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306 Cards in this Set

  • Front
  • Back
What is the integumentary system composed of?
1. Skin
2. Hair
3. Nails
4. Sweat Glands
5. Oil (sebaceous) glands
6. Mammary Glands
What are the functions of the integumentary system?
1. Physical protection from environmental hazards
2. Thermoregulation
3. Synthesis and storage of lipid reserves
4. Excretion
5. Synthesis of vitamin D3
6. Sensory information
7. Coordination of immune response to pathogens and cancers in skin
What are the components and subcomponents of the integumentary system?
1. Cutaneous membrane
-Epidermis
-Dermis (Papillary layer and Reticular layer)
2. Accessory structures
- Hair follicles
- Exocrine Glands
- Nails
What are the functions of the Epidermis?
1. Protects dermis from trauma and chemicals
2. Controls skin permeability, prevents water loss
3. Prevents entry of pathogens
4. Synthesizes vitamin D3
5. Sensory receptors detect touch, pressure, pain and temperature
6. Coordinates immune response to pathogens and skin cancers
What are the functions of the dermis?
Papillary Layer
1. Nourishes and supports the epidermis

Reticular layer
1. Restricts spread of pathogens penetrating epidermis
2. Stores lipid reserves
3. Attaches skin to deeper tissues
4. Sensory receptors detect touch, pressure, pain, vibration, and temperature
5. Blood vessels assist in thermoregulation
What are the functions of the hair follicles?
1. Produce hairs that protect the skull
2. Produce hairs that provide delicate touch sensations on general body surface
What are the functions of the exocrine sweat and sebaceous glands of the skin?
1. Assist in thermoregulation
2. Excretes wastes
3. Lubricate epidermis
What is the function of nails?
Protect and support tips of fingers and toes
The skin mirrors the general health of other systems? (True/Flase)
True

Note: For example, the skin color changes from the presence of liver disease
Does the skin cover the eyes and tympanic membranes (eardrums) at the ends of the external auditory canals?
Yes.
At the nostrils, lips, anus, urethral opening and vaginal opening the integument turns inwards to meet what kind of membrane?
Mucous membranes

Note: at these sites the transition is seamless and the epithelial defenses remain intact and functional.
Which types of tissue are found in the integument? Where are they found?
All four types:
Epithelial tissue - epidermis
Connective tissue - dermis and subcutaneous layer
Smooth muscles - blood vessels and positioning hair
Neural tissue - nerves to control smooth muscles and monitor sensory receptors
What are the two major components of the skin?
1. The cutaneous membrane (skin)
2. Accessory structures (hair follicles, exocrine (sweat and sebaceous) glands and nails)
What are the two subcomponents of the skin (cutaneous membrane)?
1. Epidermis (superficial)
2. Dermis (underlying epidermis)
Is the subcutaneous layer usually considered part of the integument?
No.
What are other names for the subcutaneous layer?
Hypodermis or superficial fascia.
What is the function of the subcutaneous layer?
It separates the integument from the deep facia around other organs such as muscles and bones.
Where are the accessory structures of the integument located?
In the dermis. They protrude through the epidermis to the surface.
What type of epithelium makes up the epidermis?
Stratified squamous epithelium.
What are the four types of cells in the epidermis and what are their functions?
1. Keratinocytes (form layers of the epidermis)
2. Melanocytes (pigment producing)
3. Merkel cells (detecting sensation)
4. Langerhans cells (wandering phagocytic cells for immune response)

Note: The last three are scattered among keratinocytes.
What are the most abundant cells in the epidermis?
Keratinocytes.
Where is thick skin found?
On the palms of the hands and soles of the feet.

Note: Thin skin covers the rest of the body
1. How many layers does thick skin have?

2. How many layers does thin skin have?
1. Five

2. Four
What are the layers of the thick skin (from deep to superficial)?
1. Stratum basale (deepest)
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum (most superficial)
What is another name for stratum basale?
Stratum Germinativum
How many layers of cells are present in the stratum basale?
One layer
What cells are dominant in the stratum basale and what is their function?
Large stem cells (basal cells)

Function: Division of stem cells replace the more superficial keratinocytes that are lost or shed at the epithelial surface.
What cells are responsible for the brown tones of the skin?
Melanocytes
What pigment do the melanocytes produce and what is its color?
Melanin, a black, yellow-brown, or brown pigment.
What is the ratio of melanocytes to stem cells in the stratum basale and where are they most abundant?
The ratio ranges between 1:4 to 1:20.

Melanocytes are most abundant in the cheeks, forehead, nipples and the genital region.
Individual and racial differences in skin color result from different levels of melanocyte activity, not different numbers of melanocytes (True/False)
True.

Note: Even albino individuals have normal numbers of melanocytes.
What is Albinism?
Albinism is an inherited condition in which melanocytes are incapable of producing melanin; it affects approximately one person on 10,000.
1. Where are Merkel cells found?

2. Are any other kind of touch receptors found in the epidermis? Where are the rest located?
1. On skin surfaces that lack hair. They are specialized epithelial cells found among the deepest cells of the stratum basale.

