a&P chp 4
A needle would pierce the skin of the forearm in which order? (1) stratum basale; (2) stratum granulosum; (3) stratum spinosum; (4) stratum corneum; (5) stratum lucidum
(4) stratum corneum, (2) stratum granulosum, (3) stratum spinosum, (1) stratum basale The correct sequence is stratum corneum, stratum granulosum, stratum spinosum, and stratum basale. The stratum lucidum is found only in the skin of the palms of the hands or in the soles of the feet.
ABCDE rule for recognizing melanoma:
(A) Asymmetry. Any two sides of the pigmented spot or mole do not match. (B) Border irregularity. The borders of the lesion are not smooth but exhibit indentations. (C) Color. The pigmented spot contains areas of different colors (black, brown, tan, and sometimes blue or red). (D) Diameter. The lesion is larger than 6 millimeters (mm) in diameter (the size of a pencil eraser). (E) Evolution. One or more of these characteristics (ABCD) is evolving, or changing.
Melanin
- a pigment that ranges in color from yellow to brown to black -produced by special spider-shaped cells called melanocytes
Synovial membranes
- composed of loose areolar connective tissue and contain no epithelial cells at all. -These membranes line the fibrous capsules surrounding joints - provide a smooth surface and secrete a lubricating fluid. -line small sacs of connective tissue called bursae and the tubelike tendon sheaths. Both of these structures cushion organs moving against each other during muscle activity—such as the movement of a tendon across a bone's surface.
sebum
- lubricant that keeps the skin soft and moist and prevents the hair from becoming brittle. -contains chemicals that kill bacteria
keratinocytes
- produce keratin -connected by desmosomes throughout the epidermis
papillary layer
- the superficial dermal region. It is uneven and has peglike projections from its superior surface, called dermal papillae - which indent the epidermis above.
stratum granulosum
-As they move away from the dermis and become part of the more superficial layers - they become flatter and increasingly keratinized. -As these cells leave the stratum granulosum, they die, forming the clear stratum lucidum
stratum spinosum
-As they move away from the dermis and become part of the more superficial layers -they become flatter and increasingly keratinized.
Functions of the Integumentary System
-It insulates and cushions the deeper body organs and protects the entire body from mechanical damage (bumps and cuts), chemical damage (such as from acids and bases), thermal damage (heat and cold), ultraviolet (UV) radiation (in sunlight), and microbes. The uppermost layer of the skin is hardened, to help prevent water loss from the body surface.
THE EPIDERMIS
-KERATINIZED STRATIFIED SQUAMOUS EPITHELIUM -AVASCULAR -CONSIST OF 4 DISTINCT CELL TYPES ARRANGED IN 4 OR 5 DISTINCT LAYERS. -EPIDERMAL CELL TYPES 1. KERATINOCYTES (STRUCTURE) 2. MELANOCYTES ( PIGMENT) 3. MERKEL CELLS (MEISNER'S CORPUSCLES) SENSATION 4. LANGERHANS CELLS (PHAGOCYTES - IMMUNE)
skin is composed of two kinds of tissue
-The outer epidermis is made up of stratified squamous epithelium that is capable of becoming hard and tough. -The underlying dermis is made up mostly of dense connective tissue.
Sweat glands
-also called sudoriferous - glands, are widely distributed in the skin. -Their number is staggering—more than 2.5 million per person. -There are two types of sweat glands, eccrine and apocrine.
Merkel cells
-associated with a nerve ending, -act as touch receptors
avascular
-epithelial tissues, the epidermis is avascular; it has no blood supply of its own. -This explains why a man can shave daily and not bleed even though he cuts off many cell layers each time he shaves.
dermal papillae
-extensions of the superficial papillary layer, which consists of areolar connective tissue. -The deeper reticular layer is dense irregular fibrous connective tissue.
melanocytes
-found chiefly in the stratum basale
stratum lucidum
-found only in thick skin, -skin is hairless and extra thick, that is, on the palms of the hands and soles of the feet -As these cells leave the stratum granulosum, they die, forming the clear stratum lucidum
Apocrine glands
-largely confined to the axillary (armpit) and genital areas of the body. - They are usually larger than eccrine glands, and their ducts empty into hair follicles.
