The heart and blood

Question 1

Name six substances that are transported in the blood.

Answer 1

• Oxygen
• Carbon dioxide
• Glucose
• Urea
• Hormones
• Antibodies

Question 2

What is the function (job) of the vena cava?

Answer 2

A vein that carries deoxygenated blood to the heart from the body’s systems

Question 3

How does blood enter the heart?

Answer 3

Through veins

Question 4

How does blood leave the heart?

Answer 4

Through arteries

Question 5

What is the function (job) of the pulmonary vein?

Answer 5

Carries oxygenated blood from the lungs to the heart

Question 6

What is the function (job) of the aorta?

Answer 6

An artery that carries oxygenated blood from the heart to the body

Question 7

What is the function (job) of the pulmonary artery?

Answer 7

Carries deoxygenated blood from the heart to the lungs

Question 8

Where does blood from the vena cava enter the heart?

Answer 8

Through the right atrium

Question 9

Where does blood from the pulmonary vein enter the heart?

Answer 9

Through the left atrium

Question 10

What is the function (job) of the heart valves between the atria and ventricles?

Answer 10

Prevents blood from flowing back into the atria

Question 11

Humans have a double circulatory system. What are the two circuits?

Answer 11

• Pulmonary circulation (lungs)

- Systemic circulation (rest of the body)

Question 12

Why is the pulmonary circulation under low pressure?

Answer 12

Because the lungs are close to the heart

Question 13

What are two ways that faulty heart valves can be replaced?

Answer 13

• with a biological valve from a human donor or made from animal tissue from a pig or cow
• with a mechanical valve made from strong, durable materials

Question 14

How does the heart beat independently from the nervous system?

Answer 14

Specialised cells in the right atrium generate electrical signals that make the heart contract, and act as a natural pacemaker

Question 15

What is an artificial pacemaker?

Answer 15

A medical device that uses electrical impulses to regulate heart beats

Question 16

Describe the structure of the arteries.

Answer 16

• Thick and elasticated walls
• Lots of connective tissue to provide strength
• Narrow lumen (channel that carries blood)

Question 17

Describe the structure of the veins.

Answer 17

• Thin walls
• Much less muscular tissue than arteries
• Less connective tissue than arteries
• Wide lumen (channel that carries blood)

Question 18

What is plasma?

Answer 18

A straw-coloured liquid that makes up just over half the volume of blood.

Question 19

What are some useful things contained in the blood plasma?

Answer 19

• Glucose
• Amino acids
• Vitamins and minerals
• Hormones
• Waste products, e.g. urea

Question 20

What are three types of blood cell and cell fragments?

Answer 20

• Red blood cells
• White blood cells
• Platelets

Question 21

What is the function (job) of the red blood cells?

Answer 21

Transporting oxygen

Question 22

What is the function (job) of the white blood cells?

Answer 22

Ingesting pathogens and producing antibodies

Question 23

What is the function (job) of platelets?

Answer 23

Involved in blood clotting

Question 24

What is the function (job) of the pigment haemoglobin in red blood cells?

Answer 24

Haemoglobin can combine reversibly with oxygen (creating oxyhaemoglobin)

Question 25

Describe FOUR ways that red blood cells are adapted for the transport of oxygen.

Answer 25

- No nucleus, so more room for haemoglobin - Small and flexible, so they can fit through narrow capillaries - Biconcave shape, to maximise their surface area for absorbing oxygen - Thin, creating a short diffusion distance for oxygen

Question 26

What is the function (job) of phagocytes?

Answer 26

Phagocytes engulf and destroy unwanted microorganisms by phagocytosis

Question 27

What is the function (job) of lymphocytes?

Answer 27

Lymphocytes produce soluble proteins called antibodies when a foreign body such as a microorganism enters the body

Question 28

What are the two ways that platelets stop bleeding?

Answer 28

- they have proteins on their surface that enable them to stick to breaks in a blood vessel and clump together - they secrete proteins that result in a series of chemical reactions that make blood clot, which plugs a wound.

Question 29

When people donate blood, it must first be screened before it is used in blood transfusions. What three things might blood be screened for?

Answer 29

- infectious agents such as HIV - their blood group - the presence of certain antibodies

Question 30

When blood is examined under the microscope, cells must first be stained. Giemsa stain is commonly used. What colour does Giemsa stain red blood cells, white blood cells and platelets?

Answer 30

Giemsa stains: - red blood cells pink - platelets pale pink - white blood cell cytoplasm pale blue - white blood cell nuclei magenta

Question 31

What substance can block coronary arteries, leading to a heart attack?

Answer 31

Cholesterol

Question 32

What is the function (job) of statins? How do they do this?

Answer 32

Statins are drugs that help to lower cholesterol in the blood. They do this by lowering its production in the liver.

Question 33

What is a stent?

Answer 33

A device used to keep a narrow or blocked coronary artery open

Question 34

What are stents made from? Why?

Answer 34

Stents are made from metal alloys, and do not lead to an immune response in the patient

Question 35

Why will someone have to take immunosuppresant drugs following a heart transplant?

Answer 35

This prevents the person's immune system from rejecting the donor heart

Question 36

What are some disadvantages of using statins to treat heart disease?

Answer 36

- Not suitable for people with liver disease. - Some side effects. - Must be taken for life.

Question 37

What are some disadvantages of using heart transplants to treat coronary heart disease?

Answer 37

- Few donor hearts are available - Recovery time is long - Risk of infection

Question 38

What are some disadvantages of using replacement heart valves to treat coronary heart disease?

Answer 38

- Biological valves may wear out | - Blood clots may stick to mechanical valves, so anti-blood clotting drugs need to be taken

Question 39

What is the equation for calculating cardiac output?

Answer 39

Cardiac output = heart rate x stroke volume

Question 40

What is cardiac output?

Answer 40

The amount of blood pumped by the heart in one minute.

Question 41

Where in the heart are pacemaker cells found?

Answer 41

In the right atrium

Question 42

Digitalis is a drug that slows the heart rate. | Where does digitalis originate from?

Answer 42

Foxgloves