A & P Module 2: The Integumentary System
What layer(s) of the skin is (are) damaged in a second-degree burn?
The epidermis and the superficial regions of the dermis are damaged.
Robert, a surfer, has a mole that has changed its shape and size. His doctor, applying the ABCD(E) rule, diagnosed a melanoma. What do the letters ABCD(E) represent?
A = asymmetry, B = border, C = color, D = diameter, E = elevation
A sunburn is generally classified as being ___________.
A first-degree burn
Hypodermis
A layer of mostly adipose tissue lies below the dermis (Also called the subcutaneous layer)
What type of mole or pigmented spot on the skin would be the most concerning?
A spot with varying colors and irregular borders
Dendritic (langerhans) cells
Activation of the immune system
Which of the following conditions would NOT be seen from overexposure to UV light?
Activation of the immune system
Albinos commonly contract skin cancer. What seems to be the reason, and what can be done to reduce the risk of skin cancer?
Albinos lack melanin and have thus lost their main defense against the damaging UV light that can cause skin cancer. They can cover all body areas and avoid bright sunlight.
What is the first threat to life from a massive third-degree burn?
Catastrophic fluid loss
Match the following gland with their secretions: Ceruminous glands
Cerumen
Sudoriferous glands vary in distribution over the surface of the body. Which of the following is correct?
Ceruminous glands secrete cerumen, which is thought to deter insects.
Chemotherapy
Chemotherapy targets all rapidly dividing cells: healthy cells as well as cancer cells. Hair follicle cells are some of the fastest-growing cells in the body. Hair follicle cells divide every 23 to 72 hours. Chemo destroys hair follicle cells resulting in hair loss
Types of Hair: Terminal
Coarse, long hair of eyebrows, scalp, axillary, and pubic regions and face of males
Nails
Comprised of dead keratinized epithelium Correspond to hooves or claws of other animals
Apocrine Sweat Glands
Confined to axillary and anogenital areas •Sweat contains fatty substances and proteins •Responsible for body odor, not the sweat itself but bacteria metabolizing it • This sweat follows the hair follicle to the surface of the skin •Become functional at puberty
The dermis is composed of what type of tissue?
Connective
Skin (Integument)
Consists of two major regions: Epidermis (superficial region) & Dermis (middle region)
Dogs track humans by the scent of epithelial cells that are constantly being shed. These cells shed from which stratum?
Corneum
A needle would pierce the epidermal layers of the forearm in which order?
Corneum, granulosum, spinosum, basale
Lanugo Coat
Covering of delicate hairs in 5th and 6th month
Nails: Grow from the matrix
Cuticle is called the eponichyum: manicures and pedicures cleanup Free edge is what you cut Nail bed is under the body
Burns: Immediate threat of extensive burns
Dehydration, electrolyte imbalance and infection
The reticular layer of the dermis is composed of which tissue type?
Dense irregular connective tissue *The deeper reticular layer, which accounts for about 80% of the thickness of the dermis, is composed of dense irregular connective tissue.
The papillary layer of the dermis is connective tissue heavily invested with blood vessels. The superficial surface has structures called:
Dermal papillae
Striae in the skin are caused by __________.
Dermal tears
Nutrients reach the surface of the skin (epidermis) through the process of __________.
Diffusing through the tissue fluid from the blood vessels of the dermis.
The sweat glands that are important in body temperature regulation are the _________ glands.
Eccrine
Which of the following glands moves its secretion to the surface of the skin through a duct?
Eccrine
Which skin appendages aid in cooling the skin when the body temperature or the external environmental temperature is high?
Eccrine Sweat Glands
The epidermis develops from which embryonic germ layer?
Ectoderm
Partial-Thickness Burns: Second Degree
Epidermal and upper dermal damage •Blisters appear
Partial-Thickness Burns: First Degree
Epidermal damage only •Localized redness, edema (swelling), and pain
Which of the following structures are primarily responsible for fingerprints?
