Accessory Structures

Question 1

What is the subcutaneous layer of the skin?

Answer 1

Hypodermis; lowermost layer of the integumentary system

tissue types: areolar and adipose tissue

functions: elasticity, reduce heat loss, energy reserve, blood resevoir

Question 2

What is a good site for injections?

Answer 2

Adipose tissue in the subcutaneous layer

Question 3

What are the appendages of the skin?

Answer 3

Hair follicles and hair, nails, sweat glands, sebaceous glands, ceruminous glands

Question 4

Where/what kind of hair are the following types ?

1) terminal hair
2) specialized terminal hair
3) vellus hair
4) lanugo

Answer 4

1) Terminal hair:

Head (scalp).
Armpits.
Pubic area.
Upper lip, cheeks and chin.
Chest and belly (abdomen).
Back.
Arms and legs.
Fingers and toes.

2) Specialized terminal hair:

eyelashes and eyebrows

3) Vellus hair:

body hair, peach fuzz

4) Lanugo:

baby hair

Question 5

What are the (4) main functions of hair?

Answer 5

a) insulates and protects the scalp
b) protects nostrils and ear canals
c) detects movement through hair plexus and sensory nerve
d) arrector pili muscle stands up = goose bumps

Question 6

What is the development of terminal (armpit) hair?

Answer 6

Prepubertal stage: vellus hair

+ androgens - testosterone

Adult stage: terminal hair

Question 7

What is the hair growth cycle? (4 stages)

Answer 7

1) The active phase: lasts 2-5 years.

• hair grows continuously at a rate of approximately 0.33mm/day

2) The follow then begins to undergo regression and transitions to the resting phase

3) The resting phase: the hair loses its attachment to the follicle and becomes a club hair

4) when follicle reactivation occurs, the club hair is shed and the hair matrix begins producing a replacement hair

hair: dead keratinocytes

Question 8

What are sebaceous glands?

Answer 8

Secrete oil through holocrine secretion

two types:

1) simple branched alveolar glands - share duct with the follicle and squeezed by arrector pill muscle
2) sebaceous follicles - not associated with hair follicles

Question 8

What is the structure of the hair shaft of a hair follicle? ** check pg. 50

Answer 8

1) Medulla: innermost; matrix produces hair shaft and outer root sheaths
2) Cortex: thickest part of the hair shaft, contains the melanin
3) Cuticle: dead, shingle like cells

Matrix: where keratinocytes are made

1) hair papilla
2) melanocytes (hair colour)

Question 9

What do sebaceous glands secrete?

Answer 9

Sebum (lipids + electrolytes + proteins + cholesterol)

Question 10

What is the function of sebum?

Answer 10

• inhibits bacterial growth due to its acidity
• lubricates and protects keratinized cells (hair and skin)
• newborn’s vernix caseosa
• can fail to discharge; collecting sebum in “whiteheads” or “blackheads” which can become inflamed causing acne in teenagers as a result of hormonal changes

Question 11

What produces hair colour?

Answer 11

Melanin in the cortex

Question 12

Does hair become thinner as you age?

Answer 12

Yes

Question 12

Do nutritional supplements stop graying?

Answer 12

No; cannot be prevented

Question 12

Does everyone get less hair as they age?

Answer 12

Yes

Question 12

Why do we get grey hairs?

Answer 12

Melanocytes slow

Question 13

Do your nails change with age?

Answer 13

Yes

Question 13

Do men get longer eyebrow, ear, and nose hairs with age?

Answer 13

Yes

Question 14

What are merocrine sweat glands?

Answer 14

Merocrine sweat glands (=eccrine sweat glands)
structure: coiled tubular duct

controlled primarily by thermoregulatory center (hypothalamus)
sweat is watery

function:
-to cool surface of skin to reduce body temperature
-excrete water and electrolytes
-flushes chemicals
-contains dermicidin (antibiotic protein) to discourage microbes

Question 14

What are sweat glands?

