(Paper 1) 2.3 Organisation: The Circulatory System Flashcards
(112 cards)
1
Q
How do small organisms transport substances?
A
By diffusion, as the distances are short.
2
Q
Why do larger organisms need transport systems?
A
Diffusion alone is too slow over long distances; transport systems ensure efficient distribution of substances.
3
Q
What are common features of transport systems?
A
Made of tubes or vessels
Make close contact with exchange surfaces and cells
4
Q
Where is oxygen transported from and to?
A
From the lungs to all body cells
5
Q
Where is carbon dioxide transported from and to?
A
From all body cells to the lungs
6
Q
Where is glucose transported from and to?
A
From the digestive system, via the liver, to all body cells
7
Q
Where is urea transported from and to?
A
From the liver to the kidneys
8
Q
What other substances are transported in the blood?
A
Antibodies and hormones
9
Q
What carries oxygen in the blood?
A
Red blood cells
10
Q
What carries dissolved substances like glucose and urea?
A
plasma
11
Q
How many chambers does the heart have?
A
Four – two atria and two ventricles.
12
Q
Which vessels bring blood into the heart?
A
Vena cavae → right atrium (from the body)
Pulmonary veins → left atrium (from the lungs)
13
Q
Which vessels carry blood away from the heart?
A
Pulmonary artery → to lungs
Aorta → to body
14
Q
What prevents backflow of blood in the heart?
A
Valves
15
Q
What are the two circulations in the human body?
A
Pulmonary circulation (heart → lungs → heart)
Systemic circulation (heart → body → heart)
16
Q
What happens in the pulmonary circulation?
A
Oxygen diffuses into the blood
Carbon dioxide diffuses out of the blood
17
Q
Why is the pulmonary circulation under lower pressure?
A
Lungs are close to the heart; lower pressure helps with efficient gas exchange.
18
Q
What happens in the systemic circulation?
A
Delivers oxygen and nutrients to the body and removes carbon dioxide and waste.
19
Q
In what order does blood pass through the heart and body?
A
- Body → right atrium
- Right ventricle → lungs
- Left atrium → left ventricle
- Aorta → body
20
Q
Why must blood flow in only one direction in the circulatory system?
A
To ensure efficient transport of substances and prevent backflow.
21
Q
What structures prevent backflow of blood in the circulatory system?
A
Valves in the heart, aorta, and veins.
22
Q
What happens when a valve closes?
A
It prevents backflow of blood.
23
Q
What are two types of faulty valve problems?
A
- The valve does not open fully (restricts flow).
- The valve does not close properly (causes backflow).
24
Q
What symptoms can faulty heart valves cause?
A
Shortness of breath, dizziness, chest pain, rapid heart rate.
25
What can untreated valve problems lead to?
Heart failure
26
What are the two types of replacement heart valves?
Biological valves (from pigs, cows, or donors)
Mechanical valves (from strong, durable materials)
27
What is a disadvantage of mechanical valves?
Blood can clot on them, so the patient needs long-term anti-clotting medication.
28
What is a disadvantage of biological valves?
They are more likely to wear out and need replacing.
29
Where are the specialised pacemaker cells found in the heart?
In the right atrium.
30
What do the pacemaker cells do?
They produce electrical signals that cause the heart to contract independently of the nervous system.
31
How does the wave of contraction move through the heart?
From the right atrium → across to the left atrium → down to the ventricles, causing them to contract together.
32
What is an artificial pacemaker?
A small battery-operated device implanted in the chest to regulate the heartbeat with electrical impulses.
33
Why might someone need an artificial pacemaker?
If their natural pacemaker is disrupted, causing the heart to beat too slowly, too fast, or irregularly.
34
How is an artificial pacemaker fitted?
A wire lead is guided through a vein into the heart and connected to the device, which is implanted under the skin in the upper chest.
35
Where is the pacemaker device placed in the body?
Between the skin of the upper chest and the chest muscle.
36
Is pacemaker surgery common in the UK?
Yes, it is one of the most common heart surgeries performed.
37
What are the three main types of blood vessels?
Arteries, veins, and capillaries.
38
What do arteries do?
Carry blood away from the heart, usually oxygenated (except pulmonary artery).
39
What do veins do?
Carry blood to the heart, usually deoxygenated (except pulmonary vein).
40
What do capillaries do?
Connect arteries and veins and allow the exchange of molecules between blood and cells.
41
Describe the pressure and structure of arteries.
Carry blood under high pressure
Have thick, muscular and elastic walls
Narrow lumen
42
Describe the pressure and structure of veins.
Carry blood under low or negative pressure
Have thin walls with less muscle and connective tissue
Wide lumen
Contain valves to prevent backflow
43
Describe the structure of capillaries.
Walls are one cell thick
Very small lumen
Allow diffusion of molecules
44
What diffuses into cells from the capillaries?
Oxygen
Glucose
45
What diffuses out of cells into the blood?
Carbon dioxide
Urea (from liver cells)
46
Why is exchange possible in capillaries but not in arteries or veins?
Because capillary walls are only one cell thick, allowing diffusion.
47
What is the function of blood?
To transport materials, distribute heat, and protect against disease.
48
What is plasma?
A straw-coloured liquid that carries blood cells and makes up just over half the volume of blood.
49
Name the four main components of blood.
Plasma
Red blood cells
White blood cells
Platelets
50
What are the functions of plasma?
Transport carbon dioxide, urea, hormones, and digested food
Distribute heat
51
What is the function of red blood cells?
To transport oxygen to respiring cells.
52
What are the functions of white blood cells?