2. No. The rest are located in the dermis.
What sensations do Merkel cells detect?
Touch and compression.

Note: Merkel cells release chemicals that stimulate nerve endings, providing information about objects touching the skin.
In which skin layer do daughter stem cells from stratum basale start to differentiate into keratinocytes?
Stratum spinosum.
Stratum spinosum is one layer thick (True/False)
False. It is several layers thick.
What are the contents of the keratinocytes in the stratum spinosum?
Tonofibrils (bundles of protein filaments) and macula adherens.

Tonofibrils extend from one side of the cell to the other and begin and end at macula adherens (desmosomes)
What is the function of the macula adherens of the keratinocytes?
Connect one keratinocyte to another. All of the keratinocytes in the stratum spinosum are tied together by a network of interlocked macula adherens and tonofibrils.
What is the function of tonofibrils?
Act as cross braces, strengthening and supporting the cell junctions.
Some of the cells entering the stratum spinosum from the stratum basale continue to divide, further increasing the thickness of the epithelium (True/False)
True
What cells make up the stratum basale?
1. Stem (basal) cells
2. Melanocytes
3. Merkel cells
What cells make up the stratum spinosum?
1. Keratinocytes
2. Melanocytes
3. Langerhans cells
What is another name for Langerhans cells?
Dendritic cells
Where are Langerhans cells most common in the stratum spinosum?
In the superficial portion of the stratum spinosum.
What is the function of the Langerhans cells?
Initiate immune response against:
1. pathogens that have penetrated the superficial layers of the epidermis
2. epidermal cancer cells
Which is the most superficial layer of the epidermis in which all of the cells still possess a nucleus?
Stratum granulosum (granular layer)
What are the two proteins produced by keratinocytes in the stratum granulosum?
1. Keratohyalin
2. Keratin
What is the function of keratohyalin proteins?
Keratohyalin accumutues in electron-dense granules called keratohyalin granules. These granules form and intracellular matrix that surrounds the keratin filaments.
Besides producing keratohyalin and keratin, what other substance do the cells of the stratum granulosum produce?
Cells of this layer also contain membrane-bound granules that release their contents by exocytosis, which forms sheets of lipid-rich substance that begins to coat the cells of the stratum granulosum.
What is the function of the lipid-rich substance produced by keratinocytes in the stratum granulosum?
1. form a complete water-resistant layer around the cells of the more superficial layers of the epidermis.
2. protect he epidermis
3. prevent the diffusion of nutrients and wastes into and out of the cells, thereby causing cells in the more superficial epidermal layers to die.
What influences the rate of synthesis of keratohyalin and keratin by keratinocytes in the stratum granulosum?
Environmental factors e.g. increased friction.
What is the local thickening of the skin due to increased friction called?
Callus (or calvus) e.f on palms of hands of weightlifters or the knuckles of boxers and karate students.
What protein forms the basic structural component of hairs and nails in humans?
Keratin

Note: In other vertebrates it forms the claws of digs and cats, horns of cattle and rhinos, feathers of birds, scales of snakes and baleen of whales.
What layer is present in the epidermis of thick skin but absent in epidermis of thin skin?
Stratum lucidum (clear layer)
What layer is called the 'glassy' layer in the epidermis?
Stratum lucidum (clear layer)
What are the characteristics of the cells stratum lucidum?
-Lack organelles and nuclei
-Flat and densely packed
-Filled with keratin filaments that are oriented parallel to the surface of the skin
What is the most superficial layer of the skin and how many layers of cells does it have?
Stratum corneum
It has 15-30 layers of cells in thick skin and only a few layers in thin skin.
What are the characteristics of cells in the stratum corneum?
-Flattened and dead
-Possess thickened plasmalemma
-dehydrated
-lack organelles and nucleus
-large amounts of keratin filaments
The interconnections in the cells of the skin established in the stratum spinosum remain intact in the stratum corneum (True/False)
True.

Note: This is why the cells of the stratum corneum shed in large groups or sheets rather than individually
What is the term used for an epithelium that contains large amounts of keratin?
Keratinized or cornified
Why is the stratum corneum unsuitable for the growth of many microorganisms?
Because it is relatively dry.

Note: Maintenance of this barrier involves coating the surface with the secretions of integumentary glands (sebaceous and sweat glands).
Which surface of the skin is not keratinized?
Anterior surfaces of the eye
The stratum corneum is waterproof (True/False)
False. It is water resistant.

Note: Therefore it allows water from the interstitial fluid to slowly penetrate the surface to be evaporated into surrounding air.
What is insensible perspiration?
Water from the interstitial fluid slowly penetrates the stratum corneum to be evaporated into surrounding air.

