Chapter 5

Question 1

The Epidermis is made up of what?

Answer 1

Keratinized stratified squamous epithelium

Question 2

The role of epidermis cell: Keratinocytes

Answer 2

produce the water-insoluble protein keratin which hardens
structures
- Approx. 90% of Epidermal cells

Question 3

The role of epidermis cell: Melanocytes

Answer 3

• produce melanin, a brown/black pigment which absorbs UV
  light and is the primary skin pigment
• Approx. 8% of Epidermal cells

Question 4

The role of epidermis cell: Langerhans

Answer 4

Langerhans cells
- produced in the bone marrow
- help provide immunity to the epidermis

Question 5

The role of epidermis cell: Merkel Cell (disk)

Answer 5

The nerve ending for touch

Question 6

Describe the deepest layer of the epidermis

Answer 6

• Stratum Basale
• a single layer of cuboidal-shaped cells
• mitotically active
• (5/5)

Question 7

Describe the epidermis layer: Stratum Spinosum

Answer 7

Stratum Spinosum
- 8 to 10 cell layers thick
- cells start to flatten as they reach the upper part of this
layer
- (4/5)

Question 7

Describe the second layer of the skin

Answer 7

Dermis
- mostly connective tissue containing collagen & elastin fibers, few cells
- Two layers

Question 7

Describe the epidermis layer: Stratum Granulsum

Answer 7

• 3 to 5 cell layers thick
• cells continue to flatten out
• cells begin to die forming a water-resistant barrier, i.e.
  keratinization
• (3/5)

Question 8

Describe the epidermis layer: Stratum Lucidum

Answer 8

• only present on the fingertips, palms, and soles of the
  feet
• 3 to 5 layers of cells
• (2/5)

Question 8

Describe the epidermis surface

Answer 8

Stratum Corneum
- 20 to 30 cell layers in thickness
- flattened dead keratinocytes, no nuclei
- outer layers are continually shed needing to be replaced
- Approx. 3/4 of the epidermal thickness

Question 9

Describe the layer of the dermis: Papillary region

Answer 9

• Dermal Papillae: tiny projections into the epidermis which increase the surface area of the Stratum Basale
• Meissner corpuscles: (corpuscles of touch) = tactile receptors
  located at the apex of Dermal Papillae
• Epidermal Ridges: Dermatoglyphics = Finger prints assoc. with the underlying papillae

Question 10

Describe the layer of the dermis: Reticular region

Answer 10

• the deepest and largest portion
• contains irregular C.T

Question 11

Describe the last layer of the skin

Answer 11

Hypodermis:
- composed of Adipose and Areolar C.T.
- stores fat
- contains vessels and nerves that supply the skin

Question 12

Melanin pigmentation is….

Answer 12

The brown pigment produced by melanocytes, made from amino acid tyrosine

Question 13

Carotene is…

Answer 13

the yellow-orange pigment produced by vitamin A

Question 14

Hemoglobin

Answer 14

pink/red pigment
- the oxygen carrying molecule in RBCs
- assoc. with translucent skin (i.e. skin lacking melanin)

Question 15

Hair = Pili/Pilus

Answer 15

• covers most skin surfaces
• columns of dead keratinized cells that are bonded together
• protects the body from heat loss and UV light

Question 16

Nails

Answer 16

plates of tightly packed, keratinized epidermal cells

Question 17

Sebaceous Glands

Answer 17

• secrete sebum, an oily substance that softens and lubricates the
  skin, water proofing, maintains hair follicles, contains
  antibacterial substances
• associated with hair follicles, lips, pubic region
• not found on palms and soles

Question 18

Sudoriferous (Sweat) Glands

Answer 18

• release secretions onto the surface of the skin

Question 19

Eccrine gland

Answer 19

• most common
• produces watery sweat that contains ions and small organic
  molecules
• help regulate body temperature
• eliminate wastes

Question 20

Apocrine gland

Answer 20

• common to axilla and groin
• watery secretion, more viscous than normal sweat, contains
  proteins and lipids
• secondary sexual function

Question 21

Superficial

Answer 21

• when only the Epidermis is damaged
• the cells surrounding the wound enlarge and migrate to fill the
  gap created by the injury
• Contact Inhibition = migration ceases when the cells on both
  sides of the wound come into contact
• mitosis in the Stratum Basale is stimulated, more cells are
  reproduced to make up for dead cell

Question 22

Deep Wound Healing

Answer 22

- damage effects the Dermis - phases:

Question 23

Inflammatory Phase

Answer 23

- clot forms over wound - local vasodilation, leukocytes (infection) and fibroblasts (rebuild tissue) move into the damaged area

Question 24

Migratory Phase

Answer 24

- scab forms - epithelial tissue migrates beneath the scab to bridge the wound - granulation (scar) tissue begins to be laid down beneath the scab - vessels begin to regrow_

Question 25

Proliferative Phase

Answer 25

- epithelial tissue begins to mature - collagen fibers continue to be laid down randomly

Question 26

Maturation Phase

Answer 26

- scab falls off after the epidermis is repaired - circulation is restored - fibroblasts decrease in number

Question 27

Fibrosis

Answer 27

scar tissue formation. (Scar tissue is not as healthy as the original tissue

Question 28

Thermoregulation:

Answer 28

- Average temperature is 98.6 F (37 C) 1. Temperature change is detected by nerve endings in the skin (i.e. Thermoceptors) 2. This information is sent to the Hypothalamus 3. Nerve signals are then sent back to the sweat glands, and the smooth muscle in the vessels of the Integumentary System.

Question 29

Ambient temperature is elevated (“This one’s too hot”).

Answer 29

) Perspiration increases, heat is lost by evaporation. 2) Smooth muscle in the dermal vessels relax causing there diameter to increase. More blood can now enter these vessels. Heat is lost to the environment by radiation.

Question 30

Ambient temperature decreases (“This one is too cold”).

Answer 30

1) Sweat gland activity decreases. Body conserves heat. 2) Smooth muscle in dermal vessels constricts, conserving heat