skin Flashcards
(215 cards)
1
Q
what is the epidermis composed of
A
epithelial cells, outermost layer
2
Q
what is the dermis composed of
A
dense cv
3
Q
what is the subcutaneous tissue
A
its superficial to the tough ct wrapping of skeletal muscle
4
Q
where is subcutaneous tissue found
A
deep to the skin also known as hypodermis
5
Q
subcutaneous tissue is made of
A
adipose tissue w some areolar cv
6
Q
how does the fatty composition affect st
A
acts as a shock absorber and insulator that reduces heat loss
7
Q
what is the role of keratinocytes
A
produce keratin which gives the skin protective protperties
8
Q
what connects keratinocytes
A
desmosomes (for strength), tight junction (hinder movement of water)
9
Q
what is the deepest cell layer of the epidermis
A
stratum basale
10
Q
in response to epidermal growth
A
stratum basale goes through continuous mitosis
11
Q
when newly keratinocytes are formed
A
they r pushed upward by production of new cells under them
12
Q
keratin cells are dead on the surface of the skin
A
true
13
Q
epidermis renews every
A
25-45 days
14
Q
what does persistent friction cause
A
thickening of epidermis called CALLUS
15
Q
what are melanocytes
A
spider-shaped cells produce melanin (deepest layer)
16
Q
what are melanosomes
A
membrane bound granules where melanin is made
17
Q
what does basale keratinocytees contain
A
more melanin than melanocytes
18
Q
melanin clusters on the side of keratinocyte nucleus forming
A
pigment shield that protects the nucleus from the damaging effects of ultraviolet (UV) radiation in sunlight.
19
Q
what are dendritic cells
A
star shapes cells arise from bone marrow to the epidermis
20
Q
dendritic cells are also called
A
langerhans cells
21
Q
what do dendrite cells do
A
ingest foreign substances and are key activators to our immune system
22
Q
dc’s processes
A
extend among keratinocytes forming a continuous network
23
Q
what are tactile epithelial cells
A
spiky hemispheres associated with nerve ending
24
Q
where are tactile epithelial cells found
A
epidermal-dermal junction
25
tactile epithelial cells are
sensory receptors for touch
26
thick skin covers
palms, fingertips, soles of feet
27
how many layers do thick and thin layers have
thick 5, thin 4
28
what is stratum basale
its the deepest epidermal layer
29
what is stratum basale attached to
underlying dermis along a wavy borderline
30
stratum basale consists of
single row of stem cells (youngest keratinocytes)
31
10-25% of cells in stratum basale are
melanocytes (branch processes surrounds the cell)
32
what is Stratum Spinosum
several cell layers thick
33
what is Stratum Spinosum named after
spinelike extentions of keratinocytes
34
the spine like extentions in keratinocytes
created during tissue preparation because cells shrink while holding tight to there desmosomes
35
Stratum Spinosum contains
thick bundles of intermediate filaments
36
what do intermediate filaments consist of
tension resisting protein and pre-keratin
37
Scattered among
the keratinocytes are
dendritic cells, which are most abundant in this epidermal layer
38
what does Stratum Granulosum consist of
1 to 5 cell layers where keratinocytes change to keratinization
39
what happens to keratinocytes
flatten their nuclei and organells disintegrate and make 2 tyes of granules
40
keratohyaline granuals
help form keratin in the upper area
41
lamellar granuales
contain water-resistant glycolipid secreted into extracellular
42
glycolipid +tight junction
major part in slowing water loss
43
what makes cells tough and water resistant
proteins within keratinocyes and lipid
44
what does stratum lucidum consist of
row of flat dead keratinocytes
45
stratum lucidum only found in
thick skin
46
where is Stratum Corneum
its the outermost layer broad zone to 20 to 30 cell thick layers
47
Stratum Corneum is
btw the nucleated cells of s.g and flattened cells of Stratum Corneum
48
keratin is consist of
pre-keratin intermediate filaments embedded in a glue from the keratohyaline granules
49
keratin + proteins
accumulate inside plasma mm of cells to protect the skin against abrasion and penetration
50
who helps makes the Stratum Corneum nearly water proof
the glycolipid btw cells
51
what is the dermis made of
strong flexible ct embedded w fibers
52
cells that r found in the dermis
fibroblasts, macrophages, mast cells wbc
53
papillary dermis is made of
areolar ct has collagen and elastic fibers form a loose mat w many small blood vessels
54
the loose ct allows
phagocytes and defensive cells to move freely
55
dermal papillae
peglike projections from its surface which indent the overlying epidermis (anchors epidermis to dermis)
56
dermal papillae contain
capillary loops
57
touch receptors called
tactile or meissner's corpuscles
58
in thick skin these papillaes lie
atop larger mounds called dermal ridges
59
dermal ridges cause
overlying dermis forms epidermal ridges
60
friction ridges
enhance our ability to grip certain kinds of surfaces
61
what contribute our sense of touch
when vibrations are enhanced detected by lamellar corpuscles
62
reticular dermis
80% of thge thickness of the dermis
63
reticular dermis is made of
dense irregular ct
64
reticular dermis is nourished
by a network of blood vessels (dermal vascular plexus btw this layer and st)
65
extracellular matrix of reticular dermis is filled with
thick bundles of interlacing collagen fibers
66
reticular dermis is named for its
network of collagen fibers which run parallel to the skin surface.
