chap 17. gas exchange & regulation of breathing

Question 1

Do gasses diffuse down or up pressure gradients?

Answer 1

• gases diffuse DOWN pressure gradients
• high pressure —> low pressure

Question 2

What is Daltons law?

Answer 2

• a mixture of gases has an overall pressure of which each gas in the mixture has a partial pressure

Question 3

Can gases in mixtures diffuse down partial pressure gradients?

Answer 3

• yes, gases diffuse down partial pressure gradients
• high partial pressure —–> low partial pressure

Question 4

Is diffusion between alveoli and blood fast due to a small diffusion barrier in capillaries and a large surface area in alveoli?

Answer 4

• diffusion between the two is very fast

Question 5

define hyperpnea

Answer 5

• increased ventilation due to increased demand
  
  • minimal change in arterial PO2
    and PCO2

Question 6

define hypoventilation

Answer 6

• ventilation does not meet demands
• arterial Po2 decreases while Pco2 Increases

Question 7

define hyperventilation

Answer 7

• ventilation exceeds demands
• arterial Po2 increases
• arterial PCO2 decreases

Question 8

What gases transport in the blood

Answer 8

• oxygen transport in the blood
• carbon dioxide transport in the blood

Question 9

How does oxygen transport in the blood?

Answer 9

• oxygen is transported by hemoglobin
• o2 isn’t very soluble in plasma
• (Only 3.0 mL of every 200 mL of arterial blood O2 is dissolved in plasma (1.5%))

Question 10

what does the chemical process behind Hb + O2 = Hb x o2

Answer 10

• hb = deoxyhemoglobin
• Hb x o2 =oxyhemoglobin

Question 11

What does the transport of oxygen by hemoglobin look like in numbers?

Answer 11

• Approx. 20-30 trillion
  RBCs circulating in
  blood (millions in a
  single drop of blood).
• Approx. 270 million
  Hb molecules per
  RBC
• Each Hb molecule
  has four heme
  groups to pick up O2
  or CO2 molecules.