The Heart And Breathing Flashcards
What is the heart?
A muscular pump
What three things are the mammalian heart made up of?
Mostly made of cardiac tissue
Some purkyne tissue (modified to conduct impulses)
Plus blood vessels, blood and connective tissue
How many valves are inside the heart? What do they do?
4 valves - control the flow of blood in the heart
Where are the valves situated?
There are 2 between the atria and ventricles
And 2 at the base of the arteries leading from the ventricles
They are all one way
Why does the heart not require nervous stimulation in order to pump blood?
It has its own pacemaker it is myogenic
What is the pump process?
1) . Two Atria fill up at the same time
2) . Pressure in atria increases and forces the AV valves to open
3) . Blood flows into the ventricles and start to fill with blood
4) . After a short delay the ventricular muscles contract
5) . Contraction forces the semilunar valves to open
6) . Contraction shuts the AV valves
7) . Blood leaves left ventricle via the aorta
8) . Blood leaves right ventricle via pulmonary artery to lungs
9) . Oxygenated blood from lung enters the left atrium via the pulmonary vein
10) . Deoxygenated blood from the rest of the body enter the right atrium via the vena cava
What is pulmonary circulation?
Blood that is pumped to the lungs to be oxygenated
What is systematic circulation?
Blood that is pumped to other parts of the body that need oxygen
What are the two advantages of a double circulatory system?
1) . Blood to tissue is always oxygenated because the two circulations are seperate
2) . Blood to tissue is under high preassure because it is pumped twice - more efficient
Why do the ventricles have a thicker muscular wall that the atria?
The ventricles have to force blood out of the heart and futher than the atria
Why does the left ventricle have a thicker wall than the right ventricle?
Left ventricle pushes blood out the aorta and around the body.
What are examples of cardiovascular disease?
Angina, heart attack, heart failure
What is coronary heart disease?
Term that describes when your hearts blood supply is blocked by a build up of fatty substances
What is bad cholesterol?
Blocks ateries when the levels are too high
What is good cholesterol?
Carries bad cholesterol to the liver to be removed from the bloodstream
What are the causes of the coronary heart disease?
Lifestyle choice, high blood pressure, genetics, gender
What happens to the coronary arteries?
The arteries surround the heart, if the arteries become blocked with fatty substances this can reduce blood flow, as the arteries become narrow. Therefore a lack of O2 to the heart muscle, without O2 the muscle tissue is unable to respire correctly causing heart attacks
What are Stents?
Small tubes made from a mesh that are insterted into the coronary arteries
How do stents work?
- inserted using a thin tube and a balloon
- balloon is inflated and stent expands
- stent remains in artery and widens the blood vessel increasing blood flow
What are statins?
Drugs that can be prescribed to a patient that has high cholesterol levels
How do statins work?
Reducing the amount of ‘bad’ cholesterol in the bloodstream and promoting the levels of good
What are the advantages of statins?
- Help lower bad cholesterol which decreases risk of stroke and heart attacks
- Help stabilise blood vessel lining - makes plaque less likely to rupture
- Help relax the blood vessels
What are the disadvantages of statins?
- Makes your body reduce chemical CO2 10 which causes muscle pain
- Could have liver or kidney damage due to them
What are Arteries?
Carry blood away from the heart
What are the artery walls like?
As heart pumps blood out at high pressure so the artery walls are:
- thick due to thick layers of muscle to make them strong
- have elastic fibres to allow them to strech and spring back
What are capillaries?
- They are Arteries that branch into capillaries
- involved in the exchange of materials in the tissue, they carry blood really close to the cell in the body to exchange substances with them
What type of walls do capillaries have?
Permeable walls so substances can diffuse in and out of them
What do capillaries supply and take away?
Supply food and oxygen and remove waste like CO2
Whay are the walls of capillaries one cell thick?
It increases the rate of diffusion by decreasing the distance over which it works
What are veins?
Capillaries that have joined to form veins that carry blood into the heart
What is the structure of veins like?