67
cleavages are
spaces less dense areas btw bundles of reticular dermis
68
cleavages r imp to surgeons
cuz when an incision is made parallel to these lines they heal more readilt
69
what do collagen fibers do
give skin strength and resiliency that prevent jabs and scrapes
70
what do elastic fibers do
stretch-recoil properties
71
flexure lines are
dermal folds that occur at or near joints (dermis is tightly secured)
72
What causes striae (stretch marks)?
Extreme stretching of the skin that tears the dermis.
73
What do stretch marks look like?
Silvery white scars.
74
What can cause a blister?
Short-term but acute trauma, like burns or repeated friction.
75
What is a blister?
A fluid-filled pocket that separates the epidermal and dermal layers.
76
what is melanin
polymer made of a.a called tyrosine
77
melanin forms
range in color from reddish yellow to brownish black
78
what does melanin synthesis depend on
an enzyme in melanocytes called tyrosinase
79
melanin is transported from
melanocytes to basal keratinocytes
80
what breaks down melanosomes
lysosomes
81
where is melanin pigment only found
in deeper layers of epidermis
82
darker skinned ppl found
near equator
83
lighter skin found
closer to poles
84
prolonged sun explosure causes
melanin buildup
85
melanin buildup helps in
protecting the DNA of skin cells from UV radiation by absorbing the rays
and dissipating the energy as heat
86
What does excessive sun exposure do to the skin's elastic fibers?
It causes them to clump, leading to leathery skin.
87
How does too much sun exposure affect the immune system?
It temporarily depresses the immune system.
88
How can sun exposure contribute to skin cancer?
It can alter the DNA of skin cells.
89
Are darker-skinned people completely protected from melanoma?
No, they are less likely but still at risk and should evaluate suspicious skin changes.
90
Which types of skin cancer can occur in all skin types?
Basal cell and squamous cell cancers.
91
What is photosensitivity?
Increased skin sensitivity to UV radiation, often leading to rashes.
92
Name some substances that can cause photosensitivity.
Certain antibiotics, antihistamines, perfumes, and detergents.
93
What skin reaction can photosensitivity cause?
Small, itchy blisters erupt all over the body.
94
what is carotene
yellow to orange pigment found in certain plants like carrot
95
Where does carotene tend to accumulate in the body?
In the stratum corneum and subcutaneous fat.
96
What important vitamin can carotene be converted into?
Vitamin A
97
What are two roles of vitamin A in the body?
It is essential for normal vision and epidermal health.
98
What causes the pinkish hue in fair skin?
The crimson color of oxygenated hemoglobin in dermal capillaries.
99
Why is hemoglobin’s color more visible in light-skinned people?
Because they have less melanin, making the epidermis nearly transparent.
100
What is cyanosis and what causes it?
A bluish-gray tint of the skin caused by poorly oxygenated hemoglobin.
101
What health issues might cyanosis indicate?
Respiratory or cardiovascular problems.
102
What is pallor and when might it occur?
Pallor is blanching or paleness of the skin, seen during emotional stress, low blood pressure, or anemia
103
What does redness or erythema of the skin typically indicate?
Embarrassment, fever, inflammation, or allergy.
104
What causes jaundice, and where is it most noticeable?
Liver malfunction causing bilirubin buildup, most noticeable in the whites of the eyes (sclerae).
105
How can eating a lot of yellow vegetables affect skin color?
It can cause a golden skin tone without affecting the sclerae.
106
What causes bruises (ecchymoses or hematomas)?
Damaged blood vessels leaking blood into surrounding tissue.
107
Why is the size, color, and shape of ecchymoses important?
They are important clues in forensic medicine.
108
What might dark brown or black patches around the neck and axillae suggest?
Insulin resistance and elevated blood glucose.