Note: Accounts for loss of roughly 500 ml or 1 pt of water per day
How many days does it take for a cell to move from the stratum basale to stratum corneum?
15-30 days
How long do dead cells remain in the exposed stratum corneum before they are shed or washed away?
2 weeks

NoteL Thus the deeper portions of the epithelium and all underlying tissues are always protected by a barrier of dead, durable and expendable cells?
What causes the cells in the stratum corneum to die?
A lipid-rich coating secreted by keratinocytes in the stratum granulosum that forms a complete water-resistant layer around the cells in the startum corneum and prevents diffusion of nutrients and wastes into and out of the cells, thereby causing the cells to die.
Excessive shedding of cells from the outer layer of skin in the scalp causes dandruff. What is the name of this layer if skin?
Stratum corneum
What is keratinization? What are the stages of this process?
Keratinization is the production of keratin by epidetmal cells. It occurs in the stratum granulosum of the epidermis. Keratin febers develop within cells of the stratum granulosum. As keratin fibers are produced, these cells become thinner and flatter, and their plasmalemmae become thicker and less permeable. As these cells die, they form the densely packed lyers of the stratum lucidum and stratum corneum.
In description of the skin, the terms thick and thin refer to the thickness of what?
The relative thickness of the epidermis and not to the integument as a whole.
What is the thickness of epidermis in thin skin?
0.08 mm
How much thicker is the epidermis of thick skin compared to thin skin?
As much as six times thicker.
What layer of the epidermis forms epidermal ridges?
Straum basale?
What is the purpose of the epidermal ridges?
Increasing are of contact between the epidermis and dermis.
What are projections from the dermis to the epidermis called?
Dermal papillae

Note: They extend between adjacent epidermal ridges.
The contours of the skin surface follow the epidermal ridge patterns (True/False)
True
What is the pattern of contours of the skin (due to epidermal ridges) on thick and thin skin?
Thin skin: small conical pegs
Thick skin: complex whorls
What is the function of the ridges on the palms and soles?
Increase surface are of the skin and increase friction, ensuring a secure grip.
Ridge shapes are genetically determined: Those of each person are unique and do not change in the course of a lifetime (True/False)
True
What influences the color of the epidermis?
Combination of:
1. Dermal blood supply
2. Thickness of the stratum corneum
3. Variable quantities of two pigments: carotene and melanin
When do red tones in the skin become more pronounced?
When blood vessels dilate, as during inflammation.
What controls the amount of melanin and carotene produced?
Genes
When circulatory supply is "temporarily" reduced what happens to the skin?
Become relatively pale.
What happens to the skin when there is a "sustained" reduction in circulatory supply?
The skin take on a bluish coloration called cyanosis due to superficial vessels losing oxygen and the hemoglobin changing color to a much darker red tone.
Where is cyanosis most apparent?
In areas of think skin such as lips or beneath the nails.
What can cause cyanosis?
Response to extreme cold or a result of circulatory or respiratory diroders, such a heart failure or severe asthma.
What is carotene? What is it's color? What is it's source?
Carotene is a orange-yello pigment found in various orange colored vegetables such as carrots, corns, and squashes.
What pigment can be converted to Vitamin A in the body?
Carotene
What is the function of vitamin A?
1. Epithelial maintenance
2. Synthesis of visual pigments by the photoreceptors of they eye.
1. Where does carotene accumulate in the skin?

2. Where is it most evident?
1. Keratinocytes

2. Stratum corneum and in the subcutaneous fat.
Melanin is produced and stored in?
Melanocytes (in intracellular vesicles called melanosomes)
Intact melanosomes are transferred from melanocytes to keratinocytes and color them till they are destroyed by lysosomes (True/False)
True
Why are superficial layers of the skin lighter?
Due to a decreased number of intact melanosomes.
Where does melanosome transfer to keratinocytes take place in
1. Light skinned individuals
2. Dark skin individuals
1. Stratum basale and stratum spinosum
2. Stratum basale, stratum spinosum and stratum granulosum
In dark skinned indivduals the melanosomes are larger (True/Flase)
True.
How does melanin prevent skin damage?
By absorbing ultraviolet (UV) radiation.
Why is a little ultraviolet radiation necessary for humans?
The skin require it to convert a cholesterol-related steroid precursor into a member of the family of hormones collectively known as vitamin D.
What is vitamin D required for in humans?
For normal calcium and phosphorus absorption by the small intestine.
What do inadequate supplies of vitamin D lead to?
Impaired bone maintenance and growth.
Too much UV radiation may damage chromosomes and cause widespread tissue damage similar to that caused by mild to moderate burns (True/False)
True
Where are melanosomes most abundant in cells? Why?
Around the cell nucleus. This increases the likelihood that the UV radiation will be absorbed before it can damage the nuclear DNA.
What protects the dermis from UV radiation?
Melanin in the epidermis.
What stimulus do melanocytes and respond to and what is the response?
To UV exposure by increasing their rates of melanin synthesis and transfer.
How long does it take for tanning to occur in response to UV exposure?
10 days.
Dark skin individuals do not get suburns (True/False)
False. They just have greater initial protection.
What kind of "long-term" damage can repeated UV exposure cause in
1. Dermis
2. Epidermis
1. Dermis: Premature wrinkling due to damage to fibrocytes which causes abnormal connective tissue structure.
2. Epidermis: Sin cancers from chormosomal damage in germinative cells or melanocytes.
Does sanding the tips of the finger permanently remove fingerprints?
No. Epidermal ridges are formed in layers of the skin that are constantly regenerating and they will eventually reappear. The actual pattern of the ridges is determine by the arrangement of the tissues in the dermis which in not affected by sanding
Describe primary difference between thick and thin skin.
Relative thickness of epidermis. Up to .5 mm for thick skin and 0.08 mm average for thin skin.
What are the two major components of the dermis?
1. Papillary layer (superficial)
2. Reticular layer (deep)
What does the papillary layer contain?
-Loose connective tissue
-Capillaries supplying epidermis
-Axons of sensory neurons (monitor receptors in epidermis and papillary layer)
What does the reticular layer consist of?
-Fibers + dense irregular connective tissue.
-blood vessels
-hair follicles
-nerves
-sweat glands
-sebaceous glands
The collagen fibers in the reticular layer extend into both the papillary layer and subcutaneous layer (True/False)
True
What are the two types of fibers in the reticular layer and what are their functions?
1. Collagen fibers - provides tensile strength

