2. Breathing & Circulation Flashcards
What is the circulatory system’s main function?
- To get food and oxygen to every cell in the body.
- To carry waste products to where they can be removed.
What is the circulatory system made up of?
- Heart
- Blood vessels
- Blood
What type of circulatory system do humans have?
A double circulatory system - two circuits joined together.
What does each of the two circulatory circuits do?
1st - Pumps deoxygenated blood to the lungs to take in oxygen and then returns it to the heart.
2nd - Pumps oxygenated blood all around the body, providing oxygen, and then returns it to the heart.
What is the heart made of?
Muscle tissue.
What is the function of the heart?
To pump blood around the body.
What does the heart have to prevent backflow?
Valves.
How many chambers does the heart have?
4 - Right atrium, right ventricle, left atrium, left ventricle.
What is the path of the blood starting in the right atrium?
Right atrium -> Right Ventricle -> Pulmonary Artery -> Lungs -> Pulmonary Vein -> Left Atrium -> Left Ventricle -> Aorta -> Body -> Vena Cava
What controls your resting heart rate?
Pacemaker
What is the heart’s pacemaker and where is it?
A group of cells in the right atrium wall.
How does the heart’s pacemaker work?
The group of cells in the right atrium wall produces a small electric impulse which spreads to the surrounding muscle cells, causing them to contract.
What is done if the heart’s natural pacemaker doesn’t work properly (e.g. the patient has an irregular heartbeat)?
An artificial pacemaker is used
What is an artificial pacemaker?
A small device implanted under the skin which has a wire that goes to the heart. It produces an electric current to keep the heart beating regularly.
What are the three types of blood vessel?
- Arteries
- Capillaries
- Veins
What is the function of arteries?
Carry blood away from the heart to the organs and tissues.
What is the function of capillaries?
Carry blood very close to every cell in the body to exchange substances with them.
What is the function of veins?
Carry blood back to the heart from the organs and tissues.
Define the heart.
A four chambered muscle pump that pumps blood under pressure around the body.
Why are there valves in the heart?
To prevent backflow of blood.
When you exercise, what does the body need to do?
- Get more oxygen and glucose to the muscles to supply energy
- Remove CO2 at a faster rate
How do muscles contract?
They use oxygen and glucose to release energy, which is used to contract the muscles.
How does the body respond to exercise?
- Increases breathing rate
- Breathing more deeply
- Increase in heart rate
- Heart contracts more powerfully (increased stroke volumes)
- Blood is diverted to muscles
How does the resting heart rate of an unfit person compare to a fit person?
An unfit person has a higher resting heart rate.
How does the heart rate of an unfit person change during exercise compared to a fit peerson?
An unfit person’s heart rate goes up more during exercise than a fit person’s.
How long does it take for an unfit person to recover compared to a fit person?
It takes longer for an unfit person to recover than a fit person.
How is some glucose stored in muscles and liver?
As glycogen.
Where is glycogen stored?
Mostly in the liver, but also in each muscle.
What happens when vigorous exercise uses up glucose rapidly?
Some of the glycogen in converted back to glucose to provide more energy.
What happens when you do exercise and your body cannot supply enough oxygen to muscles?
The muscles start doing anaerobic respiration instead of aerobic respiration.
What does anaerobic mean?
Without oxygen
What is anaerobic respiration?
The incomplete break down of glucose (without oxygen) to produce lactic acid and energy.
What is the word equation for anaerobic respiration?
Glucose -> Lactic Acid (+ Energy)
What is the symbol equation for anaerobic respiration?
C6H12O6 -> 2C3H6O3 (+ Energy)
What are the problems with anaerobic respiration?
1) It produces lactic acid which:
- Builds up in the muscles and gets painful
- Causes muscle fatigue and the muscles stop contracting efficiently
2) It is not as efficient as aerobic respiration (i.e. less energy released)
What are the advantages of anaerobic respiration?
It allows the muscles to keep contracting for longer.
How do plants and some microorganisms respire without oxygen?
They produce ethanol and CO2 (instead of lactic acid, like humans).
Apart from humans, who can respire without oxygen?
Plants and some microorganisms.
What is oxygen debt?
The amount of oxygen that has to be added to the blood adter exercise in order to oxidise the lactic acid in the muscles.
Why do you keep breathing heavily after exercise?
To repay the oxygen debt from anaerobic exercise. Breathing heavily provides oxygen to oxidise the lactic acid in the muscles.
When the oxygen debt is being repaid, what does oxidisng the lactic acid produce?
CO2 and water.
After exercise, how long do the pulse and breathing rate stay high?
Until the body detects that the levels of lactic acid and CO2 in the body are no longer at a high level.
What is the function of the atria?
They contract and push the blood into the ventricles.
What is the function of the ventricles?
They contract and push the blood into the pulmonary artery and aorta.
What are the features of an artery?
- Thick, elastic, muscular walls
- Relatively small lumen
What are the walls of an artery made of?
