Skin

Question 1

What variations can you have in the Macroscopic structure of skin?

Answer 1

Colour
Hair
Thickness
Wrinkling
Oiliness

Question 2

Define Vitiligo

Answer 2

A depigmentation of skin

Question 3

Name some autoimmune responses that lead to hair loss

Answer 3

Alopecia areata

Alopecia totalis

Question 4

What are the different layers of the Epidermis?

Answer 4

Horny layer
Granular layer
Prickle cell layer
Basal layer

Question 5

Where does Keratinocyte mitosis mainly occur?

Answer 5

Basal layer

Question 6

Where does terminal differentiation begin?

Answer 6

In the Prickle cell layer (Keratinocytes loose their ability to divide)

Question 7

What do Keratinocytes synthesise?

Answer 7

Keratins. Heterodimeric fibrous proteins - contribute to the strength of the epidermis

Question 8

What happens to Keratinocytes in the Granular layer?

Answer 8

Lose their plasma membrane

Begin differentiating to corneocytes

Question 9

What does the Granular layer contain?

Answer 9

Keratohyalin granules (Made of Keratins, fibrous proteins, enzymes)

Question 10

What is the Horny layer (Stratum Corneum) made of?

Answer 10

Layers of flattened corneocytes (Major barrier function)

Question 11

Where are Melanocytes?

Answer 11

In the Basal layer of the Epidermis (Dendric cells of Neural crest origin)

Question 12

What do Melanocytes make?

Answer 12

Melanin which creates pigmentation of the skin

Question 13

Where are Langerhan’s cells?

Answer 13

In the Prickle cell layer of the Epidermis (Dendric cells of bone marrow origin)

Question 14

What do Langerhan’s cells do?

Answer 14

Highly specialised capacity to present antigens to T lymphocytes
Mediate immune reactions

Question 15

What type of tissue makes the Dermis?

Answer 15

Dense irregular connective tissue - Fibroblasts and extra cellular matrix (Contains Collagens and Elastins)

Question 16

How are blood vessels distributed in the Dermis?

Answer 16

Few smaller ones in the more superficial layers of the Dermis, then thicker and more in the deeper layers of the Dermis

Question 17

Where are Mast cells?

Answer 17

In the Dermis

Question 18

What do Mast cells do?

Answer 18

Contain Histamine which they release to cause increased vascular permeability - causes local oedema (Can have negative effects if by respiratory tract)

Question 19

What are the Skin Appendages?

Answer 19

Hair follicles & Sebaceous glands

Sweat glands

Question 20

What type of secretion do Sebaceous glands exhibit?

Answer 20

Holocrine

Question 21

What are the types of sweat glands?

Answer 21

Apocrine

Eccrine

Question 22

Which sweat gland is usually involved in Thermoregulation?

Answer 22

Eccrine

Question 23

What do Apocrine sweat glands do?

Answer 23

No function of value

Produce odourless, protein-rich, apocrine secretion. Digestion of this by Cutaneous microbes produces body odour

Question 24

What lies deep to the Dermis?

Answer 24

Subcutaneous fat

Question 25

What are the main functions of the skin?

Answer 25

Barrier
Sensory
Thermoregulation
Psychosexual communication

Question 26

Define Psoriasis

Answer 26

Extreme proliferation of the epidermal basal layer, causing gross thickening of the prickle cell layer and production of excessive stratum corneum – this manifests clinically as excessive scaling

Question 27

Define Malignant Melanoma

Answer 27

Aggressive malignant neoplasm of melanocytes - common primary site is skin. Retention of tumour cells above the epidermal basement membrane is associated with a good prognosis