2. Elastic fibers - enables the dermis to stretch and recoil repeatedly during normal movement.
What effects the the thickness and flexibility of the dermis, producing wrinkles and sagging skin?
1. Age
2. Hormones
3. Ultraviolet radiation
What happens to skin during pregnancy or excessive weight gain?
Elastic and collagen fibers of the dermis break and the skin does not recoil to its original size after delivery or weight loss. The skin then wrinkles and creases creating a stretch marks.
What can be applied to the skin to increase blood flow to the dermis and stimulate dermal repairs? Also used to treat acne.
Tretinoin (Retin-A)

Note: Results in decrease if wrinkle formation and existing wrinkles become smaller.
What does the orientation of the collagen and elastic bundles in any one location depend on?
Stress placed on skin during normal movement; the bundles are aligned to resist the applied forces.

Note At any one location, the majority of the collagen and elastic fibers are arranged in parallel bundles.
What does the pattern of fiber bundles in the dermis establish on the skin?
Lines of cleavage.
Why are lines of cleavage clinically significant?
A cut parallel to a cleavage line will usually remain closed whereas a cut at right angles to a cleavage line will be pulled open as cut elastic fibers recoil.
Surgeons choose their incision patterns according to what?
Lines of cleavage.

Note: Incision parallel to the cleavage lines will heal fastest and with minimal scarring.
The dermis contains all of the cells of connective tissue proper (True/Flase)
True
Arteries and veins supplying the skin form an interconnected network in the subcutaneous layer along the border with the reticular layer. What is the network called?
Cutaneous plexus
The cutaneous plexus does NOT supply the adipose tissue of the subcutaneous layer (True/Flase)
Flase.
Name two structures in the dermis the branches of arteries from the cutaneous plexus supply as they travels towards the epidermis?
-Hair follicles
-Sweat glands
What network do the small arteries from the cutaneous plexus enter upon reaching the papillary layer?
Papillary plexus (or subpapillary plexus)
The capillary loops of the papillary plexus follow the contours of what boundary?
Dermal-epidermal boundary
The veins from the papillary plexus drain into what?
Cutaneous plexus
Why does the circulation to the skin need to be tightly regulated?
-Thermoregulation (control of body temperature)
-Increased blood flow to skin means decreased blood flow to other organs (since total blood volume is relatively constant in the body)
How does blood circulation in skin help in thermoregulation?
When body temperature increases, increase circulation to the skin permits the loss of excess heat.

When body temperature decreases, reduced circulation to the skin promote retention of body heat.
What systems interact to regulate blood flow to skin and other organs and system?
1. Nervous
2. Cardiovascular
3. Endocrine
What is the function of nerve fibers in the skin?
1. Control blood flow
2. Adjust gland secretion rates
3. Monitor sensory receptors in the dermis and deeper layers of the epidermis
What sensory nerve endings monitor Merkel cells?
Tactile discs.
Merkel cells are present in the dermis (True/False)
False. They are only present in the epidermis.
1. What other sensory receptors besides Merkel cells are present in the epidermis?

2. What stimulus do they respond to?
1. Dendrites of sensory nerves

2. Pain and temperature
What sensory receptors are present in the dermis, where are they located and what stimulus do they respond to?
1. Tactile corpuscles - dermal papillae - light touch
2. Root hair plexus - hair follicle - light touch
3. Ruffini corpuscle - reticular layer - stretch
4. Lamellated corpuscle - reticular layer - deep pressure and vibration
The boundaries between the dermis and the epidermis and the dermis and the subcutaneous layers are distinct (True/False)
False. They are not distinct the connective tissue fibers from dermis extending into the epidermis and subcutaneous layers.
What is the function of the subcutaneous layer?
1.Stabilize the position of the skin in relation to underlying tissues, such as skeletal muscles or other organs,

2. while still permitting independent movement.
What is the subcutaneous layer composed of?
-Loose connective tissue
-Adipocytes
What is the function of the subcutaneous fat?
-Energy reserve
-Shock absorber during rough-and-tumble activities
-Infants and small children have 'baby fat' which helps reduce heat loss
As we grow the distribution of subcutaneous fat changes (True/False)
True
Where do adult men and women accumulate fat in the subcutaneous layer?
Men: (1) Neck, (2) upper arms, (3) lower back and (4) buttocks

Women: (1) Breast, (2) buttocks, (3) hips and (4) thighs
What part of the body in adult men and women have few adipocytes?
Back of hands and the upper surfaces of the feet.
What leads to "pot belly"?
Large amounts of adipocyte tissue accumulating in the abdominal region.
Where are the large arteries and veins in the subcutaneous layer located?
In the superficial region of the subcutaneous layer. The remaining area on contain limited number of capillaries
There are many vital organs in the subcutaneous layers (True/False)
False
1. Why is the subcutaneous layer good for administering drugs via a subcutaneous injection?

