Skin

Question 1

What is the epidermis layer of skin composed of

Answer 1

Primarily of keratinocytes

Question 2

What is the dermis layer of skin composed of

Answer 2

Mainly connective tissue

Question 3

What is the hypodermic layer of skin composed of

Answer 3

Subcutaneous layer/fat layer
Mainly adipose tissue

Question 4

What are the 3 layers to skin

Answer 4

Epidermis
Dermis
Hypodermis

Question 5

What is differentiation

Answer 5

Process in which cell changes from one cell type to another

Question 6

What is stratification

Answer 6

Squamous epithelial cells arranged in layers upon a basement membrane

Question 7

What are the 4 structural layers of the epidermis

Answer 7

Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum

Question 8

What epithelium is the epidermis layer

Answer 8

Specialised stratified squamous

Question 9

What protein does the epidermis contain

Answer 9

Cytokeratin proteins

Question 10

What makes up 90% of cells

Answer 10

Keratinocytes

Question 11

How does the epidermis layer adhere to one another

Answer 11

By desmosomes - a cytoskeleton attachment junction connecting cells to one another in epithelia and muscle tissues

Question 12

How does the epidermis adhere to basement membrane

Answer 12

Via hemidesmosomes

Question 13

What is the stratum corneum layer

Answer 13

Desquamating keratinocytes layers of flattened non nucleated cells provide a barrier against trauma and infection

Question 14

What is the granular cell layer

Answer 14

Lipids produced by keratinocytes are secreted into the ECM spaces and forma barrier that retains water in the skin

Question 15

What is the spinous layer

Answer 15

Appearance due to a combination of desmosome junctions which join keratinocytes and cell shrinkage

Question 16

What is the basal layer

Answer 16

Site of stem cells high rate of cell division keratinocytes divide here before moving laterally then ascending

Question 17

How does stratum spinosum work

Answer 17

As cells commit to terminal differentiation they increase in size and switch from the expression of cytokeratin proteins K14/K5 to K1/K10

Question 18

What type of collagen is basement membrane

Answer 18

Type IV collagen

Question 19

What 4 items does the basement membrane consist of

Answer 19

Laminin
Collagen
Fibronectin
Hemidesmosomes - integrins

Question 20

What do melanocytes protect against

Answer 20

UV radiation and ROS

Question 21

What do melanocytes not contain

Answer 21

Desmosomes

Question 22

Where are dendritic cells found

Answer 22

In the mid layer of the epidermis

Question 23

Which type of cell is non dendritic

Answer 23

Merkel cells

Question 24

What are merkel cells

Answer 24

Basal distribution
Associated with nerve fibres
Sensory function
Contain small, membrane bound vesicles release neurotransmitter
Contain cytokeratins
Desmosomes attach them to keratinocytes

Question 25

What are langerhans cells associated with

Answer 25

Presentation of antigens to sensitised T lymphocytes significant role on pathogenesis of delayed type hypersensitivity states

Question 26

Where are lymphocytes found

Answer 26

In mucosal epithelia (e.g oral and gut)

Question 27

What do mast cells do

Answer 27

Important in the pathogenesis of immediate type hypersensitivity response

Question 28

What are the 2 layers of the dermis

Answer 28

Papillary dermis Reticular dermis

Question 29

What is the papillary dermis composed of

Answer 29

Loose areolar connective tissue

Question 30

What is the reticular dermis composed of

Answer 30

Dense irregular connective tissue

Question 31

What does the dermis layer contain

Answer 31

Blood and lymph vessels and nerves supplying the skin and adnexal structures

Question 32

What is the principle cell type in the dermis

Answer 32

Fibroblast

Question 33

What is the hypodermis (subcutaneous layer)

Answer 33

Fat layer insulates the body serves as energy supply allows for mobility

Question 34

What are 4 adnexal structures

Answer 34

Hairs Erector pili muscles Sebaceous glands Sweat glands

Question 35

What is eccrine

Answer 35

Major sweat glands do not involve hair follicle

Question 36

What is apocrine

Answer 36

Associated with hair follicles secret a fatty mixture into the gland tubule

Question 37

What are sebaceous glands stimulated by

Answer 37

Androgens and inhibited by estrogen They are lipid filled cells

Question 38

What do pecinian corpuscles sense

Answer 38

Deep pressure Fast vibrations

Question 39

What do meisners corpuscles sense

Answer 39

Light tough Slow vibrations

Question 40

What do free nerve endings sense

Answer 40

Temp, touch, pain

Question 41

What do merkels disks sense

Answer 41

Sustained pressure Hairless skin

Question 42

What does dry epidermis cause

Answer 42

Reduction in sebaceous gland activity

Question 43

What do fewer melanocytes cause

Answer 43

Paler skin Reduced tolerance to sun exposure

Question 44

What does thin dermis cause

Answer 44

Sagging and wrinkling due to collagen and elastin fibre loss

Question 45

What does a thin epidermis cause

Answer 45

Slower repair Decreased vitamin D production Reduced number of langerhans cells

Question 46

What does VUB (290-320nm) do

Answer 46

Damaging melanocytes, keratinocytes and causes the production of proteolytic enzymes

Question 47

What does UVA (320-400nm) do

Answer 47

Penetrates deeper than UVB exerts direct effect on both dermis and epidermis

Question 48

Which is the most common skin cancer

Answer 48

Non melanoma

Question 49

In what layer are stem cells mainly found

Answer 49

The basal layer

Question 50

Do epithelial cells have a blood supply

Answer 50

No