Integumentary system

Question 1

The Integumentary system is comprised of what dermal layers?

Answer 1

Epidermis
Dermis
Hypodermis

Question 2

What are the 6 functions of the integumentary system?

Answer 2

1. Prevents dehydration
2. Facilitates temp regulation
3. Houses cutaneous receptors for environmental sensation
4. Active metabolism
5. Excretion of wastes
6. Continuous with mucosal linings of the oral, anal, urogenital, vestibule of the nostril and palpebral fissure of the eye.

Question 3

What are the 2 distinct regions all skin is comprised of?

Answer 3

Epidermis

Dermis

Question 4

The epidermis consists of five strata; from outer to inner:

Answer 4

1. stratum corneum
2. stratum lucidum
3. stratum granulosum
4. stratum spinosum
5. stratum basale/ germinativum

Question 5

What is the most abundant cell type in the epidermis?

Answer 5

Keratinocytes

Question 6

Explain the Stratum Basale (germinativum)

Answer 6

1-2 cells thick
80% are Keratinocytes
20% are Melanocytes
Obtains nutrients from diffusion of plasma out of capillaries in the dermis but not too far away so receives sufficient nourishment.

Question 7

Explain the Stratum Spinosum

Answer 7

8-20 cells thick
Cells flatten slightly, synthesize proteins (cytokeratin or alpha-keratin)
Nuclei are darkened (pyknosis), early signs of cell death

Question 8

Explain the Stratum granulosum

Answer 8

Cells mainly dead at this stage

Flattened in appearance

Question 9

Explain the Stratum lucidum

Answer 9

Translucent band of dead cells

More prominent and thicker in regions of thickened skin such as, palmar and plantar callouses

Question 10

Explain the Stratum corneum

Answer 10

Outermost layer
Dead cells
Continually sloughed
Keratin and cellular debris combine with lipids to form a tough relatively impermeable layer

Question 11

What are the 2 layers of the Dermis?

Answer 11

Papillary (outermost next to epidermis)

Reticular (innermost next to the hypodermis)

Question 12

Explain the Papillary

Answer 12

finger-like papillae that project into the epidermis, forming dermal ridges that increase surface friction/grip and also ‘fingerprints’

Question 13

What is the hypodermis?

Answer 13

Layer of loose connective tissue separating the dermis from the underlying structures/ tissues especially muscle.
Permits movement of skin without tearing

Question 14

What are sweat glands important for?

Answer 14

Thermoregulation

Question 15

_____ are coiled structure that open to the exterior epidermal surface and produce hypotonic watery sweat.

Answer 15

Eccrine glands

Question 16

Explain Apocrine glands

Answer 16

Affected by sex-steriods and as such are only active following onset of puberty.
Abundant over the surface of dogs, horses, cattle, cats and swine.
‘horse lather’

Question 17

_____ is a mixture of lipids and cell components because sebaceous cells release _____ through a _____.

Answer 17

Sebum
Sebum
holocrine mechanism

Question 18

Name some other cutaneous glands:

Answer 18

Anal glands
Anal sacs
Mammary glands
Submental glands

Question 19

What are the functions of Vitamin D?

Answer 19

Calcium homeostasis (regulation)
Regulation of phosphate in the renal system (kidneys)
An important role in the terminal differentiation of promyelocytes to monocytes (white blood cells)
Vitamin D deficiency affects the immune system, especially T cell-mediated immunity
Excess vitamin D (vitamin D toxicity) suppresses the immune system

Question 20

Explain Vitamin D synthesis.

Answer 20

Vitamin D3 is produced photochemically in the skin from 7-dehydrocholesterol
This is then converted to cholecalciferol (vitamin D3) in relatively large quantities in the skin.