B3.2 (Transport systems in plants and animals) Flashcards
What does the circulatory system consist of and what are their functions?
The heart - Muscular pump that moves blood around the body Blood - Carries substances around the body Arteries - Carry blood AWAY from the heart Veins - Carry blood towards the heart Capillaries - Tiny blood vessels near surface of skin where exchanges happen
What are the two circuits in the circulatory system?
A smaller circuit to the lungs
A larger circuit to the rest of the body
Where must blood go first before it is pumped around the body?
To the lungs
What is blood called that has come straight from the lungs?
Oxygenated blood
How does the heart pump blood around the body?
The muscles in the heart CONTRACT forcing blood out
Why is the left hand side of the heart larger than the right side?
Blood in the right hand side of the heart is pumped only to the lungs wheras the left hand side is pumped to the whole body and so needs more force
Where are the left and right atriums?
The top left and right
Where are the left and right ventricles?
The bottom left and right
What happens to blood when the heart beats?
Blood is collected in the atrium
When the heart beats it contracts and forces this blood into the ventricle
The second beat causes the heart to contract again and push the blood out through an artery
What is the passage of deoxygenated blood through the circulatory system?
- Deoxygenated blood enters the left side of the heart through the VENA CARVA
- Blood flows into the RIGHT ATRIUM where it is pumped to the RIGHT VENTRICLE
- The blood is pumped through the pulponary artery to the lungs
What is the passage of oxygenated blood through the circulatory system?
- Blood enters from the lungs through the PULMONARY VEIN
- Blood enters the left atrium and is pumped into the left ventricle
- Blood is pumped through the AORTA to the rest of the body
Why do valves sometimes need to be replaced?
A valve can become stiff and leaky and not be as efficient at being a one way valve in the heart, causing backflow of blood.
What are the advantages and disadvantages of biological valves?
+ Does not damage red blood cells
- Can harden over time
- Further operations may need to happen to replace the valves if it is a long term solution
What are the advantages and disadvantages of mechanical valves?
+ Strong and durable so will last a lifetime
- Can damage red blood cells
- Requires patient to take anti blood clotting medication for rest of life
- Reports of being able to hear valves opening and closing
Why can artificial hearts be more useful than biological / human hearts?
A heart transplant with a compatible donor can take a long time so patients often die while waiting for it
Why are artificial hearts only used as short term alternatives to human heart transplants?
Current designs can cause blood clots to build up within them and so they are used as short term measures until a donor is available
What are the characteristic of arteries?
- Carry high pressure blood from heart
- Thick walls
- Thick elastic fibres to allow surges of blood
- Thick layer of muscle to allow blood to be diverted
Thick walls and a thinner blood pathway