7.4 The structure of the heart Flashcards
What side of the heart pumps oxygenated blood around the body
What side pumps deoxygenated blood from the heart to the lungs
The left side
The right side
How many pumps does the heart have
2
Each of the 2 pumps in the heart has two chambers, what are they
The atrium: Thin walled, and elastic as it stretches to collect blood.
The ventricle: Much thicker muscular wall because it has to contract to strongly pump blood a larger distance eg around the body, or to the lungs
Why do we have two separate pumps to transport blood around the body
Eg why couldn’t we have one pump which pumps blood through lungs to collect oxygen, then goes around the body and then back to the heart
. Because the blood has to pass through tiny capillaries in the lungs in order to present a large surface area for gas exchange.
However, in doing this, there is a large drop in pressure so if the blood was to leave here and go around the body, the blood pressure would be too low
As a result, mammals have a system to return blood to the heart to increase its pressure before it is distributed to the rest of the body
Why is the left side of the heart more muscular than the right
The right ventricle only pumps blood to the lungs and has a thinner muscular wall than the left ventricle
This is because a thick muscular wall in the left ventricle is able to contract and create enough pressure to pump blood all around the body
What are the valves between the atrium and ventricles called and what do they do
What are they called on the left side
What about the right side
Atrioventricular valves
They prevent the back flow of blood from the ventricles to the atria when the ventricles contract.
They are called bicuspid atrioventricular valve on the left
They are called tricuspid atrioventricular valves on the right
What do the ventricles do with blood
Where do the atria get blood
The blood travels from atrium to ventricles, which pump it away from the body
The atria receive blood from the veins
Each of the 4 chambers have a large vessel attached: What are the names and functions of these
. Aorta is connected to the left ventricle and carries oxygenated blood around the body
. Vena Cava is connected to the right atrium (where is can then flow to left atrium and be pumper to lungs) and it brings deoxygenated blood back from body tissues
. Pulmonary artery is connected to the right ventricle and carries deoxygenated blood to the lungs where it is oxygen replenished and its CO2 is removed
. The pulmonary vein carries oxygenated blood from the lungs to the left atrium
The pulmonary artery and vein are both unusual because usually veins carry deoxygenated blood, and arteries carry oxygenated blood.
How is the heart muscle itself supplied with oxygen
. The heart doesn’t use the oxygen carried through the left side of the heart to meet its own respiratory needs
. Instead, it has its own blood vessels v
called the CORONARY ARTERIES which branch off the aorta shortly after it leaves the heart
What happens when the coronary arteries in the heart are blocked
Leads to myocardial infarction, or a heart attack because an area of the heart muscle is deprived of blood and therefore oxygen also
The muscle cells in this region are unable to aerobically respire, so die
Why does smoking increase risk for cardiovascular disease
2 reasons
. Carbon monoxide:
Combines easily but irreversibly to the haemoglobin in red blood cells to form carboxyhaemoglobin. This means less oxygen can bind to the haemoglobin so it reduces the oxygen carrying capacity of the blood.
So the heart pumps faster to compensate for this, leading to high blood pressure which can cause heart attacks from coronary heart disease
. Nicotine: stimulates production of adrenalin hormone which increases heart rate and raises blood pressure, leading to coronary heart disease.
Also, it can make platelets sticky leading to a higher risk of thrombosis so strokes
What are 4 risk factors for cardiovascular disease
. Smoking
. High blood pressure
. Blood cholesterol
. Diet
Why does high blood pressure possibly lead to cardiovascular disease
. If ur genes make you have high blood pressure, altering your lifestyle wont help
. Higher blood pressure in arteries and heart means that the heart must work harder to pump blood into them
. Higher blood pressure in arteries means they are more likely to get a weaker wall (aneurysm) and burst causing a haemorrhage
. to resist the pressure within them, the walls of the arteries become thickened, and may harden, restricting the flow of blood
How does blood cholesterol increase risk of cardiovascular disease
. It is carried in plasma of blood by lipoproteins and there are two types
. High density lipoproteins are the good kind, and remove cholesterol from tissues and transport it to the liver, They help to protect arteries from heart disease
. Low density lipoproteins are bad and transport cholesterol from liver to tissues, including the artery walls, which they infiltrate leading to heart disease
How does diet increase risk of cardiovascular disease
. High levels of salt increase blood pressure
. High levels of saturated fats can increase low density lipoprotein levels and hence blood cholesterol concentration
