What is the name of the keratinized part of the hair?
D) Hair shaft
Which of the following glands can only be found in hairy skin and are usually associated with hair follicles?
B) Sebaceous glands
Which vascular plexus supplies the papillary layer of the dermis?
C) Dermal vascular plexus
Which of the following structures is always associated with the arrector pili msucl and a sebaceous gland?
A) Hair follicle
A 30-year old unidentified burn victim of an arson still has fingerprints intact. Which of the following layers of the skin is responsible for the fingerprints?
B) Papillary layer of dermis
Which epidermal layer lies above the stratum lucidum?
A) Stratum corneum
Which of the following structures can be found throughout the body's surface, prevent if from overheating, and secrete scent?
D) Sweat gland
The epidermis can be divided into four to five different layers. Which of the following epidermal layers consists of cells without nuclei or any other cell organelles.
A) Stratum corneum
Which structure is located in the dermal papillae and enables perception of light touch?
D) Tactile corpuscle
A 16-year old boy comes to the dermatologist due to persistent pustules on his face and upper back area. Which structure of the skin is involved in the pathogenesis of acne?
A) Sebaceous gland
Which epidermal layer contains keratinocyte stem cells attached to the basal membrane?
D) Stratum germinativum
Stratum germinativum is also known as stratum basale.
A 20-year old woman comes to the doctor with well-demarcated, scaly, erythematous plaques on her face, scalp, and elbows. She has a family history of psoriasis and physical examination confirms diagnosis of psoriasis vulgaris. Which part of the skin is affected by it?
C) Epidermis
Which layer of the skin has non-nucleated cells?
A) Stratum corneum of epidermis
The stratum reticulare of the dermis lies between which structures?
C) Papillary layer of dermis and subcutaneous tissue
Which layer of the skin lies directly above the basement membrane?
C) Stratum germinativum
Stratum germinativum is also known as stratum basale.
Which layer of the skin is regularly shed?
A) Stratum corneum
What is the name of the inversions of the epidermis, that bulge down into the dermis or subcutaneous tissue and give rise to hair?
A) Hair follicles
In which layer of the skin are the lamellar corpuscles located?
D) Subcutaneous tissue
Lamellar corpuscles, also known as Pacinian corpuscles, are responsible for the perception of vibrations.
Which vascular plexus runs along the boundary of the dermis and the subcutaneous tissue?
D) Subdermal vessel plexus
What is the name of the connective tissue layer that lies between muscles and subcutaneous fat?
A) Fascia
The epidermis contains all of the following structures, except:
C) Meissner corpuscles
It should be Merkel's discs.
Secretion of which of the following glands is stimulated by the sympathetic nervous system?
B) Sweat gland
The pigment containing cells are found in which layer of the skin?
B) Stratum basale
Stratum basale is also known as stratum germinativum.
Which of the following structures comprise the sweat gland?
C) Secretory portion and excretory duct
Which type of epithelium lines the lumen of the excretory duct in the sweat gland?
B) Stratified cuboidal epithelium
Which type of glands is widely distributed in the skin and has mainly thermoregulatory function?
A) Eccrine sweat glands
All of the following cells can be found in the secretory part of the eccrine sweat gland, except:
D) Ciliated cells
Which cells in the eccrine sweat glands are characterized by an abundance of glycogen in their cytoplasm?
C) Clear cells
Which cells of the eccrine sweat glands have a glassy appearance which is attributable to the presence of large numbers of aggregated tonofilaments in the apical cytoplasm?
B) Luminal cell layer of duct
The apocrine glands of the eyelid are called:
C) Glands of Moll
Which of the following glands is not regulated by sex hormones in terms of development and function?
D) Eccrine sweat glands
Which of the following cells in the eccrine sweat glands are characterized by an abundance of granular endoplasmic reticulum, a small number of mitochondria, a relatively large Golgi apparatus and numerous secretory granules containing glycoproteins?
A) Dark cells
Which layers comprise epithelium of the excretory duct found in the sweat gland?
