4.12 Integument

Question 1

Functions of the skin

Answer 1

-Barrier for protection (against impact, friction and UV)
-Immunologic defense and wound healing
-Homeostasis (prevention of water loss/thermoregulation)
-Conveys sensory info to nervous system
-Exocrine function (secretition via sweat, sebaceous and apocrine glands)
-Endocrine function (vitamin D3)
-Dermatoglyphics (fingerprint)

Question 2

what 3 layers is skin composed of?

Answer 2

Epidermis, dermis, hypodermis

Question 3

_____ is derived from the ectoderm, while _______ are derived from the mesoderm

Answer 3

Ectoderm
Demis/hypodermis

Question 4

what are the 2 different skin types? how are they different?

Answer 4

1. Thick (has NO hair follicles, sweat glands)
   2 Thin (has hair follicles, sebaceous glands)

Question 5

what are the layers of the epidermis? (from basal to surface)

Answer 5

S. basale
S. Spinosum
S. granulosum
S. Lucidum
S. corneum

Question 6

______ is the layer where cells divide

Answer 6

S. basale

Question 7

_____ is the layer that has many intermediate filaments and they attach to each other with desmosomes

Answer 7

S. spinosum

Question 8

____ is the layer of skin that produces ceramides and has the water-lipid barrier

Answer 8

S. granulosum

Question 9

_____ is the very top layer that can have keratinized cells

Answer 9

S. coreum

Question 10

_________ are transported from the melanocyte’s cell body along the lengths of its dendritic extensions to the dendrite tips. These are then transferred to the______

Answer 10

Melanin-bearing melanosomes
epithelial cells

Question 11

describe the process of melanin formation and transfer to keratinocytes

Answer 11

Promelanosome formation → synthesis of melanin in early melanosome → melanosome secretion → taken up by keratinocytes –> melanin goes above nucleus → protects DNA

Question 12

_____ is the layer where the sweat gland ducts are

Answer 12

S. corneum

Question 13

_____ are the most prominent cell in the epidermis. How can they be distinguished?

Answer 13

Keratinocytes
They can be distinguished from melanocytes and Langerhans cells in the epidermis by their larger size, intercellular bridges, and ample cytoplasm.

Question 14

______ are invasive wandering cells that supply keratinocytes with melanin

Answer 14

melanocytes

Question 15

where are melanocytes derived from?

Answer 15

neural crest

Question 16

Melanocytes are considered a dendritic cell. Their cell body is in the epidermis

First is true, second is false
First is false, second is true
both false
both true

Answer 16

First is true, second is false

Melanocytes cell bodies are located at the basal layer

Question 17

the Ratio melanocytes:keratinocytes is ____ in all races, but varies across the body

Answer 17

constant

Question 18

______ are dendritic cells in S. spinosum that play a role in allergies and are an APC

Answer 18

Langerhans Cells

Question 19

how can langerhans cells detect pathogenic antigens?

Answer 19

They can extend dendrites through tight junctions to detect and bind antigens

Question 20

where are langerhans cells derived from? where are they the most prevalent?

Answer 20

stem cells in bone marrow
Oral/vaginal epithelia

Question 21

_____ are modified epidermal cell that assists in acute sensory info

Answer 21

Merkel’s cells

Question 22

Merkels cells are present in _______ that have what kind of senses?

Answer 22

thick skin with acute senses (fingertips)

Question 23

Merkels cells do not bind to other cells with desmosomes. They do have dense granules

First false, second true
First true, second false
Both true
both false

Answer 23

first false, second true

They DO bind to other cells with desmoeomes, and they DO have dense granules

Question 24

what are the 2 layers in the dermis?

Answer 24

1. papillary dermis
2. reticular dermis

Question 25

The ____ layer has loose CT (type III collagen) while the _____ layer has dense irregular CT (type I collagen)

Answer 25

Papillary, reticular

Question 26

what are some things that make up the papillary layer?

Answer 26

-Loose CT (Type III collagen)
-Anchoring fibrils (Type VII collagen)
-Elastic fibers (Oxytalan and Elaunin)
-Small collagen fibers, thin elastic fibers
-Small blood vessels and nerve endings terminating in dermis are concentrated in the papillae

Question 27

The reticular layer has _____ elastic fibers

Answer 27

thick

Question 28

what are some components of the hypodermis?

Answer 28

• Hypodermis: under dermis
  -Loose CT
  -Large blood vessels
  -Adipose tissue
  -Pacinian corpuscles

Question 29

______ are more numerous in areas such as the soles of the feet, palms of the hand, armpits and groin (thick skin)

Answer 29

Sweat glands

Question 30

______ are Found in thin skin (anywhere where there is hair)

Answer 30

Sebaceous glands:

Question 31

what is a sweat gland made up of?

Answer 31

coiled tube, surrounded by a good blood supply, and a duct, which opens onto the skin surface through a pore.

Question 32

what does a sebaceous gland look like?

Answer 32

branched acinar (spherical) glands which make an oily substance called sebum

Question 33

______ sweat glands are in restricted locations and have simple coiled tubular glands. Their secretory product is viscous and odorless

Answer 33

apocrine

Question 34

Some of the circulating blood volume in the skin will flow through ______ instead of capillaries to help regulate temperature

Answer 34

arteriovenous anastomoses (AVAs)

Question 35

ABCDE rules of melanoma

Answer 35

Asymmetrical, Border, Color, Diameter, Evolving.

Question 36

what are the specialized nerve/sensory receptors? and which have encapsulated nerve endings?

Answer 36

• Free nerve endings in epidermis
• Merkel’s ending
• Pacinian corpuscles at dermo-hypodermal junction (encapsulated nerve endings)
  -Meissner corpuscles in dermal papillae (encapsulated nerve endings

Question 37

what two things are found in the epidermis/dermis junction?

Answer 37

• Epidermal ridges (rete pegs)
• Dermal infoldings (papillae)

Question 38

where are epidermal ridges increased?

Answer 38

where stresses on skin are high