Blood and Circulation Flashcards
Why do single celled organisms not need circulatory systems?
They can obtain oxygen through the surface membrane of the cell
What are the three main types of blood vessels?
Veins, arteries and capillaries
What do valves control?
The flow of blood to the heart
What does blood clotting prevent?
The entering of pathogens and the prevention of excess blood loss
Why do people need a transport system to carry sugar and oxygen to cells?
Humans have a very low surface area:volume area
What is the process of double circulation?
The heart pumps blood to the lungs, getting back oxygenated blood which is sent to the heart to pump around the body
What do valves do in veins?
Stop blood flowing in the wrong direction
How are arteries adapted?
The heart pumps the blood out at high pressure so the artery walls are strong and elastic with elastic fibres and thick layers of smooth muscle
The walls are thick compared to the lumen
How are capillaries adapted?
Arteries branch into capillaries which supply food and oxygen and take away waste products like CO2
They have very thin (one cell thick with a nucleus) walls - this increase the rates of diffusion by decreasing the distance over which it happens
They have permeable walls so sunstances can diffuse in and out
They carry the blood really close to every cell in the body to exchange substances with them
How are veins adapted?
The blood is at a lower pressure in the veins so the walls don’t need to be as thick as artery walls
They have a big lumen to help the blood flow despite the lower pressure
They have walves to help keep the blood flowing in the right direction
What do arteries do?
Carry blood AWAY from the heart
What do veins do?
Carry blood TO the heart
Where does blood enter?
The atria of the heart
What happens when the ventricles contract?
Blood leaves the heart and travels to the lungs and around the rest of the body
How many heartbeats a minute (approx)
70
Why does your heart rate increase after excercise?
When you exercise, your muscles need more energy, so you respire more
You need to get more oxygen into the cells and remove more carbon dioxide
For this to happen, the blood has to flow faster, so your heart rate increases
What changes as the heart empties and fills?
The blood pressure
What does the aorta do?
Carries oxygenated blood around the body
What does the pulmonary vein do?
Brings oxygenated blood from the lungs
What do the heart valves do?
Controls blood flow
What does the pulmonary artery do?
Takes deoxygenated blood to the lungs
What does the vena cava do?
Bring deoxygenated blood into the heart
What is different about the heart in diagrams?
The left is shown on the right side
What things does blood transport around the body?
Oxygen from the lungs to all other parts of the boys. Carbon dioxide from all parts of the body to the lungs. Nutrients from the gut to all parts of the body. Urea from the liver to the kidneys. Hormones, antibodies etc.
What is the difference between a single circulatory system and a double circulatory system? Name an animal that has a single circulatory system.
In a single circulatory system blood is pumped to the gas exchange organ and then straight to the rest of the body. In a double circulatory system blood is pumped to the gas exchange organ, back to the heart and then to the rest of the body.
Fish
What are the names of the arteries/veins that connect with the liver?
Hepatic veins and arteries (Think hepatitis)
What is the name of the veins and arteries that go to the kidneys?
Renal arteries and veins
What are the names of the vein and artery going to and from the lungs
Pulmonary vein and artery
What is the systematic circulation?
When blood is circulated through all parts of the body where it unloads oxygen.
Why is a double circulation system more effective than a single?
The heart pumps the blood twice so higher pressures can be maintained. The blood travels more quickly to organs. In the single circulatory system of a fish, blood loses pressure as it passes through the gills. It then travels relatively slowly to the other organs.
What is the function of capillaries?
They carry the blood through organs.
What side is the vena cava on?
YOUR right side DIAGRAM’s left side
What side is the aorta on?
YOUR left side DIAGRAM’S right side
What is the function of blood in a circulatory system?
It is the transport medium.
What enables the heart to pump blood at different speeds and pressures?
The cardiac muscle. It is unlike any other muscle in our body and never gets fatigued.
What is the cardiac cycle?
- Blood enters the atria but cannot yet pass into the ventricles because the bicuspid and tricuspid valves are closed. 2.The walls of the atria contract which raises the blood pressure in them and opens the valves. Blood passes through the valves into the ventricles. 3. When the ventricles are full, they contract. This increases the pressure of the blood which closes the bicuspid and tricuspid valves again. Blood cannot return to the atria. 4. The ventricles continue to contract and the pressure continues to increase. This forces open the semi-lunar valves at the base of the aorta and the pulmonary artery. Blood is ejected into these two arteries. The aorta has branches to carry the blood to all other parts of the body. 5. As the ventricles empty, higher pressure in the aorta and pulmonary artery closes the valves in these blood vessels. The cycle begins again as the atria start to fill with blood.
