The Structure & Functions of the Cardio-respiratory System (AQA GCSE Physical Education (PE)): Flashcards
Exam code: 8582
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- FrontThe Pathway of Air
State the pathway of air into the lungs.
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State the pathway of air into the lungs.
Mouth/nose → trachea → bronchi → bronchioles → alveoli
Through which structures does air enter the body?
The mouth and/or the nose.
Define trachea.
The trachea is the tube that carries air from the mouth and nose down into the lungs.
What keeps the trachea open to allow air to move through it?
Rings of cartilage within its walls.
Define bronchi.
The bronchi are a pair of smaller tubes that branch from the trachea, allowing air to travel between the trachea and the lungs.
Define bronchioles.
The bronchioles are smaller tubes that branch from the bronchi, carrying air into the alveoli.
Define alveoli.
The alveoli are tiny air sacs located at the end of the bronchioles, where gases are exchanged between the air and the blood.
Air travels from the trachea into the bronchi and then into the ＿＿＿＿＿＿＿＿.
Air travels from the trachea into the bronchi and then into the bronchioles.
True or False?
The bronchioles branch directly from the trachea.
False.
The bronchi branch from the trachea. The bronchioles then branch from the bronchi.
Where in the lungs does gas exchange take place?
In the alveoli.
Define gas exchange.
Gas exchange is the exchange of gases between the air and the blood, which occurs in the alveoli of the lungs.
Define diffusion.
Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
Name the features of the alveoli that assist gas exchange.
Large surface area
Moist, thin walls one cell thick
Short diffusion distance
Lots of capillaries
Large blood supply
Why does oxygen diffuse into the blood at the alveoli?
The blood arriving is low in oxygen compared with the air in the alveoli, so oxygen diffuses down the concentration gradient into the blood.
Why does carbon dioxide diffuse out of the blood at the alveoli?
The blood arriving is high in carbon dioxide compared with the air in the alveoli, so carbon dioxide diffuses out of the blood.
How does a large surface area help gas exchange?
There are many alveoli in the lungs, giving a large surface area across which diffusion can occur.
Why are the walls of the alveoli and capillaries only one cell thick?
To give a short diffusion pathway, so gases can move across quickly.
How does a good blood supply help gas exchange?
It maintains the concentration gradients of oxygen and carbon dioxide across the alveoli.
How does the layer of moisture on the alveoli help gas exchange?
Gases in the air dissolve in the moisture, which aids diffusion.
Oxygen binds to haemoglobin in the red blood cells to form ＿＿＿＿＿＿＿＿.
Oxygen binds to haemoglobin in the red blood cells to form oxyhaemoglobin.
True or False?
Haemoglobin can only carry oxygen.
False.
Haemoglobin can also bind to carbon dioxide, which aids its transport to the lungs.
True or False?
During gas exchange, gases move from an area of low concentration to an area of high concentration.
False.
Gases move from an area of high concentration to an area of low concentration.
Name the three main types of blood vessel.
Arteries, veins and capillaries.
What is the function of arteries?
To carry blood away from the heart at high pressure.
How is the structure of an artery adapted to its function?
Thick muscular walls withstand the high pressure
Elastic tissue allows stretch and recoil, maintaining pressure
A narrow lumen helps to maintain high pressure
What is the function of veins?
To carry blood towards the heart at low pressure.
How is the structure of a vein adapted to its function?
Thin walls, as they do not withstand high pressure
A wide lumen allows large volumes of blood to flow
Valves prevent blood flowing backwards
Which type of blood vessel contains valves, and why?
Veins, to prevent blood from flowing backwards.
What is the function of capillaries?
To carry blood to the cells of the body at low pressure, allowing gas exchange to take place.
How is the structure of a capillary adapted to its function?
Walls are one cell thick, reducing the diffusion distance
A very narrow lumen forces red blood cells through one at a time
There are many capillaries, giving a large surface area
Define vasoconstriction.
Vasoconstriction is the narrowing of the lumen of the arterioles, which restricts blood flow to an area.
Define vasodilation.
Vasodilation is the widening of the lumen of the arterioles, which increases blood flow to an area.
How is blood redistributed during exercise?
