Circulatory System Practice Questions

Question 1

5 marks

Red blood cells transport oxygen from the lungs to the respiring tissues of the body.

(a)

Name the red pigment found inside a red blood cell that combines with oxygen.

/ 1

(b)

Red blood cells have a biconcave disc shape.

Explain how this shape helps a red blood cell to carry out its function.

/ 2

(c)

Mature red blood cells do not have a nucleus.

Explain one advantage of this to the red blood cell.

/ 2

Question 2

5 marks

Blood is made up of cells and cell fragments carried in a liquid.

(a)

Which component of the blood helps the blood to clot at a wound?

A plasma

B platelets

C red blood cells

D lymphocytes

/ 1

(b)

Describe how clotting protects the body after the skin has been cut.

/ 2

(c)

Plasma is the straw-coloured liquid part of the blood.

State two substances that are transported in the plasma.

/ 2

Question 3

4 marks

Figure 1 shows a simplified diagram of the human heart. The blood vessels are labelled A, B, C and D and the chambers are labelled W, X, Y and Z.

Figure 1

(a)

Give the letter of the vessel that carries deoxygenated blood to the lungs, and the letter of the vessel that carries oxygenated blood to the body.

/ 2

(b)

Name the chamber labelled X.

/ 1

(c)

Blood flowing in vessel A enters the heart. Give the letter of the chamber it enters.

/ 1

Question 0

7 marks

Cardiac output can be calculated using the equation:

$\text{cardiac output} = \text{stroke volume} \times \text{heart rate}$

A student has a resting heart rate of 68 beats per minute and a stroke volume of 72 cm³.

(a)

Calculate the student's cardiac output at rest.

.............................................................. cm³ per minute

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(b)

While the student is running, their cardiac output is $18$ dm³ per minute and their heart rate is $150$ beats per minute.

Calculate their stroke volume during the run, in cm³.

.............................................................. cm³

/ 3

(c)

Explain why the student's cardiac output increases during the run.

/ 2

Question 0

6 marks

Figure 2 shows cross-sections through three types of blood vessel, labelled X, Y and Z. The vessels are not drawn to the same scale as each other.

Figure 2

(a)

Name the type of blood vessel shown by X and the type shown by Y.

/ 2

(b)

Explain how the wall of vessel X is adapted to the job it does.

/ 2

(c)

Explain how vessel Z is adapted for the exchange of substances with body cells.

/ 2

Question 0

7 marks

A student is given prepared slides of a cross-section of an artery and a cross-section of a vein taken from a pig. The student uses a light microscope with an eyepiece graticule to compare the thickness of the walls of the two vessels.

(a)

Describe a method the student could use to obtain a valid comparison of the thickness of the two vessel walls.

/ 3

(b)

The student views the artery at a total magnification of $\times 100$ . The wall of the artery in the image measures $45$ mm.

Calculate the actual thickness of the artery wall, in mm.

.............................................................. mm

/ 2

(c)

Later, the student dissects a fresh pig heart. State two things the student should do to reduce the risk of infection when working with the fresh tissue.

/ 2

Question 0

6 marks

Figure 3 shows the estimated rate of blood flow to some organs in an adult when at rest and during vigorous exercise.

organ	rate of blood flow in cm³ per minute — at rest	rate of blood flow in cm³ per minute — during vigorous exercise
kidneys	1100	250
skin	500	1900
skeletal muscle	1000	12500
brain	700	700
heart muscle	250	750

Figure 3

(a)

Calculate the percentage decrease in the rate of blood flow to the kidneys during vigorous exercise.

.............................................................. %

/ 2

(b)

Explain why the rate of blood flow to the skin increases during vigorous exercise.

/ 2

(c)

The total volume of blood pumped by the heart each minute is much greater during vigorous exercise than at rest.

Explain how the heart achieves this increase.

/ 2

Question 0

6 marks

White blood cells defend the body against pathogens. Two types of white blood cell are phagocytes and lymphocytes.

(a)

Describe how a phagocyte destroys a pathogen.

/ 3

(b)

Describe the role of a lymphocyte in defending the body against a pathogen.

/ 2

(c)

Unlike red blood cells, white blood cells have a nucleus. Explain why a lymphocyte needs a nucleus.

/ 1

Question 0

6 marks

Humans have a double circulatory system.

(a)

Name the blood vessel that carries blood from the heart to the lungs.

/ 1

(b)

Describe the path taken by a drop of blood from the moment it enters the heart from the vena cava until it leaves the heart on its way to the lungs.

/ 3

(c)

Explain one advantage of a double circulatory system compared with a single circulatory system.

/ 2

Question 0

6 marks

A sample of blood from an adult contains about $5.0 \times 10^{6}$ red blood cells in every $1$ mm³ of blood. This adult has a total blood volume of $5.2$ dm³.

$1 \text{ dm}^3 = 1 \times 10^{6} \text{ mm}^3$

(a)

Calculate the total number of red blood cells in the blood of this adult.

Give your answer in standard form.

.............................................................. red blood cells

/ 3

(b)

A red blood cell survives for about $120$ days before it is broken down.

Calculate the mean number of red blood cells that must be made each day to keep the number in the blood constant.

Give your answer in standard form.

.............................................................. red blood cells per day

/ 2

(c)

A red blood cell has a diameter of $7.5$ µm.

Give this diameter in metres, in standard form.

.............................................................. m

/ 1

Question 0

6 marks

The heart is a muscular pump made of four chambers. The walls of the chambers are not all the same thickness, and valves are found between the atria and the ventricles and at the base of the arteries leaving the heart.

(a)

Explain why the wall of the left ventricle is much thicker than the wall of the right ventricle.

/ 3

(b)

Explain how the valves of the heart make sure that blood flows in one direction only.

/ 3

Question 0

7 marks

Figure 4 shows measurements taken from a trained long-distance runner at rest and during exercise.

measurement	at rest	during exercise
heart rate in beats per minute	48	170
stroke volume in cm³	112	145

Figure 4

(a)

Calculate the runner's cardiac output at rest.

Give your answer in dm³ per minute.

.............................................................. dm³ per minute

/ 2

(b)

Calculate the percentage increase in the runner's cardiac output during exercise compared with at rest.

.............................................................. %

/ 3

(c)

An untrained person of the same age has a resting heart rate of 75 beats per minute, but a similar resting cardiac output to the runner.

Explain why the runner's resting heart rate is lower.

/ 2

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Exchange & Transport in Animals

Ecosystems & Material Cycles

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