Ch 6: Integumentary System

Question 1

What are the components of the skin?

Answer 1

Epidermis Dermis Derivatives Hypodermis

Question 2

What are the functions of the skin?

Answer 2

1. Regulation of Body Temperature
   - sweat, goosebumps, vasodilation/vasoconstriction
2. Protection
   - UV rays, microbes
3. Sensation
   - lots of nerve endings
4. Excretion
   - Sweat (salt, urea)
5. Immunity
   - Langerhans cells
6. Blood Reservoir
   - Can shuttle blood to or shunt away from skin
7. Synthesis of Vitamin D
   - Contact with UV light

Question 3

What are the main cell types found in the epidermis?

Answer 3

Keratinocytes (~90%)

Melanocytes (~8%)

-Level of activity determines pigment

Langerhans Cells (1%)

-Immune function

Merkel Cells (~1%)

• Touch the nerve endings in Dermis
• Receptor for touch

Question 4

What are the Epidermal layers?

Answer 4

Stratum basale (1)

Stratum spinosum

(8-10) Stratum granulosum

(3-5) Stratum lucidum (3-5) (Thick skin only)

Stratum corneum (25-30)

Question 5

What is the Stratum basale?

Answer 5

Bottom most epidermal layer

-Helps make keratin and melanin (Keratinocytes and melanocytes)

Question 6

What is the Stratum spinosum?

Answer 6

Spiny appearance due to being squeezed by newly formed keratin in the stratum basale

Question 7

What is the Stratum granulosum?

Answer 7

Makes keratin precursors in granules

Question 8

What is the Stratum lucidum?

Answer 8

THick skin in palms + soles of feet

Question 9

What is the Stratum corneum?

Answer 9

Makes keratinized water proof layer made up of dead cells

-Cells at this layer die quickly because they are farthest from blood supply

Question 10

Where are both keratinocytes and melanocytes located? How do melanocytes deliver their melanin?

Answer 10

Both located in Stratum basale Melanocytes don’t undergo mitosis Melanocytes make melanin and hand off melanin granules to newly formed keratin in the keratinocytes -keratin carries melanin to surface

Question 11

What are the layers of the dermis?

Answer 11

Papillary layer (top 1/5)

• contains areolar and elastic connective tissue (loose)
• thin for elasticity

Reticular Layer (Bottom 4/5)

• thicker to resist being pulled apart in all directions
• made of dense irregular connective tissue with elastin

Question 12

What is are the types of skin glands?

Answer 12

Sebaceous Glands (oil)

• secrete sebum
• hair follicles+oil/salts

Sudoriferous Glands (sweat)

• Eccrine: sweat glands ceruminous glands
• Apocrine: scent glands & mammary glands

Question 13

What are the protective functions of the epidermis?

Answer 13

Acid Mantle

-Sebum+Sweat=low pH cover on skin

Keratin

-Water Proofing

Stratum Corneum

-Resist abrasion. Maintains keratin barrier

Stratum Granulosum

• Repels negatively charged microbes
• Attracts positively charged microbes which get scraped of as new cells move to surface

Question 14

What role does the skin play if you want to lose heat?

Answer 14

Vasodilation of blood vessels in the dermis

-move more blood to the surface to dissipate heat into air

Sweating-Arterio-venous (AV) plexuses constrict/dilate

Question 15

What role does the skin play if you want to conserve heat?

Answer 15

Vasoconstriciton of the blood vessels in the dermis

-Shunts blood away from surface so heat is not dissipated into air

Shivering (generating heat) Arterio-venous (AV) plexuses constrict/dilate

Question 16

Go through the negative feedback loop for body temperature control.

Answer 16

CONTROLLED CONDITION Stimulus disrupts homeostasis by causing increase in body temp

RECEPTOR Thermo receptors in skin activate and send signals to control center

CONTROL CENTER Hypothalamic control center sends nerve signals to sweat glands and skin blood vessels

EFFECTORS Increased sweat output and blood vessels vasodilate RETURN TO

HOMEOSTASIS Evaporative cooling lowers body temp and turns mechanism off

Question 17

Name the components of skin pictured

Answer 17