Arterioles supplying the muscles vasodilate to increase blood flow, while arterioles supplying the digestive system vasoconstrict to restrict blood flow.
Name the four blood vessels associated with blood entering and leaving the heart.
The vena cava, the pulmonary artery, the pulmonary vein and the aorta.
What does the vena cava do?
It is the main vein carrying deoxygenated blood from the body to the heart.
What does the pulmonary artery do?
It carries deoxygenated blood from the heart to the lungs.
The pulmonary vein carries oxygenated blood from the lungs to the ＿＿＿＿＿＿＿＿.
The pulmonary vein carries oxygenated blood from the lungs to the heart.
What does the aorta do?
It is the main artery carrying oxygenated blood from the heart to the body.
True or False?
All arteries carry oxygenated blood.
False.
Most arteries carry oxygenated blood, but the pulmonary artery carries deoxygenated blood to the lungs.
How many chambers does the heart have, and what are they?
Four chambers: the left and right atria, and the left and right ventricles.
Define atrium.
An atrium is an upper chamber of the heart. It receives blood from the body or the lungs and pumps it into the ventricle below.
Define ventricle.
A ventricle is a lower chamber of the heart. It receives blood from the atrium and pumps it out to the body or the lungs.
Where does the right side of the heart pump blood to?
To the lungs.
Where does the left side of the heart pump blood to?
To the body.
The upper chambers of the heart are the atria and the lower chambers are the ＿＿＿＿＿＿＿＿.
The upper chambers of the heart are the atria and the lower chambers are the ventricles.
What is the function of the valves within the heart?
To prevent blood from flowing backwards.
True or False?
The left side of the heart pumps blood to the lungs.
False.
The right side pumps blood to the lungs. The left side pumps blood to the body.
What type of tissue is the heart made of, and why?
Muscle tissue, which allows the heart to pump blood around the body.
Where do the atria receive blood from?
The right atrium receives blood from the body. The left atrium receives blood from the lungs.
Define cardiac cycle.
The cardiac cycle is all of the events taking place within a single heartbeat.
Define diastole.
Diastole is the stage where the heart muscle relaxes and the chambers fill with blood.
Define systole.
Systole is the stage where the muscle walls of the heart chambers contract and blood is forced out.
What happens during atrial systole?
Blood is forced out of the atria and into the ventricles.
What happens during ventricular systole?
Blood is forced out of the ventricles and into the arteries.
Which chamber does deoxygenated blood from the body enter first?
The right atrium, which it enters via the vena cava.
Which vessel carries deoxygenated blood from the heart to the lungs?
The pulmonary artery, leaving from the right ventricle.
Which vessel returns oxygenated blood from the lungs to the heart?
The pulmonary vein, which returns blood to the left atrium.
Which vessel carries oxygenated blood from the heart to the body?
The aorta, leaving from the left ventricle.
State the full pathway of blood through the heart.
Right atrium → right ventricle → pulmonary artery → lungs (gas exchange) → pulmonary vein → left atrium → left ventricle → aorta → body
Gas exchange occurs in the lungs, where the blood becomes ＿＿＿＿＿＿＿＿.
Gas exchange occurs in the lungs, where the blood becomes oxygenated.
Why do the valves in the heart open?
Because of pressure differences. When the pressure behind a valve becomes higher, the valve is forced open.
Why do the valves in the heart close?
To prevent the backflow of blood, when the pressure ahead of the valve becomes higher than the pressure behind it.
True or False?
The left and right sides of the heart contract at different times.
False.
During systole the left and right sides of the heart contract at the same time.
Define cardiac output.
Cardiac output is the volume of blood pumped by the heart every minute.
Define stroke volume.
Stroke volume is the volume of blood pumped by the heart with each beat.
Define heart rate.
Heart rate is the number of beats per minute.
State the equation linking cardiac output, stroke volume and heart rate.
cardiac output (Q) = stroke volume (SV) × heart rate (HR)
A performer has a heart rate of 68 bpm and a stroke volume of 75 ml. Calculate their cardiac output in L/min.
75 × 68 = 5100 ml/min
5100 ÷ 1000 = 5.1 L/min
Why does a fitter performer have a larger stroke volume?