A) Luminal and basal cell layers
Which cells are mainly in charge of moving secretions out of the secretory portion of the sweat gland?
A) Myoepithelial cells
Which portion of the sweat gland contains cells that form small grape-like structures called acini?
C) Secretory portion
Which types of cells can be found in the secretory portion of the apocrine sweat gland?
B) Secretory and myoepithelial cells
Which type of fibers surround the baroreceptors?
B) Elastic fibers
A man is brought to the hospital by an ambulance after surviving a wildfire. He has severe second-degree burns. Which of the following tactile receptors is usually untouched with this type of burn?
A) Lamellar corpuscle
Lamellar corpuscle is also known as Pacinian corpuscle.
A 10-year old boy lost his sight due to trachoma, a severe infection caused by Chlamydia trachomitis. He is trying to learn to read the Braille alphabet with his fingers. Acute sensitivity to textural changes of which receptors in the skin is the neural basis for reading with fingers?
C) Tactile corpuscles
Which of the following mechanoreceptors are the deepest and the largest ones, and are very sensitive to vibration but not to constant pressure?
A) Pacinian corpuscle
Pacinian corpuscle is also known as lamellar corpuscle.
The Merkel cells are involved in detecting a very precise light touch, and they are hard to find on an H&E stain. Which structures they usually get mismatched with, due to their similar appearance under the microscope?
C) Langerhans cells and melanocytes
Which type of fibers surround the proprioceptors?
B) Collagen fibers
To which of the following cell type do the mechanoreceptors belong?
D) Neurons
On the borders of which skin layers is the Ruffini corpuscle located?
D) Dermis and subcutaneous tissue
What specialized receptors in the inner ear provide the sense of hearing and balance?
C) Stereocilia
Which of the following nerve structures are not encapsulated?
C) Peripheral ganglion
Which of the following receptors is especially sensitive to cold temperature?
A) Bulbous corpuscle
Which of the following mechanoreceptors is found in the dermal papillae and are rapidly adapting to light touch?
C) Tactile corpuscle
What structure surrounds the hair follicle and is sensitive to movements of hair?
D) Hair root plexus
Which of the following receptors respond mostly to continuous pressure?
A) Ruffini corpuscle
Which of the following structures represent the roof tile-like, outer protective layer of the hair?
A) Hair cuticle
Which cells produce the pigment of the hair?
B) Melanocytes
A 10-year old boy turns to his mother complaining about feeling cold for the last couple of hours. The mother takes off his t-shirt and notices that his skin looks pale and the he is shivering. She also notices goose bumps all over his arms and legs. She suspects a fever. Which structure is pulling the hair up, creating an air pocket around the skin to protect the body from cold?
A) Arrector muscle of hair
Which of the following structures secretes an oily and waxy substance that coats the hair shaft?
D) Sebaceous glands
Which of the following structures represents the birthplace of the hair fiber?
C) Hair matrix
Which structure connects the sebaceous gland and the hair follicle?
B) Pilosebaceous canal
A 27-year old man presents to the dermatologist with complaints of asymptomatic loss of hair at multiple sites over the scalp for two months. On examination, the doctor notices a multiple well-defined annular patches of non-scarring alopecia present mainly at the parietal region of the scalp. He suspects that the patient has alopecia areata, and takes a biopsy specimen. Around which structure are the immune cells typically gathered around in alopecia areata?
D) Derma papilla of hair follicle
In which area does the keratinization of the hair cells begin?
C) Hair root
Which structure is attached to the dermal papilla, and is located outwards from it?
B) Hair follicle
Which component of the hair fiber contains fusiform cells, keratin fibrils, and melanin pigment that gives the hair its color?
B) Hair cortex
Which cells produce and store fats and wax esters, which will after bursting turn into sebum?
D) Sebaceous gland cells
All of the following structures of the skin are associated with hair, except:
B) Tactile corpuscle
Which of the following structures do not comprise the dermal papilla?
B) Hair follicle
In which area do the shaft cuticles start to detach from the inner root sheath cuticle?
A) Hair root
Which of the following histological features does not represent the layers of the hair follicle?