Answer 14

Sudoriferous glands that use exocytosis

merocrine and apocrine sweat glands

Question 14

What are apocrine sweat glands?

Answer 14

Includes ceruminous glands of ear and mammary milk-producing glands

distribution: axillae, pubic region, around nipples

structure: coiled tubule structures that open into hair follicles
function: nutrient for bacteria which intensifies odour

secretion: sticky, cloudy, odourous, influenced by hormones

myoepithelial cells are contractile cells that squeeze the gland

Question 15

What are ceruminous glands?

Answer 15

Modified apocrine sweat glands located in the external ear

secretion: cerumen = ear wax using apocrine mechanism
function: trap foreign particles protecting ear drum

Question 16

Do apocrine sweat glands use apocrine secretion?

Answer 16

***** 48

Question 17

What kind of cells are the keratinocytes in nails?

Answer 17

Densely packed dead keratinocytes

Question 18

What are the common landmarks of nail structure?

Answer 18

Nail bed: body that covers an area of epidermis
Nail body: uppermost layer of the nail
Lateral nail groove
Lateral nail fold
Phalanx: bone of fingertip
Lunala: pale crescent near the root, where blood vessels may be obscured
Proximal nail fold
Eponychium
Hyponychium

Question 19

What are the types of skin cancer from most to least dangerous?

Answer 19

Melanoma
Squamous cell carcinoma
Basal carcinoma

Question 20

What is basal carcinoma?

Answer 20

Cancer of keratinocytes in stratum basale; generally forms a nodule with a ‘cratered’ center

• 2/3 on areas chronically exposed to sun
  -relatively slow-growing

Question 21

What is squamous cell carcinoma?

Answer 21

Cancer of keratinocytes in the stratum spinosum; forms plaques that bleed or ulcerate

-sun exposed areas
-Both basal and squamous cell skin cancers are relatively slow-growing, but squamous cell skin cancer is more likely to spread to other organs. If it spreads, it can be life-threatening.

Question 22

What is melanoma?

Answer 22

Least common, most dangerous type of skin cancer

site of origin: melanocytes
can occur anywhere; sun exposure increases odds (spreads fastest)

malignant melanoma are cancer of melanocytes characterized by asymmetrical shape, irregular borders, blue-black colour, large diameter, and evolving nature

ABCD
a) asymmetry - irregular shape
b) border - irregular border
c) colour - mottled
d) diameter - more than 5 mm

Question 23

What are burns?

Answer 23

Tissue damage caused by intense heat, electricity, radiation (including sunburn), some chemicals

Question 24

What are first degree burns? What does it affect?

Answer 24

Affects only the surface of the epidermis; most sunburns; usually limited to redness with minor pain

Question 25

What are second degree burns? What does it affect?

Answer 25

Affects epidermis and upper portions of the dermis, blistering, swelling

pain heals in 1-2 weeks if no infection

Question 26

What are third degree burns? What does it affect?

Answer 26

Affects epidermis, dermis, sometimes hypodermis, and possibly deeper tissues

if >10% of the body, immediately life threatening because granulation tissue cannot form to cover area

problems: fluid loss, along with electrolytes, proteins occurs 5x faster than normal

Question 27

What steps can you take to treat third degree burns (within 24 hours)?

Answer 27

1) replace lost fluids and electrolytes
2) provide massive amounts of nutrients
3) protect to try to prevent infection
4) assist in tissue repair, grafts

Question 28

Process of scarring? injury to the skin

Answer 28

1) Inflammatory phase:
-mast cells trigger inflammatory response
-bleeding occurs at the site of injury

2) Migratory phase:
-scab forms at the surface
-patrolling macrophages remove debris and pathogens
-rapid cell division and migration along would edges to replace missing cells
-formation of granulation tissue

3) Proliferation phase:
-deeper portions of the clot dissolve
-fibroblasts produce new collagen fibres and ground substances

4) Scarring phase:
-scar tissue formation