2. What is the needle used for the injection called?
1. There are no vital organs in this layer.

2. Hypodermic needle
During embryonic development what forms the accessory structures of the integument?
Invagination or infolding of the epidermis.
What parts of the human body are hair absent on the skin?
1. Sides and soles of the feet
2. Palms of the hands
3. Sides of the finger and toes
4. Lips
5. Portions of the external genitalia
How may hair are present on the human body and where are 98% of them located?
5 million hair; 98% on the general body surface, not the head.
Hair are living structures (True/False)
False
What organs are hair formed in?
Hair follicles.
Hair follicles extend deep into the dermis, often projecting into the underling subcutaneous layer (True/False)
True.
What structure at the base of the hair contains capillaries and nerves?
Hair papilla (a peg of connective tissue)
The epithelial cells surrounding the hair papilla are called?
Hair bulb
Hair production involves what process?
A specialization of the keratinization process.
What epithelial layer in the hair follicle is involved in hair production?
Hair matrix

Note: When the superficial vasal cells divide, the produce daughter cells that are pushed towards the surface as part of the developing hair.
What are the three components of the hair?
-Medulla (inner)
-Cortex (outer)
-Cuticle (single layer of dead keratinized cells that coats the hair)
What kind of keratin makes up the medulla and cortex of hair?
-Medulla: soft keratin (soft and flexible)

-Cortex: hard keratin (gives hair its stiffness)
Where is the cuticle of hair located? What is it composed of?
Coats hair; composed of single layer of dead keratinized cells.
What are the two sections of the hair?
1. Hair root
2. Hair shaft
1. What does the hair root extend between?

2. What is its function?
1. From: hair bulb
To: the point where the internal organization of the hair is complete.

2. Attaches a hair to the hair follicle.
What does the hair shaft extend between?
From: where the internal organization of the hair is complete (usually halfway to skin)

To: exposed tip of hair.
What are the main structures of the hair follicle?
1. Hair papilla
2. Hair bulb
3. Hair matrix
4. Follicle walls (internal root sheath, external root sheath, glassy membrane, dense connective tissue sheath)
What are the three layers of the hair follicle walls?
1. Internal root sheath (starts at hair cuticle)
2. External root sheath
3. Glassy membrane (outer most layer)
4. Dense connective tissue sheath
The internal and external root sheath of the hair follicle extend from ____ to ____?
Internal: Hair matrix to where duct of sebaceous gland attaches to hair follicle

External: Hair matrix to skin surface
The hair follicle is surrounded by a dense connective tissue sheath (True/False)
True
What produces the internal root hair sheath?
Hair matrix
What kind of cells are found in the external root sheath of the hair follicle walls?
1. Cell layers found in superficial epidermis (most)
2. Cells of stratum basle near hair matrix
Roughly how many hair are present on the human head? What are their functions?
100,000

1. Protect scalp from UV light.
2. Cushion blow to head
3. Provide insulation to skull
What is the function of hair on the human body (excluding hair on head)
1. Nostrils and external auditory canal: prevent entry of foreign particles and insects
2. Eyelashes: prevent entry of foreign particles and insects into the eye
3. Sensing light touch
Movement of a single hair shaft can be felt at a conscious level e.g.a mosquito near the skin (True/False)
True
1. What sensory receptor detects movement of hair?

2. Where is it located?
1. Root hair plexus

2. Surrounds base of each hair follicle
What is the smooth muscles that elevates the hair called?
Arrector pili
When contracted what does the arrector pili do?
Pulls of the follicle and elevates the hair.
What does the arrector pili extend between?
From papillary dermis to connective tissue sheath surrounding hair.
What can lead to the contraction of the arrector pili?
1. Emotional states e.g.fear or rage
2. Response to cold (produces goose bumps)
What causes "goose bumps" in response to cold?
Contraction of arrector pilli muscles that elevate the hair.
When do hair first appear during embryonic development? What are they called?
After three months of embryonic development; these hair are called lanugo
Lanugo are pigmented (True/False)
False
What are the three major types of hair in adult humans?
1. Vellus hair
2. Intermediate hair
3. Terminal hair
Where are the three types of hair located?
1. Vellus: most of the body surface
2. Intermdiate: Hairs of upper and lower limbs
3. Head, eyebrows and eyelashes
What are the characteristics of the three types of hair?
1. Vellus: fine "peach fuzz" hairs
2. Intermediate: change in their distribution
3. Terminal: heavy, more deeply pigmented and sometimes curly
Which hair types do not have a distinct medulla?
Vellus and internediate hairs.
Hair follicles may alter the structure of hair in response to what?
Circulating hormones e.g. during puberty
A hair follicle that produces a vellus hair today ma produce and intermediate hair tomorrow (True/False)
True
Is melanin that determines hair color present in the hair cortex or medulla?
Cortex
What hair color results from a biochemically distinct form of melanin?
Red
What hair characteristic are genetically determined and what are influenced by hormonal or environmental factors?
Genetically: hair structure and color

Hormonal and environmental: condition of hair
White hair results from what?
Combination of:

