STRUCTURAL AND FUNCTIONAL ORGANIZATION OF TISSUES Flashcards
(212 cards)
1
Q
What are the four types of human tissues?
A
- Muscle tissue
- Nervous tissue
- Epithelial tissue
- Connective tissue
2
Q
What tissue generates the physical force to male the body structures move?
A
Muscle tissue
3
Q
What tissue is arranged in bundles and are contractile cells that provide the ability to move the body in three dimensions?
A
Muscle tissue
4
Q
What tissue detects changes inside/outside the body and initiates and transmits impulses that coordinate body activities and help maintain homeostasis?
A
Nervous tissue
5
Q
The following is included in what tissue of the body?
- Skin
- Hair
- Nails
- Accessory structures
A
Epithelial tissue
6
Q
What is the medical term for the skin and main portion of the integumentary system?
A
Epithelium
7
Q
What covers the body surfaces; lines the body cavities, hollow organs and ducts (tubes); and forms glands?
A
Epithelial tissue
8
Q
What protects and supports the body and its organs, binds organs together, stores energy together, and helps provide immunity?
A
Connective tissue
9
Q
What provides contact or adhesion between neighboring cells or between a cell and extracellular matrix?
A
Cell junctions
10
Q
What maintains a paracellular barrier of epithelia (barrier in between cells) and controls the transport of material or signals between cells (paracellular transport)?
A
Cell Junctions
11
Q
What are dense in epithelial tissues because the tissue needs to maintain both strength and integrity in a wide variety of conditions?
A
Cell junctions
12
Q
What kind of cell junctions form a barrier against water and antigens passing between individual epithelial cells?
A
Tight junctions
13
Q
What kind of cell junctions are cell-cell adhesions continuously assembled and disassembled so cells can respond to changes in their microenvironment?
A
Adherens Junctions
14
Q
What forms stable adhesive junctions between cells?
A
Desmosomes
15
Q
What cell junction allows various molecules and electrical signals to pass freely between cells?
A
Gap junctions
16
Q
What facilitates the stable adhesion of basal epithelial cells to the underlying basement membrane?
A
Hemidesmosomes
17
Q
Epithelial tissue is broadly categorized into what?
A
- Covering and lining epithelium
2. Glandular epithelium
18
Q
What form of epithelium has the following functions?
- Covers external surfaces of the body and some internal organs
- Lines body cavities, blood vessels, and ducts
- Lines interior of respiratory, GI, urinary and reproductive systems
- Integral part of sense organs for hearing, vision, and touch
A
Covering and lining epithelium
19
Q
What form of epithelium is the secreting portion of the glands, such as sweat glands?
A
Glandular epithelium
20
Q
Epithelial Tissue
What is the most superficial layer of cells?
A
Apical layer
21
Q
Epithelial Tissue
What is the deepest layer of the cell?
A
Basal layer
22
Q
What is the thin extracellular structure composed mostly of protein fibers that is located between the epithelium and underlying connective tissue layer; helps to bind and support the epithelium?
A
Basement membrane
23
Q
What are the two ways of classifying epithelial tissue?
A
- Morphology
2. Stratification
24
Q
What is the classification of epithelial cells based on shape?
A
Morphology
25
What is the classification of epithelial cells based on the number of layers?
Stratification
26
What kind of epithelium is shaped like pancakes?
Squamous epithelium
27
What kind of epithelium is shaped like the tesseract in Captain America?
Cuboidal epithelium
28
What kind of epithelium is shaped like the column block in Tetris?
Columnar Epithelium
29
What kind of epithelium changes shape like the T-1000 in T2: Judgement Day ?
Transitional epithelium
30
What epithelium is thin and flat shaped and allows rapid passage of substances; can be keratinized or non-keratinized; "wet" or "dry" depending on their location in the body?
Squamous epithelium
31
What epithelium can be found in areas such as the lining of the esophagus, mouth, and cervix?
Squamous epithelium
32
What form of epithelium is as tall as it is wide and shaped like cubes or hexagons?
