Week 6 - Skin

Question 1

Which of the following is the correct order of the strata of the epidermis, from superficial to deep?

• a) Lucidum, Corneum, Granulosum, Basale, Spinosum
• b) Corneum, Lucidum, Granulosum, Spinosum, Basale
• c) Corneum, Granulosum, Spinosum, Lucidum, Basale
• d) Granulosum, Lucidum, Granulosum, Basale, Spinosum
• e) Spinosum, Corneum, Lucidum, Granulosum, Basale

Answer 1

Strata of Epidermis = Canadian Ladies Give Superb Backrubs

• a) Lucidum, Corneum, Granulosum, Basale, Spinosum
• b) Corneum, Lucidum, Granulosum, Spinosum, Basale
• c) Corneum, Granulosum, Spinosum, Lucidum, Basale
• d) Granulosum, Lucidum, Granulosum, Basale, Spinosum
• e) Spinosum, Corneum, Lucidum, Granulosum, Basale

Question 2

The Stratum Lucidum is only found in what is known histologically as thick skin. Name the two locations in the body where this type of skin is found?

Answer 2

Locations of thick skin = presence of stratum lucidum:

• thick skin of the palms, soles, and digits.

The Stratum lucidum is composed of 3-5 layers of dead, flattened keratinocytes. The keratinocytes of the stratum lucidum do not feature distinct boundaries and are filled with eleidin, an intermediate form of keratin.

Question 3

Label the following image with its approximate dermatomes.

Answer 3

Question 4

Melanocytes are located within the stratum _________________ of the epidermis. Compared to individuals with light skin, dark-skinned individuals generally have (select the correct answer):

a) A lower number of melanocytes
b) A greater number of melanocytes
c) A similar number of melanocytes

Answer 4

Melanocytes are located within the stratum basale of the epidermis. Compared to individuals with light skin, dark-skinned individuals generally have (select the correct answer):

• a) A lower number of melanocytes
• b) A greater number of melanocytes
• c) A similar number of melanocytes

Same number of melanocytes but more melanin produced in darker skinned people.

The keratinocytes found in all epidermis strata but in the stratum corneum = corneocytes - no nucleus etc.

Question 5

Label the components of the Pilosebaceous unit in the following image:

Answer 5

Question 6

List five major functions of the skin:

Answer 6

• Provides a protective barrier against mechanical, thermal and physical injury and hazardous substances.
• Prevents loss of moisture.
• Thermal regulation
• Reduces harmful effects of UV radiation - melanin.
• Acts as a sensory organ (touch, detects temperature).
  
  • Sexual stimulation
• Helps regulate temperature.
• An immune organ to detect infections etc.
• Production of vitamin D.