Apocrine glands
-secretion contains fatty acids and proteins, as well as all the substances present in eccrine sweat; - it may have a milky or yellowish color. -The secretion is odorless, but when bacteria that live on the skin use its proteins and fats as a source of nutrients for their growth, it can take on a musky, sometimes unpleasant odor.
melanocytes
-special spider-shaped cells that produce melanin -found chiefly in the stratum basale
STRATUM SPINOSUM
2ND DEEPEST LAYER OF EPIDERMIS CONSIST OF 8-10 LAYERS OF CELLS CELLS BEGIN TO FLATTEN GOING UPWARD MAKE PRECURSOR OF KERATIN AKA PRICKLY LAYER BC THEY SHRINK AND PULL BACK.
STRATUM GRANULOSUM
3-5 CELL LAYERS THICK CELL MORPHOLOGY CHANGE DRASTICALLY AS CELLS CONT. TO FLATTEN AND THEIR NUCLEI AND ORGANELLES DISINTEGRATE. ACCUMULATE GRANULES CONTAINING PRECURSOR OF KERATIN AND A WATER PROOFER
STRATUM LUCIDUM
3-5 LAYERS OF FLAT, DEAD KERATINOCYTES. APPEARS CLEAR BC IT LACKS NUCLEI AND ORGANELLES
A needle would pierce the skin of the forearm in which order? (1) stratum basale; (2) stratum granulosum; (3) stratum spinosum; (4) stratum corneum; (5) stratum lucidum
4-2-3-1
What name is given to the rule for recognizing the signs of melanoma?
ABCDE rule.
CUTANEOUS MEMBRANES
ARE DRY MEMBRANES
SQUAMOUS CELL CA
ARISES FROM KERATINOCYES OF STRATUM SPINOSUM 25% OF CASES GOOD PROGNOSIS IS CAUGHT EARLY CAN BE FATAL IS METASTIZES TO LYMPH NODE
Jaundice (jon′dis), or a yellow cast
An abnormal yellow skin tone usually signifies a liver disorder in which excess bile pigments accumulate in the blood, circulate throughout the body, and become deposited in body tissues.
skin ulcers.
Any restriction of the normal blood supply to the skin results in cell death and, if severe or prolonged enough, skin ulcers.
SKIN CANCER
BC OF THE ABUSE SKIN TAKES CANCER CAN RESULT. 3 TYPES OF SKIN CA: -BASAL CELL -SQUAMOUS CELL CARCINOMA -MALIGNANT MELANOMA
BASAL SIDE OF CELL IS
BOTTOM FACING BASEMENT MEMBRANE
Why do no skin cancers develop from stratum corneum cells?
Because stratum corneum cells are dead and thus no longer are dividing.
Which of the following statements regarding the significance of alterations in skin color is FALSE?
Blanching (or pallor) may signify anemia, low blood pressure, allergy, or impaired blood flow into an area.
How do secretions of apocrine glands differ from those of the eccrine sweat glands?
Both are dilute salt solutions containing vitamins and wastes. Apocrine secretion also contains proteins and fatty acids.
vernix caseosa
By the time the infant is born, it has usually shed this hairy cloak, and instead its skin is covered with an oily coating called the vernix caseosa
In which epidermal layer do cells begin to die?
Cells begin to die as they leave the stratum granulosum.
One important role of the skin is to produce vitamin _______, which is essential for healthy cell functioning.
D
SUBCUTANEOUS TISSUE - AKA HYPODERMIS OR SUPERFICIAL FASCIA
DEEP TO THE DERMIS CONSIST OF PRIMARILY ADIPOSE AND SOME AREOLAR CONNECTIVE TISSUE STORES ENERGY, PROVIDES INSULATION ANCHORS THE SKIN TO UNDERLYING MUSCLE DIFFERNT DIST. BETWEEN SEXES.
