Skin - Dermis and Appendages

Question 0

What layer of the dermis is stained darkly?

Answer 0

The reticular dermis because of dense collagen with eosin

Question 1

Composition of dermis

Answer 1

Mostly keratinocytes with multiple epidermal sublayers
Papillary dermis - thin collagen and elastic fibers, fibroblasts, rich with capillaries to nourish avascular epidermis and regulate temp
Reticular dermis - thick collagen and elastic fibers, fibroblasts, glands, hair follicles, smooth muscle

Question 2

What is the function of dermal papillae?

Answer 2

Prevent tearing and separation that results from friction. Skin integrity. Also called epidermal-dermal interdigitations. Also rich with capillaries

Question 3

What controls blood flow to the dermal interdigitatons?

Answer 3

Autonomic nervous system to control body heat loss/retention. Causes the flush or pale look of skin.

Question 4

Where are sweat glands most often found? Function?

Answer 4

In the dermis and hypodermis. Cools via evaporation of secreted sweat.

Question 5

Epidermal and dermal junctions are characterized by?

Answer 5

Epidermal ridges and dermal papillae interdigitating. Make up fingerprints and footprints

Question 6

What are cleavage lines?

Answer 6

Orientations of collagen fibers making up the reticular dermis. Characteristic in different areas of the body. Surgeons cutting along these allow skin to heal faster and with less scarring.

Question 7

What are the two types of sweat glands?

Answer 7

Eccrine and Apocrine

Question 8

Name the appendages of the skin

Answer 8

Sweat glands, sebaceous glands, hair follicles, nails, specialized mechanosensory receptors

Question 9

Sweat glands have what morphology?

Answer 9

Simple tubular

Question 10

Where are apocrine glands found?

Answer 10

In the axilla and perineal region

Question 11

Apocrine glands release?

Answer 11

Sweat, but also bits of cytoplasm along with the watery sweat

Question 12

T or F: Apocrine sweat gland lumens tend to be wider than eccrine glands

Answer 12

T

Question 13

Describe eccrine glands

Answer 13

Most numerous and produce true sweat

Question 14

Describe apocrine glands

Answer 14

Confined to axillary and perineal areas
Secrete sweat with bits of cytoplasm into hair follicle
Tubular glandular lumens wider than those of eccrine glands

Question 15

What is sweat?

Answer 15

Blood filtrate that is 99% water with some salts.

Contains traces of metabolic waste (urea)

Question 16

What is the function of myoepithelial cells along sweat glands?

Answer 16

Contract to move sweat along the tubes

Question 17

Sweat ducts have what cell morphology?

Answer 17

Stratified cuboidal epithelium (2 layers)

Question 18

Describe the morphology of apocrine glands?

Answer 18

Much larger lumens than eccrine glands
Contain viscous secretory product that produces distinctive odor after being metabolized by bacteria
Secretion is mediated by hormones

Question 19

Describe the structure of a hair follicle

Answer 19

Invagination in the sruface epithelium into the underlying dermis or hypodermis. Keratinous hair shaft produced by hair bulb epithelial cells in the same way that keratinocytes make keratin. Typically has a sebaceous gland and small smooth muscle bundle that connects the tissue around the hair shaft to the basement membrane. Under autonomic control - goose bumps/hair stand

Question 20

What is the arrector pilli?

Answer 20

Smooth muscle bundle associated with the hair shaft. Under autonomic control

Question 21

T or F: Sebaceous glands are commonly associated with hair follicles

Answer 21

T

Question 22

Nail matrix is composed of?

Answer 22

Keratinized epithelial cells arranged into plates of hard keratin. Can be used clinically by examining color, rigidity and texture.

Question 23

What are nails derived from? Function?

Answer 23

Develop from cells in the nail matrix that proliferate and become keratinized. The nail plate occupies the function and position of the stratum corneum

Question 24

What can we tell by the transparency of fingernails?

Answer 24

General health. Pinkness indicates well-oxygenated blood supply

Question 25

What are Merkel cells?

Answer 25

Found in basal layer of the epidermis
Most abundant sensory receptor in skin
Respond to pain, temperature, and touch
Non-encapuslated mechano-receptors specialized for perceiving discriminatory touch

Question 26

What are Meissner’s corpuscles?

Answer 26

Enclosed capsules found in the dermal papillae and specialized for fine touch and tactile discrimination

Question 27

What are Pacinian’s corpuscles?

Answer 27

Found int he deep dermis and in the hypodermis and are sensitive to pressure, touch, and vibration.
Resemble sliced onions in histological sections

Question 28

What are Ruffini’s endings?

Answer 28

Found in paillary dermis and joints, etc.

Specialized for perceiving stretching and pressure

Question 29

What is Krause’s end bulb?

Answer 29

Unknown function but may detect low-frequency vibration

Question 30

Describe Meisner’s corpuscles

Answer 30

Small 80x30 um
Located in the dermal papillae of the skin and numerous in the tips of fingers and toes
Composed of 3-4 nerve terminals and their associated Schwann cells encapsulated in CT

Question 31

Describe Pacinian’s Corpuscles

Answer 31

Large, ovoid receptors 1-2 mm
Located in the dermis and hypodermis in the digits of the hands and in the breasts as well as in the CT of the joints (sensitve areas)
Composed of single unmyelinated fiber that courses the entire length of the corpuscle and is surrounded by many layers of modified fibroblasts
Detects deep pressure, touch and vibration

Question 32

Cause of most skin cancer?

Answer 32

UV exposure

Question 33

Describe basal cell carcinoma

Answer 33

Pearly translucency to fleshy color

Tiny blood vessels on the surface and sometimes ulceration

Question 34

Describe squamous cell carcinoma

Answer 34

Commonly red, crusted, or scaly patch or bump

Rapidly growing. Pain is common

Question 35

Describe malignant melanoma

Answer 35

Asymmetrical area with irregular border, color variation, and often greater than 6 mm diameter