C) Hair root plexus
The layers of the hair follicle include the dermal sheath, glassy membrane, and internal and external root sheaths.
All of the following components of hair can be found at the surface of the skin, except:
B) Glassy membrane
Around which structures is the hair matrix formed?
C) Derma papilla of hair follicle
Which of the following structures represent a network of free nerve endings that respond to movements of the hair?
C) Hair root plexus
All of the following structures make the layers of the scalp, except:
D) Reticular connective tissue
The scalp consists of skin, loose connective tissue, epicranial aponeurosis, areolar connective tissue, and periosteum.
Which area contains the melanocytes, but not the melanin pigment accumulations?
A) Hair bulb
What condition is associated with this presentation? A pink pearly nodule with telangiectasis, ulceration, and rolled borders on the upper lip.
C) Basal cell carcinoma
This is a classical presentation of basal cell carcinoma, a malignant proliferation of basal cells and the most common skin cancer. Risk factors include excessive sunlight exposure, xeroderma pigmentosum and albinism. Treatment is surgical excision.
What disease is associated with dermatitis herpetiformis?
B) Coeliac disease
In coeliac disease, there are IgA antibodies against gluten that cross-react with reticulin fibres that anchor the basement membrane to the dermis. Thus, IgA is deposited at the tips of dermal papillae, presenting as grouped pruritic vesicles, papules or bullae. Usually found on elbows.
What is the pathogenesis of pemphigus vulgaris?
D) IgG antibody against desmoglein
Desmosomes are located in the stratum spinosum between keratinocytes. Antibodies against the desmoglein component result in painful flaccid bullae or blisters that rupture easily on both skin and oral mucosa. It is treated with corticosteroids.
Hemidesmosomes IgG is bullous pemphigoid.
IgA in dermal papillae is dermatitis herpetiformis.
Defects in tyrosinase can result in albinism.
What is the most common causative agent of erythema multiform (EM)?
A) HSV infection
HSV is the most common etiologic agent of EM, which presents as a targetoid rash and bullae. All the other options are also associated with the disorder, but less commonly.
What condition is associated with acanthosis ingrains?
A) Type 2 diabetes and gastric adenocarcinoma
Acanthosis nigricans is epidermal hyperplasia with darkening of the skin, especially in the axilla, neck or groin. It is associated with malignancy especially GIT adenocarcinoma or insulin resistance as seen in type 2 diabetes and metabolic syndrome.
What disorder is characterised by an initial ‘herald patch’ which is then followed by scaly erythematous plaques usually in a ‘Christmas tree’ distribution?
C) Pityriasis rosea
Pityriasis rosea classically presents with a salmon coloured solitary patch ‘herald patch’ which enlarges over a few days followed by generalised bilateral and symmetric macules with collarette scale. Pruritus is sometimes present. It self resolves within 6 – 8 weeks.
What is the infective agent implicated in acne?
D) Propionibacterium acnes
Propionibacterium acnes infection produces lipases resulting in inflammation and breakdown of sebum, leading to pustule formation.
How does impetigo present?
D) Golden honey-colored crust over an erythematous base
Impetigo is a superficial skin infection caused by Staph aureus or Strep pyogenes. It frequently affects children. It is treated with penicillin and topical preparations e.g. mupirocin.
How does lichen planus present clinically?
A) Pruritic, purple, polygonal, planar papules and plaques
Learn the 6 P’s of lichen planus. It also often occurs with reticular white lines on the mucosal surfaces (Wickham striae). There is an association with hepatitis C.
What is the pathogenesis of vitiligo?
B) Autoimmune destruction of melanocytes
Vitiligo is the localised loss of skin pigmentation due to the autoimmune destruction of melanocytes. Melanocytes synthesise melanin in melanosomes. Thus, if melanocytes are destroyed, melanin cannot be produced.
An elderly lady presents to her doctor with a raised, round discoloured plaque, ‘stuck on appearance’ on her face. What skin condition is this?
D) Seborrheic keratosis
Seborrheic keratosis is a benign squamous proliferation and is seen frequently in the elderly.