109
main function of hair in us humans is
to sense insects on the skin before they bite or sting us
110
what are hairs or pili
flexible strands produced by hair folicles consist of largely dead keratinized cells
111
What are two advantages of hard keratin over soft keratin?
(1) It is tougher and more durable, and (2) its individual cells do not flake off.
112
What are the two chief regions of a hair?
The root (embedded in the skin) and the shaft (projects above the skin’s surface).
113
What hair shape corresponds to kinky hair?
Flat and ribbonlike in cross section.
114
Which cross-sectional shape of hair results in straight, coarse hair?
perfectly round
115
What are the three concentric layers of a hair?
Medulla, cortex, and cuticle
116
What part of the hair contains soft keratin and is absent in fine hairs?
The medulla.
117
What part of the hair is the most heavily keratinized?
The cuticle.
118
What causes split ends in hair?
Wearing away of the cuticle, exposing keratin fibrils in the cortex and medulla.
119
What pigment colors red hair?
Pheomelanin.
120
Why does hair turn gray or white?
Decreased melanin production and air bubbles replacing melanin in the hair shaft.
121
Where do hair follicles extend from and into?
From the epidermal surface into the dermis (and sometimes the subcutaneous tissue).
122
What is the expanded deep end of a hair follicle called?
hair bulb
123
What wraps around each hair bulb and acts as a touch receptor?
hair follicle receptor (or root hair plexus).
124
What is the function of the hair papilla?
It supplies nutrients and signals the hair to grow.
125
What happens if the hair papilla is destroyed?
The hair follicle permanently stops producing hair.
126
What are the three layers of the hair follicle wall from external to internal?
peripheral ct sheath, glassy mm, epithelial root sheath
127
What are the two parts of the epithelial root sheath?
External root sheath and internal root sheath.
128
What is the hair matrix?
A group of rapidly dividing cells adjacent to the hair papilla that produces new hair cells.
129
What muscle is associated with hair follicles and what does it do?
Arrector pili muscle; it pulls the hair upright to produce goose bumps.
130
What additional role does the arrector pili muscle play in humans?
It helps force sebum out of hair follicles to lubricate the skin.
131
What are the two classifications of hair?
Vellus hair (pale, fine) and terminal hair (coarse, longer, often darker).
132
Where is terminal hair found before puberty?
Eyebrows, eyelashes, and scalp.
133
What causes the appearance of terminal hair in new body areas at puberty?
The effects of androgens (male sex hormones, mainly testosterone).
134
What is hirsutism?
Excessive growth of coarse terminal hair in a masculine distribution in women.
135
What is a common cause of hirsutism?
pcos or androgen-secretin tumors
136
How fast do hairs typically grow?
2mm per week
137
What happens during the resting phase of the hair growth cycle?
The hair matrix becomes inactive, and the follicle shrinks.
138
Why don't all human hairs shed at the same time?
Hair follicles go through growth cycles independently of each other.
139
What happens to hair during normal aging (around 60–65 years)?
Hair thins as terminal hairs are replaced by wispy vellus hairs.
140
What causes male pattern baldness?
A genetic and androgen-influenced shortening of the hair growth cycle.
141
What is telogen effluvium (TE)?
Abrupt hair thinning when many follicles enter the resting phase at once, often after physical or emotional stress.
142
What are some other causes of hair thinning besides TE?
Low thyroid hormone, certain drugs (antidepressants, chemotherapy), and severe dietary deficiencies.
143
What is the primary function of nails?
To protect the distal surface of fingers and toes and assist in picking up small objects or scratching.
144
What type of keratin is found in nails?
hard keratin
145
What are the three main parts of a nail?
The proximal root, the nail plate (body), and the free edge.
146
What is the nail bed?
A bed of epidermis under the nail plate that contains only deeper epidermal layers.
147
What structure is responsible for nail growth?
nail matrix
148
why does the nail appear pink
Due to the rich bed of capillaries in the underlying dermis.
149
What is the lunule?
The white crescent-shaped area over the thick nail matrix.
150
What is the eponychium?
Another name for the cuticle, the projection of the proximal nail fold onto the nail body.
151
What is the hyponychium?
The thickened region beneath the free edge of the nail that secures the nail to the fingertip.
152
What does yellow-tinged nails often indicate?
A respiratory or thyroid gland disorder, or fungal infection if the nail is thickened.
153
What does koilonychia ("spoon nail") suggest?
iron deficiency.
154
What do Beau’s lines across the nails signify?
Severe illness such as uncontrolled diabetes, heart attack, or effects from chemotherapy.
