Chapter Five

Question 1

Label components of the Integumentary System

Answer 1

See Image of Skin + Accessory Organs

Question 2

Describe the general functions of skin

Answer 2

Protection, sensation, thermoregulation, vitamin D, water retention

Question 3

Location where thin and thick skin is found

Answer 3

Thick: Palms, soles, areas of fingers and toes located in highly mechanical areas!
Thin: Hair follicles, sebaceous glands, sweat glands

Question 4

Functions and location of Epidermal Cells

Answer 4

Stem cells: Divide and replace dead epidermal cells. (basement of epidermis and the hair follicle bulge)!
Keratinocytes: Responsible for forming tight junctions with the nerves of the skin. (skin, hair, and nails)!
Melanocytes: Produce melanin which is a protein that is responsible for the pigmentation of the skin, eyes and the hair. This protein protects the skin cells from UV radiation effects. (hair and skin)!
Merkel Cells (sensory receptors): Involved in the sensation of light touch, for example when feeling the texture of an object. (fingertips, lips)!
Dendritic (immune) cells: Act as a communication vehicle between multiple key cells. They function in tandem with macrophages and lymphocytes to transport antigens, which are molecules that trigger an immune response. (skin)

Question 5

Distinguish between the dermis, epidermis and hypodermis

Answer 5

The epidermis is the outer layer of the skin while the dermis is a layer of skin that is in between the epidermis and subcutaneous tissues. The hypodermis is the subcutaneous tissue in the innermost layer of the integumentary system.

Question 6

What layer of the integument would be thicker in an obese person

Answer 6

Adipose tissue

Question 7

Describe the factors that define skin color

Answer 7

The epidermis has special cells called melanocytes, some 60,000 in every square inch of skin. Melanocytes produce a dark pigment called melanin. Melanin gives skin its color. People with black or brown skin have more melanin in their skin that people with white or yellow skin. Melanin protects the body from the damaging effects caused by the sun. When the skin is exposed to sunlight, the melanocytes produce additional melanin.

Question 8

Identify the general structure of a hair follicle

Answer 8

Hair follicles fold down from the epidermis into the dermis and occasionally into the hypodermis. The deep end of a hair follicle is expanded, forming a hair bulb, which is surrounded by a knot of sensory nerve endings called a hair follicle receptor, or root hair plexus. The wall of a hair follicle is composed of an outer connective tissue root sheath, a thickened basement membrane called a glassy membrane, and an inner epithelial root sheath

Question 9

Explain why eyebrow hair is short and head hair longer?

Answer 9

The growth cycle of hair follicles go through various stages; anagen (growing stage), catagen (transitional stage) and telogen (resting stage). The hair on our scalp has an anagen stage of 2-7 years depending on the individual’s diet, age, and health in general. Eyebrows have a shorter anagen stage. For example, eyebrows take around 4 months in this stage

Question 10

Describe the factors that determine the texture of hair (curly vs. straight) and the color of hair?

Answer 10

These factors are determined mainly by genetics. Hair color is mostly the result of pigments. Textures are determined as the result of the shape hair follicles.

Question 11

Identify the general structure of a fingernail

Answer 11

• nail root: where nails are formed (skin under cuticle)!
• nail bed: where nails slide forward and attach over layer of epithelium (under nail)! • nail body: pink because underlying vascular tissue (between nail edge & lunula)!
• lunula: half-moon shaped area at the base of the nails (below nail body)

Question 12

Explain how nails provide general information about your health

Answer 12

• Any changes in color are an important indicator of deficiencies, lack of nutrients or more obviously, an accident.!
• White nails indicate lack of iron and poor circulation.!
• Red nails can result from high content of fatty acids and cholesterol due to excess
of dairy, sugar and salt.!
• Red/Purple nails idicate an upset digestive system caused by over consumption of
sugar, pharmaceutical drugs, fruits and juices.!
• Texture of nails can reveal a person’s physical and mental condition.

Question 13

Why is nail fungus difficult to treat?!

Answer 13

• Onychomycosis: more difficult to treat because of inherent slow growth of the nail.

Question 14

Sebaceous glands

Answer 14

Sebaceous glands are small and sacculated in appearance. They are made up of a cluster of about 2-6 piriform alveoli. (scalp)

Question 15

Sweat glands

Answer 15

Eccrine (merocrine) glands
- tubular structures that open directly at the top of the skin, between the hair follicles. (forehead)
Apocrine gland
- Usually associated with hair follicles, continuously secrete a fatty sweat into the gland tubule. Emotional stress causes the tubule wall to contract, expelling the fatty secretion to the skin, where local bacteria break it down into odorous fatty acids. (armpit)

Question 16

Ceruminous Glands!

Answer 16

Simple, coiled, tubular glands made up of an inner secretory layer of cells and an outer myoepithelial layer of cells. (ear)

Question 17

Why are you able to feel pain when someone pulls your hair and detect the temperature of a cup of hot coffee when you hold it in your hand?

Answer 17

When you pull on them you are making the hair pull on your scalp, which contains nerves
and thus cause a pain signal to be sent to the brain. Also, neurons in the skin transmit
signals to the brain and the brain processes the hot coffee as a hot sensation.

Question 18

Why does your professor’s face turn red when she exercises?

Answer 18

The capillaries in her face and throughout her body dilate and blood flows through them in an effort to move the heat her body is generating to the skin’s surface, where it can be radiated off. This effort helps to keep her cool while she works out, but it can also make her skin look flushed, especially in the face.!

Question 19

vitiligo

Answer 19

Vitiligo is a condition in which skin loses melanin, the pigment that determines the color of your skin, hair and eyes. Vitiligo occurs when the cells that produce melanin, or melanocytes die or no longer form melanin, causing slowly enlarging white patches of irregular shapes to appear on your skin

Question 20

tattoos

Answer 20

The tattooist uses a machine that penetrates the skin with a need that travels 50 to
3000 times per minute. The ink that goes into the skin appears on the epidermis, but it is actually placed in the dermis. This is because the dermis properties are a lot more stable so the ink will not move. In fact there is hardly any fading through a lifetime.

Question 21

Identify the three main types of skin cancer

Answer 21

1. Melanoma
2. Basal cell skin cancer
3. Squamous cell skin cancer

Question 22

Describe the steps involved in healing wounds and why deeper wounds that penetrate the
dermis and hypodermis often heal with a scar

Answer 22

1. Fibroblasts (cells that are capable of forming skin and other tissue) gather at the site of injury and begin to produce collagen, which will eventually fill in the wound under the scab and create new capillaries to bring oxygen-rich blood to the recovering wound.!
2. Skin along the edges of the wound becomes thicker and then gradually migrates (or stretches) under the scab to the center of the wound, where it meets skin from the other side and forms a scar (about three weeks after the initial injury).!
3. Scar tissue will become stronger and fade gradually over the next several years as more collagen is added, but will only have about 80 percent of the strength of the original skin.!
4. Repair of damaged dermis is dependent on the level of trauma. Healed superficial dermal damage may be clinically indistinguishable from normal skin. Full-thickness damage to the dermis is repaired by a process called granulation and can result in the formation of a permanent, visible scar.