What is Leser-Trélat sign?
B) Sudden appearance of multiple seborrheic keratoses and is an indicator of gastrointestinal tract carcinoma
Note that the presentation of gastric carcinoma can include Leser-Trélat sign, Virchow node, Sister Mary Joseph nodule and Krukenberg tumour.
Presentation
Description
Virchow node
Left supraclavicular node associated with gastric carcinoma
Sister Mary Joseph nodule
Palpable nodule bulging into the umbilicus, which is indicative of metastatic tumor in the pelvis or abdomen
Krukenberg tumor
Mucin-rich signet ring adenocarcinoma, which is indicative of a metastatic tumor in the ovary
What type of melanoma is often seen in dark skinned individuals?
D) Acral lentiginous
The acral lentiginous variant of melanoma arises in dark skinned individuals on their palms or soles. It is not linked to UVB induced DNA damage unlike the other types. This was the disease that caused the death of Bob Marley.
What are the histological findings of psoriasis?
B) Acanthuses, parakeratosis, and Munro microabscesses
Psoriasis is as a result of increased keratinocyte proliferation. It presents as salmon coloured papules and plaques with silvery scaling, especially on extensor surfaces and scalp. On histology, there is epidermal hyperplasia (acanthosis), hyperkeratosis with retention of nuclei in stratum corneum (parakeratosis) and groups of neutrophils in the stratum corneum (Munro microabscesses).
What is the most common mole found in adults?
B) Intradermal nevus
A mole/nevus is a benign neoplasm of melanocytes. It can be congenital or acquired. If acquired, it progresses from a junctional nevus (most common in children) to a compound nevus and eventually to an intradermal nevus. Note that the mole can undergo dysplasia and the dysplastic nevus is a precursor to melanoma.
What is a precursor to squamous cell carcinoma (SCC)?
B) Actinic keratosis
Actinic keratosis is a premalignant lesion to SCC, caused by prolonged sun exposure. It presents as scaly, rough, erythematous and small plaques, most commonly on the face, back or neck.
What skin condition is caused by poxvirus?
B) Molluscum contagiosa
Molluscum contagiosum is an umbilicated papule. It is commonly seen in children and sexually transmitted in adults.
What childhood infection is associated with Koplik spots?
D) Measles
Measles is a paramyxovirus. Koplik spots are small bright red spots with a white centre on the buccal mucosa that precede the measles rash by 1-2 days and are pathognomonic for measles. Measles present initially with cough, coryza and conjunctivitis then the Koplik spots. Eventually a maculopapular rash develops, beginning at the head/neck and spreading downwards.
What is the best indicator of prognosis for a melanoma?
C) Invasion of dermis
Invasion/ depth of extension measured by Breslow thickness is the most significant prognostic factor in predicting metastasis. Asymmetry, border irregularity, colour variation and diameter (>6mm) are known as the ‘ABCD’ criteria for describing melanomas.
True or False: The skin can be considered an organ as well as a system.
True
True or False: Epidermal cells usually grow and divide from the upper layers of the skin and migrate towards the dermis.
False
Epidermal cells usually grow and divide from the lower layers of the skin and migrate towards the epidermis.
True or False: There are usually no blood vessels in the epidermis.
True
Blood vessels are found in the dermis.
True or False: The cells in the epidermis are only comprised of stratified squamous epithelial cells.
True
True or False: The subcutaneous region has adipose cells that help insulate the body from heat as well as cold.
True
True or False: Most accessory structures found within the dermis are actually of epidermal origin.
True
Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands. All of these originate embryologically from the epidermis.
True or False: Hairs are non-cellular structures comprised of compacted chemicals such as keratin.
False
Within the follicle, stem cells in the root of the hair divide rapidly.
True or False: Sebaceous glands are only associated with hair follicles and do not exist alone by themselves.
False
Unlike the other major membranes of the body, _______________ membranes lack an epithelial layer.
D) Synovial
The functions of the skin include all of these, except:
D) Taking in nutrients
Within the skin, a basement membrane can be found separating the ________________ and the __________________.