Their heart muscle is stronger and their heart is larger, so more blood can be pumped with each beat.
Why does a fitter performer have a lower resting heart rate?
Their larger stroke volume means they achieve the same cardiac output with fewer beats.
Define anticipatory rise.
The anticipatory rise is the increase in heart rate that occurs before exercise begins, caused by the release of adrenaline.
A fitter performer will have a lower resting heart rate and a higher ＿＿＿＿＿＿＿＿ volume.
A fitter performer will have a lower resting heart rate and a higher stroke volume.
What happens to heart rate after exercise ends?
It takes time to return to the resting heart rate. This is the recovery period, and a fitter performer recovers more quickly.
True or False?
A less fit performer's heart rate stabilises at a lower rate during exercise than a fitter performer's.
False.
A less fit performer's heart rate stabilises at a higher rate during exercise.
How does exercise intensity affect heart rate?
Heart rate increases as intensity increases, for example walking around 115 bpm, jogging around 150 bpm and sprinting around 185 bpm.
Define ventilation.
Ventilation is the process of breathing in and out.
Name the three structures involved in breathing.
The intercostal muscles, the rib cage and the diaphragm.
What happens to the diaphragm during inhalation?
It contracts and flattens.
What happens to the intercostal muscles and ribs during inhalation?
The intercostal muscles contract, pulling the ribs up and out.
How does a change in chest volume cause air to move in during inhalation?
The volume of the chest cavity increases, so air pressure inside the lungs decreases. Air then moves in from an area of high pressure to an area of low pressure.
What happens to the diaphragm during exhalation?
It relaxes and moves upwards back into a dome shape.
What happens to the intercostal muscles and ribs during exhalation?
The intercostal muscles relax, allowing the ribs to drop down and in.
How does a change in chest volume cause air to move out during exhalation?
The volume of the chest cavity decreases, so air pressure inside the lungs increases. Air then moves out from an area of high pressure to an area of low pressure.
Which additional muscles help inhalation during exercise?
The pectorals and the sternocleidomastoid, which increase the chest volume further so more air can be drawn in.
Which additional muscles help exhalation during exercise?
The abdominal muscles, which pull the rib cage down and in more quickly to force air out faster.
The diaphragm is a muscular membrane that separates the chest cavity from the ＿＿＿＿＿＿＿＿ organs.
The diaphragm is a muscular membrane that separates the chest cavity from the abdominal organs.
True or False?
Exhalation at rest is an active process requiring muscles to contract.
False.
Exhalation at rest is a passive process, in which the intercostal muscles and diaphragm relax.
Define spirometer.
A spirometer is a piece of equipment used to measure and analyse an individual's breathing, producing a spirometer trace.
Define tidal volume.
Tidal volume is the volume of air breathed in and out with each normal breath.
What is the approximate tidal volume at rest?
Approximately 500 ml.
Define inspiratory reserve volume.
The inspiratory reserve volume is the difference between the tidal volume and the total volume of air breathed in during a deep inhalation.
Define expiratory reserve volume.
The expiratory reserve volume is the difference between the tidal volume and the total volume of air breathed out during an active exhalation.
Define residual volume.
The residual volume is the volume of air that remains in the lungs even after a maximal exhalation.
The four volumes identified on a spirometer trace are tidal volume, inspiratory reserve volume, expiratory reserve volume and ＿＿＿＿＿＿＿＿ volume.
The four volumes identified on a spirometer trace are tidal volume, inspiratory reserve volume, expiratory reserve volume and residual volume.
What happens to tidal volume during exercise?
It increases, because we breathe more deeply.
What happens to the inspiratory and expiratory reserve volumes during exercise?
They both decrease as tidal volume increases.
True or False?
Residual volume changes during exercise.
False.
The residual volume does not change, even during exercise.
What happens to breathing rate during exercise?
It increases.
How do you work out breathing rate from a spirometer trace?
Count the number of peaks in a set time and scale up to one minute.
For example, 6 peaks in 30 seconds = 6 × 2 = 12 breaths per minute.
How do you work out tidal volume from a spirometer trace?
Subtract the minimum volume of a breath from the maximum volume of that breath.
For example, 4.1 − 2.3 = 1.8 dm³.
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