9. Transport in Animals Flashcards
Circulatory system definition
The circulatory system is a system of blood vessels with a pump and valves to ensure one-way flow of blood
What type of circulatory system do fish have?
Fish have a two-chambered heart and a single circulation
What does single circulation mean?
This means that for every one circuit of the body, the blood passes through the heart once
What type of circulatory system do mammals have?
Mammals have a four-chambered heart and a double circulation
What does double circulation mean?
This means that for every one circuit of the body, the blood passes through the heart twice
What does the right side of the heart do?
The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs
What is the blood flowing in the lungs called?
Pulmonary circulation
What does the left side of the heart do?
The left side of the heart receives oxygenated blood from the lungs and pumps it to the body
What is the blood flowing through the body called?
Systemic circulation
What is the advantage of a double circulatory system?
Blood travelling through the small capillaries in the lungs loses a lot of pressure that was given to it by the pumping of the heart, meaning it cannot travel as fast
By returning the blood to the heart after going through the lungs its pressure can be raised again before sending it to the body, meaning cells can be supplied with the oxygen and glucose they need for respiration faster and more frequently
In what direction do veins carry blood?
Blood is pumped towards the heart in veins
In what direction do arteries carry blood?
Blood is pumped away from the heart in arteries
What separates the two sides of the heart?
The two sides of the heart are separated by a muscle wall called the septum
What is the heart made of?
The heart is made of muscle tissue
What supplies the heart muscle with blood?
supplied with blood by the coronary arteries
Do ventricles or atria have thicker muscle walls? Why?
VENTRICLES
The ventricles have thicker muscle walls than the atria as they are pumping blood out of the heart and so need to generate a higher pressure
Does the left ventricle or the right ventricle have a thicker muscle wall? Why?
The left ventricle has a thicker muscle wall than the right ventricle as it has to pump blood at high pressure around the entire body, whereas the right ventricle is pumping blood at lower pressure to the lungs
What is the role of the septum?
The septum separates the two sides of the heart and so prevents mixing of oxygenated and deoxygenated blood
What is the basic function of valves?
The basic function of all valves is to prevent blood flowing backwards
What are the 2 sets of valves in the heart?
- atrioventricular (bi and tricuspid)
- semilunar valves
What do the atrioventricular valves separate?
The atrioventricular valves separate the atria from the ventricles
What is the valve in the right side of the heart called?
Tricuspid valve
What is the valve in the left side of the heart called?
Bicuspid valve
When are the atrioventricular valves opened and closed?
These valves are pushed open when the atria contract but when the ventricles contract they are pushed shut to prevent blood flowing back into the atria
Where are the semilunar valves found?
The semilunar valves are found in the two blood arteries that come out of the top of the heart
What is unusual about the semilunar valves?
They are unusual in that they are the only two arteries in the body that contain valves
When do the semilunar valves open and close?
These valves open when the ventricles contract so blood squeezes past them out of the heart, but then shut to avoid blood flowing back into the heart
- What type of blood comes from the body and where does it go?
Deoxygenated blood coming from the body flows into the right atrium via the vena cava
- What happens once the right atrium has filled with blood?
Once the right atrium has filled with blood the heart gives a little beat and the blood is pushed through the tricuspid (atrioventricular) valve into the right ventricle
- What happens when the blood enters the right ventricle?
The walls of the ventricle contract and the blood is pushed into the pulmonary artery through the semilunar valve which prevents blood flowing backwards into the heart
- Where does the blood go when it’s pushed through the pulmonary artery? What happens here and what process occurs?
The blood travels to the lungs and moves through the capillaries past the alveoli where GAS EXCHANGE takes place
- Why does there have to be a low pressure on the right side of the heart?
blood is going directly to capillaries which would burst under higher pressure
- What happens to the blood which has travelled from the lungs?
Oxygen-rich blood returns to the left atrium via the pulmonary vein
- What happens to the blood once it enters the left atrium?
It passes through the bicuspid (atrioventricular) valve into the left ventricle
- How is the blood transported around the body from the left ventricle?
The thicker muscle walls of the ventricle contract strongly to push the blood forcefully into the aorta and all the way around the body
- What prevents the blood from flowing back into the heart?
The semilunar valve in the aorta prevents the blood flowing back down into the heart
How can heart activity be monitored?
Heart activity can be monitored by using:
- an ECG,
- measuring pulse rate - listening to the sounds of valves closing using a stethoscope
What is heart rate measured in?
Immediately after they do some exercise, record the pulse rate every minute until it returns to the resting rate
How can you investigate the effects of exercise on heart rate?
To investigate the effects of exercise on heart rate, record the pulse rate at rest for a minute
Immediately after they do some exercise, record the pulse rate every minute until it returns to the resting rate
What should this experiment show? (investigating the effects of exercise on heart rate)
This experiment will show that during exercise the heart rate increases and may take several minutes to return to normal
Why, (generally), does heart rate increase during exercise?
So that sufficient blood is taken to the working muscles to provide them with enough nutrients and oxygen for increased respiration
What does an increased heart rate allow the removal of?
An increase in heart rate also allows for waste products to be removed at a faster rate
- Following exercise, the heart continues to beat faster for a while to ensure that all excess waste products are removed from muscle cells
In what way will muscles likely have been respiring? What does this cause?
It is also likely that muscle cells have been respiring anaerobically during exercise and so have built up an oxygen debt
How can an oxygen debt be “repaid”?
This needs to be ‘repaid’ following exercise and so the heart continues to beat faster to ensure that extra oxygen is still being delivered to muscle cells
What is the extra oxygen produced by the rapid beating of the heart also used for?
The extra oxygen is used to break down the lactic acid that has been built up in cells as a result of anaerobic respiration
What can happen to coronary arteries if a person has a diet high in saturated fats/cholesterol?
A coronary artery becomes partially or completely blocked by fatty deposits called ‘plaques’/ atheromas (mainly formed from cholesterol),
Why are atheromas harmful?
the arteries are not as elastic as they should be and therefore cannot stretch to accommodate the blood which is being forced through them – leading to coronary heart disease
What does partial blockage of the coronary arteries cause? What is this called?
Partial blockage of the coronary arteries creates a restricted blood flow to the cardiac muscle cells and results in severe chest pains called angina
What does complete blockage of the coronary arteries cause? What is this called?
Complete blockage means cells in that area of the heart will not be able to respire and can no longer contract, leading to a heart attack
How does a poor diet affect your chance of developing coronary heart disease?
eating more saturated fat increases cholesterol levels, increasing the chance of the buildup of fatty plaques
How does stress affect your chance of developing coronary heart disease?
when under stress, hormones produced can increase blood pressure, increasing the chance of a blockage in the coronary arteries