B) Epidermis; dermis
The protective dead layer of cells of the outer epidermis is called the:
B) Stratum corneum
Melanocytes lie within the _________________ of the skin.
C) Stratum basale and upper dermis
Which of these phrases does not characterize the dermis?
B) Thinner in areas receiving greater friction and use
Dermis is thicker in areas receiving greater friction and use.
Adipose tissue is most abundant in the ________________ layer of the skin.
A) Subcutaneous
Hairs arise from which layer of the skin?
A) Stratum basale of epidermis
Within nails, the most rapidly dividing cells can be found in the:
A) Lunula
It is the body's __________________ glands that respond to higher body temperature and release water to the skin surface.
A) Eccrine
Eccrine sweat glands are also known as merocrine sweat glands.
Modified sweat glands, called __________________ glands, secrete wax in the ear canal.
A) Ceruminous
Heat loss occurs from the body by each of these methods, except:
A) Cellular respiration
Choose the response that the body employs to raise body temperature only when the others listed have failed.
D) Shivering
Which statement is true about tans and tanning?
A) A tan indicates sun damage to the skin.
A(n) _________________ is the transplanting of one's own skin from an unburned region of the body to a burned area.
A) Autograft
Which term does not belong with the others?
A) Epidermis
Which term does not belong with the others?
A) Stratum corneum
What is one important function for melanin?
A) Absorb harmful radiation
The yellowish color of some persons skin is due to:
A) Carotene
The epidermal ridges or fingerprints are probably caused by the:
D) Dermal papillae
The strength of the dermis would mainly be due to:
B) The presence of collagen fibers
The part of the hair below the surface of the skin is called the ____________.
C) Root
What is the medical term for male pattern baldness?
A) Androgenic alopecia
In men, androgenic alopecia is also known as male-pattern baldness. Hair is lost in a well-defined pattern, beginning above both temples. Over time, the hairline recedes to form a characteristic "M" shape.
Alopecia areata is an autoimmune disorder that usually results in unpredictable, patchy hair loss.
The term goose bumps is directly related to which structures?
D) Arrector pili
The ___________ is the thick white area of the nail that reflects the rapid growth of the cells below it.
B) Lunula
True or False: The epidermis contains a greater variety of cell types in comparison to the dermis.
False
The dermis contains a variety of cell types from all four tissue types while the epidermis is purely epithelium.
True or False: The dermis has a rich blood supply while the epidermis is totally devoid of blood vessels.
True
There are no blood vessels in the epidermis. This becomes evident if one has what is called a shallow paper-cut with no bleeding.
True or False: The amount of blood supply is directly proportional to the ability of a cell to divide and remain vital.
True
All cells require nutrients for their functioning. The greater the distance from a nutrient supply, the higher the probability of dying.
True or False: The process of keratinization is directly related to the waterproofing function of the dermis.
False
Keratin synthesis is a function of the stratified squamous cells of the epidermis and does make the layer relatively impermeable to water.
True or False: A decubitus ulcer is a bedsore caused by an infectious agent or toxic organism.
False
Decubitus ulcers are areas of dying skin tissue which result from the lack of an adequate blood supply, usually caused by pressure. It is possible to also be infected secondarily.
True or False: Increased exposure to sunlight actually maintains healthy skin and reduces the effects of aging.
False
Although sunlight has its benefits such as vitamin D synthesis, studies have shown that excessive exposure to sunlight not only causes drying but damages the cell layers resulting in the wrinkles and loss of elasticity seen in aging.
True or False: The dermis of the face contains skeletal muscle fibers that cause the skin to contract during facial gestures.
True
Facial gestures are caused by contraction of skeletal muscles that lie beneath the skin but may be attached to it with fibers.
True or False: Dark-skinned persons have a higher probability of developing melanomas because they have more melanocytes.
False
The darkness of the skin is not proportional to the number of melanocytes but to the density of pigment. Melanin actually reduces the risk for cancer because of its protective effect on sunlight.