STRATUM BASALE
DEEPEST EPIDERMAL LAYER FIRMLY ATTACHED TO UNDERLYING DERMIS SINGLE ROW OF CUBODIAL KERATINOCYTES WITH MELANOCYTES MERKEL CELLS INTERSPERSED. CELLS IN THIS LAYER ARE HIGHLY MITOTIC (DIVIDING OFTEN) AKA THE STRATUM GERMINATIVUM
excessive exposure to UV light
Despite melanin's protective effects, excessive exposure to UV light (via sunlight or tanning beds) eventually damages the skin, leading to a leathery appearance. It also depresses the immune system. Overexposure to the sun can also alter the DNA of skin cells, leading to skin cancer. People with very dark skin seldom have skin cancer, attesting to melanin's amazing effectiveness as a natural sunscreen.
lanugo
During the fifth and sixth months of development, a fetus is covered with a downy type of hair called lanugo
THERE ARE 4 PRIMARY TISSUE TYPES IN THE HUMAN BODY
EPITHELIAL- -Cutaneous membrane -mucous membrane -serous membranes CONNECTIVE- MUSCLE- NERVOUS-
GLANDS ARE DERIVATIVES OF EPITHELIAL TISSUE.
EVEN THOU THEY RESIDE IN THE DERMIS, THEY ARE NOT MADE FROM CONNECTIVE TISSUE.
medulla
Each hair is made up of a central core called the medulla (mĕ-dul′ah), consisting of large cells and air spaces, surrounded by a bulky cortex layer composed of several layers of flattened cells
What are the criteria for classifying burns as first-, second-, third-, or fourth-degree?
First-degree burns are red and swollen; only epidermis damaged. Second-degree burns damage the epidermis and the superficial part of the dermis; blisters appear, but epithelial regeneration can occur. Third-degree burns destroy the entire skin thickness and can extend into the subcutaneous tissue; the burn is gray and painless; must graft. Fourth-degree burns destroy all layers of the skin; appear charred; extend into deep tissues such as muscle or bone.
Melanin
Freckles and moles are seen where melanin is concentrated in one spot.
epidermis is composed of up to five layers or strata
From the inside out these are the stratum basale, spinosum, granulosum, lucidum, and corneum
hair
Hormones account for the development of hairy regions—the scalp and, in the adult, the pubic and axillary areas. Despite these functions, however, our body hair has lost much of its usefulness. Hair served early humans (and still serves hairy animals) by providing insulation in cold weather, but now we have other means of keeping warm.
amount of oxygen-rich hemoglobin
In light-skinned people, the crimson color of oxygen-rich hemoglobin in the dermal blood supply flushes through the transparent cell layers above and gives the skin a rosy glow.
Which of the following is NOT a function of skin?
It produces vitamin C in the presence of sunlight This is not a function of the skin. The skin produces vitamin D in the presence of sunlight.
You have just gotten a paper cut, but it doesn't bleed. Which layer(s) of the skin has/have the cut penetrated?
Just the epidermis.
What cell type is most abundant in the epidermis?
Keratinocytes are the most abundant cell type in the epidermis.
MALIGNANT MELANOMA
LEAST COMMON/MOST DANGEROUS CA OF MELANOCYTES OFTEN ARISES FROM A PRE-EX MOLE FOLLOW ABCD RULE FOR EARLY DET.
RETICULAR DERMIS
LOWER 4/5 OF DERMIS AND CONSIST OF DENSE IRREGULAR CONNECTIVE TISSUE - THE PROMINENT, HORIZONTALLY RUNNING COLLAGENOUS FIBERS GIVE THE SKIN STRENGTH AND RESILIENCY. ELASTIN GIVES THE SKIN THE ABILITY TO STRETCH AND RECOIL.
dermis
Like the epidermis, the dermis varies in thickness. For example, it is particularly thick on the palms of the hands and soles of the feet but is quite thin on the eyelids.
Where would you find a synovial membrane?
Lining a fibrous capsule surrounding a joint.
What are the two life-threatening consequences of a severe burn?
Loss of body fluids containing needed proteins and electrolytes, resulting in circulatory shock, and overwhelming infection.
APPENDAGES OF THE SKIN
MAJORITY OF THE APPENDAGES OF THE SKIN FOUND IN DERMIS 1. SEBACEOUS GLANDS 2. SUDORIFEROUS GLANDS 3. CERUMINOUS GLANDS 4. HAIR 5. NAILS
SKIN COLOR IS DUE TO 3 PIGMENTS
MELANIN - ONLY PIGMENT MADE IN SKIN CAROTENE - FOUND IN PLANT PRODS. HEMOGLOBIN - PIGMENTED PROTEIN IN BLOOD THAT TRANSPORTS OXYGEN.
