Organisation 2 Flashcards
Respiratory system, circulatory system, CHD
Why do we need to get oxygen into our bloodstream?
To supply our cells for respiration.
What happens in the lungs?
Gaseous exchange:
-Oxygen diffuses into our bloodstream
-Carbon dioxide diffuses out of our bloodstream
What is the thorax?
The top part of the body, separated from the lower body by the diaphragm.
What are the lungs protected by?
The ribcage.
The pleural membranes.
What are the pleural membranes?
A two-layered membrane that covers each lung.
What is the role of the pleural membranes?
To cushion the lung and reduce any friction that may develop between the lung, rib cage, and chest cavity.
What is the trachea?
Where the air that you breathe goes through to get to the lungs.
Also known as the windpipe.
What does the trachea split into?
Two tubes called bronchi.
One goes to each lung.
What is one bronchi called?
Bronchus
What doe the bronchi split into?
Progressively smaller tubes called bronchioles.
What can we find at the end of bronchioles?
Small air sacs called alveoli where gaseous exchange occurs.
There are millions and millions of these.
What are the alveoli surrounded by?
A network of blood capillaries.
What does the blood passing next to the alveoli contain?
-Lots of carbon dioxide
-Very little oxygen
-because it’s just returned to the lungs from the rest of the body
Where does oxygen diffuse in gaseous exchange?
From a high concentration in the alveolus to a low concentration in the blood.
Where does carbon dioxide diffuse in gaseous exchange?
From a high concentration in the blood to a low concentration in the alveolus to be breathed out.
What happens to oxygen in the blood when body cells are reached?
It is released from the red blood cells (high concentration of oxygen) and diffuses into the body cells (low concentration of oxygen).
What happens to carbon dioxide in cells when reached by the blood?
It diffuses from the body cells (high concentration of carbon dioxide) into the blood (low concentration of carbon dioxide).
It’s then carried back to the lungs.
How do we calculate breathing rate?
Number of breaths ÷ number of minutes.
What is the heart?
An organ that pumps blood around the body in a double circulatory system.
Which ventricle pumps deoxygenated blood to the lungs?
The right ventricle.
Which ventricle pumps oxygenated blood to the rest of the body?
The left ventricle.
What is the circulatory system made up of?
-The heart
-Blood vessels
-Blood
After gaseous exchange has occurred in the lungs, where does the blood go?
It returns to the heart.
(The blood is now oxygenated).
Once blood has lost its oxygen to the body cells, where does it go?
It returns to the heart.
What are the blood vessels associated with the heart?
-The aorta
-The vena cava
-The pulmonary artery
-The pulmonary vein
-The coronary arteries
What are the walls of the heart made of?
Muscle tissue (mostly)
What is the role of heart valves?
To prevent blood flowing backwards.
Name the four chambers of the heart.
-Right atrium
-Right ventricle
-Left atrium
-Left ventricle
What is the plural of ‘atrium’?
Atria
Blood flows into the right atrium from where?
The vena cava.
Is blood flowing into the vena cava oxygenated?
No. Blood flowing into the vena cava is deoxygenated because it has come from the body.
Is blood flowing into the pulmonary vein oxygenated?
Yes. Blood flowing into the pulmonary vein is oxygenated because it has come from the lungs.
Blood flows into the left atrium from where?
The pulmonary vein
Pulmonary
To do with the lungs.
How does blood move from the atria to the ventricles?
The atria contract, which pushes the blood into the ventricles.
Blood flows into the pulmonary artery from where?
The right ventricle.
Blood flows into the aorta from where?
The left ventricle.
What is the role of arteries?
To carry blood away from the heart.
What is the role of veins?
To carry blood to the heart.
How does blood get from the ventricles and out of the heart?
The ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart.
Where are the coronary arteries located?
They branch of the aorta and surround the heart.
What is the role of the coronary arteries?
To supply the heart muscle with the oxygenated blood it needs.
When looking at an image of he heart…
left is right and right is left
(imagine your looking at a person whose heart it is)
Where is the right atrium located?
The top left of the heart.
Where is the right ventricle located?
The bottom left of the heart.
Where are the heart valves located?
Between the atria and the ventricles.
How is the natural resting heart rate controlled?
By a group of cells in the right atrium that act as a pacemaker.
Where are pacemaker cells located?
