Ch.4: Skin and Body Membranes Flashcards

1
Q

What are the functions of body membranes?

A

• Cover body surfaces
• Line body cavities
• Form protective sheets around organs
*Classified according to tissue types

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2
Q

Which types of membranes are classified as epithelial membranes?

A
  • Cutaneous membranes
  • Mucous membranes
  • Serous membranes
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3
Q

Which types of membranes are classified as connective tissue membranes?

A

• Synovial membranes

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4
Q

What are epithelial membranes?

A
  • Simple organs

* Also called covering and lining membranes

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5
Q

What are the two main layers of epithelial membranes?

A
  • Epithelial tissue layer

* Connective tissue layer

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6
Q

What are the main properties of cutaneous membranes?

A

• Dry membrane
• Outermost protective boundary
• Construction:
*Epidermis is composed of keratinized stratified squamous epithelium
*Dermis is mostly dense (fibrous) connective tissue
• Cutaneous = skin

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7
Q

What are the main properties of mucous membranes (mucosae)?

A

• Moist membranes
• Line all body cavities that open to the exterior body surface
• Adapted for absorption or secretion
• Construction:
*Epithelium type depends on site
*Loose connective tissue (lamina propria)

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8
Q

What are the main properties of serous membranes (serosae)?

A

• Line open body cavities that are closed to the exterior of the body
• Occur in pairs, separated by serous fluid, with a visceral and parietal layer
• Construction:
*Simple squamous epithelium
*Areolar connective tissue

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9
Q

What are specific serous membranes and where are they located?

A
• Peritoneum
*Abdominal cavity
• Pleura
*Around the lungs
• Pericardium
*Around the heart
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10
Q

What are the main properties of synovial membranes?

A

• Loose areolar connective tissue only (no epithelial tissue)
• Line fibrous capsules surrounding joints
*Line bursae
*Line tendon sheaths
• Secrete a lubricating fluid to cushion organs moving against each other during muscle activity

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11
Q

What does the integumentary system consist of?

A
• Skin (cutaneous membrane)
• Skin appendages
*Sweat glands
*Oil glands
*Hair
*Nails
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12
Q

What are the functions of the integumentary system?

A

• Insulates and cushion deeper body organs
• Protects the entire body from:
*Mechanical damage (bumps and cuts)
*Chemical damage (acids and bases)
*Thermal damage (heat or cold)
*Ultraviolet (UV) radiation (sunlight)
*Microbes (bacteria)
*Desiccation (drying out)
• Aids in loss or retention of body heat as controlled by the nervous system
• Aids in excretion of urea and uric acid
• Synthesizes vitamin D

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13
Q

Which two kinds of tissue compose the skin?

A
  • Epidermis

* Dermis

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14
Q

What are the main functions of the hypodermis (subcutaneous layer)?

A
  • Anchors the skin to underlying organs
  • Not technically part of the integumentary system
  • Composed mostly of adipose tissue
  • Serves as a shock absorber and insulates deeper tissues
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15
Q

What are the main properties of the epidermis, the outer layer of the skin?

A
  • Capable of being hard and tough
  • Stratified squamous epithelium
  • Keratinocytes (the most common cell) produce a fibrous protein called keratin
  • Avascular
  • Composed of five layers (strata)
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16
Q

What are the layers of the epidermis from deepest to most superficial?

A
  • Stratum basale
  • Stratum spinosum
  • Stratum granulosum
  • Stratum lucidum (thick, hairless skin only)
  • Stratum corneum
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17
Q

What are the main properties of the stratum basale (stratum germinativum)?

A
  • Deepest layer of epidermis
  • Lies next to dermis
  • Wavy borderline with the dermis anchors the two together
  • Cells undergoing mitosis
  • Daughter cells are pushed upward to become the more superficial layers
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18
Q

What is the main property of the stratum spinosum?

A

Cells become increasingly flatter and more keratinized

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19
Q

What are the main properties of the stratum lucidum?

A
  • Formed from dead cells of the deeper strata

* Occurs only in thick, hairless skin of the palms of hands and soles of feet

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20
Q

What are the main properties of the stratum corneum?

A
  • Outermost layer of epidermis

* Shingle-like dead cells are filled with keratin (protective protein prevents water loss from skin)

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21
Q

What is melanin?

A
  • Melanin is a pigment produced by melanocytes
  • Melanocytes are mostly in the stratum basale of the epidermis
  • Color is yellow to brown to black
  • Amount of melanin produced depends upon genetics and exposure to sunlight
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22
Q

Melanin accumulates in membrane-bound granules called:

A

Melanosomes

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23
Q

What is the main function of epidermal dendritic cells?

A

Alert and activate immune cells to a threat (bacterial or viral invasion)

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24
Q

What are the main functions of Merkel cells?