1. Lack of pigment
2. Presence of air bubbles in medulla of shaft
You hair can turn white overnight (True/False)
False. The hair is dead and inert, changes in coloration are gradual.
Pigment production decreases with?
Age
What accounts of individual difference in uncut hair length?
Variation in
1. Hair growth rate

2. Duration of hair growth cycle
1. What is the average length of the hair growth cycle?

2. What is the average rate of hair growth?
1. 2-5 years

2. 0.33 mm/day (1/64 inch)
When hair growth is underway, the root of the hair is firmly attached to the
a. Hair matrix
b. Hair papilla
c. Hair bulb
a. Hair matrix
At the end of the growth cycle what is the hair called?
Club hair
When does the follicle become inactive and what happens to it when it becomes inactive?
The follicle becomes inactive at the end of the growth cycle. It gets smaller, and over time the connections between the hair matrix and the root of the club hair break down.
When another hair growth cycle begins, what happens?
1. Follicle produces new hair
2. Old club hair gets pushed towards surface
1. What is the rate of hair loss in health adults?

2. What is a rate of hair loss that is of concern and indicates something is wrong?
1. 50 hairs/day

2. Sustained loss of more than 100 hairs/day
What can cause temporary increase in hair loss?
1. Drugs
2. Dietary factors
3. Radiation
4. High fever
5. Stress
6. Hormonal factors related to pregnancy
Collecting hair samples can be helpful in diagnosing several disorders (True/False)
True
What conditions can be diagnosed with hair samples?
Lead or heavy metal poisoning
1. In males, changes in the level of sex hormones circulating in the blood can cause what changes in the hair?

2. What is this called?
1. Shift from terminal hair to vellus hair production.

2. Male pattern baldness
Describe the major features of the hair
Each hair has a medulla, produced by the central portion of the hair matrix, surrounded by a cortex and covered by a cuticle. The shaft of the hair begins where its internal organization is complete (roughly half way towards the surface.
The hair medulla and cortex are made of keratinized cells (True/False)
False. The are made of keratin protein. The cuticle that covers the hair is made of dead keratinized cells.
What are the two types of exocrine glands in the skin and what are their functions?
1. Sebaceous (oil) glands: produces oily lipid that coats hair shaft and epidermis

2. Sweat glands: produce a water solution and perform other special functions
Where to sebaceous glands discharge their secretion?
Hair follicles
How is the lipid product of the sebaceous gland cells secreted?
Holocrine secretion (destroys gland cell)
The ducts of sebaceous glands are short and several sebaceous glands may open into a single follicle (True/False)
True
What is the structure of sebaceous glands?
Simple alveolar and simple branched alveolar
What forces the secretions of the gland into the hair follicle and onto the skin?
Contraction of the arrector pili muscle (squeezes sebaceous gland)
What is the name of the waxy secretion of the sebaceous glands?
Sebum
What is the function of sebum?
1. Provide lubrication
2. Inhibit growth of bacteria
Why do keratinized cells need sebum?
Dead keratinized cells become dry and brittle once exposed to the environment. Sebum lubricates and protects the keratin of the hair shaft and conditions the surrounding skin.
Why is excessive shampooing bad for hair?
It removes the natural oil coating (sebum) making hairs stiff and brittle.
How are sebaceous follicles different from sebaceous glands?
Sebaceous follicles communicate directly with the epidermis. These follicle never produce hair.
Where are sebaceous follicles (not glands) found?
1. Face
2. Back
3. Chest
4. Nipples
5. Male sex organs
When bacteria invade sebaceous glands or follicles causing inflammation, what is this condition called?
Folliculitis

Note: This can happen despite sebum having antibacterial qualities
1. If the duct of a sebaceous gland or follicle becomes blocked, what happens?
2. What is this condition called?
3. What is the treatment?
1. A distinctive abcess (collection of pus) develops
2. The abcess is called furuncle or "boil"
3. Cut it open or "lance" it, so that normal drainage and healing can occur.
What is an abcess?
An abscess is a collection of pus in any part of the body that, in most cases, causes swelling and inflammation around it.
What are the two different types of oil glands in the skin?
1. Sebaceous glands
2. Sebaceous follicles
What are the two different types of sweat glands in the skin?
1. Apocrine (exocytosis) sweat glands
2. Merocrine (loss of cytoplasm + secretion) sweat glands
How is the secretion from sweat glands discharged onto the skin?
Myoepithelial cells (specialized epithelial cells between the gland cells and the underlying basal lamina) squeeze the gland and discharge the accumulated secretions
What controls the secretions of the sweat glands and contraction of myoepithelial cells?
1. Autonomic nervous system
2. Circulating hormones
Where are apocrine glands found?
1. Axillae (armpits)
2. Nipples
3. Groin
Apocrine sweat gland actually produce their secretion through merocrine secretion (True/False)
True
What are the characteristics of the apocrine sweat gland secretions?
-Viscous
-Cloudy
-Potentially odorous
Apocrine sweat glands are active throughout life (True/False)
False; they begin secreting at puberty
What results from action of bacteria on apocrine sweat gland secretions?
A noticeable odor
What are pheromones? What integument exocrine produce them?
Chemicals that communicate information to another individual at a subconscious level. Secreted by apocrine sweat glands.

