LEC1 - Skin: Structure & Function

Question 1

Name the organ system that the skin belongs to and provide examples of other components also belonging to the same system.

Answer 1

Integumentary system.

Hair, nails, sweat glands, mammary glands.

Question 2

State the functions of the skin

Answer 2

• Barrier
• Temperature regulation
• Excretion
• Synthesis of Vitamin D
• Sensory organ

Question 3

Explain how the skin acts as a barrier against microorganisms

Answer 3

Physical barrier - organisms cannot enter through the skin

Oily skin - acts as antibacterial

Sweat - slightly acidic and suboptimal for microorganisms to survive

Cytokines - inflammatory functions

Question 4

State the 3 layers of the skin

Answer 4

• Epidermis
• Dermis
• Hypodermis

Question 5

State the 5 zones of the epidermis (CLGSB)

Answer 5

• Stratum Corneum
• Stratum Lucidum
• Stratum Granulosum
• Stratum Spinosium
• Stratum Basale

Question 6

State the 4 cell types in the epidermis and provide a brief description of their function

Answer 6

Melanocytes - produce melanin

Keratinocytes - produce keratin

Langerhans cells - involved in immune responses

Merkel cells - sends signals to the brain through axons, involved in sensing touch

Question 7

Explain keratin

Answer 7

A protein that is involved in the make up of the outer layer of the skin. Keratin helps form intermediate filaments which are tough and insoluble, provide strength, protection and waterproofing to the skin..

Question 8

Explain melanin

Answer 8

A light-absorbant protein that protects skin cells from UV radiation damage. Produced by active melanocytes.

Question 9

Discuss the formation of fingerprints with reference to the epidermis and dermis

Answer 9

Fingerprints are the epidermal ridges that arise from the attachment between the epidermis and dermis.

Question 10

State the two layers of the dermis

Answer 10

• Papillary

- Reticular

Question 11

Comment on the papillary layer of the dermis, with reference to its function and key features

Answer 11

The layer sitting directly under the epidermis made of collagen and elastin.

Function - allows for movement of macrophages upon detection of foreign particles entering the skin.

Features - blood vessels which provide nutrients to the epidermis.

Question 12

Describe the reticular layer of the dermis and explain the significance of its ‘irregular’ pattern

Answer 12

The layer below the papillary layer consisting of dense, irregular connective tissue surrounding hair follicles, blood vessels and glands.

The irregular pattern allows for movement of the skin in multiple directions.

Question 13

State and briefly explain the different cell types in the dermis

Answer 13

Fibroblasts - produces dermal proteins which are involved in skin repair

Mast cells - involved in immune responses

Macrophages - removes foreign material and bacteria

Question 14

Describe the functions of dermal proteins; collagen and elastin

Answer 14

Collagen provides the skin with strength.

Elastin provides elasticity and allows the skin to return to original position after stretching and contracting.

Question 15

Outline the two main functions of the hypodermis structure

Answer 15

• Binds skin to the underlying adipose tissues

- Padding and thermal regulation

Question 16

The skin can be classified into two categories, thick and thin. Outline the key differences between both.

Answer 16

Thick skin consists of an extra epidermal layer, the stratum lucidum.

Thick skin can be found on the palms of the hand and soles of feet whereas thin skin covers the rest of the body.