Epidermal ridges and sweat pores
An injection is administered through the skin using a hypodermic needle. Identify the first integumentary structure through which the needle will pass.
Epidermis
Hair and nails are modifications of the _________.
Epidermis
Which layer of the skin has no blood vessels?
Epidermis
Cuticle
Eponichyum
Hirsutism is a condition that is characterized by _____________.
Excessive hairiness
Hair Follicle: Hair Bulb
Expanded deep end
Hair Follicle
Extends from the epidermal surface into dermis
T/F Destruction of the matrix of the hair bulb would result in its inability to produce oil.
False
T/F For humans, food is the only source of vitamin D.
False
T/F Hair and nails are made primarily of calcium.
False
T/F Keratin protects the skin from the damaging effects of ultraviolet (UV) radiation
False
T/F The hypodermis is composed of adipose and dense connective tissue.
False
T/F The protein found in large amounts in the outermost layer of the epidermal cells is collagen.
False
T/F The skin is not able to receive stimuli because the cells of the epidermis are not living and therefore there are no sensory receptors in the skin.
False
T/F When an individual is exposed to extremely low air temperatures, the dermal blood vessels will dilate so that blood and heat will be dissipated.
False
T/F Follicles that give rise to eyebrows remain active longer than follicles of the scalp.
False *The follicles of the scalp remain active for up to 10 years while those of the eyebrows are only active for up to 4 months. Because of this difference in follicle activity, the hair on your head can grow longer than the hair of your eyelashes/eyebrows.
T/F The reason that the nail bed appears pink is the presence of a large number of melanocytes in the underlying dermis.
False (Due to capillaries in underlying dermis)
Joe just burned himself on a hot pot. A blister forms and the burn is painful. Joe's burn would best be described as a third-degree burn.
False (Second-degree burn)
Sebaceous glands belong to which of the following classes?
Simple branched alveolar
Hypodermis
Skin anchoring
What of the following statements is FALSE?
Skin does not have a role in regulating body temperature. *Skin acts as a chemical, physical and biological barrier. Denfensins, cathelicidins, sebum, salt, and an acidic pH limit bacterial growth on the skin. Also, skin acts as a means to regulate body temperature.
What type of skin cancer affects cells in the stratum spinosum?
Squamous cell carcinoma
Which of the following thick skin strata is the thickest?
Stratum Corneum
In thick skin, you would expect the ______ to be more prominent than it is in thin skin.
Stratum Lucidum
Which of the following strata is NOT visible as a distinct layer in the thin skin?
Stratum Lucidum
Which of the following layers of the skin is avascular and relies on capillaries in the underlying connective tissues to provide nutrients?
Stratum basale
Which of the following lists the correct order of the layers of the epidermis in thick skin from deep to superficial?
Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
Sweat is secreted by:
Sudoriferous glands.
Match the following gland with their secretions: Sudoriferous glands
Sweat
Sudoriferous glands are also known as ________ glands.
Sweat
Which of the following is a metabolic function of skin?
Synthesis of a vitamin D precursor
Despite its apparent durability, the dermis is subject to tearing. How might a person know that the dermis has been stretched and/or torn?
The appearance of visible, silvery-white scars is an indication of stretching of the dermis
Why might soap that has an alkaline base not be healthy for some patients to use daily?
The base will neutralize the acid on the skin that retards the growth of bacteria, and the removal of the normal microbiota of skin will leave the person exposed to opportunistic pathogens.
Sweat Glands
Two main types of sweat (sudoriferous) glands: Located in the dermis - Eccrine (merocrine) sweat glands and Apocrine sweat glands
What protects the fetus's skin within the water-filled amniotic sac?
Vernex caseosa
All of the following are functions of the skin except:
Vitamin A production (Does provide protection, is a blood reservoir and provides excretion)
Which vitamin is produced in the dermis?
