Question
The image shows the changes in heart rate of an athlete during exercise.
What is likely to have occurred between 0 and 4 minutes and between 24 and 28 minutes?
Answer/Explanation
Question
Blood clotting involves a cascade of reactions. Which statement describes the blood-clotting
process?
A. Red blood cells release clotting factors that result in the production of fibrin.
B. Clotting factors trigger the conversion of the inactive thrombin to prothrombin.
C. Insoluble fibrinogen is converted into soluble fibrin.
D. Fibrin forms a mesh that traps platelets and blood cells.
Answer/Explanation
Question
A cell from the lungs, observed under the microscope, contains a large number of
secretory organelles. Which conclusion can be drawn about the cell?
A. It is a type I pneumocyte.
B. It is a type II pneumocyte.
C. It could be either a type I or type II pneumocyte.
D. It is a red blood cell.
Answer/Explanation
Question
The image shows a neuron.
What is the function of X?
A. Increases the speed of transmission along the axon
B. Increases the rate of exchange of sodium and potassium ions
C. Holds bundles of neurons together to form a nerve
D. Determines the direction of the action potential
Answer/Explanation
Question
Pressure changes inside the thorax cause the movement of air in and out of the lung alveoli
during ventilation. Alveolar pressure correlates to thoracic pressure. The diagram shows pressure
changes in lung alveoli during ventilation in relation to normal atmospheric pressure. What causes
forced movement of air out of the lungs at T?