Topic 8 Transport in mammals

why is the mammalian circulatory system described as a double circulation?

• blood flows twice through the heart in one complete cardiac cycle

• blood flows twice through the heart in one complete circuit of the body

• blood remains within arteries, veins and capillaries

• blood transport both oxygen and carbon dioxide

Identify cell labelled X.

This is a diagram of a vertical section through the mammalian heart. The label Q to X represent valves and blood vessels of the heart.

State which label represents the valve that prevents the backflow of blood from the aorta into the ventricle.

Name the blood vessel labelled X.

Name the structure in the heart that acts as the pacemaker to initiate the cardiac cycle

what combines with haemoglobin to form carbaminohaemoglobin?

The diagram shows the pressure changes in some structures of the right side of the heart during the cardiac cycle. Which structure is represented by X?

what describes the role of atrio-ventricular node of the heart?

• it causes the muscles of the ventricles to contract from the apex upwards

• it delays the transmission of a wave of electrical activity from the sinoatrial node

• it initiates a new wave of electrical activity in the ventricles

• it provides a non-conducting barrier between the atria and the ventricles

what effect does decreasing carbon dioxide concentration have on haemoglobin?

• it is less efficient at taking up oxygen and less efficient at releasing oxygen

• it is less efficient at taking up oxygen and more efficient at releasing oxygen

• it is more efficient at taking up oxygen and less efficient at releasing oxygen

• it is more efficient at taking up oxygen and more efficient at releasing oxygen

The diagram shows the Bohr effect. What causes the shift from X to Y?

• decreased concentration of carbon dioxide and high pH

• decreased concentration of carbon dioxide and low pH

• increased concentration of carbon dioxide and high pH

• increased concentration of carbon dioxide and low pH