Vitamin D
Skin Color: Hemoglobin (Red pigment in blood)
•Responsible for the pinkish hue of skin (in light skinned individuals)
Hair Follicle Receptor
•Sensory nerve endings around each hair bulb •Stimulated by bending a hair
Basal Cell Carcinoma
•Stratum basale cells proliferate and slowly invade dermis and hypodermis •Cured by surgical excision in 99% of cases •Most common skin cancer, least dangerous
Dermis
•Strong, flexible connective tissue •Cells include fibroblasts, macrophages, mast cells and dendrocytes
Other Structures of the Skin:
•Sweat glands •Oil glands •Hairs and hair follicles •Nails
Skin Markings: Friction Ridges
•These ridges in the epidermis form your unique fingerprints. •The pattern comes from the deeper dermal papillary ridges.
Reticular Layer: Deeper Dermis
•Thicker, tougher, deeper layer •Comprised of dense irregular connective tissue •Collagen fibers provide strength and resiliency •Elastic fibers provide stretch-recoil properties •This layer of skin is your hide.
Rule of Nines
•Used to determine the severity of the burn. •Helps estimate the volume of fluid loss from burns •Body is divided into 11 areas, each accounting for 9% of the total body area
We are told that every surface we touch is teeming with bacterial cells, and bacteria are found in the pools we swim in, the water we wash with, and on the hands of friends. Why are we not inundated with bacterial infections on our skin?
* Not all bacteria are harmful or thrive on the skin. *Many bacteria are killed by bactericidal substances in the sebum and sweat. *The low pH of the skin secretions retards the multiplication of bacteria on the skin.
Full-Thickness Burns: Third degree
*Entire thickness of skin damaged *Gray-white, cherry red, or black *No initial edema or pain (nerve endings destroyed) *Skin grafting usually necessary
Hair Growth
*Growth phase (weeks to years) followed by regressive stage and resting phase (1-3 months) *Growth phase varies (6-10 years in scalp, 3-4 months in eyebrows)
Arrector pili (Goosebumps)
*Smooth muscle attached to follicle *When it contracts hair stands on end *Responsible for "goose bumps" *Caused by cold or emotions
Your skin is a protective barrier. It...
1. It protects all underlying structures from mechanical damage 2. It prevents the invasion of microorganisms 3. It produces chemicals which suppress bacteria (acid mantle) 4. It contains cells which can attack microorganisms 5. It prevents water loss from the body 6. It protects the body from UV damage 7. It produces Vitamin D (important for calcium metabolism) 8. Involved body temperature regulation 9. Sensory receptors in skin detect environmental stimuli (touch, temp. pressure) 10. Some wastes are excreted through the skin. (ammonia, urea, uric acid)
Three major types of skin cancer
1.) Basal cell carcinoma *Least malignant, most common 2.) Squamous cell carcinoma *Second most common 3.) Melanoma *Most dangerous
The composition of the secretions of the eccrine glands is ________.
99% water, sodium chloride, trace amounts of wastes, and vitamin C
These glands produce a secretion that bacteria metabolize resulting in body odor.
Apocrine
Which integumentary gland is believed to function as a sexual scent gland?
Apocrine sudoriferous gland
Cells of epidermis: Dendritic cells
Are macrophages that remove debris and activate immune system
The smooth muscle associated with a hair follicle is called ________.
Arrector pili
Sam is so cold that he has "goose bumps." What causes goose bumps?
Arrector pili muscles pulling hair follicles into an upright position
The most common type of skin cancer is:
Basal cell carcinoma
Mitosis occurs primarily in which stratum of the epidermis?
Basale
Which layer of the epidermis is closest to a blood supply with oxygen and nutrients?
Basale
Apocrine sweat glands _________.
Begin functioning at puberty.
A hematoma in the skin appears as ___________.
Black and blue marks
Terminal hair is located in all the following areas EXCEPT the ___________.
Body hair of females
Burns are devastating and debilitating because of loss of fluids and electrolytes from the body. How do physicians estimate the extent of burn damage associated with such dangerous fluid loss?
