hypodermis and dermis

What type of tissue is the dermis composed of?

Dense irregular connective tissue.

What structures does the dermis contain?

Nerves, blood vessels, sweat glands, and hair follicles.

What is the wavy layer between the epidermis and dermis called?

The dermal papillae.

What causes fingerprints (epidermal ridges)?

The irregular surface formed by the dermal papillae.

What are the two layers of the dermis?

The papillary layer and the reticular layer.

What type of tissue makes up the papillary layer?

Loose connective tissue.

What type of fibers make up the reticular layer?

Bundles of collagen fibers.

What are lines of cleavage (tension lines)?

Lines formed by the arrangement of collagen fibers in the dermis.

Why are lines of cleavage important for surgeons?

Cuts made parallel to lines of cleavage heal better and leave less scarring.

How does blood flow in the dermis change when you are hot?

Blood vessels in the dermis swell, causing redness and allowing heat to dissipate to cool the body.

What happens when blood supply to the skin is restricted for too long?

Decubitus ulcers (bedsores) can form.

What is the hypodermis also known as?

The subcutaneous layer.

Is the hypodermis part of the skin?

No, it’s not actually part of the skin.

What type of tissue makes up the hypodermis?

Loose, fatty connective tissue (adipose tissue).

What does the hypodermis do?

Connects the skin to muscle or bone, acts as an insulator, and stores nutrients.

What attaches the dermis to underlying organs?

The hypodermis (subcutaneous layer).

Summary: What does the dermis contain and what are its layers?

The dermis is just below the epidermis, contains blood vessels and nerves, and has a papillary layer and a reticular layer made of collagen that forms lines of cleavage.