The Right Atrium.
What is an artificial pacemaker?
An electrical device used to correct irregularities in the heart rate.
How does an artificial pacemaker work?
It produces an electric current to keep the heart beating regularly.
Where is an artificial pacemaker implanted?
It is implanted under the skin with a wire going to the heart.
How do pacemaker cells control a person’s natural resting heartbeat?
The cells produce tiny electrical impulses which spread to the surrounding muscle cells, causing them to contract.
What colour is the ‘right’ side of the heart (hypothetically) - also this is your left.
Blue because the blood is deoxygenated.
What is the role of capillaries?
To exchange materials at the tissues.
Name the three types of blood vessel that the body contains.
-Arteries
-Veins
-Capillaries
How are arteries adapted for their function?
-Artery walls are strong and elastic
-Artery walls are thick so the lumen is small
How are artery walls are strong and elastic?
Arteries are made of thick layers of smooth muscle to make them strong and elastic fibres to allow them to stretch and spring back.
Why do artery walls need to be strong and elastic?
To withstand high pressure blood pumped from the heart.
How are capillaries adapted for their function?
-Thin, permeable walls (only one cell thick)
-Small, with a very small lumen
Why do capillaries have permeable walls?
So that substances can diffuse in and out.
Why are capillaries so small?
So they can carry the blood really close to every cell in the body to exchange substances with them.
What do arteries branch into?
Capillaries
What substances do capillaries exchange?
They supply food and oxygen, and take away waste like CO₂.
Why do capillaries have thin walls?
To increase the rate of diffusion by providing a short diffusion path for substances.
How are veins adapted for their function?
-Large lumen to help the blood flow despite low pressure
-So smaller proportions of smooth muscle and elastic fibre
-Valves to prevent blood from flowing backwards
Why do the walls of veins not need to be as thick as the walls of arteries?
Blood flowing back to the heart is at lower pressure
How do we calculate the rate of blood flow?
volume of blood ÷ number of minutes
Make sure you are using the units that are in the question!!!
What is blood?
A tissue consisting of plasma, in which the red blood cells, white blood cells, and platelets are suspended
What is one major job of the blood?
To act as a huge transport system.
What is the role of red blood cells?
To carry oxygen from the lungs to all the cells in the body.
How are red blood cells adapted for their function?
-Their shape is a biconcave disc
-No nucleus
-Contain a red pigment called haemoglobin
Why is the shape of red blood cells a biconcave disc?
To give a large surface area for absorbing oxygen.
Why don’t red blood cells have a nucleus?
To allow more room for carrying oxygen.
What happens to haemoglobin in the lungs?
In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin.
What happens to oxyhaemoglobin in body tissues?
In body tissues, oxyhaemoglobin splits up into haemoglobin and oxygen.
This is so oxygen can diffuse to the cells.
Why do people living at high altitudes produce more red blood cells than the average person?
At high altitudes, there is less oxygen in the air.
So, people who live here produce more blood cells to compensate .
The more red blood cells you’ve got, the more oxygen can get into your cells.
What is the role of white blood cells?
They are part of the immune system, protecting the body from infection.
How are white blood cells adapted for their function?
-Some change shape to undergo phagocytosis
-Some produce antibodies to fight microorganisms
-Some produce antitoxins to neutralise any toxins produced by the microorganisms
-They have a nucleus
What is the role of platelets?
To help blood clot at a wound.
This prevents blood pouring out and microorganisms getting in.
How are platelets adapted for their function?
-They are fragments of cells with no nucleus
What can a lack of platelets cause?
Excessive bleeding and bruising.
What is the blood plasma?
It is a pale straw-coloured liquid that carries every component of the blood.
What substances does the blood plasma carry?
-Red blood cells
-White blood cells
-Platelets
-Nutrients like glucose and amino acids
-Carbon dioxide from the organs to the lungs
-Urea from the liver to the kidneys
-Hormones
-Proteins
-Antibodies and antitoxins produced by WBCs
What does CHD stand for?
Coronary heart disease.
What happens in a person with coronary heart disease?
Layers of fatty material build up inside the coronary arteries, narrowing them.
This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
What are stents used for?
To keep the coronary arteries open.
This ensures blood can pass through to the heart so it continues beating.
What are statins widely used for?
To reduce blood cholesterol levels.
