Complete Fig. 2.1 by adding the names of the missing blood vessel types through which red blood cells travel.
With reference to Fig. 2.2, explain how water functions as a solvent for sodium chloride.
Draw a line on Fig. 2.4 to indicate where the oxygen dissociation curve for penguin haemoglobin would lie.
Penguin haemoglobin is highly sensitive to a fall in pH brought about by an increase in the carbon dioxide concentration in the blood. Explain how a decrease in pH affects penguin haemoglobin, and suggest how this helps the penguin to swim underwater for a long time.
The heart rate of a penguin decreases while it is swimming underwater. Heart rate is controlled by a group of specialised cells in the wall of the right atrium. The activity of these cells is altered by nerve impulses. Name the group of specialised cells in the wall of the right atrium that regulates heart rate.