A
  • Associated with sensory nerve endings

* Serve as touch receptors called Merkel discs

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25
Q

What are the main functions of the dermis?

A
  • Connective tissue

* Underlies the epidermis

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26
Q

Which two layers compose the dermis?

A

• Papillary layer (upper dermal region)

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27
Q

What are the main properties of the papillary layer (upper dermal region)?

A
  • Contains projections called dermal papillae
  • Indent the epidermis above
  • Many projections contain capillary loops, and others house pain and touch receptors
  • On palm and sole surfaces, papillae increase friction and gripping ability
  • Fingerprints are identifying films of sweat
28
Q

What are the main properties of the reticular layer (deepest skin layer)?

A
  • Blood vessels
  • Sweat and oil glands
  • Deep pressure receptors (lamellar corpuscles)
29
Q

What are other dermal features?

A
  • Cutaneous sensory receptors
  • Phagocytes
  • Collagen and elastic fibers
  • Blood vessels
30
Q

What are the three pigments which contribute to skin color?

A
  1. Melanin
    • Yellow, reddish brown, or black pigments
  2. Carotene
    • Orange-yellow pigment from some vegetables
  3. Hemoglobin
    • Red coloring from blood cells in dermal capillaries
    • Oxygen content determines the extent of red coloring
31
Q

What causes skin redness (erythema)?

A
  • Embarrassment
  • Inflammation
  • Hypertension
  • Fever
  • Allergy
32
Q

What causes pallor (blanching)?

A
  • Emotional stress (such as fear)
  • Anemia
  • Low blood pressure
  • Impaired blood flow to an area
33
Q

What does jaundice (yellow cast) indicate?

A

A liver disorder

34
Q

What is another term for “bruises?”

A

Hematomas

35
Q

What are the appendages of the skin?

A
• Cutaneous glands are all exocrine glands
*Sebaceous glands
*Sweat glands
• Hair
• Hair follicles
• Nails
36
Q

What are the main functions and properties of sebaceous (oil) glands?

A

• Located all over the skin except for palms and soles
• Produce sebum (oil)
*Makes skin soft and moist
*Prevents hair from becoming brittle
*Kills bacteria
• Most have ducts that empty into hair follicles; others open directly onto skin surface
• Glands are activated at puberty

37
Q

What are the two types of sudoriferous (sweat) glands?

A
  • Eccrine glands

* Apocrine glands

38
Q

What are the main functions of eccrine glands?

A

• Open via duct to sweat pores on the skin’s surface
• Produce acidic sweat
*Water, salts, vitamin C, traces of metabolic waste
• Function in body temperature regulation

39
Q

What are the main functions of apocrine glands?

A
  • Ducts empty into hair follicles in the armpit and genitals
  • Begin to function at puberty
  • Release sweat that also contains fatty acids and proteins (milky or yellowish color)
  • Play a minimal role in body temperature regulation
40
Q

What are the main properties of hair?

A
  • Produced by hair follicle
  • Root is enclosed in the follicle
  • Shaft projects from the surface of the scalp or skin
  • Consists of hard keratinized epithelial cells
  • Melanocytes provide pigment for hair color
  • Hair grows in the matrix of the hair bulb in stratum basale
41
Q

What is the anatomy of hair?

A

• Central medulla
• Cortex surrounds medulla
• Cuticle on outside of cortex
*Most heavily keratinized region of the hair

42
Q

What are the main functions and properties of hair follicles?

A
  • Composed of an epithelial root sheath and fibrous sheath
  • Dermal region provides a blood supply to the hair bulb (deepest part of the follicle)
  • Arrector pili muscle connects to the hair follicle to pull hairs upright when we are cold or frightened
43
Q

What are the main properties of nails?

A
  • Heavily keratinized, scale-like modifications of the epidermis
  • Stratum basale extends beneath the nail bed, which is responsible for growth
  • Lack of pigment makes nails colorless
44
Q

What are the parts of the nail?

A
  • Free edge
  • Body is the visible attached portion
  • Nail folds are skin folds that overlap the edges of the nail; the cuticle is the proximal edge
  • Root of nail is embedded in skin
  • Growth of the nail occurs from nail matrix
45
Q

What is athlete’s foot and what is it caused by?

A
  • Caused by fungal infection (Tinea pedis)

* Itchy, red peeling skin between the toes

46
Q

What are boils (furuncles) and carbuncles and what are they caused by?

A
  • Caused by inflammation of hair follicles

* Carbuncles are clusters of boils caused by bacteria

47
Q

What are cold sores (fever blisters) and what are they caused by?

A
  • Caused by human herpesvirus 1

* Blisters itch and sting

48
Q

What is contact dermatitis and what is it caused by?