Muscle and elastic fibres
What are the features of a capillary?
- Very narrow
- Thin, permeable walls (1 cell thick)
- Very small lumen
What are the features of a vein?
- Thin, elastic, muscular walls
- Relatively large lumen
- Valves
What do arteries branch into?
Arterioles and then capillaries .
What to capillaries join up into?
Venules and then veins.
What is the blood pressure like in arteries?
High
What is the blood pressure like in veins?
Low
Where are capillaries found?
Organs (lungs) and tissues
What do capillaries supply and take away?
Supply: Food and oxygen
Take away: Waste like CO2
Why do arteries have their specific features?
- Thick, muscular wall -> Resist high blood pressure
- Elastic fibres in wall -> Allow artery to stretch and spring back
Why do veins have their specific features?
- Thin, muscular walls -> Lower pressure than in arteries
- Relatively large lumen -> Help blood flow
- Valves -> Prevent backflow
Why do capillaries have their specific features?
- Very narrow -> Can reach every cell
- Thin, permeable walls (1 cell thick) -> Maximise diffusion
What are the 4 MAIN parts of the blood?
- Red blood cells
- White blood cells
- Platelets
- Plasma
What is the job of red blood cells?
Carry oxygen from lungs to all cells in the body.
How are red blood cells adapted?
- Concave shape -> Increases surface area
- Contain haemoglobin -> Allows oxygen to be transported
- No nucleus -> More room for haemoglobin
What happens to haemoglobin in the lungs?
Oxygen diffuses from the alveoli into the blood and it combineswith haemoglobin to make oxyhaemoglobin.
What happens to oxyhaemoglobin in the body tissues?
It splits into haemoglobin and oxygen. The oxygen diffuses into the cells.
What is the job of white blood cells?
Defend against disease.
How do white blood cells defend against disease?
1) Change shape to ingest microorganisms
2) Produce antibodies to fight microorganisms
What are platelets?
Small fragments of cells. No nucleus.
What is the job of platelets?
Help to clot blood at a wound - this stops blood pouring out and microorganisms getting in.
What controls the reactions involved in clotting a wound?
Enzymes
How does a wound clot form?
- Fibrinogen (a soluble protein) is changed into fibrin (solid insoluble fibres).
- The fibrin fibres tangle together and form a mesh
- Platelets and RBCs get trapped in this, which forms a clot
What can a lack of platelets result in?
Excessive bleeding and bruising.
What is plasma?
A pale straw-coloured liquid which carries everything in blood.
What does plasma carry?
1) RBCs, White blood cells and Platelets
2) (Soluble) Nutrients like glucose and amino acids
3) Carbon dioxide
4) Urea
5) Hormones
6) Antibodies and Antitoxins (from white blood cells)
Where does the plasma carry nutrients from and to?
From gut to cells in the body.
Where does the plasma carry carbon dioxide from and to?
From organs to lungs.
Where does the plasma carry urea from and to?
From liver to kidneys.
Why do you need to get oxygen into the blood?
To get it to the cells for respiration.
What is breathing?
How air gets in and out of the lungs.
What is the top part of the body called?
The thorax.
What is the lower part of the body called?
The abdomen.
What separates the thorax and the abdomen?
The diaphragm.
What protects the lungs?
The ribcage
Through what tube does air enter the lungs?
Trachea
What is the difference between the oesophagus and the trachea?
Oesophagus - Food pipe
Trachea - Windpipe
What does the trachea split into?
Two bronchi (each one is a ‘bronchus’)
What do the bronchi split into?
Bronchioles
What do the bronchioles split into?
Alveoli
What is the order of tubes in the respiratory system?
Trachea -> Bronchus -> Bronchioles -> Alveoli
What are alveoli?
Small bags where gas exchange takes place.
How are alveoli adapted for gas exchange?
- Large surface area (to volume ratio)
- Thin walls
- Constant blood supply
What is ventilation?
Breathing in and breathing out
How does breathing in work?
1) Intercostal muscles contract, pulling ribcage up
2) Diaphragm contracts and flattens out
3) Thorax volume increases
4) This decreases air pressure in the lungs, so it is lower than the air outside, drawing air in.
How does breathing out work?
1) Intercostal muscles relax, so the ribcage moves down
2) Diaphragm relaxes and becomes dome shaped
3) Thorax volume decreases
4) This increases air pressure in the lungs, so that it is higher than outside, pushing air out.
What is required when a person can’t breathe by themselves?
An artificial ventilator.
When might people be unable to breathe by themselves?
- Under general anaesthetic
- Lung injury or disease
What is a ventilator?
A machine that moves air in and out of the lungs.
What are the two types of ventilator?
- Negative pressure
- Positive pressure
How does a negative pressure ventilator work?
1) Sealed case is placed around patient’s chest
2) Air is pumped out of the case, lowering the pressure
3) This makes the lungs expand and air is drawn into them
4) Air is pumped into the case to produce the opposite effect
How does a positive pressure ventilator work?