- The blood is at low pressure in the veins so the walls aren’t as thick as the artery walls
- They have a bigger lumen to help the blood flow despite low pressure
What do veins have that help to keep the blood flowing in the right direction?
Valves
What is the equation of blood flow?
Rate of blood flow = volume of blood ➗ number of minutes
What are red blood cells?
Carry oxygen from the lungs to all the cells in the body
What is the structure of a red blood cell like?
- ,Shape is bioconcave disc which gives a large SA for absorbing O2.
- Dont have a nucleus which lets them hold more O2.
What pigment do red blood cells contain?
Red pigment - Haemoglobin
What does heamoglobin do?
- In lungs it binds to the O2 to become oxyhaemoglobin.
- In body tissue the oxyhaemoglobin splits in to haemoglobiin and O2, to release oxygen to cells
What do white blood cells do?
Defend against infection
What three things can white blood cells do to fight pathogens?
- change their shape and engulf in phagocytosis
- produce antibodies to fight as well as antitoxins to neutralise any toxins produced
- extend their membranes and make own enzymes to engulf pathogens
What else do white blood cells have?
A nucleus
What are platelets?
Small fragments that have no nucleus that help form clots
What is the process for how platelets work?
- damaged blood vessels emit signals
- platelets arrive at the site of damage
- they become active and bind to the site
- this traps red blood cells & forms a clot to reduce bleeding
What is Plasma?
The substance that carries everything in the blood
What does plasma carry?
- red&white blood cells & platelets
- nutrients eg glucose&amino acids (products of digestion) from gut to cells of body
- CO2 from lungs
- urea from liver to kidneys
- hormones & proteins
- antibodies and antitoxins by WBC’s
What is cardiovascular disease?
Term used to describe the diseases of the heart or blood vessels
What is the natural resting heart rate controlled?
Controlled by a group of cells located in the right atrium that act as a pacemaker is
What are artificial pacemakers?
Electrical devices that are used to correct irregularities in the heart rate
What is blood?
A tissue consisting of plasma, in which the red blood cells, white blood cells and platelets are suspended
What does a faulty valve do?
the damage may cause the valve tissue to stiffen, so it wont open properly. or it may become leaky, allowing blood to flow in the both directions therefore blood doesn’t circulate as effectively as normal
What could happen in the case of heart failure?
A donor heart, or hear and lungs can be transplanted.
Why are artificial hearts used?
To keep paitents alive whilst waiting for a heart transplant, or to allow the heart to rest as an aid to recovery
What do valves do?
Ensure blood flows in the right direction and to prevent it flowing backwards
how does gas exchange occur in the alveoli?
- blood passing next to the alveoli has just returned to the lungs from the rest of the body, so it has lots of CO2 and little O2.
- oxygen diffuses out of the alveolus (high conc) into the blood (low conc), while CO2 diffuses out of the blood (high conc) into the alveolus (low conc) to be breathed out
what happens when blood reaches body cells?
- O2 is released from the red blood cells where there’s a high conc and diffuses into the body cells where the conc is low
- at the same time, CO2 diffuses out of the body cells where there a high conc into the blood where there’s a low conc and carried back to the lungs
where does deoxygenated blood enter?
enters from the body through the right atrium of the heart, the right ventricle pushes the blood into the pulmonary artery where it will travel to the lungs and gas exchange will take place
where does oxygenated blood enter?
enters from the lungs via the left atrium through the pulmonary vein, the left ventricle pushes blood into the aorta, where it will travel to the body
what are the advantages of artificial hearts?
- they’re less likely to be rejected by the immune system as they’re made from metal or plastic so the body doesn’t recognise it as foreign
what are the disadvantages of artificial hearts?
- surgery to fit the heart can lead to bleeding and infection
- they don’t work as well as parts of it could wear out or the electrical motor could fail
- blood doesn’t flow as well and therefore could lead to strokes
What’s artificial blood?
A blood substitute eg saline used to replace thr volume of blood lost