True or False: Persons who remain indoors frequently may have a higher risk of developing a malignant melanoma than those who are highly exposed to sunlight because of their work or other reasons.
True
Studies have shown that sporadic exposure to high intensity sunlight, such as during some vacations, may cause cancer more likely than a constant level of daily exposure.
True or False: Transdermal medications are delivered by inserted a hypodermic needle into the subcutaneous region.
False
Transdermal medications such as those for angina pectoris, are applied to the surface of the skin. Needles are used for intradermal or hypodermal injection routes.
True or False: The papillary layer of the dermis partially explains the presence of fingerprints in the epidermis.
True
The wavelike appearance of the junction between the dermis and epidermis explains the appearances of ridges on the skin surface. If the fingerprints were removed by friction or disease, they would re-appear as long as the papillary dermis is intact.
True or False: Hair is actually a structure comprised mainly of keratin.
False
Hairs are compacted, dead epithelial cells that contain the protein keratin.
True or False: Excessive hair growth on regions of the body is alopecia.
False
Alopecia is a term which indicates a condition of hair loss or baldness and can occur on any part of the body.
True or False: Albinism is a condition resulting from the genetic inability to produce melanin throughout the body.
True
Albinism is the lack of melanin pigmentation in the skin or eyes, caused by the genetic lack of the enzyme necessary to convert tyrosine to melanin.
True or False: Sebaceous glands are always associated with each hair follicle.
False
Sebaceous glands can open directly onto the surface without association with hair follicles, such as in the genitals or lips.
True or False: The nail plate is the part of the fingernail, which lies on top of the nail bed.
True
The nail plate is the external area of dead skin that is the part of the fingernail attached to the lower cells of the bed below.
True or False: The eccrine sweat glands are located in the axillary areas and respond to emotional upsets.
False
The apocrine sweat glands in the armpits and other areas produce a characteristic odor in response to chemical, psychological, or hormonal changes. The eccrine glands produce a watery secretion.
True or False: As one ages, the ability to sweat increases as evidenced by increased moisture on the skin of the elderly.
False
During aging, the number of sweat glands decreases as they are replaced by fibrous scar tissue.
True or False: The elimination of sweat can have an excretory as well as temperature regulating function.
True
Several salts, uric acid, urea, excess water and other chemicals are eliminated through mechanisms in the skin. The most common waste that is removed through the skin is excessive heat.
True or False: The application of an ice pack is an example of temperature control by means of convection.
False
Convection involves the movement of air across a surface, while conduction occurs through direct contact with a solid surface.
True or False; In order to conserve heat, blood vessels in the skin constrict.
True
The blood vessels in the skin are caused to constrict by impulses from nerves from the hypothalamus. The result is a reduction of sweating and loss of radiation heat also.
True or False: Heat exhaustion occurs when the body undergoes excessive sweating on hot, humid days.
False
Heat exhaustion occurs when the body is unable to eliminate excess body heat fast enough. It includes cramping and fatigue.
True or False: Regardless of race, all persons, except albinos, have the same relative numbers of melanocytes.
True
Darkness in the skin is caused by the amount and distribution of melanin rather than the number of melanocytes.
True or False: Antipyretic drugs are used to treat pyrexia, which is an abnormal drop in body temperature.
False
Pyrexia means fever production which is an abnormal increase in body temperature.
True or False: The white blood cells secrete interleukins, which are known to block the causes of fevers.
False
Interleukin is a class of compounds that cause many reactions including the development of a fever, by stimulating the hypothalamus.
Which type of membrane is comprised of only connective tissue?
D) Synovial
Most membranes are comprised of epithelial and connective tissues but the synovial membranes in joints are made of various types of connective tissue only.
Mesothelium is a term that refers to ____________ membranes.
B) Serous
Serous membranes are made of a thin layer of simple squamous epithelium called mesothelium.
The skin is called the ____________ membrane.
A) Cutaneous
The cutaneous membrane is commonly called the skin, and includes its accessory structures such as hair.
Which membrane can be comprised of the most diverse types of epithelial and connective tissues?