By using the "rule of nines"
Which of the following are NOT considered critical burns?
First-degree burns on 30% of the body
If dermal papillae were missing, then _________.
Friction ridges would be absent.
Hair Thinning and Baldness: Alopecia
Hair Thinning in both sexes after age 40
If an individual were unable to produce sebum, what problem would he or she most likely develop?
He or she would have brittle, more easily broken hair.
Adipose tissue is concentrated in which of the following layers?
Hypodermis
When people gain weight, they often also grow inches due to an accumulation of fat in which layer?
Hypodermis
Which layer is not actually part of the skin?
Hypodermis
Which of the following is NOT strictly a component of the integumentary system?
Hypodermis
The region deep to the skin is the _________.
Hypodermis *From deep to superficial, the main regions of the skin are the dermis and epidermis. Deep to the skin is the hypodermis.
Apocrine glands, which begin to function at puberty under hormonal influence, seem to play little role in thermoregulation. Where would we find these glands in the human body?
In the axillary and anogenital area
One main difference between thin skin and thick skin is that __________.
In thin skin, the stratum lucidum appears to be absent.
In addition to protection (physical and chemical barrier), the skin serves other functions. Which of the following is another vital function of the skin?
It converts modified epidermal cholesterol to a vitamin D precursor important to calcium metabolism.
Melanoma is particularly dangerous because ____________.
It grows rapidly and metastasizes
The protein found in our hair and nails is called ________.
Keratin
What waterproofing protein is found in the epidermis?
Keratin
Which of the following is not associated with the dermis?
Keratin
All of the following contribute to skin color except:
Keratin (Hemoglobin, carotene, and melanin do contribute to skin color)
The epidermis is composed of which of the following tissues?
Keratinized stratified squamous epithelial tissue
Epidermis
Keratinized stratified squamous epithelium Epidermis is avascular and must obtain nutrients and O2 from superficial dermis. Cells in the deepest layer are metabolically active because they are closest to a blood supply. Cells in superficial layers are dead.
Which of the following cells would NOT be present in the dermis?
Keratinocytes
Which of the following epidermal components possess(es) a waterproofing glycolipid that functions in preventing water loss?
Lamellar granules
Which of the following cells is part of the immune system?
Langerhans cell
Fetal hair is:
Lanugo
Fetal Skin
Lanugo coat & Vernix caseosa
Cells of epidermis: Tactile (Merkel) cells
Light touch receptors
Dependent on thickness of epidermis: Thick Skin
Located in palms, fingertips and soles, is hairless
Cells of epidermis: Melanocytes
Located in the deeper epidermis Produce the pigment melanin
Eccrine (merocrine) Sweat Glands
Located throughout the body: abundant on palms, soles, and forehead •Located throughout the body: abundant on palms, soles, and forehead •Ducts connect to pores on the surface of skin •Function in thermoregulation •Sweat: 99% water: Contains NaCl, antibodies, dermicidin, metabolic wastes and is normally acidic
Which stratum of the epidermis is found only in thick skin?
Lucidum
Male pattern baldness has a genetic switch that turns on in response to ________.
Male hormones
Hair Thinning and Baldness: Androgenic Alopecia
Male pattern baldness is caused by hair follicles response to androgens (testosterone) and genetics
Hair grows from the _________.
Matrix
Which of the following cutaneous receptors is specialized for the reception of touch or light pressure?
Meissner's corpuscles
What is the only pigment synthesized in the skin?
Melanin
Which skin pigment is made in the skin itself?
Melanin
Which of the following cells function as sensory receptors for touch?
Merkel cells
Match the following gland with their secretions: Mammary glands
Milk
Dependent on thickness of epidermis: Thin Skin
Most of the skin of the body, contains hair
Hair Follicle: Two-layered wall
Outer connective tissue root sheath, inner epithelial root sheath
Types of Hair: Vellus
Pale, fine body hair of children and adult females
Sebaceous glands are located in all of the following areas EXCEPT the ___________.