Cuboidal epithelium
33
What epithelium frequently have microvilli at the apical surface and function in either secretion or absorption?
Cuboidal epithelium
34
What epithelium is found in areas such as the salivary glands and thyroid follicles?
Cuboidal epithelium
35
What form of epithelium is taller than it is wide, protects underlying tissues, and the apical surface may have cilia or microvilli?
Columnar epithelium
36
What form of epithelium often is specialized for secretion and absorption and lines most organs of the GI tract, respiratory tract, and fallopian tubes?
Columnar epithelium
37
What epithelium is able to change shape from flat to cuboidal and back depending on tension and distension of tissue?
Transitional epithelium
38
What epithelium is useful for organs such as the urinary bladder, when it is stretching (distend) to a larger size and then as it collapses to a smaller size?
Transitional epithelium
39
What form of epithelium is a single layer of cells that function in diffusion, osmosis, filtration, secretion, and absorption?
Simple epithelium
40
What is the production and release of substances?
Secretion
41
What is the intake of fluids or other substances?
Absorption
42
What is the movement of water across a semipermeable membrane from an area or lower solute concentration to an area of higher solute concentration?
Osmosis
43
What is the movement of particles from an area of high concentration to an area of low concentration?
Diffusion
44
What is simple epithelium that appears stratified because the nuclei lie at different levels and not all cells reach the apical surface, but still simple epithelium because all the cells rest on the basement membrane?
Cells that extend to the apical surface may contain cilia
Pseudostratified epithelium
45
What is one specialized type of pseudostratified cells that secrete mucus and are an integral part of mucous membranes?
Goblet cells
46
What provides two forms of locomotion depending on the cell?
1. Movement of the cell itself, like bacteria or some parasites
2. Movement of particles or substances across or around the cell
Cilia in ciliated epithelial cells
47
True or false
In mammals, cilia help remove contaminant or move particles by moving fluids over the cell layers
True
48
True or False
Microvilli on epithelial cells increase the surface area of a cell by multiplying the area from 2 dimensions to 3 dimensions
True
49
What on the cellular surface enables the absorption and secretion of far more nutrients/materials because they expand the active surface area by orders of magnitude?
Microvilli
50
These are all uses of what?
1. Help anchor sperm to the egg for easier fertilization
2. In WBC, they act as an anchoring point and aid in the migration of white blood cells
3. May sweep unwanted material toward and absorptive area of the cell
Microvilli
51
What is a highly-insoluble fibrous protein with water proofing qualities and high friction resistance?
Keratin
52
What are epithelial cells infused with keratin in the stratum basale of the epithelium called?
Keratinocytes
53
True or False
Keratinocytes lose their nucleus and organelles to make room for keratin. They are still living cells
False
They are no longer living cells after losing their nucleus and organelles
54
Non-keratinized or Keratinized Epithelium?
1. Found on wet/interior surfaces exposed to considerable wear and tear
2. Found in the lining of the mouth cavity, tongue, pharynx, esophagus, and vagina
Non-keratinized Epithelium
55
Non-keratinized or Keratinized Epithelium?
1. Found on dry/outer surfaces where resistance to both friction and water is needed
2. outer epidermis provides protection against water, friction, abrasion, and microorganisms
Keratinized epithelium
56
What kind of tissue supports and physically connects other tissues/cells together to form the organs of the body?
Connective tissue
57
What form of tissue has a lot of cells but has low extracellular space?
Epithelial tissue
58
What kind of tissue has a low amount of cells but a larger extracellular surface?
Connective tissue
59
What are the three components of connective tissues?
1. resident cells
2. extracellular matrix (ECM)
3. Protein fibers
60
What is the extracellular material produced by the connective tissue cells embedded within it?
Matrix
61
True or False
Major component of the matrix is ground substance crisscrossed by protein fibers (ground substance is fluid, mineralized or solid)
True
62
What are the most common cells in the connective tissue that produce and maintain most of the tissues extracellular components?
Fibroblasts
63
What CT cells synthesize and secretes collagen and elastin, major component of the reparative capacity of connective tissue?