What is special about veins?
They have ‘watch-pocket’ valves which prevent the backflow of the blood.
What is the purpose of ‘watch-pocket’ valves?
They prevent the back flow of blood. Especially important in veins when the deoxygenated blood must be pumped back to the heart.
What are all the components in blood?
Plasma, red blood cells, white blood cells and platelets
a) What is plasma? b) What is plasma’s function?
a) plasma is the pale yellow liquid part of the blood, mainly water
b) plasma carries almost everything that needs transporting around your body: red and white blood cells, platelets, hormones, carbon dioxide, urea, digested food products (e.g. glucose and amino acids) and heat energy
What is the function of red blood cells and how are they adapted to this?
They transport oxygen from the lungs to all the cells in the body
They are small and have a biconcave shape to give a large surface area for absorbing and releasing oxygen
They contain haemoglobin (containing iron) - in the lungs haemoglobin reacts with oxygen to become oxyhaemoglobin and in the body the reverse reaction happens to release oxygen into the cells
They don’t have a nucleus - this frees up space for more haemoglobin so they can carry more oxygen
a) What are lymphocytes? b) What are their function?
a) they are white blood cells which are bigger than red blood cells with a large spherical nucleus.
b) every pathogen has unique molecules (called antigens) on its surface. When lymphocytes come across a foreign antigen, they will start to produce proteins called antibodies - these lock on to the invading pathogens and mark them out for destruction by other white blood cells. Antibodies are then produced rapidly and flow around the body to mark all similar pathogens
a) What are phagocytes? b) What are their function?
a) they are white blood cells with a lobed nucleus
b) they detect anything foreign to the body e.g. pathogens and then engluf them. Then they produce digestive enzymes that digest and breakdown the pathogen
a) What are platelets? b) What are their function?
a) they are smal fragments of cells that help blood clot
b) when you damage a blood vessel or skin is cut, exposure to air stimulates the platelets and damaged tissue to produce a chemical. This chemical causes the soluble plasma protein fibrinogen to change into insoluble fibres of another protein, fibrin. The fibrin forms a network across the wound, in which red blood cells become trapped. This forms a clot, which prevents futher loss of blood and the entry of pathogens
How are do lymphocytes turn into memory cells?
Some of the lymphocutes stay around in the blood as memory cells after the original infection has been fought off. They can reproduce very fast if the same antigen enters the body a second time.
The body carries a ‘memory’ of what the antigen was likem and can produce the same antibodies at a much faster rate and higher concentration if the same pathogen enters the body, so the pathogen is fought off much faster and more effectively
What does vaccination involve?
Vaccination involves injecting dead or inactive pathogens into the body. These carry antigens, so even though they’re harmless, they still trigger an immune response - your lymphocytes produce antibodies to attack them
Some of these lymphocytes will remain in the blood as memory cells so if live pathogens of the same type ever enter your body, the antibodies to kill them will be produced much faster and in greater numbers
How does your heart rate increase during exercise?
Exercise increases the amount of CO2 in the blood
High levels of CO2 in the blood are detected by recpetors in the aorta and carotid artery (in the neck)
These receptors send signals to the brain
The brain sends signals to the heart, causing it to contract more frequently and with more force, in order to get more oxygen into the cells and remove more CO2
How does heart rate change under the influence of adrenaline?
When an organism is threatened (e.g. by a predator) the adrenal glands release adrenaline
Adrenaline binds to specific receptors in the heart - this causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and the heart pumps more blood
This increases oxygen supply to the tissues, getting the body ready for action
What happens on the right side of the heart?
The right atrium of the heart recieves deoxygenated blood from the body (through the venacava)
The deoxygenated blood moves through the tricuspid valve to the right ventricle which pumps it to the lungs through a semi-lunar valve through the pulmonary artery
What happens on the left side of the heart?
The left atrium recieves deoxygenated blood from the lungs (through the pulmonary vein)
The oxygenated blood moves through the bicuspid valve to the left ventricle which pumps it around the whole body through a semi-lunar valve through the aorta
Why is the left ventricle wall much thicker than the right ventricle wall?
Because it needs more muslce to pump the blood around the whole ody, whereas the right ventricle onlu has to pump it to the lungs - this also means that the blood in the left ventricle is under higher pressure than the blood in the right ventricle
What does the general defence system consist of?
White blood cells (phagocytes and lymphocytes)
Skin is a protective barrier
HCl in the stomach kills bacteria
Blood can clot to seal wounds and prevent the entry of pathogens
What is a pathogen?
A microorganism that can cause disease