Palms and Soles
Peglike folds of the superficial layer of the dermis are called dermal:
Papillae
Which layer of the dermis is closest to the epidermis?
Papillary
What layer of the dermis is directly below the epidermis?
Papillary Layer
Which of the following is not a layer of the epidermis?
Papillary Layer
There are two layers of the dermis
Papillary Layer: Superficial dermis & Reticular Layer: Deeper Dermis
This layer of our skin is responsible for fingerprints.
Papillary layer
Cells of epidermis: Keratinocytes
Predominant cells of the epidermis •Produce the protein keratin
Keratinocytes in the stratum spinosum are known as ___________.
Prickle cells
The role of ceruminous glands is to __________.
Produce earwax.
Keratinocytes
Production of fibrous protein for skin protection
Melanin
Protection from ultraviolet (UV) radiation
Nails: Function
Protects ends of fingers Helps to manipulate small objects Scratching
Which of the following is NOT a function of the skin?
Respiratory gas exchange
Skin eruption produced by dilated small blood vessels of the face, especially on the nose and cheeks, is descriptive of which skin disorder?
Rosacea
These glands in the skin are associated with acne.
Sebaceous
Vernix Caseosa
Sebaceous gland secretion; protects skin of fetus
Match the following gland with their secretions: Sebaceous glands
Sebum
Susan sat out in the sun watching a baseball game. She developed small blisters on her unprotected shoulders and neck. What type of burn is represented by the formation of the blisters?
Second-Degree Burn
Tactile (Merkel) Cells
Sensory detection
What is the role of the hair matrix?
The hair matrix produces hair.
John, a younger teenager, notices that he is experiencing a lot of pimples and blackheads, which frequently become infected. What is causing this problem?
The hormonal changes are causing the sebaceous glands to become overactive, resulting in them becoming clogged and infected.
What part of the dermis gives rise to friction ridges (fingerprints)?
The papillary layer
The dermis has two major layers; which of the following constitutes 80% of the dermis and is responsible for the tension lines in the skin?
The reticular layer
Which of the following statements is NOT true of apocrine sweat glands and sebaceous glands?
They are both widely distributed over most of the body
The design of a person's epidermal ridges is determined by the manner in which the papillae rest upon the dermal ridges to produce the specific pattern known as handprints, footprints, and fingerprints. Which of the following statements is true regarding these prints or ridges?
They are genetically determined, therefore unique to each person.
What is the primary function of melanin?
To provide protection against the sun's UV rays
T/F A physician is often able to detect homeostatic imbalances in the body by observing changes in the skin color.
True
T/F Keratin is found in hair and nails.
True
T/F Our skin helps us to regulate our body temperature.
True
T/F Regardless of race, all human beings have about the same number of melanocytes.
True
T/F The biggest risk factor for the development of skin cancer is excessive exposure to ultraviolet light.
True
T/F The dense fibrous connective tissue portion of the skin is located in the reticular region of the dermis.
True
T/F The dermis is rich in blood vessels and nerve fibers.
True
T/F The epidermis uses a modified form of cholesterol to produce a vitamin D precursor.
True
T/F The most dangerous skin cancer is cancer of the melanocytes.
True
T/F The pinkish hue of individuals with fair skin is the result of the crimson color of oxygenated hemoglobin (contained in red blood cells) circulating in the dermal capillaries and reflecting through the epidermis.