Fibroblasts
64
What CT cells are also known as fat cells, adipose cells, or adipose tissue?
Adipocytes
65
What CT cells are specialized for cytoplasmic storage of lipids as neutral fats, or less commonly for production of heat?
Adipocytes
66
What large population of cells serves to cushion and insulate the skin and other organs?
Adipocytes
67
What do mast cells secrete?
Histamine
68
What CT cells are components of loose connective tissue often located near small blood vessels in the skin?
Mast cells
69
What CT cells function in the localized release of compounds important to the inflammatory response, innate immunity, and tissue repair?
Mast cells
70
What CT fibers are very abundant (25% of all protein in the body), very strong and resistant to shearing forces, and are a key element of all connective tissues, as well as epithelial basement membranes?
Collagen fibers
71
What CT fibers are composed of elastin, function in strength and elasticity, have rubberlike properties that allow tissues containing to be stretched or distended and return to their original shape?
Elastic fibers
Found in areas such as the stroma of the lungs
72
What CT fibers are compromised of glycogen and glycoprotein?
Reticular fibers
73
What CT fibers provide strength and support in the walls of small blood vessels?
Reticular fibers
74
True or False
Reticular fibers
Stroma supporting framework of many soft organs; most notably the immune system, liver, endocrine glands, spleen, and lymph nodes
True
75
What lines the entire GI, respiratory, reproductive, and much of the urinary system?
Mucous membranes
Epithelial layer secretes mucous (mucin) via goblet cells
76
What serves the following functions?
1. General: Prevents cavities from drying out
2. Resp: traps particles in the respiratory tract
3. GI: lubricates and absorbs food as it moves through the tract, secretes digestive enzymes
4. Derm: helps bind the epithelium to underlying structures
Mucous membranes
77
What lines body cavities that don't open directly to the exterior and covers organs that lie within the cavity?
Serous membrane
78
Parietal, Visceral, or Mesothelium?
Attached to cavity wall
Parietal
79
Parietal, Visceral, or Mesothelium?
Part that covers and attaches to the organs
Visceral
80
Parietal, Visceral, or Mesothelium?
Secretes serous fluid and provides lubrication for organ movement
Mesothelium
81
What is the lining of the thoracic cavity and covers the lungs?
Pleura
82
What is the lining of the heart cavity and covers the heart?
Pericardium
83
What is the lining of the abdominal cavity and the abdominal organs?
Peritoneum
84
What lines joints and is composed of areolar connective tissue and adipose tissue with collagen fibers?
Synovial membranes
85
What contains no epithelial layer and secretes synovial fluid?
Synovial membranes
86
What fluid reduces friction, lubricates and nourishes cartilage, and removes microbes/debris from the joint cavity?
Synovial fluid
87
What is the surface layer of the skin and is comprised of epithelial tissue?
Epidermis
88
What lies inferior/deep to the epidermis and is comprised of connective tissue?
Dermis
89
What lies inferior/deep to the dermis and is not part of the skin?
Subcutaneous (hypodermis)
90
What is the outermost later of the skin and consists primarily of continually regenerating keratinocytes?
Epidermis
91
What is the approximate lifecycle of keratinocytes in the epidermis?
30 days
92
What layer of the skin lacks any vascular structures and obtains all nutrients from the dermal vasculature by diffusion?
Epidermis
93
What layer of the epidermis are cells that consist mostly of keratin and cells are shed and replaced from below?
Stratum corneum
94
What layer of the epidermis is found only in the palms of the hands and soles of the feet?
Stratum lucidum
95
What layer of the epidermis is where it is losing cell organelles and nuclei and the infusion of waterproofing lipids?
Stratum Granulosum
96
In what layer of the epidermis are cells beginning to flatten?
Stratum spinosum
97
In what layer of the epidermis is the stem cell layer where new cells are arising?
Stratum Basale
98
What is the layer of skin between the epidermis and subcutaneous (hypodermis) tissues?
Dermis
99
What layer if skin primarily consists of dense irregular connective tissue and functions to cushion the body from stress and strain?