A) Mucous
Mucous membranes can employ different types of epithelium depending on location. Stratified squamous lines the oral cavity while simple columnar epithelium lines the small intestine.
Which type of membrane is found around the abdominal organs?
A) Serous
Serous membranes are wet and slippery and serve as a covering for abdominal organs, allowing them to freely move with reduced friction. Epithelium is a type of tissue, not membrane.
The ____________ separates the epidermis from the dermis.
D) Basement membrane
The basement membrane is a connective tissue structure that represents the end of the dermis and the beginning of the epidermis. Nutrients must cross this barrier to diffuse to the upper skin cells.
The youngest cells would be found in the stratum ___________.
D) Basale
The youngest and most actively dividing cells rest on the basement membrane such as those in the stratum basale (germinativum).
Where is the greatest amount of keratin found?
D) Stratum corneum
The cells in the outermost skin layer, stratum corneum, contain the greatest percentage of keratin protein molecules, making them the toughest and driest.
The stratum basale is also called the stratum _____________.
D) Germinativum
The first layer of the epidermis contains the most active cell division and could also be called the germinativum.
Calluses are thickened areas that are formed in response to a/an :
A) Increase in friction or pressure
Calluses are thick areas of the skin in areas such as the soles that are subjected to pressure and a constant loss of cells.This loss causes the cells in the basale to increase their division and replacement rate.
The following terms belong together except which one?
B) Necrosis
Necrosis is a general term for cell death but the other terms refer to bedsores (decubitus) or pressure ulcers.
The pigment producing melanocytes are found in the _________ layer.
B) Basale
Some of the stratum basale cells are specialized to produce melanin and are a type of differentiated stratified squamous epithelial cell, known as melanocyte.
What is the major factor that protects skin from the damaging effects of sunlight?
C) The presence of melanin
Melanin is a pigment which absorbs radiation, especially UV(B), and converts it into heat, thereby reducing the chance for cell damage or cancer from developing.
The following are functions of the skin except which one?
B) Protects joints
The skin protects against water loss, infection, and harmful chemicals. Joints are protected by a synovial, connective tissue membrane.
Cells that surround melanocytes may contain more melanin than the melanocytes because of the process of:
A) Cytocrine secretion
Although the melanocytes synthesize the melanin, some pigment can be secreted into surrounding areas by cytocrine secretion, therefore increasing the total amount of melanin into areas of wide dispersal.
Skin cancer most likely arises from which type cells?
D) Epithelial cells
Skin cancer or carcinoma arises from non-pigmented epithelial cells in the deepest layer, most likely.
Which structures are associated with detecting deep pressure within the skin?
A) Pacinian corpuscles
Because of their deep location as well as structure, the Pacinian corpuscles will respond to heavy pressure on the skin.
Most of the sensory fibers and structures are located in the _____________ region.
C) Dermis
Most of the sensory structures are dispersed throughout the dermis, but there are some in the subcutaneous areas, such as the receptors for deep pressure.
Meissner corpuscles respond to a stimulus of:
D) Light touch
Meissner corpuscles are dermal receptors specialized to respond to light touch on the skin. There are other temperature receptors, such as the Krause or Ruffini organs.
The subcutaneous layer can also be referred to as the:
C) Hypodermis
Hypodermis means below the skin. The skin is defined to include the dermis and epidermis.
Stratum malphigii is another name for stratum basale.
The presence of __________ is an indication of being in the hypodermis.
A) Adipose
Adipose or fat cells are only found in the areas below the dermis. Although no sharp line of distinction is present, the occurrence of adipose indicates the possibility of being in the dermis.
The main tissue in the dermis is:
A) Loose connective tissue
The dermis contains elastic, reticular and collagen fibers. Dense connective tissue is mainly found within structures such as tendons.
What is the main factor in preserving body heat?
C) The presence of adipose
Adipose in the hypodermis acts as a cushion as well as an insulator and barrier for heat loss. The thickness of the epidermis may be the result of exposure to the cold but it does little to conserve heat.