This slows down the rate of fatty material deposit.
How can faulty heart valves be replaced?
Using biological or mechanical valves.
‘Cardiovascular disease’ is a term used to describe what?
Diseases of the heart and blood vessels.
What can a lack of oxygen for the heart muscle lead to?
A heart attack.
How do stents keep the coronary arteries open?
By pushing the artery wall out and squashing the fatty deposit.
Stents benefits
-They lower the risk of a heart attack in people with CHD
-They are effective for a long time
-The recovery time from surgery is relatively quick
Stents disadvantages
-There is risk of complications during the surgery e.g. a heart attack
-Infection from the surgery
-Patients could develop a blood clot near the stent (thrombosis).
Which type of cholesterol do statins reduce?
LDL cholesterol (bad cholesterol)
What is cholesterol?
An essential lipid that your body produces and needs to function properly.
What health problems can arise from having too much LDL cholesterol in the bloodstream?
It can cause fatty deposits to form inside arteries, which can lead to coronary heart disease.
What are statins a type of?
Drug
Statins benefits
-By reducing the amount of LDL cholesterol in the blood, statins can reduce the risk of strokes, CHD, and heart attacks
-Statins can increase the amount of HDL (‘good’) cholesterol in your bloodstream
-Some studies suggest that statins may also help prevent some other diseases.
What can HDL cholesterol do?
Remove LDL cholesterol from the blood.
Statins disadvantages
-They are a long-term drug that must be taken regularly
-Someone could forget to take them
-They can cause negative side effects e.g. headaches and some are serious
-The effect of statins isn’t instant
What are the serious side effects of statins?
-Kidney failure
-Liver damage
-Hearing loss
How can heart failure be treated?
By surgeons performing a heart transplant (or a heart and lung transplant if the lungs are also diseased).
Where do the organs for heart transplants come from?
They are donor organs from people who have recently died.
Why may doctors use an artificial heart instead of a donor heart?
-If the donor heart is not available straight away
-If a donor heart is not the best option
What are artificial hearts?
Mechanical devices that pump blood for a person whose own heart has failed.
What are artificial hearts usually only used as?
(though sometimes used as a permanent fix)
A temporary fix, keeping a person alive until a donor heart can be found.
Or to help a person recover by allowing the heart to rest and heal.
Artificial heart benefits
-Less likely to be rejected by the body’s immune system than a donor heart
Why is an artificial heart less likely to be rejected by the body’s immune system than a donor heart?
They are made from metals or plastics.
So the body does not recognise them as foreign and attack them in the same way as it does with living tissue.
Artificial heart disadvantages
-Surgery can lead to bleeding and infection
-They don’t work as well as healthy natural ones (parts could wear out or the electrical motor could fail)
-Blood doesn’t flow through as smoothly
Because blood doesn’t flow through artificial hearts as smoothly as biological ones, what can this cause?
Blood clots which can lead to strokes.
To prevent this, patients must take drugs to thin their blood.
This can cause problems with bleeding if they are hurt in an accident.
What can faulty heart valves be replaced with?
-Biological valves taken from humans or other mammals like cows or pigs
-Mechanical valves which are man-made
How can the valves in the heart become damaged or weakened?
-Heart attacks
-Infection
-Old age
What can the damage/weakening of heart valves lead to?
-Stiffening of the valve tissue, meaning the valve won’t open properly
-Leaky valves
What is the problem with leaky valves?
Leaky valves allow blood to flow in both directions, rather than just forward.
This means that blood doesn’t circulate a effectively as normal.
Heart valve replacement evaluation
-A less drastic procedure than a whole heart transplant
but…
-Fitting artificial valves is still a major surgery and there can be problems with blood clots
What is artificial blood?
A blood substitute e.g. a salt solution.
When is artificial blood used?
-To replace lost volume of blood if someone loses a lot of blood e.g. in an accident
-But their heart can still pump their remaining red blood cells around to supply their organs with oxygen
Artificial blood benefits
-Safe as long as no air bubbles get into the blood
-Can keep people alive even if they lose 2/3 of their red blood cells
-This may give a patient time to produce new blood cells
If a patient doesn’t have enough time to produce new RBCs when supplied with artificial blood, what will they need?
A blood transfusion - where they are given donated blood.
Ideally an artificial blood product would do what?
Replace the function of the lost RBCs.