Dermis
100
True or False
Dermis
A basement membrane always occurs between the stratum basale of the epidermis and the dermis
True
101
True or False
Nutrients from keratinocytes diffuse into the avascular epidermis from the dermal vasculature through the basement membrane
True
102
What is the layer of the epidermis directly underneath the epidermis?
Papillary layer (loose areolar tissue)
103
What layer of the dermis contains the terminal endings of capillaries, lymph vessels and sensory neurons; these extend from the dermis toward the epidermis in the dermal papillae?
Papillary layer
104
What layer of the dermis is thicker than the overlying papillary dermis; compromised of a dense concentration of collagenous, elastic, and reticular fibers that weave throughout it?
Reticular layer
105
True or False
The reticular layer of the dermis contains the roots of hairs, sebaceous glands, sweat glands, receptors, nails, and blood vessels
True
106
What are specialized cells of the epidermis and the hair follicles whose primary function is synthesis and transfer of melanin to adjacent keratinocytes?
Melanocytes
107
Where does melanin synthesis occur?
Melanosomes
108
What are expanded dendritic endings the epidermis of glabrous skin that responds to sustained pressure and touch?
Merkel cells
109
What consists of tactile discs and neurons for touch sensation?
Merkel cells
110
What is typically found within the stratum spinosum, form a mobile and dense network of cells that samples any antigens that attempt to pass through the epidermis, and these monocyte-derived cells represent a large part of the skin's adaptive immunity?
Dendritic cells
111
What derm glands release secretions directly into the blood stream?
Endocrine glands
112
What derm glands release secretions onto an epithelial serface via a duct and plays a major role in derm?
Exocrine glands
113
What are some examples of derm exocrine glands
1. Sebaceous
| 2. Sudoriferous (sweat glands)
114
What is an exocrine gland in the skin that opens into a hair follicle and secretes an oily/waxy sebum?
Sebaceous glands
115
What lubricates the hair in humans and other mammals ?
Sebum
116
Are sebaceous glands found in the palms of the hands or the soles of the feet?
NOPE
117
Sebaceous glands work in conjunction with _____ in thermoregulation
apocrine glands
118
What sudoriferous glands cover nearly the entire body surface; especially dense on the palms, soles, foreheads and upper limbs?
Eccrine glands
119
What glands empty directly onto the surface of the skin, not from hair follicles and serves a major role in the thermoregulation component of the integumentary system?
Eccrine glands
120
True or False
There is odor associated with eccrine glands
False
Minimal odors from eccrine sweat
121
What sudoriferous glands are largely confined to the axillae, perineum, and concentrated in hairy areas?
Apocrine glands
122
What glands are attached to the hair follicle, the sweat produced from these glands empties onto the skin via the follicle opening?
Apocrine glands
123
What sudoriferous glands do not become functional until puberty and have a hormonal activation pattern ?
Apocrine glands
124
True or False
Apocrine sweat is cloudy, viscous, and initially odorless; however, serves as a nutrient source for microbes and attain its characteristic odor upon being degraded by bacteria
True
125
What is the distal margin of the nail plate?
Free edge
126
What is the portion of the nail that is visible; colored pink because of underlying capillaries?
Nail body (plate)
127
What portion of the nail is surrounded by a soft tissue border known as the lateral and proximal nail folds?
Nail body (plate)
128
What is the visible part of the matrix of the nail, the whitish crescent at the base of the nail plate?
Lunula (little moon)
129
What is the semi-circular later of epithelial cells (stratum corneum) covering the proximal portion of the nail plate?
Cuticle
130
What is the thicker area of the stratum corneum beneath the free edge that attaches the free edge to the fingertip?
Nail bed
131
What is the portion of the nail that is not visible?
Nail root
132
What is the proximal portion of the epithelium deep to the nail root where new nail cells are produced?
Nail matrix
133
What protects distal phalanxes and surrounding tissues from injuries?
Nails
134
What enhances precise and delicate finger movement by exerting counter pressure on the pulps of the fingers when grasping and manipulating objects as well as enable "extended precision grip" for pulling and certain cutting or scraping actions?
