Integumentary System

Question 1

Layers of the skin: Epidermis

Answer 1

• Outermost layer
• Keratinised stratified squamous epithelium (provides toughness and water resistance)
• You would swell after a bath without them

Question 2

Layers of epidermis

Answer 2

Strata corneum - outermost layer
Stratum lucida, granulosum, spinosum - intermediate layers
Stratum basale - Deepest layer

Question 3

Epidermis cell types

Answer 3

Keratinocytes: produces keratin, arises from the deepest layer of the epidermis
Melanocytes: Spider-shaped cells, produces melanin, provides colour of skin
Langerhan’s cells: star-shaped macrophage cells, activate immune system, originate from bone marrow, protects anything that accidentally makes it way through
Merkel cells: associated with nerve endings, sensory receptors, present at the epidermis-dermis junction.

Question 4

Layers of the skin: Dermis

Answer 4

• Middle layer of skin
• Makes up bulk of the skin
• Composed of connective tissue
• Highly vascularised (high blood supply)
• Highly innervated (access to touch, temperature, pressure and pain)

Question 5

Dermis cell types

Answer 5

Fibroblasts: build fibres and restores connective tissue
Macrophages: protect against infection
Mast cells: related to allergic responses
WBC: help fight infections

Question 6

Layers of the skin: Hypodermis

Answer 6

• Subcutaneous (fat) layer (we lose this as we age)
• Lies beneath the dermis
• Anchors the skin to underlying structures (bone, muscles)
• Ideal spot to inject drugs

Question 7

Skin colour

Answer 7

Melanin - Pigment made in skin (melanocytes)
Carotene - Yellowish/orange pigment
Haemoglobin - red pigment
Jaundice - Liver disorder causing yellow bile in tissues
Bruises - blood has escaped from vessels and clotted beneath the skin