Note: Apocrine secretions of mature women have been shown to alter the menstrual timing of other women.
What is the role of apocrine secretions and pheromones in human males?
In human males role of apocrine secretions and pheromones remains unknown.
1. Which type of sweat gland is far more numerous and widely distributed?

2. How many are in the adult integument?
1. Merocrine sweat gland

2. 3 million
What is another name for merocrine sweat glands?
Eccrine sweat glands
Are merocrine sweat gland larger or smaller than apocrine sweat glands?
Smaller
Merocrine sweat glands extend farther into the dermis than apocrine sweat glands.
False
What is the structure of apocrine and merocrine sweat glands?
Coiled tubular glands
Where are merocrine sweat glands most numerous?
Palms and soles; palm has about 500 glands per cm square or 3000 glands per inch square)
Which glands produces sweat?
Merocrine sweat glands
What is prespiration by merocrine sweat glands called?
Sensible prespiration
What is the composition of sweat?
1. Water (99%)
2. Electrolytes (mostly Sodium Chloride)
3. Metabolites
4. Waste products
What gives sweat a salty taste?
Sodium chloride
Excretions produced by the apocrine sweat glands are generally known as sweat (True/Flase)
False
What are the functions of the merocrine sweat glands?
1. Thermoregulation (primary function): cools surface of skin and reduces body temperature
2. Excretion: water, electrolytes, prescription and non-prescription drugs
3. Protection: dilute harmful chemicals and discourage growth of microorganisms
Which integument exocrine glands are regionally controlled and which are not?
Regionally controlled (amount of sweat and region involved): merocrine sweat glands (e.g. palms can sweat more than other areas of the body)

Not Regionally controlled: sebaceous and apocrine (so when one gland is activated so are the rest)
Which integument exocrine glands are found over most of the body and which are in relatively restricted areas?
Over most of the body: Sebaceous glands and merocrine sweat gland

Restricted areas: apocrine sweat glands
What are the special types of apocrine glands?
1. Ceruminous glands (found in external ear canal)
2. Mammary glands
What are the four phases of the hair growth cycle?
1. Active phase (2-5 years): hair grows
2. Regression: transition to resting phase
3. Resting phase: hair loses attachment to follicle and becomes club hair
4. Reactivation: club hair is lost and the hair matrix produces replacement hair
What controls the development and secretions of the mammary glands?
Sexual and pituitary hormones
Where are ceruminous glands located?
External auditory canal
How are ceruminous glands different from merocrine sweat glands?
1. Larger lumen
2. Gland cells contain pigment granules and lipid droplets
1. What is another name for earwax?

2. What is earwax composed of?
1. Cerumen

2. Mixture of secretions from Ceruminous glands and sebaceous glands
What is the function of earwax (cerumen)?
Along with tiny hair in the ear canal, earwax helps trap foreign particles ad small insects and keeps them from reaching the eardrum.
Deodorants target which sweat gland?
Apocrine swear glands
What is responsible for odor in apocrine sweat gland secretions?
1. Some organic compounds in the secretion are themselves odorous.
2. Other organic compounds in the secretion produce odor when acted on by bacteria.
Where do nails form?
Dorsal surfaces of the tips of fingers and toes
Nails limit distortion when the digits are subjected to mechanical stress e.g. in grasping object or running (True/False)
True
What are the components of a nail?
1. Nail root
2. Nail body
The nail body covers what?
The nail bed
The deepest portion of the nail root lies close to what structure?
Periosteum of the bone of the fingertips
The nail is recessed beneath the surface of the surrounding epithelium and is bound by?
1. Nail grooves (laterally)
2. Nail folds.
What is the portion of the stratum corneum of the nail fold that extends over the exposed nail near the root called?
Eponychium
The thickened stratum corneum the free edge of the nail extend over is called?
Hyponychium
What is the lunula?
Pale crescent near the root of the nail (due to blood vessels being obscured)
What gives mails their characteristic pink color?
Underlying blood vessels.
Changes in the shape, structure or appearance of the nails are clinically insignificant (True/False)
False

Note: A change may indicate a disease process affecting metabolism throughout the body.
What can cause yellow nails?
1. Chronic respiratory disorders
2. Thyroid gland disorders
3. AIDS
What can cause pitted and distorted nails?
Psoriasis
What can cause concave nails?
Some blood disorders
What are the four steps in the repair process for injuries the skin?
1. Bleeding + inflammatory response (mast cells)
2. Clotting + scab formation + cleaning removal
3. Meshwork of collagen fibers and ground substance produced by fibroblast activity appears
4. Formation of scar tissue + shedding of scab
Why can skin regenerate even after considerable injury?
Because stem cells persist in both epithelial and connective tissue components.
What are the stems cells of the epidermis and dermis called?
Epidermis: germinative cells
Dermis: mesenchymal cells
What can complicate a large skin injury?
1. Infection
2. Fluid loss
An incision (straight cut) heals faster than an abrasion (deep scrape) (True/False)
True
What forms a scab?
Blood clot consisting of fibrin, a fibrous protein formed from blood proteins during the clotting response.
What is responsible for the color of a clot?
Trapped red blood cells.
In injured skin what is the combination of blood clot, fibroblasts and an extensive capillary network called?
Granulation tissue.
How is repaired skin different from undamaged skin?
1. Abnormally large number of collagen fibers
2. Few blood vessels
Which of the following are repaired after severe skin injury?
a. Blood vessels
b. Hair follicles
c. Sebaceous and sweat glands
d. Muscle cells
e. Nerves
a. Blood vessels

