UNIT 2 Handout PART 2 Flashcards
1
Q
- contributes to homeostasis by protecting the body and helping regulate body temperature.
- sense pleasurable, painful, and other stimuli in your external environment.
- Vulnerable to damage from trauma, sunlight, microbes, and pollutants in the environment, the skin’s protective features ward off such damage.
- skin reflects our emotions (frowning, blushing) and some aspects of normal physiology (such as sweating).
- Changes in skin color may also indicate homeostatic imbalances in the body.
A
integumentary system
2
Q
FUNCTIONS OF THE SKIN
A
- thermoregulation
- blood reservoir
- protection
- cutaneous sensation
- excretion and absorption
- synthesis and vitamin D
3
Q
- liberating sweat at its surface adjusting the flow of blood
- In response to high environmental temperature or heat produced by exercise, sweat production from ___________ increases
- Blood vessels in the dermis of the skin dilate (become wider)
- More blood flows through the dermis, which increases the amount of heat loss from the body.
- In response to low environmental temperature, production of sweat from eccrine sweat glands is decreased, Which helps conserve heat.
- Blood vessels in the dermis of the skin constrict (become narrow), which decreases blood flow through the skin and reduces heat loss from the body.
A
- THERMOREGULATION
- eccrine sweat glands
4
Q
- _______ houses an extensive network of blood vessels that carry ______ of the total blood flow in a resting adult.
- For this reason, the skin acts as a ___________
A
- BLOOD RESERVOIR
- dermis
- 8–10%
- blood reservoir
5
Q
- PROTECTION
A
- keratin
- lipids
- oily sebum
- acidic pH of perspiration
- melanin
- immunological in nature: epidermal langerhans cells and macrophages
6
Q
protects underlying tissues
A
keratin
7
Q
- released by lamellar granules
- inhibit evaporation of water from the skin surface, thus guarding against dehydration
A
lipids
8
Q
- from the sebaceous glands
- keeps skin and hairs from drying out
- bactericidal chemicals
A
oily sebum
9
Q
retards the growth of some microbes
A
acidic pH of perspiration
10
Q
helps shield against the damaging effects of ultraviolet light
A
melanin
11
Q
alert the immune system to the presence of potentially harmful microbial invaders
A
epidermal langerhans cells
12
Q
phagocytize bacteria and viruses that manage to bypass the Langerhans cells of the epidermis
A
macrophages
13
Q
sensations that arise in the skin
A
- CUTANEOUS SENSATIONS
- tactile sensation
- thermal sensation
- pain
14
Q
sensations that arise in the skin,
A
tactile sensation
15
Q
warmth and coolness
A
thermal sensations
16
Q
- An indication of impending or actual tissue damage
- there is a wide variety of nerve endings and receptors distributed throughout the skin, including the tactile discs of the epidermis, the corpuscles of touch in the dermis, and hair root plexuses around each hair follicle.
A
pain
17
Q
- Besides removing water and heat from the body, _____ also is the vehicle for excretion of small amounts of salts, carbon dioxide, and two organic molecules that result from the breakdown of proteins— ______ & ______
A
EXCRETION
- sweat
- ammonia and urea
18
Q
- the passage of materials from the external environment into body cells
- water-soluble substances
- lipid soluble substances
A
ABSORPTION
19
Q
absorption is negligible
A
water-soluble substances
20
Q
- Penetrate to the skin
o Fat soluble vitamins (__, __, __, __)
o Certain drugs
o Oxygen and carbon dioxide
o Toxic materials that can be absorbed through the skin include organic solvents such as
- _______ (in some nail polish removers)
- _______ (dry cleaning fluid)
- salts of heavy metals such as lead, mercury, and arsenic
- Substances in poison ivy and poison oak
A
LIPID-SOLUBLE SUBSTANCES
- A, D, E, K
- Acetone
- Carbon tetrachloride
21
Q
- Most drugs are either absorbed into the body through the __________ or __________
- An alternative route, _________, enables a drug contained within an adhesive skin patch to pass across the epidermis and into the blood vessels of the dermis.
- drug is released continuously at a controlled rate over a period of one to several days.
- specially useful for drugs that are quickly eliminated from the body because such drugs, if taken in other forms, would have to be taken quite frequently.
- Because the major barrier to penetration of most drugs is the __________, transdermal absorption is most rapid in regions of the skin where this layer is thin, such as the scrotum, face, and scalp
A
- digestive system
- injected into subcutaneous tissue or muscle
- transdermal (transcutaneous) drug administration
- stratum corneum
22
Q
- SYNTHESIS AND VITAMIN D
A
- UV rays in sunlight
- enzyme sin the liver and kidneys then modify the activated molecule, finally producing calcitriol
23
Q
Precursor - vitamin D
A
UV rays in sunlight
24
Q
- The most active form of vitamin D.
- aids in the absorption of calcium
A
enzymes in the liver and kidneys then modify the activated molecule, finally producing calcitriol
25
SKIN WOUND HEALING
- epidermal wound healing
- deep wound healing
26
common types of epidermal wounds
1. abrasions (a portion of skin has been scraped away)
2. minor burns
27
In response to an epidermal injury:
- basal cells of the epidermis surrounding the wound break contact with the basement membrane.
- cells then enlarge and migrate across the wound which appears to migrate as a sheet until advancing cells from opposite sides of the wound meet.
- When epidermal cells encounter one another, they stop migrating due to a cellular response called ___________.
- Migration of the epidermal cells stops completely when each is finally in contact with other epidermal cells on all sides.
- contact inhibition
EPIDERMAL WOUND HEALING
28
As the basal epidermal cells migrate:
- a hormone called __________ stimulates basal stem cells to divide and replace the ones that have moved into the wound.
- The relocated basal epidermal cells divide to build new ____, thus thickening the new epidermis
- epidermal growth factor
- strata
EPIDERMAL WOUND HEALING
29
Deep wound healing occurs in four phases
1. inflammatory phase
2. migratory phase
3. proliferative phase
4. maturation phase
30
- blood clot
_________:
- a vascular and cellular response that helps eliminate microbes, foreign material, and dying tissue in preparation for repair.
- vasodilation and increased permeability of blood vessels associated with inflammation enhance delivery of helpful cells.
o __________
o __________: macrophages that phagocytize microbes; and mesenchymal cells, which develop into fibroblasts.
DEEP WOUND HEALING
- inflammation
o Neutrophils
o Monocytes
31
- clot → scab → epithelial cells migrate beneath the scab
- ________ migrate along _____ threads and begin synthesizing scar tissue (_____ & _____), and damaged blood vessels begin to regrow.
- ________ tissue
MIGRATORY PHASE
- Fibroblasts; fibrin
- collagen fibers and glycoproteins
- granulation tissue
32
- extensive growth of _________ beneath the scab
- deposition by fibroblasts of collagen fibers in random patterns
- continued growth of blood vessels
PROLIFERATIVE PHASE
- epithelial cells
33
- the scab sloughs off once the epidermis has been restored to normal thickness.
- Collagen fibers become more organized, fibroblasts decrease in number, and blood vessels are restored to normal
MATURATION PHASE
34
FIBROSIS
- hypertrophic scar
- keloid/cheloid scar
35
If such a scar remains within the boundaries of the original wound
hypertrophic scar
36
If it extends beyond the boundaries into normal surrounding tissues
keloid scar/cheloid scar
37
Scar tissue differs from normal skin:
- collagen fibers are more densely arranged
- decreased elasticity
- fewer blood vessels
- may or may not contain the same number of hairs, skin glands, or sensory structures as undamaged skin
- lighter in color