1) Air is pumped into the lungs, expanding the ribcage
2) When it stops pumping, the ribcage relaxes and pushes air back out of the lungs
Is respiration the same as breathing?
No
What is respiration?
The process of releasing energy from glucose in every cell in the body.
Where does respiration happen?
In every cell of the body.
Do all living things respire?
Yes
What is aerobic respiration?
Respiration without oxygen.
Which is the most efficient type of respiration?
Aerobic
In which organisms does aerobic respiration happen all the time?
Plants and animals
In which part of the cell does aerobic respiration happen?
Mitochondria
What is the word equation for aerobic respiration?
Glucose + Oxygen -> Carbon Dioxide + Water
What is the symbol equation for aerobic respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O
What 4 things is energy for respiration used for?
1) To build up larger molecules from smaller ones (e.g. proteins from amino acids)
2) To allow muscles to contract (in animals)
3) Maintain body temperature in the cold (in mammals and birds)
4) To build sugars, nitrates and other nutrients into amino acids, which are built up into proteins (in plants)
What is a blood transfusion?
When blood is given from a donor to a patient.
When might a blood transfusion be needed?
If you’re in an accident or having surgery and lose a lot of blood.
What are the 4 main blood groups?
A, B, O, AB
What do the letters in blood groups (e.g. A) refer to?
The antigens on the surface of the RBCs.
What are antigens?
Proteins on the surface of cells.
What can antigens trigger?
A response from a person’s immune system.
What types of antigens can RBCs have on their surface?
A or B (or neither or both)
What antibodies can blood plasma contain?
Anti-A or Anti-B (or neither or both)
What happens when an Anti-A antibody and an A antigen meet?
The blood clumps together, which can be dangerous.
What is blood clumping called?
Agglutination
What are ‘things that make stuff clump together’ called?
Agglutinins
Why does your blood type decide what type of blood you can receive in a transfusion?
If the wrong blood type is given, the antibodies and antigens will clump together, which is dangerous.
Which blood group is the universal donor?
O
Which blood group is the universal acceptor?
AB
Which blood types can A receive?
A and O
Which blood types can B receive?
B and O
Which blood types can AB receive?
Any
Which blood types can O receive?
Only O
What is an organ transplant?
When an organ is severely damaged, it can be removed and replaced by one from someone else.
Where are transplant organs usually taken from?
People who have died suddenly and who are on the organ donor register or carry a donor card.
Why might an transplanted organ be rejected by a patient?
The foreign antigens on the donor organ may be attacked by the patient’s antibodies.
How is organ rejection prevented?
- Donor with a similar tissue type is chosen (i.e. One with similar antigens)
- Use of immunosuppressants (drugs which supress the immune system)
What happens to blood pH during exercise?
It lowers due to extra CO2 in the blood.
What is an artificial heart?
A mechanical device that is put into a person to pump blood if their own heart fails.
Are artificial hearts usually used permanently or temporarily?
Usually temporarily, although sometimes they are permanent, which reduces the need for a donor heart.
When is an artificial heart used TEMPORARILY?
To keep a person alive until a donor heart can be found or to help a person’s heart to heal and rest.
What are the advantages of artificial hearts?
- Can keep a patient alive until a donor organ is found
- Less likely to be rejected by the patient
What are the disadvantages of artificial hearts?
- Risks of surgery
- Not as effective as a healthy natural one (parts wear out and electric motor can fail)
- Blood doesn’t flow through as smoothly, which can cause blood clots and strokes.
- Patient has to take drugs to thin their blood and prevent clots (which can cause problems with bleeding in an accident)
What can damage valves in the heart?
Heart attacks, infections and old age.
What can damage to heart valves cause?
1) Valve tissue may stiffen, so it won’t open properly.
2) Valve may become leaky, so blood flows in both directions -> This reduces blood circulation
How can damage to heart valves be treated?
Replacing the valve with an articula one.
What are the types of artificial heart valves?
Biological - Ones taken from humans or other mammals
Mechanical - Ones which are man-made
Is replacing a heart valve as drastic as a heart transplant?
No, but it is still major surgery.
What is coronary heart disease?
- Coronary arteries (that supply the blood to the muscle of the heart) get blocked by fatty deposits.
- Arteries become narrow
- Blood flow is restricted so there is a lack of oxygen to heart muscle
- Can result in heart attack
What are the risks of coronary heart disease?
It can result in a heart attack.
What are stents?
Tubes that are inserted into arteries to keep them open.
When are stents needed?
When arteries become blocked by fatty deposits. Stents keep them open so blood can pass through.
What is a way of lowering the risk of a heart attack in a person with coronary heart disease?
Stents - They keep arteries open, so blood can flow to the heart muscles, keeping the hearts beating.
What are the risks of stents?
- Arteries can narrow again (as they irritate the artery and scar tissues grow)
- Patient has to take drugs to stop blood clotting