CERUMINOUS GLANDS
MODIFIED APOCRINE GLANDS FOUND IN INNER LINING OF THE EXT. EAR CANAL. SECRETE STICKY WAX CALLED CERUMEN
BASAL CELL CARCINOMA
MOST COMMON TYPE OF SKIN CANCER LEAST VICIOUS CURED VIA SURGICAL REMOVAL CONSIST OF TUMOR GROWTH IN STRATUM BASALE. OFTEN OCCUR ON SUN EXPOSED AREAS
What pigments determine skin color?
Melanin, carotene, and hemoglobin all contribute to skin color.
Which of the following statements is NOT true regarding melanin?
More melanin is produced when the skin is not exposed to sunlight. This is false. Sunlight stimulates the melanocytes to produce more melanin, and tanning occurs. As a result, the increased melanin forms a protective pigment layer over the nuclei and shields the genetic material from the ultraviolet radiation in sunlight.
This type of membrane lines body cavities that are open to the exterior.
Mucous
KERATINOCYTES
NEW CELLS ARE CONT MADE IN THE DEEPEST LAYER PUSHING THE OLDER CELLS UP. AS THE KERATINOCYTES MOVE FARTHER FROM THE DEEPEST LAYER, THEY MAKE THE KERATIN.
When a factory worker caught his finger in a machine, the entire nail, plus the nail matrix and bed, was torn off. Will his nail grow back? Why or why not?
No, the nail won't regrow, because the growth region (nail matrix) is torn off.
INTEGUMENTARY SYSTEM
ONE OF OUR 11 ORGAN SYSTEMS CONSISTS OF THE SKIN -sweat glands sebacceous glands -hair -nails
THE DERMIS IS HEAVY IN BLOOD VESSELS, IN COLD WEATHER THEY CONSTRICT AND IN WARM WEATHER THEY DIALATE, WHY?
OUR BLOOD CARRIES ALOT OF OUR BODY TEMP. DOING THIS IS TO PRESERVE HEAT OR RADIATE HEAT
STRATUM CORNEUM
OUTERMOST STRATUM - 20-30 LAYERS OF FLAT HIGHLY KERATINIZED DEAD CELLS. PROTECTS AGAINST MECHANICAL ABRASION PROTECTS AGAINST PATHOGENS PREVENTS DISICCATION (DRYING OUT) AKA THE CORNIFIED LAYER
dermal papillae
On the palms of the hands and soles of the feet, the papillae are arranged in definite patterns that form looped and whorled ridges on the epidermal surface that increase friction and enhance the gripping ability of the fingers and feet.
MELANIN
POLYMER OF TYROSINE AMINO ACID ITS SYNTHESIS IS CATALYSED BY TYROSINASE. (LACKING IN ALBINOS) FRECKLES AND MOLES ARE LOCAL ACCUMULATIONS OF MELANIN
A scalpel penetrates the left lung and enters the heart. Name the six serous membrane layers the blade passes through as it moves from the body surface into the heart.
Parietal pleura, visceral pleura, (lung), visceral pleura, parietal pleura, parietal pericardium, visceral pericardium, (heart).
TISSUE REPAIR IS POSSIBLE
REGENERATION GRANULATION FIBROSIS - SCAR TISSUE
Redness, or erythema
Reddened skin may indicate embarrassment (blushing), fever, hypertension, inflammation, or allergy.
MELANOCYTES
SPIDER SHAPED EPITHELIAL CELLS THAT SYNTHESIZE THE PROTEIN PIGMENT MELANIN. FOUND IN THE DEEPEST LAYER OF THE --EPIDERMIS-- MELANIN IS MADE AND THEN PACKAGED INTO MEMBRANE-BOUND GRANULES CALLED MELANOSOMES GRANULES ARE TRANSFERRED TO THE KERATINOCYTES IN THE 2 DEEPEST LAYERS OF THE EPIDERMIS. MELANIN GRANULES ACCUMULATE ON THE "SUNNY SIDE" OF THE NUCLEUS OF THE KERATINOCYTES. PROTECT DNA FROM UV RADIATION
DERMIS
STRONG FLEXIBLE FIBROUS CONNECTIVE TISSUE DIVIDED INTO PAPILLARY AND RETICULAR
APICAL SURFACE IS THE
SUNNY SIDE
epidermal dendritic cells
Scattered in the epidermis
Merkel cells
Seen here and there at the epidermal-dermal junction
What kind of membranes line body cavities that do not open to the outside of the body (except for the dorsal body cavity and joint capsules)?