A
  • Caused by exposure to chemicals that provoke allergic responses
  • Itching, redness, and swelling of the skin
49
Q

What is impetigo and what is it caused by?

A
  • Caused by bacterial infection

* Pink, fluid-filled raised lesions around mouth/nose

50
Q

What is psoriasis and what is it caused by?

A
  • Triggered by trauma, infection, hormonal changes, or stress
  • Red, epidermal lesions covered with dry, silvery scales that itch, burn, crack, or sometimes bleed
51
Q

What are the properties of burns?

A

• Tissue damage and cell death caused by heat, electricity, U V radiation, or chemicals
• Associated dangers
*Protein denaturation and cell death
*Dehydration and electrolyte imbalance
*Circulatory shock
• Result in loss of body fluids and infection from the invasion of bacteria

52
Q

How is the extent of a burn is estimated?

A

• Using the rule of nines
• Body is divided into 11 areas for quick estimation
• Each area represents about 9 percent of total body surface area
*The area surrounding the genitals (the perineum) represents 1 percent of body surface area

53
Q

What classifies a first-degree burn (superficial burn)?

A
  • Only epidermis is damaged

* Skin is red and swollen

54
Q

What classifies a second-degree burn (partial-thickness burn)?

A
  • Epidermis and superficial part of dermis are damaged
  • Skin is red, painful, and blistered
  • Regrowth of the epithelium can occur
55
Q

What classifies a third-degree burn (full-thickness burn)?

A
  • Destroys epidermis and dermis; burned area is painless
  • Requires skin grafts, as regeneration is not possible
  • Burned area is blanched (gray-white) or black
56
Q

What classifies a fourth-degree burn (full-thickness burn)?

A
  • Extends into deeper tissues (bone, muscle, tendons)
  • Appears dry and leathery
  • Requires surgery and grafting
  • May require amputation
57
Q

What are the criteria for deeming burns critical (if any one is met)?

A
  • Over 30 percent of body has second-degree burns
  • Over 10 percent of the body has third- or fourth-degree burns
  • Third- or fourth-degree burns of the face, hands, feet, or genitals
  • Burns affect the airways
  • Circumferential (around the body or limb) burns have occurred
58
Q

What are the two ways which cancer can be classified?

A
  • ​Benign means the neoplasm (tumor) has not spread

* ​Malignant means the neoplasm has invaded other body areas

59
Q

Concept link

A

Recall that mitosis gone wild is the basis for cancer (Chapter 3, pp. 104–105). In malignant cancers, the stages of mitosis occur so quickly that errors are made. As a result, these cells lack normal control of cell division. Cells experiencing rapid, uncontrolled growth become cancerous.

60
Q

What are the most common types of skin cancer?

A
  • ​Basal cell carcinoma
  • ​Squamous cell carcinoma
  • ​Malignant melanoma
61
Q

What are the properties of basal cell carcinoma?

A
  • ​Least malignant and most common type of skin cancer
  • ​Arises from cells in stratum basale that are altered so that they can no longer make keratin
  • ​Lesions appear as shiny, dome-shaped nodules that develop a central ulcer
62
Q

What are the properties of squamous cell carcinoma?

A
  • ​Believed to be induced by UV exposure
  • ​Arises from cells of stratum spinosum
  • ​Lesions appear as scaly, reddened papules that gradually form shallow ulcers
  • ​Early removal allows a good chance of cure
  • ​Metastasizes to lymph nodes if not removed
63
Q

What are the properties of malignant melanoma?

A
  • ​Most deadly of skin cancers, but accounts for only 5 percent of skin cancers
  • ​Arises from melanocytes
  • ​Metastasizes rapidly to lymph and blood vessels
  • ​Detection uses ABCDE rule for recognizing melanoma
64
Q

What is the ABCDE rule for recognizing melanoma?

A

A = Asymmetry
• ​Two sides of pigmented mole do not match
B = Border irregularity
• ​Borders of mole are not smooth
C = Color
• ​Different colors in pigmented area
D = Diameter
• ​Spot is larger than 6 millimeters in diameter
E = Evolution
• ​One or more of the A B C D characteristics is evolving

65
Q

What are the developmental aspects of skin and body membranes?

A
  • ​Lanugo, a downy hair, covers the body by the fifth or sixth month of fetal development but disappears by birth
  • Vernix caseosa, an oily covering, is apparent at birth
  • Milia, small white spots, are common at birth and disappear by the third week
  • Acne may appear during adolescence
  • In youth, skin is thick, resilient, and well hydrated
  • With aging, skin loses elasticity and thins
  • Skin cancer is a major threat to skin exposed to excessive sunlight
  • Balding and/or graying occurs with aging; both are genetically determined; other factors that may contribute include drugs and emotional stress