Nails
135
Fingernails grow approx ___ mm per month and require ____ months to regrow completely
1. 3.5mm
| 2. 3-6 months
136
Toenails grow approx ___ per month and require ____months to regrow completely
1. 1.6 mm
| 2. 12-18 months
137
A lack of oxygen in the blood will make the skin appear bluish, also called what?
Cyanosis
138
A buildup of the yellow pigment bilirubin, indicating liver disease is also referred to as what?
Jaundice
139
What is due to an engorgement of the capillaries in the dermis with blood and is due to a skin injury, exposure to heat, inflammation, or allergic reaction?
Erythema
140
Pallor or paleness may occur with conditions such as what?
Shock or anemia
141
What are the three main pigments that influence skin pigmentation?
1. Melanin (epidermis)
2. Carotene (dermis)
3. Hemoglobin (red blood cells within capillaries of the dermis)
142
What produces a darker brown to black skin tone?
High melanin rate
143
What produces a yellow to reddish skin tone?
High carotene rate
144
What produces a red to pinkish skin tone?
High hemoglobin rate
145
What is the primary determinant of skin color, hair color and eye color?
Melanin
146
What causes the skin color to vary from pale yellow to reddish-brown to black?
Melanin
147
True or False
Melanocyte numbers are approximately the same (3-5%) in all people, regardless of their skin tone or Fitzpatrick scale; however the amount of melanin pigment produced by melanocytes and imparted to keratinocytes can vary massively
True
148
What are yellow colored, lipid-soluble compounds found in red, orange, yellow and green vegetables and fruit?
Carotenoids (carotene)
149
Excessive intake of carotenoids found in vegetables can cause what that is characterized by yellow-orange discoloration of the skin?
Carotenemia
150
What is the iron containing oxygen transporting protein in erythrocytes (RBC)?
Hemoglobin
151
Prolonged decreased oxygen levels increases deoxygenated hemoglobin, subsequently causing _____
cyanosis
152
What is a genetic (recessive-inherited) condition characterized by little or no melanin pigment in the eyes, skin or hair?
Albinism
153
What are the main health complications of albinism?
1. Sunburns easily during UV exposure
| 2. Increased risk for skin cancer over their lifetime
154
What is an acquire depigmentation of the skin characterized by the loss of melanocytes?
Vitiligo
155
What is thought to be a systemic autoimmune disorder in which the antibodies attack the melanocytes?
Vitiligo
156
True or False
Tattoos
Pigment is injected through the epidermis and activates an immune response, resulting in phagocytes and macrophages engulfing pigment particles. Macrophages containing the pigment in the papillary dermis are trapped in the collagen matrix, forming a homogenized layer below the dermal/epidermal boundary
True
157
What are the two methods by which homeostatic temperature regulation occurs?
1. Transfer of heat via sweating (evaporation)
| 2. Maximizing or minimizing heat loss (radiation) via blood flow in the dermis
158
In high environmental temperatures, sweat production increases from the skin surface and helps lower the body temperature meaning evaporation does what?
Evaporation increases
159
In high environmental temperatures dermal blood vessels dilate to allow more blood flow and increase heat loss from the body meaning radiation does what?
Radiation increases
160
In cold environments evaporation ____ and radiation ____
1. Evaporation decreases
| 2. Radiation decreases
161
What is produced in the epidermis that protects from microbes, abrasion, heat, water loss and chemicals?
Keratin (protein)
162
What is released by lamellar granules, inhibits evaporation of water from the skin surface and prevents dehydration?
Lipids (fats)
163
What provides protection against the damaging effects of UV light?
Melanin (pigment)
164
What prevents hair from drying out, are mildly bactericidal and have acidic pH?
Sebum (fat, wax, esters, fatty acids)
165
Tactile sensations (exteroceptors) detect what?
1. Touch (mechanoreceptors)
2. Pressure (baroreceptors)
3. Vibration (Meissner corpuscles)
166
Thermal sensations are detected by what?
Thermoreceptors
167
Pain, impending or actual tissue damage is detected by what?