True
Sebaceous (Oil) Glands
• Widely distributed •Glands associated with hair follicles •Sebum follows hair follicle to surface of skin •Become active at puberty •Sebum •Oily secretion •Bactericidal •Softens hair and skin, prevents drying •Acne: excessive sebum production, blocked follicles, followed by infection and inflammation
Layers of the epidermis: Stratum Corneum
•20-30 rows of dead, flat, keratinized cells •Thickest layer of the epidermis •Stratum corneum provides: •Protection from abrasion and penetration •Waterproofing •A barrier against biological, chemical, and physical assaults •Outer layer gets sloughed off (dandruff and dander)
Burns
•Caused by heat, electricity, radiation, certain chemicals, tissue damage, and cell death
Layers of the epidermis: Stratum Spinosum (Spiny layer)
•Cells contain protein filaments which attach to desmosomes giving cells a spiny appearance •This layer contains abundant melanin granules and dendritic cells
Layers of the epidermis: Stratum Granulosum (Granular layer)
•Cells flatten and organelles disintegrate •Keratinization occurs; cells fill up with the protein keratin •Waterproofing lipids are secreted into the extracellular space
Melanoma: Characteristics
•Characteristics (ABCD rule) A: Asymmetry; The halves of the lesion don't match B: Borders are irregular C: Color is variable: black, brown, tan D: Diameter is larger than 6 mm (size of a pencil eraser)
Layers of the epidermis: Stratum Lucidum (Clear Layer)
•Clear layer in thick skin only •Provides more protection •A few rows of flat, dead keratinocytes
Papillary Layer: Superficial Dermis
•Comprised of areolar connective tissue with collagen, elastic fibers and blood vessels •Dermal papillae project into epidermis and contain: •Capillary loops •Light touch receptors: (Meissner's corpuscles) •Free nerve endings
Hair: Keratin
•Consists of dead keratinized cells •Contains a harder keratin than the keratin of skin
Skin Markings: Cleavage Lines
•Correspond to the orientation of collagen fibers in the dermis •Incisions made parallel to cleavage lines heal more readily
Layers of the epidermis: Stratum Basale (Base layer)
•Deepest layer of the epidermis is firmly attached to the dermis •Single row of stem cells •Also called stratum germinativum: cells undergo rapid division •One daughter cell stays and one travels to the surface •Journey to the surface takes 25-45 days
Hair: Distribution
•Distribution •Entire surface except palms, soles, lips, nipples, and portions of external genitalia
Aging Skin
•Effects of cumulative environmental assaults show after age 30 •Dermatitis becomes more common •Epidermal replacement slows, skin becomes thin, dry, and itchy •Subcutaneous fat and elasticity decrease, leading to cold intolerance and wrinkles •Increased risk of cancer due to decreased numbers of melanocytes and dendritic cells
Skin Markings: Flexure Lines
•Form as a result of continual folding of the skin •Visible on hands, wrists, fingers, soles, toes
Hair: Functions
•Functions •Protects the scalp from physical trauma, heat loss, and sunlight •Alerting the body to presence of insects on the skin
Hair: Matrix
•Hair grows from the matrix in the bulb •Matrix is supplied with nutrients from capillaries in the hair papilla
Squamous Cell Carcinoma
•Involves keratinocytes of stratum spinosum •Most common on scalp, ears, lower lip, and hands •Good prognosis if treated by radiation therapy or removed surgically
Melanoma
•Involves melanocytes •Highly metastatic and resistant to chemotherapy •Treated by wide surgical excision accompanied by immunotherapy •Characteristics (ABCD rule)
Skin Color: Melanin
•Main pigment that determines skin color •This dark pigment also determines hair and eye color •Produced by melanocytes in the epidermis •Migrates to keratinocytes where it shields nuclei from UV radiation •Freckles and moles •Local accumulations of melanin •Lack of melanin, albinism and vitiligo
Hair Pigments
•Melanins, yellow, brown, black •Red hair is colored by iron containing pigments •Gray/white hair: decreased melanin production, increased air bubbles in shaft
Skin Cancer
•Most skin tumors are benign (do not metastasize) •Risk factors *Overexposure to UV radiation *Frequent irritation of the skin
Skin Color: Carotene
•Orange pigment in fruits and vegetables •Deposits in fat tissue, most obvious in palms and soles