Serous
What kind of membranes line body cavities and, except for the dorsal body cavity and joint capsules, do not open to the outside of the body?
Serous Serous membranes are double-layered. The parietal layer lines the body wall and folds on itself to form the visceral layer, which covers the outside of the organs in that cavity.
How do the body locations of serous and mucous membranes differ?
Serous membranes line ventral body cavities closed to the exterior. Mucous membranes line body cavities open to the exterior (respiratory, digestive, urinary, and reproductive organ cavities).
Serous Membranes
Serous membranes occur in pairs -The parietal layer lines a specific portion of the wall of the ventral body cavity -the visceral) layer, which covers the outside of the organ(s) in that cavity.
Cutaneous Membrane
Skin -It's an organ system consisting of a keratinized squamous epithelium firmly attached to a thick layer of dense irregular connective tissue. Exposed to the air. composed of two layers, the superficial epidermis and the underlying dermis. The epidermis is composed of stratified squamous epithelium, whereas the dermis is mostly dense (fibrous) connective tissue. Unlike other epithelial membranes, the cutaneous membrane is exposed to air and is a dry membrane
arrector pili
Small bands of smooth muscle cells—arrector pili (ah-rek′tor pi′li; "raiser of hair")—connect each side of the hair follicle to the dermal tissue. When these muscles contract (as when we are cold or frightened), the hair is pulled upright, dimpling the skin surface with "goose bumps."
Which of the following is NOT a characteristic of malignant melanoma?
Smooth border
stratum basale, (aka - stratum germinativum)
Stem cells in this layer are constantly dividing, and millions of new cells are produced daily
Mitosis occurs in which layer of the epidermis?
Stratum basale The stratum basale is the deepest layer of the epidermis. The cells in this layer are constantly undergoing mitosis.
Connective Tissue Membranes
Synovial membranes
Bruises
The black-and-blue marks of bruising reveal sites where blood has escaped from the circulation and has clotted in the tissue spaces. Such clotted blood masses are called hematomas. An unusual tendency to bruise may signify a deficiency of vitamin C in the diet or hemophilia (bleeder's disease).
cortex
The cortex is, in turn, enclosed by an outermost cuticle formed by a single layer of cells that overlap one another like shingles on a roof. This arrangement of the cuticle cells helps to keep the hairs apart and keeps them from matting
cuticle
The cuticle is the most heavily keratinized region; it provides strength and helps keep the inner hair layers tightly compacted.
Which structure(s) are responsible for fingerprints?
The dermal papillae in the papillary layer of the dermis are responsible for fingerprints.
EPITHELIAL MEMBRANES
The epithelial membranes, also called covering and lining membranes, include the cutaneous membrane (skin), the mucous membranes, and the serous membranes A CONTINUOUS MULTICELLULAR SHEET COMPOSED OF AT LEAST 2 PRIMARY TISSUE TYPES; AN EPITHELIUM BOUND TO AN UNDERLYING LAYER OF FIBROUS CONNECTIVE TISSUE.
BODY MEMBRANES
The majority of the body's structures are lined by epithelial membranes. -Such structures include: body cavities, tracts, external surfaces of organs, and the external surface of the body itself.
the stratum corneum
The outermost layer accounts for about three-quarters of the epidermal thickness. The shinglelike dead cell remnants, completely filled with keratin, are referred to as cornified, or horny, cells (cornu = horn). The common saying "Beauty is only skin deep" is especially interesting in light of the fact that nearly everything we see when we look at someone is dead!
. What is the source of the vernix caseosa that covers the skin of the newborn baby?
The sebaceous glands of the baby.
. Which of the cutaneous gland types can make your hair limp and oily?
The sebaceous glands, which produce oily secretions.
Explain the relationships between the words skin, cutaneous membrane, integument, and integumentary system.
The skin is the epithelial membrane that covers the body surface. Cutaneous membrane is a synonym for skin, as is integument, which means "covering." The integumentary system is the skin and its derivatives (nails, hair, glands).
