Integumentary System

Question 1

What are the three layers of the integumentary system?

Answer 1

Epidermis, Dermis, and Hypodermis

Question 2

What is the layer of dead tissue called that covers the epidermis and what is its function?

Answer 2

Keratinized tissue is dead tissue that covers the outer most portion of the epidermis. Its purpose is to prevent infection from entering lower layers of the epidermis; protect against UV rays, act as a waterproof barrier (both from outside environment and keeping moisture in), and as a thermoregulatory barrier (allowing sweat to permeate to the external environment).

Question 3

The epidermis has five (5) layers. Name each (from outer most to deepest) and provide a characteristic of each.

Answer 3

1. Stratum corneum - outer most layer containing keratinized cells.
2. Stratum Lucidum - translucent layer who’s cells have no nucleus or organelles
3. Stratum Granulosum - flat keratinocytes that cut off surface strata from nutrient supply. This layer also provides lipid-filled vesicles that release glycolipids to help waterproof the skin.
4. Stratum Spinosum - contains keratinocytes and macrophages. These macrophages help protect underlying tissue from infection/pathogens.
5. Stratum Basale - Deepest layer of the epidermis that sits on the basement membrane. This layer contains keratinocytes and melanocytes that synthesize melanin to help protect skin layers against UV rays. This layer also contains Merkel cells associated with detecting touch.

Question 4

What its the layer of collagen, elastic, and reticular fibers called that extends upward in the dermis forming ridges?

Answer 4

This layer is called the dermal papillae. It is part of the dermis that extends upward forming the fingerprints (aka friction ridges).

Question 5

The lowest layer of the integumentary system (by some, considered an extension of the dermis) is called _______________.

Answer 5

Hypodermis. This layer is highly vascularized and contains more adipose tissue than the dermis. It acts as an insulator (thermoregulatory) and energy reservoir.

Question 6

When the skin looks flushed (reddish), what chemical is this attributed to?

Answer 6

Hemoglobin is the red pigmentation of red blood cells visible through the dermal collagen fibers.

Question 7

Blueness of the skin is called ____________ and is associated _______________.

Answer 7

Cyanosis

deficiency of oxygen

Question 8

What causes “goose bumps” to occur and in response, the hair standing on end?

Answer 8

Hair is hard keratinized tissue that lies in the dermal layer of the integumentary system. When hair stands on end (or a person experiences “goose bumps”), this is a result of the piloerector muscle(s) contracting within the hair follicle.