Dermis and Hypodermis

What forms fingerprints?

Stratum Basale buckles on itself and forms epidermal ridges.

How many days does it take for cells to work from stratum basale to stratum corneum?

30 - 40 days, slows with age, speeds up with injury/stressed skin (hives/eczema).

Where do calluses result from?

Mechanical stress which speeds up keratinocyte multiplication.

What is the dermis made of?

Connective tissue

How thick is dermis tissue?

0.2 mm - 4 mm thick

Collagen Fibers

tough and flexibility, resist stretch

Reticular Fibers

thin collagen fibers

Elastic Fibers

stretch and recoil

Subcutaneous Tissue

Fat tissue , under dermis AKA hypodermis or adepose tissue

What else is in the dermis?

Blood vessels, sweat glands, sebaceous glands, hair follicles, nail roots, sensory nerve endings, and smooth muscle attached to hairs (many more)

Dermal Papillae

Extensions of dermis into the epidermis, extend further in sensitive skin.

What causes sensitive skin?

The dermal papillae extends further in, causing blood vessels and nerve endings to be closer to the surface.

Papillary Layer

1/5 thickness of dermis, right underneath the epidermis. It is loose areolar tissue that allows room for immune cells to move and protect from harmful cells especially if the epidermis is damaged.

Reticular Layer

4/5 of the dermis, dense connective tissue, collagen forms thicker bundles.

How do stretch marks form?

Due to torn collagen fibers in reticular layer.

Hypodermis Tissue (made of??)

Areolar and Majority of Adipost tissyes. Between skin and muscle, 8% thicker in woman than men

What are hypodermis' main functions?

Binds skin to underlying tissue, cushion and insulate the body, store energy.

How does melanin contribute to skin color?

Variety of hues (black, tan, yellow, brown, red). Varies throughout the body, more spread = darker

How does hemoglobin contribute to skin color?

Red pigment in blood vessels and white collagen fibers = pinkish hue.

List the layers of epithelium making up the epidermis from deepest layer to surface layers.

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.

List the epithelial layers in the epidermis that are dead.

Stratum Lucidum and Stratum Corneum.

How does carotene contribute to skin color?

Yellowish orange pigment that is impacted by diet . Ex: egg yolks and yellow/orange vegetables.