Which layer of the epidermis produces new epidermal cells?
The stratum basale.
Excess shedding of dead cells from the superficial layer of the skin of the scalp causes dandruff. What is the name of that skin layer?
The stratum corneum.
PAPILLARY DERMIS
UPPER 1/5 OF THE DERMIS CONSISTING OF LOOSE AREOLAR CONNECTIVE TISSUE. PROVIDES ARENA FOR IMMUNE CELLS TO FIGHT INVADERS PROJECTS UPWARD AND STRONGLY CONNECTED TO EPIDERMIS HEAVILY INVESTED WITH BLOOD VESSELS MULTIPLE SENSORY RECEPTORS
What is the single most common risk factor for skin cancer?
UV radiation exposure (sun or tanning bed).
Pallor, or blanching
Under certain types of emotional stress (fear, anger, and others), some people become pale. Pale skin may also signify anemia, low blood pressure, or impaired blood flow into the area.
Loss of subcutaneous fat.
What change in aging skin accounts for wrinkles and cold intolerance in older adults?
cyanosis
When hemoglobin is poorly oxygenated, both the blood and the skin of light-skinned people appear blue,
acne appears on the skin surface.
When sebaceous gland ducts are blocked by sebum
Sweat is acidic
a characteristic that inhibits the growth of certain bacteria, which are always present on the skin surface.
hair
a flexible epithelial structure
dermis
abundantly supplied with blood vessels that play a role in maintaining body temperature homeostasis
blackhead
accumulated material oxidizes and dries, it darkens
Apocrine glands
activated by nerve fibers during pain and stress and during sexual arousal.
Most minor skin afflictions are attributed to infection or _______.
allergies
hair
among the fastest growing tissues in the body.
Glands usually associated with the skin of the genitals and the axillary region, and which secrete fatty acids and proteins, are called _______.
apocrine glands These glands are largely confined to the axillary and genital regions of the body.
cutaneous glands
are all exocrine glands
Lamellar corpuscles __________.
are deep pressure-sensitive receptors
Pacinian corpuscles _______.
are deep pressure-sensitive receptors The Pacinian corpuscles are the deep pressure receptors in the reticular layer of the dermis of the skin.
Squamous cell carcinoma
arises from the cells of the stratum spinosum. The lesions appear as scaly, reddened papules (small, rounded swellings) that gradually form shallow ulcers with firm, raised borders appears most often on the scalp, ears, back of the hands, and lower lip, but can appear anywhere on the skin. It grows rapidly and metastasizes to adjacent lymph nodes if not removed. This epidermal cancer is also believed to be induced by UV exposure. If it is caught early and removed surgically or by radiation therapy, the chance of complete cure is good.
The structure that contracts to cause "goose bumps" is the _______.
arrector pili muscle The arrector pili muscle is attached to the hair follicle and moves the hair when it contracts.
Merkel cells
associated with sensory nerve endings and serve as touch receptors called Merkel discs.
Collagen fibers
attract and bind water and thus help to keep the skin hydrated
The deepest layer of the epidermis is the
basal layer
Apocrine glands
begin to function during puberty under the influence of androgens.
blister.
burn or friction (such as the rubbing of a poorly fitting shoe) may cause them to separate, allowing interstitial fluid to accumulate in the cavity between the layers
When body temperature is high
capillaries of the dermis become engorged, or swollen, with heated blood, and the skin becomes reddened and warm. This allows body heat to radiate from the skin surface. If the environment is cool and body heat must be conserved, blood bypasses the dermis capillaries temporarily, allowing internal body temperature to remain high.
Cyanosis
common during heart failure and severe breathing disorders
Serous Membranes
composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue.
All epithelial membranes have a layer of __________ underneath them.
connective tissue
All epithelial membranes have a layer of _______ underneath them.
connective tissue The layer of connective tissue underlying a mucous membrane has a special name-lamina propria.
dermal papillae
contain capillary loops
reticular layer
contains dense irregular connective tissue, as well as blood vessels, sweat and oil glands, and deep pressure receptors called lamellar corpuscles.
