Ch. 4 - Skin

Question 1

Melanin

Answer 1

Effects skin pigment and protects against UV light. Is a block for UV light, at the base of the epithelium? Helps to tan.

Question 2

Carotene

Answer 2

Vitamin A precursor. Effects skin pigment, and you can get it from carrots

Question 3

Smooth muscle sphincters

Answer 3

(Often?) in capillary loops. Regulate blood flow. This can be used to regulate heat loss. When you get cold they constrict to reduce blood flow, and regulate how much heat you lose

Question 4

Function of skin

Answer 4

• Protection: Barrier to bacteria; Cushioning
• Thermoregulation: Sweating to loose heat, Hair to retain heat; sensory, Blood supply to capillaries
• Sensation: Heat, cold, touch, pain, etc.
• Excretion and absorption: Urea and ammonia
• Vitamin D production

Question 5

Vitamin D Production

Answer 5

UV light needed. There is a trade off, skin cancer or weak bones?

Question 6

Melanin//Vitamin D trade off

Answer 6

Depending on ones geographic location, one may have higher or lower amounts of melanin and vitamin D. They are inversely related. Higher melanin leads to decreased vitamin D absorption

Question 7

Arrestor pili

Answer 7

Muscles that help hairs stand up and lie flat

Question 8

Structure of Skin

Answer 8

Epidermis, dermis, hypodermis, hair, follicle, sebaceous gland, Arrector pili, sweat gland, fat

Question 9

Keratinocytes

Answer 9

Form the protective layer (keratin)`

Question 10

Melanocytes

Answer 10

Protection from ultraviolet light (melanin)

Question 11

Langerhans cells

Answer 11

Immune response

Question 12

Merkel cells

Answer 12

Touch sensation

Question 13

Cells in the EPIDERMIS

Answer 13

Keratinocytes, melanocytes, langerhans cells, merkel cells

Question 14

Layering of the epidermis

Answer 14

Ordered from nearest to furthest from the surface:

Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basale, Dermal papilla (dermis)

Question 15

Stratum basale

Answer 15

• Deepest layer
• Stem cells (Mitosis)
• Replaces lost skin cells

Question 16

Stratum spinosum

Answer 16

• Cells bound by desmosomes
• Support for epidermis
• Some mitosis

Question 17

Stratum granulosum

Answer 17

• Cells become squamous (flatten)
• Fills with keratin
• Produce lipids (waterproofing)
• Apoptosis

Question 18

Stratum lucidum

Answer 18

• Only in thick skin (lucid…)

- CLEAR layer of dead cells

Question 19

Stratum corneum

Answer 19

• Dead cells containing keratin
• Multiple layers of overlapping cells for protection (Stratified)
• Gradually lost off surface

Question 20

Thick Skin

Answer 20

Location: Palms, fingers, soles of feet

• Thick stratum spinosum and corneum
• Stratum lucidum is present
• Dermal papillae: fingerprints

Question 21

Thin Skin

Answer 21

Location: Everywhere else

- Fewer dermal papillae

Question 22

Dermis

Answer 22

Two layers: Papillary, and reticular

Question 23

Papillary layer (Dermis)

Answer 23

• Areoloar connective tissue and elastic fibers.
• Many capillaries.
• Loose tissue allows movement of WBC.

Question 24

Reticular layer (Dermis)

Answer 24

• Dense irregular connective tissue.
• Collagen fibers in all directions.
• Provides strength for the skin.

Question 25

Dermal papilla

Answer 25

Blood vessels in a dermal papilla reduces the distance to each cell Nutrients can reach the cells and waste does not accumulate

Question 26

Capillary loops

Answer 26

Regulates heat loss through smooth muscle sphincters that regulate blood flow. The more blood, the more heat loss

Question 27

Color of skin

Answer 27

Determined by CAROTENE (vitamin A precursor) and MELANIN in melanocytes protects against ultraviolet

Question 28

Hair Follicle

Answer 28

Consists of the hair (Medulla, cortex, cuticle) and the follicle (interior and exterior epithelial root sheath, and dermal root sheath)

Question 29

Hair Growth

Answer 29

Papilla: Area of the hair with blood vessels going in for nutrients Matrix: Stem cells going through mitosis Melanocytes: produces melanin (melanin effects hair color) Process: Cells rise up the hair follicle, becoming keratinized, then eventually die

Question 30

Nails

Answer 30

Consists of matrix, root, epinychium (provides a seal to protect), hyponychium, nail bed (blood), free edge

Question 31

Nail Growth

Answer 31

Similar to hair growth. As cells move from the matrix to the outside they fill up with keratin and die

Question 32

Sebaceous glands

Answer 32

Secretes oil onto the hair cuticle

Question 33

Eccrine sweat glands

Answer 33

Secretes sweat onto the skin

Question 34

Apocrine sweat glands

Answer 34

Secretes sweat onto the hair | Located in the armpits and groin

Question 35

Deep Wound Healing

Answer 35

Inflammatory, migratory, proliferative, maturation

Question 36

Inflammatory (Healing)

Answer 36

Blood clot to stop bleeding Basophils signal the presence of bacteria through histamines Histamines signal phagocytes and vasodilation increasing blood flow as an immune response mounts WBC's show up as well

Question 37

Migratory (Healing)

Answer 37

Scab forms Migration of st. basale to close the wound Fibroblasts (immature cells) migrate and divide, sitting on the edge of the wound making collagen and replacing the dermis Blood vessels start to form in to bring living blood cells

Question 38

Proliferative (Healing)

Answer 38

Epidermis: Mitosis occurs to gradually replace cell layers Dermis: fibroblasts multiply, replacing the collagen fibers to add strength

Question 39

Maturation (Healing)

Answer 39

Scab sloughs off Organized collagen, but you get a scar because the collagen is not organized in the same way Normal circulation

Question 40

Burns

Answer 40

1st degree = epidermis 2nd degree = dermis 3rd degree = hypodermis and beyond