respiration gas exchange

Question 1

how do gases move?

Answer 1

down concentration gradients by diffusion

Question 2

what does partial pressure/tensions need to be equal to?

Answer 2

total pressure

Question 3

how is partial pressure of a gas calculated?

Answer 3

fraction of gas in gas mixture x barometric pressure
- once breathes into body its humidified so PlO2= FractionO2(Pb-PH2O)

Question 4

what is barometric pressure at sea level?

Answer 4

760 mmHg

Question 5

what is the unit of pressure?

Answer 5

mmHg

Question 6

what is the partial pressure of water at body temperature?

Answer 6

47mmHg

Question 7

what is the smallest branch of the respiratory tree?

Answer 7

alveolar ducts

Question 8

what are conducting airways?

Answer 8

bronchi containing cartilage and non-respiratory bronchioles
- anatomic dead space, not involved in gas exchange

Question 9

what is the volume of the conducting airways?

Answer 9

150ml (30% of average breath)

Question 10

what is the alveoli volume?

Answer 10

2500ml

Question 11

what is another name for the respiratory unit?

Answer 11

gas exchange unit

Question 12

how many alveolar sacs are in an adult?

Answer 12

300-400 million
- polygonal shape
- type 1 and 2 epithelial cells

Question 13

what occupies 97% of surface area of alveoli?

Answer 13

type 1 epithelial cells- primary site of gas exchange

Question 14

what occupies 3% of surface area of alveoli?

Answer 14

type 2 epithelial cells- produce pulmonary surfactant which reduces surface tension (common problem in premature babies which cant produce this)

Question 15

what is the function of alveolar macrophages?

Answer 15

removal of debris

Question 16

what are characteristics of alveoli which make them good for gas exchange?

Answer 16

• large surface area
• thin walls

Question 17

what are the two separate blood supplies of the lungs?

Answer 17

• pulmonary circulation
• bronchial circulation

Question 18

what is the pulmonary circulation blood supply to the lungs?

Answer 18

brings deoxygenated blood from the heart to lung and oxygenated blood from lung to heart and then rest of body

Question 19

what is the bronchial circulation blood supply to the lungs?

Answer 19

brings oxygenated blood to lung parenchyma (lung cells and tissues)

Question 20

what is the total blood volume in the pulmonary circulation?

Answer 20

500ml

Question 21

what happens to the pulmonary circulation during exercise?

Answer 21

alveolar capillary network volume increases due to recruitment of new capillaries

Question 22

what is different about the arteries in the pulmonary system?

Answer 22

• thinner walls
• larger diameter
• lower resistance
  (than systemic system arteries)

Question 23

what is the distance between the alveoli and blood?

Answer 23

very small- ideal for gas exchange

Question 24

what happens to CO2 and O2 in the pulmonary circuit?

Answer 24

O2 enters blood, CO2 leaves

Question 25

what happens to CO2 and O2 in the systemic circuit?

Answer 25

CO2 enters blood, O2 leaves

Question 26

does CO2 or O2 have a larger pressure gradient?

Answer 26

O2

Question 27

is CO2 or O2 more diffusible?

Answer 27

CO2