skin structure and function

Question 1

Embryological source of Epidermis?

Answer 1

Ectoderm cells form the single-layered periderm.
Then the numbers of layers gradually increase.
Periderm cells are cast off.

Question 2

What is the embryological origin of the dermis?

Answer 2

It is formed from mesoderm, below ectoderm

Question 3

The emryological origin of melanocytes is ….

Answer 3

…the neural crest

Question 4

What are the layers of the epidermis?

Answer 4

• keratin layer (stratum corneum)
• granular layer (stratum granulosum)
• prickle cell layer (stratum spinosum)
• basal layer (stratum basale)

Question 5

What is the cause of psoriasis?

Answer 5

Rapid growth of keratinocytes

Question 6

What type of cells are present in the basal layer?

Answer 6

small cuboidal cells

Question 7

What cell type makes up the prickle/spineous cell layer?

Answer 7

larger polyhedral cells

Question 8

What cell type is present in the granular layer?

Answer 8

cells with large heratohyalin granules

-these contain filaggrin and involucrin

Question 9

What are korneocytes?

Answer 9

overlapping non-nucleated cell remnants

Question 10

What are the important components of keratinocytes?

Answer 10

• 80% keratin and filaggrin

- lamellar granules which release lipids

Question 11

_____ glands are associated with hairs.

Answer 11

sebaceous

Question 12

The ___ ___ is the embryological origin of melanocytes.

Answer 12

neural crest

Question 13

What epidermal layers are melanocytes found in?

Answer 13

basal layer and above

Question 14

What is vitiligo?

Answer 14

An autoimmune disease resulting in loss of melanocytes.

-treat with phototherapy

Question 15

What is albinism?

Answer 15

Genetic disorder resulting in loss of melanin production by melanocytes.

Question 16

Nelson’s Syndrome is…

Answer 16

excess melanin due to melanin stimulating hormones produced by the pituitary.

Question 17

Langerhans cells originate from the ____ layer in the embryo.

Answer 17

mesenchymal

Question 18

What is the role of Langerhans cells?

Answer 18

Antigen presenting cells

-carry antigen from skin to lymph nodes

Question 19

Merkel cells are _____

Answer 19

mechanoreceptors

-found in the basal layer

Question 20

What is the cause of Merkel cell carcinoma?

Answer 20

viral infection

Question 21

What is the function of the arrector pili muscle?

Answer 21

moving the hair shaft up

Question 22

What is Telogen effluvium?

Answer 22

Mass progression into the Telogen phase of hair cycle

-e.g. post partum

Question 23

What is Alopecia areata?

Answer 23

autoimmune hair loss

-destruction of hair papilla

Question 24

The layers of the dermis are:

Answer 24

1. Lamina lucida
2. lamina densa
3. Sub-lamina densa zone

Question 25

Cause of Epidermolysis Bullosa?

Answer 25

Genetic

-damaged dermo-epidermal junction

Question 26

Function of elastin in dermis?

Answer 26

provides elasticity

Question 27

Dermis contains __% collagen and __% elastin

Answer 27

80% collagen, 4% elastin

Question 28

____ corpuscles detect pressure. _____ corpuscules detect vibration.

Answer 28

Pacinian - pressure

Meissner - vibration

Question 29

Neurofibromatosis results in the overgrowth of ___ ____

Answer 29

nerve endings

Question 30

What is the function of the Sebaceous gland?

Answer 30

Secretion of sebum into the pilary canal

-become blocked in acne

Question 31

Apcorine sweat glands are found in ___ and ____. They secrete ___ ____

Answer 31

found in Axillae and Perineum

secrete oily fluid

-function unknown

Question 32

Eccrine glands are found where?

Answer 32

While skin surface

Question 33

Functions of eccrine glands?

Answer 33

Cooling by evaporation

moistens soles and palms for grip

Question 34

What are the metabolic functions of skin?

Answer 34

• Vitamin D metabolism

- Thyroid hormone metabolism