gas exchange

Question 1

how do gasses move in alveoli and capillaries?

Answer 1

by diffusion- down conc gratients

Question 2

what composes the conducting airways?

Answer 2

trachea, bronchi, nonrespiratory bronchioles

Question 3

what comprises the respiratory airways?

Answer 3

bronchioles, alveolar ducts and alveoli

Question 4

where does gas exchange occur?

Answer 4

respiratory airways

Question 5

how many alveoli do adults have?

Answer 5

300-400 million

Question 6

what are alveoli composed of?

Answer 6

types 1 & 2 epithelial cells

Question 7

what is the diameter of alveoli?

Answer 7

250 microm

Question 8

what is the function and amount of type 1 epithelial cells in alveoli?

Answer 8

97% surface area, primary site of gas exchange

Question 9

what is the amount and function of type 2 epithelial cells in alveoli?

Answer 9

3% SA, produce pulmonary surfactant

Question 10

why are alveoli perfect for gas exchange?

Answer 10

large SA, very thin walls, good diffusion characteristics

Question 11

what does the pulmonary circulation do?

Answer 11

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

Question 12

what does bronchial circulation do?

Answer 12

brings deoxygenated blood to lung parenchyma

Question 13

what does the lymphatic system do?

Answer 13

defence and removal of lymph fluid

Question 14

how much blood is in the pulmonary circulation?

Answer 14

10% of total = 500ml

Question 15

what is the difference in vol. pulmonary blood at rest and at exercise?

Answer 15

at rest = 75ml

exercise = 150-200ml

Question 16

describe the pressure in the pulmonary system

Answer 16

no high pressure unlike systemic circulation

Question 17

describe arteries in the pulmonary system

Answer 17

thin walled, highly compliant, larger diameter, low resistance

Question 18

where does gas exchange occur?

Answer 18

alveolar-capillary network

Question 19

describe gas exchange in the pulmonary circuit

Answer 19

O2 enters blood

CO2 leaves blood

Question 20

describe gas exchange in the systemic circuit

Answer 20

O2 leaves blood

CO2 enters

Question 21

is the pressure gradient for O2 greater or lesser than CO2?

Answer 21

much bigger

Question 22

is O2 or CO2 more diffusible?

Answer 22

CO2

Question 23

in which capillary does PO2 go from 100 alveolar air to 40 venous blood ?

Answer 23

pulmonary capillary

Question 24

in which capillary does PCO2 go from 46 venous blood to 40 alveolar air?

Answer 24

pulmonary capillary