Practise gas-transport questions by following haemoglobin saturation, carbon-dioxide conversion, chloride shift and Bohr-shift changes on dissociation curves.
Control of heartbeat is myogenic. This means the electrical activity controlling the rhythm of a regular heartbeat begins in the heart muscle itself.
Atrial fibrillation (AF) is an abnormal heart rhythm that causes rapid and irregular contractions of the atria. Untreated cases of AF can lead to a stroke.
Red blood cells are involved in the transport of oxygen and carbon dioxide in the blood.
Fig. 5.1 is a diagram representing the exchange of oxygen and carbon dioxide between a red blood cell in a capillary and a respiring cell. Some of the reactions that take place in the red blood cell are also shown. The diagram is not drawn to scale.
Fig. 5.1
Identify enzyme X and molecule Y in Fig. 5.1.
X
Y
The hydrogencarbonate ions shown in Fig. 5.1 leave the red blood cell and are replaced by chloride ions.
State why it is necessary for chloride ions to enter the red blood cell as hydrogencarbonate ions leave.
How is most carbon dioxide transported in the blood?
as carbaminohaemoglobin
as carbonic acid
as hydrogencarbonate ions
in solution in cytoplasm