The thick proximal nail fold is commonly called the _______.
cuticle The cuticle consists of stratum corneum.
stratum basale (stratum germinativum)
deepest cell layer of the epidermis, - lies closest to the dermis and is connected to it along a wavy border that resembles corrugated cardboard. -This basal layer contains the most adequately nourished of the epidermal cells because nutrients diffusing from the dermis reach them first.
reticular layer
deepest skin layer
The type of tissue making up the bulk of the dermis is _______.
dense (irregular) connective tissue The dermis is a strong stretchy structure that consists of dense (irregular) connective tissue.
The underlying dermis is made up mostly of
dense connective tissue
The _______ is the avascular, keratinized layer of skin.
epidermis
The __________ is the avascular, keratinized layer of skin.
epidermis
The layer of the skin that is made of stratified squamous epithelium is called the _______.
epidermis This is the outer, keratinized layer of the skin.
The epidermis is composed of _______ tissue.
epithelial
Deep to the dermis is the subcutaneous tissue, or hypodermis
essentially is adipose (fat) tissue. It is not considered part of the skin, but it does anchor the skin to underlying organs and provides a site for nutrient storage. Subcutaneous tissue serves as a shock absorber and insulates the deeper tissues from extreme temperature changes occurring outside the body. It is also responsible for the curves that are more a part of a woman's anatomy than a man's.
Mucous membranes line all body cavities that open to the
exterior
exocrine glands
fall into two groups: sebaceous glands and sweat glands.
eccrine glands
far more numerous and are found all over the body They produce sweat, a clear secretion that is primarily water plus some salts (sodium chloride), vitamin C, traces of metabolic wastes (ammonia, urea, uric acid), and lactic acid (a chemical that accumulates during vigorous muscle activity).
Both collagen and elastic fibers
found throughout the dermis.
Which of these factors is/are the most likely cause of permanent hair loss?
genes
Medications and stress can affect hair graying and loss; however, _______ factors play more of a key role.
genetic
Elastic fibers
give the skin its elasticity when we are young As we age, the number of collagen and elastic fibers decreases, and the subcutaneous tissue loses fat. As a result, the skin loses its elasticity and begins to sag and wrinkle.
hair
guarding the head against bumps, shielding the eyes (via eyelashes), and helping to keep foreign particles out of the respiratory tract (via nose hairs). Hair may also help to attract sexual partners, as evidenced by its place in our body image.
The terms sheath, bulb, and follicle all relate to which of the following?
hair
Sebaceous glands are usually associated with _______.
hair follicles Sebaceous glands produce sebum (oil), which keeps hair pliable, and has an antimicrobial effect.
The dermis
has a rich nerve supply. many of the nerve endings are designed to detect different types of stimuli (pressure, temperature, pain, etc.), then send messages to the central nervous system for interpretation.
dermal papillae
house pain receptors (free nerve endings) and touch receptors
epidermal dendritic cells
important "sentries" that alert and activate immune system cells to a threat such as bacterial or viral invasion
eccrine sweat glands
important and highly efficient part of the body's heat-regulating equipment. They are supplied with nerve endings that cause them to secrete sweat when the external temperature or body temperature is too high.
The skin appendages
include cutaneous glands, hair and hair follicles, and nails
What are three important functions of the integumentary system?
insulates and cushions protects the entire body from mechanical
Malignant Melanoma
is a cancer of melanocytes. It accounts for only about 5 percent of skin cancers, but it is often deadly. Melanoma can begin wherever there is pigment; most such cancers appear spontaneously, but some develop from pigmented moles. It arises from accumulated DNA damage in a skin cell and usually appears as a spreading brown to black patch (Figure 4.11c) that metastasizes rapidly to surrounding lymph and blood vessels. The chance for survival is about 50 percent, and early detection helps.
As the melanocytes produce melanin
it accumulates in their cytoplasm in membrane-bound granules called melanosomes.
Synovial membranes line
joint cavities
Hair, nails, and the outer layer of the skin are made mostly of a tough waterproof protein called _______.
keratin
Seborrhea
known as "cradle cap" in infants, is caused by overactivity of the sebaceous glands. It begins on the scalp as pink, raised lesions that gradually form a yellow-to-brown crust that sloughs off oily scales and dandruff.
