Multicellular organisms require transport systems to supply their cells and remove waste products. In humans, one of the functions of the circulatory system is to transport substances.
Why do multicellular organisms need a transport system?
To Increase the surface area to volume ratio of their bodies
To move molecules internally when the rate of diffusion would be too slow
To provide additional exchange surfaces
Which path describes the movement of oxygenated blood?
Vena cava to right atrium to right ventricle
Pulmonary vein to left atrium to left ventricle
Right ventricle to pulmonary artery to lungs
Which statement is true of pulmonary circulation?
Blood is under high pressure
Blood is being delivered to the extremities of the body
Blood is collecting oxygen from the alveoli
Which type of blood cell does not have a nucleus?
Red blood cell
Which type of blood cell produces antibodies?
Which statement is true of the heart beat?
It is produced by nerves that lead to the heart
It originates in a group of specialised cells in the wall of the heart
It spreads over the heart from the right ventricle
Which statement best describes a vein?
Veins have thin walls and a wide lumen
Veins have thick, muscular walls
Veins always carry deoxygenated blood
What is a stent?
An electrical device used to control the regularity of heart beat
A tube of wire mesh used to keep a coronary artery open
A hollow, flexible tube inserted into an organ to introduce a medical device
A patient is warned that their cholesterol levels are high. Which statement is correct?
The cause is a build up of fatty materials in coronary arteries
A course of statins will lower the patient's cholesterol levels
The patient requires a heart transplant urgently
An elite athlete's cardiac output is measured as 35 dm3 per minute.
If his measured heart rate is 180 beats per minute, what is his stroke volume?