155
What are sweat glands also called?
Sudoriferous glands.
155
What are the two types of sweat glands?
Eccrine glands and apocrine glands.
156
What do myoepithelial cells do in sweat glands?
They contract to push sweat through ducts to the skin surface.
157
Where are eccrine sweat glands most abundant?
Palms, soles, and forehead.
158
What type of secretion do eccrine sweat glands produce?
A hypotonic filtrate of blood, mainly 99% water with salts, wastes, and dermcidin.
159
What is the major role of eccrine sweating?
To prevent body overheating
160
Where are apocrine sweat glands located?
Axillary and anogenital areas.
161
What is different about apocrine sweat compared to eccrine sweat?
It contains fatty substances and proteins, making it viscous and sometimes yellowish.
162
When does apocrine gland activity begin?
At puberty, under the influence of androgens.
163
What are the two modified types of apocrine glands?
Ceruminous glands (earwax) and mammary glands (milk).
164
What do ceruminous glands produce?
Cerumen, or earwax.
165
What do sebaceous glands secrete?
Sebum, an oily substance.
166
What type of gland are sebaceous glands functionally?
Holocrine glands.
167
What are three functions of sebum?
Softens and lubricates hair and skin, prevents brittle hair, and has bactericidal properties.
168
What is acne caused by?
Inflammation of sebaceous glands and infection by Propionibacterium acnes.
169
What is seborrhea, and what is it called in infants?
Overactive sebaceous glands causing oily scaling; called "cradle cap" in infants.
170
What are the main functions of the skin?
rotection, body temperature regulation, cutaneous sensation, metabolic functions, blood reservoir, and excretion.
171
What are the three types of barriers that the skin provides?
Chemical, physical, and biological barriers.
172
how do chemical barriers protect the skin?
Skin secretions like sweat and sebum kill bacteria, melanin protects against UV radiation, and defensins punch holes in bacteria, preventing infection.
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What is the acid mantle?
The low pH of skin secretions that retards bacterial multiplication.
174
How does the skin serve as a physical barrier?
The epidermis’ continuity and keratinized cells provide a tough, flexible barrier. The stratum corneum's structure (bricks and mortar) helps block water and water-soluble substances.
175
What are the biological barriers in the skin?
Dendritic cells (immune cells) and dermal macrophages, which engulf foreign invaders and trigger immune responses.
175
What substances can penetrate the skin?
Lipid-soluble substances (e.g., oxygen, fat-soluble vitamins), oleoresins (poison ivy), organic solvents (e.g., acetone), heavy metals (e.g., lead), and selected drugs.
175
Why are organic solvents and heavy metals dangerous when absorbed through the skin?
They can cause kidney failure, brain damage, anemia, and neurological defects.
176
What happens during insensible perspiration?
Sweat glands secrete about 500 ml of sweat per day without noticeable sweating, helping to maintain body temperature.
177
How does the skin regulate body temperature in hot conditions?
Dermal blood vessels dilate, and sweat glands produce visible sweat (sensible perspiration), which evaporates to cool the body.
178
What happens when the body is exposed to cold temperatures?
Dermal blood vessels constrict, conserving body heat by reducing heat loss through the skin.
179
What is the role of cutaneous sensory receptors?
They allow the skin to respond to external stimuli, such as touch, pressure, pain, and temperature changes.
180
What are the four types of cutaneous receptors, and what do they sense?
-tactile (Meissner’s) corpuscles: Detect light touch (e.g., caresses).
-Lamellar (Pacinian) corpuscles: Sense deep pressure and bumps.
-Hair follicle receptors: Detect movement of hair (e.g., wind or tugging).
-Free nerve endings: Sense pain (e.g., heat, cold, or irritating chemicals).
181
How does the skin contribute to metabolic functions?
the skin helps in the synthesis of vitamin D, disarms cancer-causing chemicals, and activates steroid hormones like cortisone to hydrocortisone.
182
What is the role of the skin in regulating body temperature?
The skin helps cool the body by producing sweat and dilating blood vessels, while it helps conserve heat by constricting blood vessels in cold environments.
183
How much of the body’s blood volume can the dermis hold?
The dermal vascular supply can hold about 5% of the body's total blood volume.
184
What is basal cell carcinoma, and how is it treated?
It is the least malignant and most common type of skin cancer, arising from stratum basale cells. It often appears as shiny, dome-shaped nodules. Treatment usually involves surgical excision, with a 99% cure rate.
184
What is excretion, and how does the skin participate in this function?
The skin helps excrete waste products like ammonia, urea, and uric acid through sweat, and also plays a role in the loss of water and salts.