Nociceptors
168
True or False
Excretion and Absorption
Skin has a small role in excretion compared to the kidneys, GI tract, and respiratory system, however, the skin can absorb a wide variety of substances readily
True
169
Exposure of the skin to UV radiation activates what?
Vitamin D
170
After UV radiation activates Vitamin D it is then converted to ____ which aids in the absorption of calcium and phosphorous
Calcitriol
171
What is the interaction between invading microbes and the reaction of the body's immunologic response; specifically requires some form of microbes to invade the cellular environment?
Infection
172
What is the immunovascular response, without regard to the cause, to any potentially harmful stimuli, this is a generic response and is not tailored to the specific stimuli?
Inflammation
173
These are all signs of what?
1. Localized hyperthermia (due to increased blood flow)
2. Erythema (due to dilation of blood vessels)
3. Localized edema (due to increased vessel permeability and extravasation of fluid)
4. Pain (due to chemical mediators like bradykinin)
5. Loss of function (due to all of the above)
Acute inflammation
174
What is characterized by formation of granulomas and is common in certain diseases (tuberculosis, leprosy, syphilis, etc.)?
Granulomatous inflammation (cystic)
175
What is an aggregation of macrophages from chronic inflammation; the immune system attempts to isolate the foreign substance that it cannot eliminate (pathogens, foreign objects, keratin, suture fragments)?
Granuloma
176
What is characterized by the presence of an amorphous mass (abscess) composed of neutrophils, cellular debris, and microbes?
Suppurative Inflammation (abscesses)
177
What is generally caused by certain pyogenic bacteria (staph) and often forms an abscess?
Suppurative Inflammation
178
What inflammation occurs near the epithelium that results in necrotic loss of surface tissue that exposes lower layers, the subsequent evacuation in the epithelium is known as what as well?
1. Ulcerative inflammation
| 2. Ulcers
179
What is the inevitable physiologic changes of the skin that occurs with time and are influenced by genetic and hormonal factors, this form of aging is not preventable and happens to everyone?
Intrinsic aging
180
What is the preventable structural and functional changes of the skin that occurs with exposure to the following:
1. Environmental factors
2. Lifestyle (smoking, alcohol, drugs, etc.)
3. Social determinants
4. Elective cosmetic surgeries
Extrinsic aging
181
What is the most important source of preventable extrinsic aging?
UV radiation exposure
Termed "photo aging"
182
Epidermal Aging
Between the ages of 30 and 80 the epidermal turnover rate decreases by ___% to ____%, resulting in decreased wound repair capacity
30% to 50%
183
Epidermal Aging
Between the ages of 30 and 80 the unexposed epidermis thins by __% to ___% resulting in easier injury to underlying tissues
10% to 50%
184
True or False
Between age 30 & 80 there is a decrease in the number and function of melanocytes by up to 20% per decade, giving an increased risk of skin cancer in the elderly
True
185
True or False
Between age 30 & 80 there is a reduction in the number and responsiveness of Langerhans cells, resulting in weakened cutaneous immunity in the elderly
True
186
In dermal aging, the reduction of what production enhances the rate and amount of UV exposure (photodamage) ?
Collagen fibers
187
In dermal aging the reduction of what production decreases the elastic recovery and resilience in aged skin?
Elastin fibers
188
True or False
Dermal aging
Abnormalities in ground substance of the connective tissue results in decreased skin hydration and characteristic elderly xerosis (dry skin)
True
189
Tissue repair is the restoration of tissue architecture after an injury and encompasses what two separate processes?
1. Regeneration
| 2. Replacement
190
What form of tissue repair is when the damaged tissue is completely restored to its pre-injury/normal state via new growth?
Regeneration (can happen continuously)
191
What form of tissue repair is when severely damaged or non-regenerable tissue is repaired by laying down connective tissue, resulting in scarring?
Replacement
192
True or False
Most tissue repair consists of a combination of regeneration and replacement, depending on the location and extent of damage
True
193
What is the most rapidly regenerating and repairing tissue and has the capacity for continuous renewal?