The part of the hair from the surface into the dermis is the:
A) Root
The root of the hair is the portion below the skin surface, while the shaft is the part outside the skin.
A group of cells that surrounds the developing hair is called the:
B) Follicle
A follicle is an arrangement of cells that supports the development of something in the center. There are several types of follicles in the body, including in the ovary, hair, or thyroid gland.
The darkness of hair is due mainly due to:
B) Melanin concentration
Although gaps in the hair are part of the reason for gray hair, melanin is the main chemical pigment that causes hair to become black.
The color of red hair is due to:
B) Trichosiderin
Red hair contains large amounts of the iron-containing pigment trichosiderin.
Goose bumps in the skin are caused by contraction of the ____________ in response to cold or emotions.
D) Arrector pili muscles
Arrector pili muscles are attached to the hair follicles and cause the hair to bend and pull on the skin causing bumps (goose bumps).
The following relate to sebaceous glands except which one?
B) Use merocrine methods
Sebaceous glands are lined with cells that use holocrine methods of secretion in which the entire cell is sloughed of with the sebum.
The oil, sebum, acts to prevent water loss.
The following belong together except which one?
A) Alopecia
Alopecia refers to a loss of hair and the other terms relate to the development of skin conditions commonly referred to as pimples.
Hair and fingernails are derived from the ____________ cells.
B) Epidermal
Although in the dermis anatomically, the outgrowths of the skin are epidermal in tissue origin. Most epithelial cells have the ability to produce keratin, hair, and fingernails.
The most active growing region of the nails is the:
B) Lunula
The lunula is the half moon shaped white area at the base of the plate which also is the area of most rapid mitoses.
Sweat glands can also be called _____________ glands.
D) Sudoriferous
Sweat glands are called sudoriferous glands, while sebaceous glands produce sebum which is oily.
What actually controls and maintains body temperature?
C) Hypothalamus
There is a region in the brain called the hypothalamus which acts as the computer or thermostat to control body temperature homeostasis.
The major loss of heat through the skin is by:
A) Radiation
The skin loses heat by many processes including direct radiation from dry skin, but the main loss is from the conversion of water from a liquid to a vapor or evaporation.
The greatest source of body heat is through:
D) Contraction of skeletal muscle
Skeletal muscle contraction is the greatest source of heat by virtue of its mass and large number of metabolic reactions.
Cyanosis usually is the result of a reduction in:
D) Oxygen levels
The cyanosis or blue color in light skin is primarily caused by a shift in the amount of oxygen in hemoglobin.
The pigment ___________ found in vegetables can impart a yellow or orange color to the skin.
C) Carotene
The pigment beta-carotene found in vegetables is the precursor to vitamin A but can also give the skin an orange appearance.
A ______________ is a procedure that uses skin from a deceased person to treat a burned area.
D) Homograft
Homografts are tissues taken from cadavers that can be used to cover a burn. An autograft employs tissue taken from another area of the same patient with the burn.
A 39-year-old man incurs a burn injury to his hands and arms while working on a propane furnace. Over the next 3 weeks, the burned skin heals without the need for skin grafting.
Which of the following is the most critical factor in determining whether the skin in the region of the burn will regenerate?
A) Persistence of skin appendages
The skin appendages have epithelium from which the surface epidermis can regenerate. A partial-thickness burn retains epithelial elements in the skin, allowing for regeneration. A full-thickness burn results in the complete loss of skin appendages, meaning the epidermis is unable to regenerate.
Name the bacteria that produces a fruity smell in culture?
A) Pseudomonas aeruginosa
The characteristic fruity smell is associated with 2-aminoacetophenone production by Pseudomonas aeruginosa.
The other choices are incorrect because:
1. Escherichia coli produces a floral odor.
2. Salmonella enterica does not produce an odor.
3. Campylobacter jejuni does not produce an odor when cultured.
4. Staphylococcus aureus does not produce an odor when cultured, although Staphylococcus lugdunensis (associated with septic arthritis, wound infections and sepsis) produces a sweet hay-like earthy odor.