To ingest pathogens and produce antibodies.
53
What is the function of platelets?
To help with blood clotting.
54
What protein do red blood cells contain?
Haemoglobin
55
What does haemoglobin do?
Combines reversibly with oxygen to transport it and release it where needed.
56
Why do red blood cells have no nucleus?
To make more space for haemoglobin.
57
Why is the biconcave shape of red blood cells important?
It gives a large surface area for oxygen absorption.
58
How do red blood cells move through narrow capillaries?
They are small and flexible.
59
Why does their thin structure help red blood cells?
It reduces the diffusion distance for oxygen.
60
What are the two main types of white blood cells?
Phagocytes and lymphocytes
61
What is the role of phagocytes?
They engulf and destroy microorganisms by phagocytosis.
62
What percentage of white blood cells are phagocytes?
About 70%
63
What is the role of lymphocytes?
They produce antibodies to target pathogens.
64
What percentage of white blood cells are lymphocytes?
About 25%
65
What are platelets?
Cell fragments made in the bone marrow that help with blood clotting.
66
How do platelets help stop bleeding?
Stick to breaks in blood vessels and clump together
Secrete proteins that cause a clotting reaction
67
What are blood products?
Components of blood given by transfusion, including red blood cells, plasma, platelets, and antibodies.
68
Where do blood products come from?
From blood donors
69
Why are white blood cells often removed from blood for transfusion?
To reduce the risk of infections or immune reactions.
70
What is blood screened for before transfusion?
Infectious agents (e.g. HIV)
Blood group compatibility
Presence of antibodies
71
Why is high magnification needed to view blood cells?
Many blood cells are 10 μm or less in size.
72
What is Giemsa stain used for?
It helps identify blood cells by staining different components.
73
What colour does Giemsa stain each blood component?
Red blood cells = pink
Platelets = pale pink
White blood cell cytoplasm = pale blue
White blood cell nuclei = magenta
74
What is the function of the coronary arteries?
To supply the heart muscle with oxygenated blood for aerobic respiration.
75
What causes coronary arteries to become narrowed or blocked?
A build-up of fatty material, often due to 'bad' cholesterol.
76
What effect does narrowing of coronary arteries have on the heart?
It reduces oxygen supply to the heart muscle.
77
What symptom may result from reduced oxygen supply to the heart?
Chest pain
78
What can happen if the coronary artery becomes fully blocked?
A heart attack, causing damage to or death of heart muscle.
79
Why does the heart muscle need oxygen?
For aerobic respiration, which releases energy for contraction.
80
What are statins used for?
To lower cholesterol levels in the blood and reduce the risk of heart disease.
81
How do statins work?
They reduce cholesterol production in the liver.
82
Who might be prescribed statins?
People with heart disease or those at high risk of developing it.
83
What happens if someone stops taking statins?
Their cholesterol levels may rise again.
84
What are some possible side effects of statins?
Headaches
Memory loss
Risk of type 2 diabetes
Liver damage
85
Who should not take statins?
People with liver disease
Pregnant or breastfeeding women
86
What other possible benefit of statins is being researched?
They may protect against Alzheimer’s disease.
87
What is a stent?
A small mesh tube inserted into a narrowed coronary artery to restore blood flow.
88
When are stents used?
When drugs are less effective or when a longer-term solution is needed.
89
What are stents made of?
Metal alloys that do not cause an immune response.
90
What are the benefits of stents?
Restore blood flow
Minimally invasive (no major surgery required)
Long-term effectiveness
91
What are the risks of stent procedures?
Bleeding
Heart attack
Stroke
92
When is a heart transplant needed?
In cases of heart failure, when the heart cannot pump enough blood to meet the body's needs.
93
What can cause heart failure?
Conditions like coronary heart disease.
94
What happens if the heart cannot pump blood effectively?
Organs become starved of oxygen, which can be life-threatening.
95
What is considered before a patient is recommended for transplant?
Severity of their condition
Success of other treatments
Their overall health
96
Why are heart transplants rare in the UK?
There is a shortage of donor hearts – only about 200 transplants are carried out each year.
97
What is an artificial heart used for?
To keep a patient alive while waiting for a transplant
To allow the heart to rest and recover
98
What are artificial hearts made from?
Plastic and metal
99
What drugs must a heart transplant patient take?
Immunosuppressant drugs
100
Why are immunosuppressant drugs necessary?
To prevent rejection of the donor heart by the patient’s immune system.
101
What is the downside of immunosuppressant drugs?
They increase the patient’s risk of infection.
102
What is the pulse?
A surge of blood through the arteries each time the heart beats.
103
Where can you feel a pulse?
In areas where an artery passes over bone, e.g. wrist, neck, upper arm.
104
How is pulse rate expressed?
In beats per minute.
105
How do you measure pulse rate?
Count the number of beats in 30 seconds and double it, or count for 1 full minute.
106
What does a lower resting pulse rate generally indicate?
Greater fitness.
107
Why does pulse rate increase during exercise?
To deliver more oxygen to muscles and remove more carbon dioxide.
108
What is cardiac output?
The volume of blood the heart pumps per minute.
109
What is the formula for cardiac output?
Cardiac output = heart rate × stroke volume
110
What is stroke volume?
The volume of blood pumped per beat by the heart.
111
What units are used for cardiac output?
Typically cm³/min, or dm³/min if converted (1000 cm³ = 1 dm³).
112
If heart rate = 130 bpm and stroke volume = 150 cm³, what is cardiac output in dm³/min?
130 × 150 = 19,500 cm³/min
= 19.5 dm³/min