184
What are the three major types of skin cancer?
Basal cell carcinoma, squamous cell carcinoma, and melanoma.
185
What is the most common type of cancer, and what is its primary risk factor?
skin cancer is the most common type, with UV radiation from sunlight and tanning beds being the primary risk factor.
186
What is squamous cell carcinoma, and how does it behave?
Squamous cell carcinoma arises from stratum spinosum keratinocytes, appearing as a scaly, reddened papule. It grows rapidly and can metastasize if not treated, but it is curable if detected early.
187
What makes melanoma the most dangerous type of skin cancer
melanoma is highly metastatic (spreads easily) and resistant to chemotherapy. It accounts for most skin cancer deaths, despite only making up 1% of cases.
188
How can melanoma be detected early?
The ABCD rule is used for recognizing melanoma:
A: Asymmetry
B: Border irregularity
C: Color (multiple colors)
D: Diameter (larger than 6 mm)
E: Evolution (changes over time)
189
Where can melanoma develop, and what is its common appearance?
Melanoma can begin anywhere there is pigment, often appearing as a brown to black patch. It can develop from preexisting moles, spreading rapidly.
190
What is the immediate life-threatening effect of severe burns?
Severe burns can lead to catastrophic loss of body fluids, causing dehydration, electrolyte imbalance, renal failure, and circulatory shock.
191
1st degree burn
Damage only to the epidermis; redness, swelling, and pain. Heals in 2-3 days.
192
2nd degree burn
Damage to epidermis and upper dermis; blisters, red, and painful. Heals in 3-4 weeks with minimal scarring.
193
3rd degree burn
Full-thickness burns involving all skin layers; no pain due to nerve destruction, requires skin grafting.
194
When are burns considered critical?
Over 25% of the body has second-degree burns
Over 10% of the body has third-degree burns
Third-degree burns occur on the face, hands, or feet
195
How is the extent of burns assessed in adults?
the rule of nines is used to estimate the percentage of body surface burned, dividing the body into areas each accounting for 9% of the total surface area, plus 1% for the genital area.
196
What are the main dangers of severe burns aside from pain?
The main dangers include loss of fluids (leading to dehydration), electrolyte imbalance, renal failure, and circulatory shock
197
What is the treatment for third-degree burns?
Treatment for third-degree burns often involves skin grafting due to the full-thickness nature of the burn, as the skin may not regenerate properly on its own.
197
What does the rule of nines help with?
The rule of nines is used to estimate the percentage of body surface area affected by burns, helping in assessing the severity and determining treatment.
198
What role does the skin play in metabolic functions?
The skin helps synthesize vitamin D when exposed to sunlight, which is important for calcium metabolism. It also "disarms" cancer-causing chemicals and activates certain steroid hormones.
199
How does the skin help regulate body temperature?
The skin regulates body temperature by adjusting blood flow (constricting or dilating dermal blood vessels) and producing sweat. Sweating evaporates, cooling the body. In cold environments, the skin retains heat by constricting blood vessels.
200
What is insensible perspiration?
Insensible perspiration is the unnoticed loss of about 500 mL of sweat per day under normal resting conditions, which helps in regulating body temperature.
201
What is sensible perspiration?
Sensible perspiration is the noticeable sweating that occurs when body temperature rises, helping cool the body through evaporation.
202
What happens when the skin is exposed to UV radiation?
UV radiation can damage DNA, leading to mutations, and can cause skin cancers such as basal cell carcinoma, squamous cell carcinoma, and melanoma.
203
What is the primary concern for burn patients after the initial crisis?
After the initial crisis, infection becomes the main threat, with sepsis (widespread bacterial infection) being the leading cause of death.
204
Why is IV hydration critical for burn patients?
IV hydration is critical to replace lost fluids, as burn patients experience significant fluid loss due to tissue damage.
205
What role do antibiotics play in burn treatment?
Antibiotics are important in treating burns to prevent infections, as bacteria, fungi, and other pathogens can invade the burned areas.
206
207
Why is synthetic skin sometimes used for skin grafts?
Synthetic skin, made of silicone and a spongy dermal layer, is used when autografts are not possible, and it allows the patient's own tissue to gradually absorb and replace the artificial material.
208
What is 3D bio-printing and how does it assist in burn treatment?
3D bio-printing is a tissue engineering technology that creates skin grafts using a bio-ink composed of keratinocytes, fibroblasts, pericytes, and endothelial cells. It helps create a functional epidermis and vascularized dermis, improving graft survival and integration with the patient’s tissue.
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