Epithelial tissue
194
What tissue has an adequate renewal capacity; slower than epithelial tissues and is prone to hyperproliferation (scarring)?
Connective tissue
195
What tissue has a relatively poor capacity for renewal, the tissue does not divide rapidly enough to replace the extensive damage?
Muscular tissue
196
What tissue has the poorest capacity for renewal because it does not undergo mitosis to replaced its damaged cells?
Nervous tissue
197
What phase of healing is 1-3 days post injury and serves mainly to clear bacteria and debris from the wound and to prepare the wound environment for repair?
Inflammatory phase
198
Healing - Inflammation phase
_____ and ____ forms in the injured space, providing hemostasis and inducing both cellular and chemical inflammatory responses
Platelet and fibrin clots
199
Healing - Inflammation phase
_____ release chemical mediators causing local capillary vasodilation, increasing permeability and augmenting local blood flow and migration of inflammatory cells to the injured area
Mast cells
200
Healing - Inflammation phase
_____ phagocytize cellular debris, bacteria, and foreign material, and release multiple factors that further the inflammatory reaction. After ____ are done, they are removed via physical sloughing or are phagocytized themselves by macrophages
Neutrophils
201
What phase of injury happens 2-10 days post injury and the purpose is to construct granulation tissue to fill the defect caused by the wound?
Proliferative phase
202
Healing - Proliferative Phase
What are the major cellular agents in this phase and produce Type III collagen to provide structural integrity to new tissue
Fibroblasts
203
Healing - Proliferative Phase
What provides contractile force to minimize wound surface area during healing; once enough extracellular matrix has been laid down most fibroblasts undergo apoptosis ?
Collagen
204
Healing - Proliferative Phase
_____ from wound edges migrate onto the wound surface and advance across the wound, leaving proliferating _____ behind until they reach the ____ on the opposite edge?
Keratinocytes
205
These are all associated with what phase of healing?
1. 2-3 weeks post injury; tissue defects have been replaced with granulation tissue and covered by new epithelial cells
2. Wound tissue now consists of disorganized collagen and extracellular matrix proteins without dermal appendages (hair follicles/sweat glands) and is covered with epithelium
3. Surface of the wound contracts, causing base of the wound to be wider than the surface
4. Fibroblasts, macrophages, and endothelial cells in wound space begin to apoptosis or exit wound
Healing - Early remodeling phase
206
The following is associated with what phase of healing?
1. Happens months to >1 year post injury
2. The type III collagen laid down by the fibroblasts are replaced with type I collagen and collagen fibrils become more organized
3. As collagen rearranges, the tensile strength of the wound increases from 20% at 3 weeks after injury, to 70–80% at 6 weeks, but never reaches the full strength of uninjured tissue
4. Over time, collagen fiber rearrangement makes the scar become less thick & firm
5. The initial capillaries formed in the inflammatory phase regress and the scar becomes and less erythematous
Healing - Late remodeling phase
207
What form of healing relies on dermal edges that are close together and closely approximated?
Healing by primary intention
208
The following are pros associated with what?
1. Most often results in a complete return to function with minimal scarring and loss of skin appendages
2. Sutures, staples, and dermal adhesive are readily available to the IDC
Healing by Primary Intention
209
These are cons associated with what?
1. Requires relatively clean wounds without major avulsion or asymmetric/jagged edges
2. Easily mismanaged by providers who lack experience and technique
3. Potential for scarring and poor cosmetic outcome due to patient non-compliance
Healing by Primary Intention
210
What form of healing relies on formation of granulation tissue to fill the space between the wound opening or edges?
Healing by Secondary Intention
211
These are pros associated with what?
1. Decrease chance of wound infection by allowing exudate drainage from the wound
2. Closure of choice when dealing with a large wound made by infection
Healing by Secondary Intention
212
These are cons associated with what?
1. Wounds take much longer to heal
2. Greater likely of scar formation because edges are not approximated
3. Wounds must be regularly examined and re-evaluated to ensure proper care
Healing by Secondary Intention
