Integumentary System

Question 1

Components of system

Answer 1

Cutaneous membrane (epidermis, dermis)
Accessory structures 
Subcutaneous layer

Question 2

Functions

Answer 2

Protection 
Excretion 
Temperature maintenance 
Nutrient storage 
Vitamin D3 synthesis 
Sensory detection

Question 3

Epidermis

Answer 3

Composed of layers of keratinocytes
Thin skin = 4 layers (strata)
Thick skin = 5 layers
Provides mechanical protection
Prevents fluid loss
Keeps microorganisms from invading the body
Cells accumulate keratin and eventually shed
Epidermal ridges are interlocked with dermal papillae (finger prints = improve gripping ability and improve sensations)
Langerhans cells (immunity), Merkel cells (sensitivity)

Question 4

Keratin

Answer 4

Fibrous structural protein
Key material in epidermis (nails = B) (hair = a)
Callus formation
Epithelial cells become “cornified” with keratin (makes skin waterproof)

Question 5

Skin colour

Answer 5

Depends on =
Blood supply
Carotene and melanin (melanocytes produce melanin and protect from UV rays)
Epidermal pigmentation

Question 6

Epidermal cells

Answer 6

Synthesize vitamin D3 when exposed to UV

Respond to epidermal growth factor (growth, division, repair, secretion)

Question 7

Vitamin D deficiency

Answer 7

~50% of North Americans

Especially prominent in elderly populations

Question 8

Importance of vitamin D

Answer 8

Bone and teeth health

Activates innate immune system

Question 9

Increase vitamin D

Answer 9

Supplementation (tablets)

Foods fortified with vitamin D (milk, juice)

Question 10

Dermis

Answer 10

Papillary layer = contains blood vessels, lymphatic vessels, sensory nerves of epidermis
Reticular layer = contains network of collagen and elastic fibres to resist tension
Cutaneous plexus of arterioles found in subcutaneous layer/papillary dermis
Cutaneous sensory receptors (light touch, pressure)

Question 11

Stretch marks

Answer 11

Caused by excessive stretching of the dermis

Patterns of collagen and elastic fibres forms lines of cleavage

Question 12

Lines of cleavage

Answer 12

Naturally occurring
Allow for movement
Form over “typical” areas of stress (compression/tension)
Not related to your love life or longevity

Question 13

Hypodermis

Answer 13

Stabilizes skins position against underlying organs and tissues
Attaches to fascia and adipose tissue

Question 14

Hair follicles

Answer 14

Hair originates in follicle 
Composed of root and shaft 
Root (papilla) surrounded by bulb and plexus 
Soft medulla, hard cortex 
Cuticle = protective layer

Question 15

Glands

Answer 15

Sebaceous
Suderiferous
Mammary
Ceruminous

Question 16

Sebaceous glands

Answer 16

Discharge waxy sebum onto hair shaft

Sebaceous follicles discharge onto epidermal surface

Question 17

Suderiferous glands

Answer 17

Sweat glands (produce odorous secretion) 
Precipitation = temperature secretion

Question 18

Other glands

Answer 18

Mammary glands = structure similar to sweat glands

Ceruminous glands = in ear, produce waxy cerumen

Question 19

Nails

Answer 19

Nail body covers the bed
Nail production occurs at the root
Eponychium (cuticle) overlies root