Skin and the Integumentary System (Crash Course Notes)

Flashcards covering skin structure, cell types, epidermal and dermal layers, and key functions mentioned in the lecture notes.

What is the largest organ of the body, often described as the integumentary system's main organ?

The skin.

What are the three main layers of the skin?

Epidermis, dermis, and hypodermis (subcutis).

What tissue type makes up the epidermis?

Stratified squamous epithelial tissue.

Which epidermal cells are the building blocks of keratin and make up the bulk of the epidermis?

Keratinocytes.

Which epidermal cells synthesize melanin and contribute to skin color?

Melanocytes.

Which epidermal cells act as immune sentinels and originate in the bone marrow?

Langerhans cells (dendritic cells).

Which epidermal cells form the sensory receptor for touch in the skin?

Merkel cells (tactile cells).

What is the outermost layer of thick skin called, and how many layers does it have?

Stratum corneum; about 20–30 sheets of dead keratinocytes.

Which epidermal layer is present only in thick skin and consists of two to three rows of clear, flat dead keratinocytes?

Stratum lucidum.

Which epidermal layer contains living keratinocytes forming keratin and appears grainy?

Stratum granulosum.

Which epidermal layer contains prickly cells that help cells stay attached to each other?

Stratum spinosum.

Which epidermal layer is the deepest and is the site of new cell production?

Stratum basale (basal layer).

What is the dermal layer beneath the epidermis that contains dermal papillae and forms fingerprints?

The papillary layer of the dermis.

What makes up about 80% of the dermis and is composed of dense irregular connective tissue?

The reticular layer.

What types of structures reside in the dermis and are essential for sensation and glandular function?

Nerve fibers, capillaries, hair follicles, and oil and sweat glands.

What is the hypodermis (subcutis) and what is it primarily made of?

A layer of adipose (fat) tissue that provides insulation, energy storage, and cushioning; anchors the skin.

Why can tattoos be permanent only if the ink is deposited in the dermis rather than the epidermis?

Because the epidermis is avascular and constantly shed; the dermis retains ink.

Why does sun exposure affect the skin, and what are some consequences?

UV radiation damages the epidermis, can cause elastin clumping (leathery skin), temporary immune suppression, and DNA damage leading to skin cancer; sunscreen is advised.

Approximately how much does your skin weigh and how much area does it cover when spread out?

About 3–5 kilograms and about 2 square meters.