divides.

emotional sweating

eccrine sweat glands also release sweat in response to an emotional stress such as fear or embarrassment. This type of sweating is rendered to as ______ ___ or a cold sweat.

Thin skin

epidermis 4 layers (1) stratum basale (2) stratum spinous (3) stratum granulosum (4) a thin stratum corneum

thick skin

epidermis 5 layers (1) stratum basale (2) stratum spinous (3) stratum granulosum (4) stratum lucidum (5) a thick stratum corneum

regression stage

following the growth stage is the ___ ___, when the cells of the hair matrix stop dividing, the hair follicle atrophies( shrinks), and their hair stops growing.

lamellar granules

fuse with the plasma membrane and release a lipid-rich secretion. this secretion is deposited in the spaces between cells of the stratum granulosum, stratum lucidum, and stratum corneum

Accessory structures of the skin

hair, skin glands, and nails- develop from the embryonic epidermis. They have a host of important functions

Psoriasis

is a common and chronic skin disorder in which keratinocytes divide and move more quickly than normal from the stratum basal to the stratum corneum. They are shed permaturely in as little as 7 to 10 days.

external root sheath

is a downward continuation of the epidermis

melanin

is a yellow-red or brown-black pigment that contributes to skin color and absorbs damaging ultraviolet (UV) light

integumentary system

is composed of skin, hair, oil and sweat glands, nails and sensory receptors

stratum lucidum

is present only in the thick skin of areas such as the fingertips, palms and the soles. consists of 4-6 layers of flattened clear, dead keratinocytes that contain large amounts of keratin and thickened plasma membranes.

internal root sheath

is produced by the matrix and forms a cellular tubular sheath of epithelium between the external root sheath are referred to as epithelial root sheath

dermatology

is the medical speciality that deals with the structure, function, and disorders of the integumentary system

skin graft

is the transfer of a patch of healthy skin taken from a donor site to cover a wound

nail body (plate)

is the visible portion of the nail

melanosome

melanocytes synthesize melanin from the amino acid tyrosine in the presence of an enzyme called tyrosinase. synthesis occurs in an organelle called a _______. exposure to UV light increase the enzymatic activity within ______ and thus increases melanin production

ceruminous glands

modified sweat glands in the external ears, called ____ ____, produce a waxy lubricating secretion

keratinization

newly formed cells in the stratum basal are slowly pushed to the surface. As the cells move from one epidermal layer to the next, they accumulate more and more keratin, a process called _______. Then they undergo apoptosis.

corpuscles of touch

or Meissner corpuscles, nerve endings that are sensitive to touch

sebaceous glands

or oil glands are simple branched acinar (rounded) glands

hairs

or pili, are present on most skin surfaces except the palms, palmar surfaces of the fingers, the soles, and plantar surfaces of the feet.

apoptosis

orderly, genetically programmed cell death in which the nucleus fragment before the cell die

terminal hairs

prior to birth eyebrows, eyelashes etc.. called

sebum

sebaceous glands secrete an oily substances called ____, a mixture of triglycerides, cholesterol, proteins, and inorganic cells

lamellate corpuscles

sensitive to pressure

dermal papillae

small, nipple-shaped structures that project into the undersurface of the epidermis. All the dermal papillae contain capillary loops (blood vessels)

stratum spinosum

superficial to stratum basale, consists mainly of numerous keratinocytes arranged in 8-10 layers. cells in the more superficial layers become somewhat flattened

hair root plexus

surrounding each hair follicle are dendrites of neurons that form a ___ ___ ___, which is sensitive to touch. the hair root plexuses generate nerve impulses in their hair shafts are moved.

hair follicle

surrounding the root of the hair is the ____ ____, which is made up of an external root sheath and an internal root sheath, together referred to as an epithelial root sheath.

insensible perspiration

sweat that evaporates from the skin before it is perceived as moisture is termend

sensible perspiration

sweat that is excreted in larger amounts and is seen as moisture on the skin is called

nail root

the ___ ___ is the portion of the nail that is buried in a fold of skin

free edge

the ____ ___ is the part of the nail body that may extend past the distal end of the digit

root

the ____ is the portion of the hair deep to the shaft that penetrates into the dermis, and sometimes into the subcutaneous layer. consists of three concentric layers of cells: medulla, cortex, and cuticle

shaft

the ____ is the superficial portion of the hair, which projects above the surface of the skin. consists of three concentric layers of cells: medulla, cortex, and cuticle

papillary region

the _____ region makes up about one-fifth of the thickness of the total layer. It contains thin collagen and fine elastic fibers.

bulb

the base of tax hair follicle and its surrounding dermal root sheath is an onion-shaped structure, the ____

hair matrix

the bulb also contains a germinal layer of cells called the ___ ___

extensibility

the combination of collagen and elastic fibers in the reticular region provides the skin with strength, _______, the ability to stretch, and elascitiy, the ability to return to original shape after stretching.

elasticity

the combination of collagen and elastic fibers in the reticular region provides the skin with strength, extensibility, the ability to stretch, and _______ , the ability to return to original shape after stretching.

cerumen

the combined secretion of the ceruminous and sebaceous glands is a yellowish material called ____ or earwax.

dermal root sheath

the dense dermis surrounding the hair follicle

thermoregulation

the homeostatic regulation of the body temperature is known as ___

epidermal growth factor (EGF)

the mechanism that regulates this remarkable growth are not well understood, but hormone like proteins such as _____ _____ ______ play a role.

alopecia

the partial or complete lack of hair, may result from genetic factors, aging, endocrine disorders, chemotherapy or skin disease.

vitiligo

the partial or complete loss of melanocytes from patches of skin produces irregular white spots.

vellus hairs

the rest of hair on body called "peach fuzz"

arrestor pili

the smooth muscle is the ___ ___. it extends from the superficial dermis of the skin to the dermal root sheath around the side of the hair follicle

dermatoglyphics

the study of the pattern of epidermal ridges is called

lunula

the whitish, present-shaped area of the proximal end of the nail body is called the

sudoriferous glands

there are three million to four million sweat glands or _____ ____ in the body. the cells of these glands release sweat, or perspiration, into hair follicles or onto the skin surfaces through pores.

dermis

thicker portion, deeper and composed of connective tissue; vascular

epidermis

thinner portion, superficial and composed of epithelial tissue; avascular

thermoregulatory sweating

this role of eccrine glands is helping the body to achieve thermoregulation is known as

papilla of the hair

this structure houses a nipple-shaped indentation, the ______ __ __ __, which contains areolar connective tissue and many blood vessels that nourish the growing hair follicle

cyanotic

when blood is not picking up an adequate amount of oxygen from the lungs, as in someone who has stopped breathing, the mucous membranes, nail beds, and skin appear bluish or ______