Integumentary System

Question 1

integumentary system is composed of?

Answer 1

epidermis, dermis and subcutaneous tissue

Question 2

skin

Answer 2

• largest organ of the body
• 15% of total body weight
• surface area ranges from 1.5 to 2 square meters for an average individual

Question 3

the scientific study and treatment of the integument is called?

Answer 3

Dermatology

Question 4

Functions of the Integument: It is said to be a selectively permeable membrane

Answer 4

prevents water loss, provides protection and regulates the bodies temperature

Question 5

Integument is associated with:

Answer 5

• sensory reception
• metabolic regulation
• immunological defense mechanisms

Question 6

Protection

Answer 6

the integument provides protection of underlying tissue

 - as a barrier offers limited protection against injury and           trauma 
 - also integument offers protection against harmful UV light, microbes, toxins radiation and chemicals while minting its ability to selectively absorb other substances (estrogen or nicotine patches).

Question 7

Sensory Reception

Answer 7

-Integument acts as a site of sensory reception (pain, heat cold touch, press)

Question 8

specialized sensory nerve endings

Answer 8

are capable of detecting slight variations in temperature, press, vibration and texture

Question 9

nociceptors

Answer 9

• integument possesses nerve cells specialized to perceive damage to the skin
• they register a positive pain response when stimulated

Question 10

Temperature Regulation

Answer 10

the integument acts in the regulation of body temperature (erect hairs, sweat)

Question 11

evaporative cooling

Answer 11

when the body is too warm, excessive perspiration evaporates on the skins surface (thus reducing the body’s temperature)

• thermoregulation can be accomplished through vasodilation or vasoconstriction

Question 12

Temperature Regulation: Vasodilation

Answer 12

• When the body is too warm, blood vessels of the integument dilate (bigger)
• this allows more blood to flow through the tissues giving off heat along the way; thus lowering the body’s temperature

Question 13

Temperature Regulation: Vasoconstriction

Answer 13

• when the body is too cold. blood vessels of the integument constrict
• preventing blood to flow to the outer tissues and conserving body heat

Question 14

Water & Salt Excretion

Answer 14

• the integument functions in salt excretion (sweat)
• the integument is water resistant (not entirely waterproof) Water and salts and urea, can be actively secreted through sweat glands

Question 15

transepidermal water loss

Answer 15

process when small amounts of interstitial fluids can escape through the skins surface

Question 16

water loss prevention

Answer 16

• Whether perspiration is “sensible” or “insensible”, an estimated 500mL of water is secreted through the integument each day.
• To prevent additional water loss, the water that is secreted mixes with sebum to produce a oily, slightly acidic, barrier which prevents too much water from escaping.

Question 17

Metabolic Regulation

Answer 17

• The integument causes the formation of vitamin D, which is essential for calcium absorption from the foods we eat.
• Vitamin D is important to promote calcium and phosphorous absorption through the small intestines.

Question 18

Cholecalciferol

Answer 18

is the chemical produced when exposure to UV radiation triggers cells of the integument

Question 19

Calcitriol (Vitamin D)

Answer 19

Cholecalciferol travels through the circulatory system to the kidneys where it is synthesized into this

Question 20

Metabolic Regulation Cont.

Answer 20

• calcium and phosphorous are essential for proper bone development
• As little as 15 minutes of exposure to the sun is sufficient to obtain enough vitamin D to sustain the body’s needs for calcium and phosphorous.

Question 21

Immunological Defense Mechanisms: specialized cells of the immune system

Answer 21

• Langerhans cells or epidermal dendritic cells
• These cells are specialized to destroy pathogens that have invaded the outer layers of the integument via phagocytosis.

Question 22

Integument Structure

Answer 22

the skin is made up of two distinct layers that differ in their appearance and function:

  - epidermis 
  - dermis 
      - both of these layers lie on an underlying layer called the subcutaneous tissue or hypodermis

Question 23

Integument Structure: Cont.

Answer 23

• the thickness of the integument varies from location to location throughout the body
• the thickest integument is found along the back and can range up to 1/2cm in thickness
• the thinnest area of integument is associated with the eyelids

Question 24

epidermis

Answer 24

• this is the outermost layer of the integument and is the portion of the skin which is visible
• the epidermis is comprised of keratinized. stratified squamous epithelium
• the epidermis is avascular but does not contain nerves and nerve endings

Question 25

epidermis: cont.

Answer 25

• The deepest layers of the epidermis have cells that undergo mitosis and migrate to the outermost layers, where they become desiccated, convert to keratin and eventually slough off.
• It takes about 30 days far a skin cell to go from birth to slough. Thus, the epidermis (not the total skin) is constantly being replaced.

Question 26

Epidermis: seen to exist in strata (5 layers)

From superficial to deep:

Answer 26

• Stratum Corneum
• Stratum lucidum
• Stratum Granulosum
• Stratum Spinosum
• Stratum Basale

Question 27

Stratum Basale

Answer 27

the deepest layer of the epidermis and is made up of a single layer of cuboidal/columnar cells called Keratinocytes

Question 28

Keratinocytes

Answer 28

• are stem cells that divide continuously throughout life

- keratinocytes produce the structural protein keratin which lends rigidity and insolubility to the cells cytoskeleton