Lesson 2: Microscopic Anatomy of the Epidermis

Question 1

What are the four main types of cells forming the epidermis?

Answer 1

Keratinocytes, melanocytes, Langerhans cells, and Merkel cells

Question 2

Epidermal cells that produce keratin and another substance that makes the skin waterproof. Cells multiply at the basement membrane and move upward becoming increasingly keratinized.

Answer 2

Keratinocytes. As cells move away from the nutrients of the dermis, they die and flake away upon reaching the surface.

Question 3

Epidermal cells that produce melanin granules, absorb UV radiation, and are partly responsible for skin color

Answer 3

Melanocytes

Question 4

Epidermal cells that are part of the immune system, recognize foreign microbes, engulf and destroy them, and present their antigens to the immune system for further action

Answer 4

Langerhans cells

Question 5

Epidermal cells that form the border between the epidermis and the dermis, associated with a sensory nerve ending, and together, they act as a slowly adapting touch receptor

Answer 5

Merkel cells (aka tactile cells)

Question 6

A tough and fibrous protein that serves to protect the skin

Answer 6

Keratin

Question 7

A pigment in the skin that gives hair and skin its color and also helps protect the living cells of the epidermis from ultraviolet (UV) radiation damage

Answer 7

Melanin

Question 8

What are the five layers of the epidermis?

Answer 8

Stratum corneum
Stratum lucidum (only in hairless skin)
Stratum granulosm
Stratum spinosum
Stratum basale

Question 9

The outermost layer of the epidermis comprising 20–30 layers of dead keratinocytes; helps waterproof the skin (with glycolipids) and prevent water loss, resists friction and protects skin from physical damage

Answer 9

Stratum corneum

Question 10

An additional layer appearing between the stratum granulosum and corneum; found only in the hairless, thick skin of the fingertips, palms, and soles of the feet

Answer 10

Stratum lucidum

Question 11

Three to five layers of mature keratinocytes that help make the skin waterproof

Answer 11

Stratum granulosum

Question 12

8 to 10 layers of living keratinocytes joined together by adhesive protein connections, (Langerhans cells and melanin granules are also present here)

Answer 12

Stratum spinosum

Question 13

A single layer of cuboidal-shaped cells made up of stem cells, keratinocytes, and melanocytes; these cells divide to create new epidermal cells

Answer 13

Stratum basale

Question 14

Describe hairy skin?

Answer 14

Referred to as thin skin, epidermal thickness of 0.10-0.15 mm, dermal thickness of 1-2 mm, has sebaceous glands present, but sweat glands and sensory receptors are sparsely distributed

Question 15

Describe non-hairy skin?

Answer 15

Thicker epidermis 0.6 - 1.55 mm, thick skin, dermal thickness of 3 mm, hair follicles and sebaceous glands are absent, where as sweat glands and sensory receptors are abundant