The rest are not repaired if severely damaged.
What are the characteristics of scar tissue?
1. Inflexible
2. Fibrous
3. Noncellular
Surgical procedures on a fetus do not leave scars (True/False)
True
Scar tissue that forms beyond the requirements of tissue repair and is most often seen in dark skinned adults is called? What are its characteristics?
Keloid; it is thick, raise and covered by a shiny smooth epidermal surface.
Where do keloids most often form?
1. Upper back
2. Shoulders
3. Anterior chest
4. Earlobes
During tatoosing which part of the integument is injected with pigment?
The dermis
Removal of tattoos can leave scar tissue (True/False)
True
In what aspects does the integument respond directly to local influences with involvement of the nervous or autonomic systems?
1. Local mechanical stresses leads to a thickened epidermis (called callus)

2. Repair of injury to skin
How long does it take to repair a blister in a young individual vs a 65-75 year old?
Young individual: 3-4 weeks

65-75 yr old: 6-8 weeks
Summarize the changes to the integumentary system due to aging to the follow: epidermis, Langerhans cells, Vitamin D production, melanocytes and glands
1. Epidermis thins
2. Number of Langerhans cells decreases (50%)
3. Vitamin D production declines by 75%
4. Melanocyte activity declines
5. Glandular activity declines
Summarize the changes to the integumentary system due to aging to the follow: blood supply, hair follicles, dermis, secondary sexual characteristics and skin repair
1. Blood supply to dermis is reduced
2. Hair follicles stop functioning
3. Dermis becomes thinner
4. Secondary sexual characteristics in hair and body fat distribution begin to fade.
5. Skin repairs proceed relatively slowly.
Why are older people more prone to:
1. Skin injury and skin infection
2. Muscle weakness and reduction in bone strength
3. More likely to experience sunburn
4. Dry and scaly skin
1. Thinner epidermis and decrease in number of Langerhans cells
2. Decline in Vitamin D production
3. Decline in melanocyte activity
4. Decline in sebum production
Why are older people more prone to:
1. Overheating
2. Thinner, finer, gray/white hair
3. Sagging and wrinkling
4. Recurring infections
1. Less active merocrine glands leading to impaired perspiration and reduced blood supply to dermis
2. Hair follicles stop functioning and melanocyte activity decreases
3. Dermis become thinner (elastic fiber network decreases)
4. Skin repairs proceed slowly
Why do people age 90-100 of both sexes and all races look alike?
Secondary sexual characteristic in hair and body fat distribution begin to fade as the result of changes in levels of sex hormones.
What are lesions?
Changes in skin structure cause by trauma or disease process. A "skin sign" because they are measurable, visible abnormalities of the skin surface.
What is psoriasis? What are the signs?
-Stem cells in stratum basale are unusually active
-Hyperkeratosis in some areas like scalp, elbows, palms, soles, groin and nails
Signs: Affected areas have red bases covered in small, silvery scales that continuously flake off.
A skin stem cell in an individual divides in how many days?
1. Normally
2. In individual with psoraisis
1. 20 days
2. May divide every day and a half
Psoraisis is aggravated by stress and anxiety (True/False)
True
What is hyperkeratosis? What are the signs?
Excessive production of keratin

Signs: Calluses (palms or soles) and corns (thin skin on or between toes)
1. What is xerosis?

2. What is the most significant effect?
1. Dry skin. Scaly surface due to deteriorate plasmalemmae of the outer layer of skin making it more permeable.

2. Insensible perspiration may increase up to 75 times.
What causes acne?
Sebaceous gland ducts become blocked and secretions accumulate, causing inflammation and providing a fertile ground for bacterial infections.
What is another name for seborrheic dermatitis? What causes it?
Dandruff (adults) or cradle cap (infants)

Inflammation around abnormally active sebaceous gland accompanied by redness and epidermal scaling.
What are the three types of skin cancers? Which are more common? Which are more life threatening?
1. Basal cell carcinoma (most common)
2. Squamous cell carcinoma (common)
3. Malignant melanomas (life-threatening)
Basal cell carcinomas (origin, malignancy, location)
Origin: Stratus basale
Malignancy: malignant
Location: areas subject to chronic UV exposure (in 2/3rd of cases)
Squamous cell carcinomas are totally restricted to areas of sun-exposed skin (True/False)
True
Basak cell carcinomas are totally restricted to areas of sun-exposed skin (True/False)
False; about 1/3rd are in other areas of the skin
1. Does metastasis occur commonly in basal and squamous cell carcinomas?

2. In malignant melanomas?
1. No

2. Yes
1. What is the common treatment for basal and squamous cell carcinomas?

2. What is the 5-year survival rate?
1. Surgical removal of tumor

2. 95%
What cells grow rapidly in malignant melanomas?
Melanocytes

Note: Metastasize throughout the lymphoid systems
What is the 5-year survival rate for malignant melanomas if the condition is

1. Localized
2. Widespread
1. 90%

2. 10%