Histology Skin

Question 1

What is the largest organ of the human body?

Answer 1

Skin

The skin accounts for approximately 15% of body weight.

Question 2

What is the thickness range of the skin?

Answer 2

1.5 - 5 mm

Thickness varies depending on the body location.

Question 3

List the functions of the skin.

Answer 3

• Protective
• Biomechanical synthesis
• Homeostasis
• Major sensory organ

Functions include protection against microbial organisms, mechanical, chemical, osmotic, thermal, and UV radiation damage.

Question 4

What vitamin does skin synthesise?

Answer 4

Vitamin D

Question 5

What are the predominant cells in the epidermis?

Answer 5

Keratinocytes

Keratinocytes undergo continuous renewal throughout life.

Question 6

What is the main role of Langerhans cells?

Answer 6

Immune function

Langerhans cells are distributed in both the basal and spiny layers of the epidermis.

Question 7

What is the function of melanocytes in the skin?

Answer 7

Produce melanin pigment

Melanocytes lack desmosome connections with keratinocytes.

Question 8

Name the layers of the epidermis.

Answer 8

Corneum

Lucidum (thick skin)

Granulosum

Spinosum

Basale

Each layer has distinct cellular features and functions.

Question 9

What is the primary characteristic of the basal layer of the epidermis?

Answer 9

Site of epidermal cellular proliferation

Keratinocyte stem cells are found in this layer.

Question 10

What shape are Keratinocytes?

Answer 10

Columnar

Question 11

Basal Keratinocytes are in contact with what?

Answer 11

The basal lamina (lamina lucida and lamina densa)

Question 12

What does the basal layer cytoplasm contain?

Answer 12

Melanosomes and keratinofilaments.

Question 13

What are the cells present in the Basal layer?

Answer 13

Melanocytes, Langerhans cells, Merkel cells.

Question 14

How are the keratinocytes arranged in the stratum spinosum?

Answer 14

Closely packed and connected by desmosomes

Question 15

What are tonofibrils and what do they do?

Answer 15

Keratin intermediate filaments that form desmosomes which provide tensile strength

Question 16

Densely stained keratocyte hyaline granules from the?

Answer 16

Water barrier (hydrophobic glycophospholipids)

Question 17

What happens to cells in the granular layer of the epidermis?

Answer 17

Nuclei and organelles become disintegrated

Cytokeratin filament bundles become more compact in this layer.

Question 18

Fill in the blank: The _______ layer is the final stage of epidermal differentiation.

Answer 18

Cornified

This layer consists of closely packed flatted cells or corneocytes.

Question 19

What are the two regions of the dermis?

Answer 19

• Papillary layer
• Reticular layer

The papillary layer is immediately next to the epidermis.

Question 20

What type of connective tissue primarily makes up the dermis?

Answer 20

Irregular, moderately dense connective tissue

The dermis contains a meshwork of collagen and elastin fibers.

Question 21

What is the primary function of the hypodermis?

Answer 21

Increase mobility of the skin

The hypodermis also provides thermal insulation and acts as a shock absorber.

Question 22

What are the accessory structures of the skin?

Answer 22

• Hair
• Sebaceous glands
• Sweat glands

Hair plays a role in sensory perception and thermoregulation.

Question 23

What type of sweat glands are responsible for thermoregulation?

Answer 23

Eccrine sweat glands

Apocrine sweat glands also contribute but are more involved in scent.

Question 24

True or False: Meissner’s corpuscles are sensitive to pressure and vibration.

Answer 24

False

Meissner’s corpuscles are sensitive to touch.

Question 25

What type of mechanoreceptor is Pacinian corpuscles?

Answer 25

Rapidly adapting mechanoreceptors ## Footnote They are sensitive to pressure and vibration.