Skin

Question 1

What are the 3 layers of skin?

Answer 1

Epidermis, dermis, hypodermis

Question 2

What protein is prevalent around the cells of the epidermis?

Answer 2

Keratin

Question 3

What is the dermis? What structures are contained within it?

Answer 3

an underlying layer of dense collagenous connective tissue that contains hair follicles, sweat glands, blood and lymphatic vessels, sensory receptors and nerves, and connective tissue cells.

Question 4

What is the hypodermis? What structures are contained within it?

Answer 4

the hypodermis, another connective tissue layer that is rich in white adipose cells and contains large blood vessels that supply the smaller vessels of the dermis.

Question 5

What are the four layers of the epidermis?

Answer 5

Basal cell layer
stratum spinosum
stratum granulosum
stratum corneum

Question 6

What happens to keratinocytes in the stratum spinosum?

Answer 6

They grow short projections that attach to adjacent cells with desmosomes, and produce cytokeratin

Question 7

What is cytokeratin?

Answer 7

A intermediate filament precursor to keratin

Question 8

What happens to keratinocytes in the stratum granulosum?

Answer 8

Keratinocytes become squamous cells that produce granules of keratiohyaline, another precursor of keratin

Question 9

What is in the stratum corneum?

Answer 9

Flat keratinized scales that are continuously shed and replaced.

Question 10

What two precursors make up keratin?

Answer 10

cytokeratin and keratohyaline

Question 11

What are melanocytes?

Answer 11

cells that produce melanin, and are located among the basal keratinocytes. Variable skin color is a result of variable melanocyte activity

Question 12

How is melanin produced and distributed?

Answer 12

It is synthesized in granules by melanocytes from tyrosine. It is then transferred to neighboring epithelial cells

Question 13

What are Langerhans cells?

Answer 13

Skin macrophages located in the stratum spinosum

Question 14

What are Merkel cells?

Answer 14

They are touch receptors, attached to keratinocytes by desmosomes

Question 15

What are the two layers of the dermis?

Answer 15

The papillary layer, consisting of loose connective tissue below the basement membrane of the epidermis
The Reticular layer, made up of dense irregular collagenous connective tissue

Question 16

In what layer of the dermis do most vessels and nerves reside?

Answer 16

The papillary layer

Question 17

What are pacinian corpuscles?`

Answer 17

touch receptors in the hypodermis responsible for deep touch sensations

Question 18

What is in the hypodermis?

Answer 18

Fat, fibroblasts and pacinian corpuscles

Question 19

What are the three states of hair follicles?

Answer 19

Anagen - growing follicles synthesizing hair
Catagen - resorbing follicles, a short regressive phase at the end of hair growth
Telogen - resting follicles containing a full hair

Question 20

What are the three glands in skin?

Answer 20

Sebaceous glands
Eccrine sweat glands
Apocrine sweat glands

Question 21

What are sebaceous glands?

Answer 21

pear-shaped alveolar glands that secrete an oily substance called sebum, which moisturizes and waterproofs hair

Question 22

What are muscles cause hair to stand up?

Answer 22

arrector pili muscles

Question 23

What are eccrine sweat glands?

Answer 23

long tubules extending from the epidermis deep into the dermis or hypodermis. They produce most of the sweat on the body and are controlled by myoepithelial cells on their secretory tubules

Question 24

What are apocrine sweat glands?

Answer 24

Sweat glands in the axilla, areola, labia and circumanal region which secrete a thick sweat and are associated with hair follicles

Question 25

What are the 3 types of exocrine secretion?

Answer 25

Merocrine/eccrine - secretion by exocytosis. Both eccrine and apocrine glands do this
Apocrine secretion - secretion by budding off of the plasma membrane (see mammary glands and mucus glands - NOT apocrine glands)
Holocrine secretion - secretion by cell disintegration. See sebaceous glands

Question 26

What are Meissner’s corpuscles?

Answer 26

light touch sensors i the papillary layer of the dermis