Human Physiology 5

Question 1

Gases diffuse…

Answer 1

from an area of high to low pressure

Question 2

Explain the partial pressure of O2 and CO2

Answer 2

Oxygen is constantly being used by tissue cells, always low pp of O2 in cells, O2 always moves into cells, required for cellular respiration

Carbon dioxide is constantly being produced by tissue cells, always high pp of CO2 in cells, CO2 always moves out of cells, product of cellular respiration

Question 3

Describe Oxygen transport.

Answer 3

oxygen diffuse from alveoli into blood (due to high pp of O2 in lungs), oxygen binds with hemoglobin in red blood cells to form oxyhemoglobin, oxygen is carried in this form to body cells

Question 4

Describe hemoglobin

Answer 4

O2 not very soluble in plasma, hemoglobin is an oxygen carrying molecule (protein and iron pigment), increases amount of O2 that blood can carry

Question 5

Describe Carbon Dioxide transport.

Answer 5

more soluble than O2, 9% dissolve in plasma (fluid part of blood, 27% combines with hemoglobin, 64% combines with H2O forming carbonic acid (H2CO3)
CO2 continually diffuses into blood plasma, enzyme in red blood converts some CO2 and water into carbonic acid, which breaks into H+ and bicarbonate ions
when blood reaches lungs, new O2 combine with hemoglobin, displacing CO2, CO2 diffuse into alveoli to be exhaled