A straw-coloured liquid in which the other blood components are suspended. It transports substances such as carbon dioxide, digested food, urea, hormones and heat energy.

The protein found in red blood cells that binds to oxygen to form oxyhaemoglobin .

What are the four components of blood?

Red blood cells , white blood cells , platelets and plasma .

Give three ways red blood cells are adapted to carry oxygen.

They are full of haemoglobin , which binds oxygen. They have no nucleus , leaving more room for haemoglobin. They are a biconcave disc shape, giving a large surface area to volume ratio for diffusion.

What are the two types of white blood cell and their roles?

Lymphocytes – produce antibodies to destroy pathogens and antitoxins to neutralise toxins. Phagocytes – carry out phagocytosis by engulfing and digesting pathogens.

How do platelets cause the blood to clot?

They release chemicals that convert soluble fibrinogen into insoluble fibrin , forming a mesh that traps red blood cells and forms a clot (which dries into a scab).

Why is blood clotting important?

It prevents continued/significant blood loss from wounds. The scab seals the wound and prevents entry of microorganisms that could cause infection.

Describe the structure of an artery and how it is adapted to its function.

Arteries carry oxygenated blood (except the pulmonary artery) at high pressure away from the heart . They have thick muscular walls with elastic fibres to withstand and maintain the high pressure, and a narrow lumen to help maintain that pressure.

Describe the structure of a vein and how it is adapted to its function.

Veins carry deoxygenated blood (except the pulmonary vein) at low pressure towards the heart . They have thin walls , a large lumen to reduce resistance, and valves to prevent the backflow of blood.

How are capillaries adapted for the exchange of substances?

They have walls that are one cell thick (short diffusion distance) so substances diffuse easily, and 'leaky' walls that allow plasma to leak out and form tissue fluid.

The volume of blood pumped by the heart (a ventricle) per unit of time. An average adult has a cardiac output of roughly 4.7 litres per minute at rest.

The arteries that supply the cardiac muscle tissue of the heart with oxygenated blood (and glucose) for aerobic respiration.

Why is the heart described as a double pump?

The right side pumps deoxygenated blood to the lungs (pulmonary circuit). The left side pumps oxygenated blood to the rest of the body (systemic circuit).

Why does the left ventricle have a thicker muscle wall than the right ventricle?

It must pump blood at high pressure all the way around the entire body , whereas the right ventricle only pumps blood at lower pressure to the nearby lungs.

Trace the path of deoxygenated blood through the right side of the heart.

Vena cava → right atrium → (tricuspid valve) → right ventricle → (semilunar valve) → pulmonary artery → lungs.

Trace the path of oxygenated blood through the left side of the heart.

Pulmonary vein → left atrium → (bicuspid valve) → left ventricle → (semilunar valve) → aorta → body.

What is the function of the valves in the heart?

To prevent blood flowing backwards .

Name the blood vessels, in order, as blood travels from the heart through an organ and back.

Artery → arterioles → capillaries (within the organ) → venules → veins.

Define heart rate and stroke volume.

Heart rate : the number of times the heart beats per minute. Stroke volume : the volume of blood pumped out of the left ventricle during one cardiac cycle.

Why do fitter individuals often have a higher cardiac output?

They have thicker and stronger ventricular muscle in their hearts, allowing more blood to be pumped per minute.

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Circulatory System (Edexcel GCSE Combined Science: Biology): Flashcards

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FrontThe Blood & Blood Vessels
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Cards in this collection (24)

Plasma
A straw-coloured liquid in which the other blood components are suspended. It transports substances such as carbon dioxide, digested food, urea, hormones and heat energy.
Haemoglobin
The protein found in red blood cells that binds to oxygen to form oxyhaemoglobin.
What are the four components of blood?
Red blood cells, white blood cells, platelets and plasma.
Give three ways red blood cells are adapted to carry oxygen.
They are full of haemoglobin, which binds oxygen.
They have no nucleus, leaving more room for haemoglobin.
They are a biconcave disc shape, giving a large surface area to volume ratio for diffusion.
What are the two types of white blood cell and their roles?
Lymphocytes – produce antibodies to destroy pathogens and antitoxins to neutralise toxins.
Phagocytes – carry out phagocytosis by engulfing and digesting pathogens.
How do platelets cause the blood to clot?
They release chemicals that convert soluble fibrinogen into insoluble fibrin, forming a mesh that traps red blood cells and forms a clot (which dries into a scab).
Why is blood clotting important?
It prevents continued/significant blood loss from wounds.
The scab seals the wound and prevents entry of microorganisms that could cause infection.
Describe the structure of an artery and how it is adapted to its function.
Arteries carry oxygenated blood (except the pulmonary artery) at high pressure away from the heart. They have thick muscular walls with elastic fibres to withstand and maintain the high pressure, and a narrow lumen to help maintain that pressure.
Describe the structure of a vein and how it is adapted to its function.
Veins carry deoxygenated blood (except the pulmonary vein) at low pressure towards the heart. They have thin walls, a large lumen to reduce resistance, and valves to prevent the backflow of blood.
How are capillaries adapted for the exchange of substances?
They have walls that are one cell thick (short diffusion distance) so substances diffuse easily, and 'leaky' walls that allow plasma to leak out and form tissue fluid.
Red blood cells are full of to carry oxygen and have no to make more room for it.
haemoglobin / nucleus
carry blood at high pressure away from the heart, while carry blood at low pressure back towards it.
Arteries / veins
Cardiac output
The volume of blood pumped by the heart (a ventricle) per unit of time. An average adult has a cardiac output of roughly 4.7 litres per minute at rest.
Coronary arteries
The arteries that supply the cardiac muscle tissue of the heart with oxygenated blood (and glucose) for aerobic respiration.
Why is the heart described as a double pump?
The right side pumps deoxygenated blood to the lungs (pulmonary circuit).
The left side pumps oxygenated blood to the rest of the body (systemic circuit).
Why does the left ventricle have a thicker muscle wall than the right ventricle?
It must pump blood at high pressure all the way around the entire body, whereas the right ventricle only pumps blood at lower pressure to the nearby lungs.
Trace the path of deoxygenated blood through the right side of the heart.
Vena cava → right atrium → (tricuspid valve) → right ventricle → (semilunar valve) → pulmonary artery → lungs.
Trace the path of oxygenated blood through the left side of the heart.
Pulmonary vein → left atrium → (bicuspid valve) → left ventricle → (semilunar valve) → aorta → body.
What is the function of the valves in the heart?
To prevent blood flowing backwards.
Name the blood vessels, in order, as blood travels from the heart through an organ and back.
Artery → arterioles → capillaries (within the organ) → venules → veins.
Define heart rate and stroke volume.
Heart rate: the number of times the heart beats per minute.
Stroke volume: the volume of blood pumped out of the left ventricle during one cardiac cycle.
Why do fitter individuals often have a higher cardiac output?
They have thicker and stronger ventricular muscle in their hearts, allowing more blood to be pumped per minute.
Arteries carry blood from the heart, while veins carry blood the heart.
away / towards
Cardiac output is calculated as heart rate multiplied by .
stroke volume

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