chapter 5 part 4

Question 1

hair growth stage 1

Answer 1

cells added at base and hair elongates.

Question 2

hair resting stage 1

Answer 2

Follicle shortens and holds hair in place. Rest, then hair falls out of follicle. New hair begins.
The amount of time spent in each stage depends on the type or location of the hair.
* Regular hair loss means hair is being replaced

Question 3

Alopecia areata 1

Answer 3

is spot baldness most likely due to an
autoimmune response.

Question 4

Arrector pili 1

Answer 4

Type of smooth muscle.
* Extends from the dermal root sheath of the follicle to the papillary layer of the dermis.
* Muscle contraction causes hair to “stand on end”.
* Skin pushed up by movement of hair follicle to produce “goose bumps”.

Question 5

Sebaceous Glands 1

Answer 5

• Holocrine (death of secretory cells).
• Oily secretion called sebum.
• Prevents drying and inhibits some bacteria.
• Most empty into hair follicle.
• Exceptions: lips, meibomian glands of eyelids, genitalia

Question 6

Eccrine (merocrine) glands. 1

Answer 6

type of sweat gland
* Most common; numerous in palms and soles.
* Simple coiled tubular glands.
* Open directly onto surface of skin. Have own pores.
* Coiled part in dermis, duct exiting through epidermis.
* Important role in body temperature regulation.

Question 7

Apocrine glands. 1

Answer 7

type of sweat gland
* Active at puberty.
* Simple coiled tubular, usually open into hair follicles superficial to opening of sebaceous gland.
* Secretion: organic compounds that are odorless but, when acted upon by
bacteria, may become odiferous.
* Found in axillae, genitalia (external labia, scrotum), around anus.
* Do not help regulate temperature

Question 8

Ceruminous glands 1

Answer 8

modified eccrine sweat glands in the external auditory canal.
* Earwax (cerumen). Composed of a combination of sebum and secretion from ceruminous.
* Function- In combination with hairs, prevent dirt and insects from entry

Question 9

Mammary glands 1

Answer 9

modified apocrine sweat glands that produce milk.

Question 10

nail growth 1

Answer 10

Structure – thin plate of layers of dead stratum corneum cells with hard keratin.
* The nail matrix and bed are composed of epithelial tissue with a stratum basale that gives rise to the cells that form the
nail.
* Grow continuously unlike hair.
* Fingernails grow 0.5 to 1.2 mm/day; faster than toenails.
* Lunula – small part of nail matrix seen through the nail, crescent-shaped area at the base of the nail.

Question 11

Physiology of the Integumentary System

Answer 11

• Against abrasion, sloughing off of bacteria as desquamation occurs.
• skin contains cells of the immune system.
• Melanin against UV radiation.
• Hair on head is insulator and protection against light, and from abrasion. Eyebrows keep sweat out of the eyes;
  eyelashes protect eyes from foreign objects. Hair in nose and ear against dust, bugs, etc.
• Nails protect ends of digits, self defense.
• Acts as barrier to diffusion of water.

Question 11

Lunula

Answer 11

small part of nail matrix seen through the nail, crescent-shaped area at the base of the nail

Question 12

sensation

Answer 12

Pressure, temperature, pain, heat, cold, touch,
movement of hairs.

Question 13

temperature regulation

Answer 13

sweating and radiation
* Arterioles in dermis change diameter as temp
changes. More or less blood flows through the dermis

Question 14

Heat Exchange In the Skin

Answer 14

1. When arterioles in the dermis dilate, more warm blood flows from deeper structures to the skin.
2. Heat loss increases, resulting in a reduction in body temp.
3. Body temp tends to increase as a result of
   exercise, fever, or a rise in environmental
   temperature. In order to maintain homeostasis,
   this excess heat must be lost. The body
   accomplishes this by producing sweat. The sweat spreads over the surface of the skin; as it
   evaporates, the body loses heat.
4. When blood vessels in the dermis constrict, less warm blood flows from deeper structures to the skin.
5. As a result of reduced blood flow through the skin, heat loss decreases. If body temperature begins to drop below normal, heat can be conserved by a decrease in the diameter of the dermal blood
   vessels

Question 15

vitamin D production over view

Answer 15

• Begins in skin; aids in calcium absorption
• Vitamin D3 (calcitriol): hormone.
• Stimulates uptake of calcium and phosphorus from intestines
• Promotes calcium and phosphrous release from bones
• Reduces calcium loss from kidneys
• Increases blood calcium levels
• Sources: dairy, liver, egg yolks, supplements

Question 16

production of vitamin D steps

Answer 16

1. Vitamin D synthesis involves a molecule, 7-dehydrocholesterol, which is stored in the skin. When exposed to UV light, the molecule is converted into cholecalciferol, which is released into the blood.
2. Cholecalciferol is transported first to the liver where it is modified. The modified cholecalciferol re-enters the blood and is transported to the kidneys.
3. At the kidneys, the substance is again modified to form active vitamin D3, also called calcitriol. Calcitriol stimulates the uptake of calcium and phosphate at the small intestine.

Question 17

excretion

Answer 17

Removal of waste products from the body.
* Sweat: water, salt, urea, ammonia, uric acid.
* Insignificant when compared with kidneys.

Question 18

Physiology of the Integumentary System components

Answer 18

Sensation
temperature regulation
vitamin D production
excretion

Question 19

burns

Answer 19

Partial thickness.
* First-degree.
* Second-degree.
Full-thickness.
* Third-degree.
Fourth-degree affect
deeper structures.

Skin Grafts
* Split skin.
* Artificial skin.
* Cadavers or pigs.

Question 20

type of sweat glands

Answer 20

eccrine sweat gland
apocrine sweat gland
mammary gland
ceruminous gland
sebaceous gland