L12 STRUCTURE OF THE SKIN & ACCESSORY STRUCTURES

What are the main layers of the skin?

The main layers of the skin are the epidermis, dermis, and hypodermis.

What type of epithelium is found in the epidermis?

The epidermis is made of nonvascular, keratinized stratified squamous epithelium.

What cells are primarily responsible for skin pigmentation?

Melanocytes are responsible for skin pigmentation.

What is the role of keratin in the skin?

Keratin provides mechanical strength and waterproofing to the skin.

What is the difference between thick skin and thin skin?

Thick skin has a thicker epidermis and lacks hair follicles; thin skin contains hair follicles and sebaceous glands.

What structure in the dermis provides nutrient supply and immune defense?

Blood vessels in the dermis provide nutrients and house immune cells for defense.

What is the significance of the stratum basale layer of the epidermis?

The stratum basale is the deepest layer that contains stem cells for skin regeneration.

What is the function of Langerhans cells in the skin?

Langerhans cells are antigen-presenting cells involved in the immune response.

What kind of glands are eccrine and apocrine glands, and where are they located?

Eccrine glands are sweat glands found all over the body, while apocrine glands are located in specific areas like the armpits and groin.

What happens to melanin production with prolonged UV exposure?

Prolonged UV exposure increases melanin production, leading to darker skin pigmentation.

How does the epidermis prevent water loss?

The epidermis contains lamellar granules that release glycolipids to create a waterproof barrier.

What are the primary types of melanin affecting skin color?

The two primary types of melanin are eumelanin (brown-black) and phaeomelanin (red-yellow).

What layer of the skin is responsible for sensory perception?

The dermis contains sensory nerve endings that enable perception of heat, cold, touch, pain, and pressure.

What layers make up the dermis?

The dermis is composed of the papillary layer and the reticular layer.

What is the process of keratinization in the skin?

Keratinization is the process where keratinocytes fill with keratin, causing them to flatten and die, forming the outer protective layer.

What is the role of sebum secreted by sebaceous glands?

Sebum lubricates and waterproofs the skin and hair, preventing dehydration.

How does the skin respond to injury and repair?

The skin initiates repair through inflammation, proliferation of cells, and formation of new tissue.

What is albinism and what causes it?

Albinism is a genetic condition resulting from defective melanocytes that cannot produce or distribute melanin.

What are dermal papillae and their function?

Dermal papillae are projections of the dermis into the epidermis that increase surface area for exchange and contain capillaries.

What is the function of Merkel cells?

Merkel cells act as mechanoreceptors and are involved in the sensation of touch.

Describe the structure of nails in relation to the epidermis.

Nails are made of tightly packed, hard, keratinized epidermal cells and do not desquamate easily.