A mucous membrane _______.
lines the digestive and respiratory tracts The mucous membrane consists of an epithelium resting on an areolar connective tissue membrane called the lamina propria. composed of epithelium (the type varies with the site) resting on a loose connective tissue membrane called a lamina propria (Figure 4.1b). This membrane type lines all body cavities that open to the exterior, such as those of the hollow organs of the respiratory, digestive, urinary, and reproductive tracts.
Melanocytes
make the pigment melanin
Three pigments contribute to skin color:
melanin, carotene, and hemoglobin.
This type of membrane lines body cavities that are open to the exterior.
mucous
Burns are assessed by the rule of _______.
nines
Decubitus ulcers (bedsores)
occur in bedridden patients who are not turned regularly or who are dragged or pulled across the bed repeatedly.
The sebaceous (se-ba′shus) glands
oil glands, are found all over the skin, except on the palms of the hands and the soles of the feet. Their ducts usually empty into a hair follicle but some open directly onto the skin surface.
Apocrine glands
play a minimal role in thermoregulation.
, sebum
product of the sebaceous glands
star-shaped epidermal dendritic cells
protective immune cells
A mucous membrane lines all body cavities that open to the exterior, such as those of the hollow organs of the
respiratory, digestive, urinary, and reproductive tracts
Collagen fibers
responsible for the toughness of the dermis
the stratum corneum
rubs and flakes off slowly and steadily as the dandruff we have a totally "new"epidermis every 25 to 45 days.
nail
scalelike modification of the epidermis that corresponds to the hoof or claw of other animals. Each nail has a free edge, a body (visible attached portion), and a root (embedded in the skin) (Figure 4.8). The borders of the nail are overlapped by folds of skin called nail folds. The edge of the thick proximal nail fold is commonly called the cuticle.
Acne is an active infection of the
sebaceous glands
peritoneum
serosa lining the abdominal cavity and covering its organs
What kind of membranes line body cavities that do not open to the outside of the body (except for the dorsal body cavity and joint capsules)?
serous
pericardia
serous membranes surrounding the heart
pleurae
serous membranes surrounding the lungs
The cutaneous membrane is your
skin
people who eat large amounts of carotene-rich foods
skin tends to take on a yellow-orange cast.
Skin exposure to sunlight
stimulates melanocytes to produce more melanin pigment, resulting in tanning of the skin.
Sebaceous glands produce oils whereas the _______ glands produce sweat.
sudoriferous
Two types of glands found in the skin are the _______ and _______ glands.
sudoriferous; sebaceous
sweat pore
sweat reaches the skin surface via a duct that opens externally as a funnel-shaped
exocrine glands
that release their secretions to the skin surface via ducts.
keratinization
the fibrous protein that makes the epidermis a tough protective layer
whitehead
the material does not dry or darken
Inside the keratinocytes,
the melanin forms a pigment umbrella over the superficial, or "sunny," side of their nuclei and shields their genetic material (DNA) from the damaging effects of UV radiation in sunlight
The connective tissue making up the dermis consists of two major regions
the papillary and the reticular areas
serous fluid
the serous layers are separated not by air but by a scanty amount of thin, clear fluid, called serous fluid - The lubricating serous fluid allows the organs to slide easily across the cavity walls and one another without friction as they carry out their routine functions. This is extremely important when mobile organs such as the pumping heart and expanding lungs are involved.
You can cut your hair without feeling pain because _______.
the shaft of the hair consists of dead cells The cytoplasm of the hair cells is replaced very shortly after leaving the hair bulb; therefore, the hair is dead.
Serous membranes are composed of two layers,
the visceral and parietal layers.
As cells progress from the deeper portion of the epidermis toward the surface, _______.
they tend to die The cells tend to die as they move toward the surface from the deeper layers of the epidermis.
As humans age, the skin's elasticity declines and skin gets _______.
thinner
sebaceous glands
very active when androgens (male sex hormones) are produced in increased amounts (in both sexes) during adolescence. Thus, the skin tends to become oilier during this period of life.
vernix caseosa
white, cheesy-looking substance, produced by the sebaceous glands, protects the baby's skin while it is floating in its water-filled sac inside the mother.
dermis
your "hide." It is a strong, stretchy envelope that helps to bind the body together. When you purchase leather goods (bags, belts, shoes, and the like), you are buying the treated dermis of animals.