2H-transport humans Flashcards
why can simple, unicellular organisms rely on diffusion for the movement of substances in and out of the cell? why do they have to rely on diffusion?
single-celled organisms have no circulatory system so materials can easily move around without a special system. they also have no lungs, gills, etc.,, instead, they obtain oxygen via diffusion through the surface membrane of the cell. they have high surface area to volume ratio so their surface membrane is large enough to be able to supply all the oxygen that their volume demands.
what can the supply to demand can be written as?
surface area/volume
why do multicellular organisms need a transport system?
large animals (multicellular organisms) can’t get all the oxygen they need through their surface (even if their body would allow it) because there isn’t a high enough surface to supply all the volume. to overcome this they have special gas exchange organs and circulatory systems (same idea applies to circulatory system)
what are the two main types of circulatory systems?
single and double
what is a single circulatory system?
when the blood is pumped from the heart to the gas exchange organ and then directly to he rest of the body
what is the double circulatory system?
the blood is pumped from the heart to the gas exchange organ, back tot he heart, and then to the rest of the body
what are the 2 parts of the double circulatory system?
pulmonary circulation- deoxygenated blood leaves the heart through the pulmonary arteries and is circulated through the lungs, where it becomes deoxygenated. the oxygenated blood returns to the heart through the pulmonary veins
systemic circulation- oxygenated blood leaves the heart through the aorta and is circulated through all other parts of the body, where it unloads its oxygen. the deoxygenated blood returns to the vena cava.
why is a double circulatory system more efficient than a single circulatory system?
this is because the blood it pumped twice, so the pressure is maintained and the blood is carried more quickly to organs
what is the human circulatory system comprised of?
the heart, blood, blood vessels (carry blood around the body)
what do the veins, arteries, capillaries do? what are the exceptions?
arteries - carry blood away from the heart towards other organs
veins- carry blood towards the heart and away from other organss
capillaries- carry blood through organs, linking the arteries and veins
APART FROM VENA CAVA VEIN AND PULMONARY VEIN
wher eis the renal artery and vein?
goes to and away from kidneys
where are the hepatic veins and arteries?
towards and away from liver
what is the hepatic portal vein?
connects digestive system to liver??
label the heart.
it must include:
aorta, vena cava, pulmonary artery, pulmonary vein, left atrium, bicuspid (mitral valve), left ventricle, right ventricle, right atrium, semi-lunar valves
how is blood moved around the heart? explain it step by step. what are these series events called?
the cardiac cycle:
1. blood enters the atria. it cannot yet pass into the ventricles because the bicuspid (mitral) and tricuspid valves are closed
2. the walls of the atria contract. this raises the pressure of the blood in the atria which forces open the bicuspid and tricuspid valves. blood passes through these valves into the ventricles
3. when the ventricles are full, they contract. this increases the pressure of blood in the ventricles 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 pulmonary artery carries blood to the lungs. the aorta had branches that carry 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 then begins again as the atria starts to fill with blood
how is blood moved around the heart? explain it step by step. what are these series events called?
the cardiac cycle:
1. blood enters the atria. it cannot yet pass into the ventricles because the bicuspid (mitral) and tricuspid valves are closed
2. the walls of the atria contract. this raises the pressure of the blood in the atria which forces open the bicuspid and tricuspid valves. blood passes through these valves into the ventricles
3. when the ventricles are full, they contract. this increases the pressure of blood in the ventricles 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 pulmonary artery carries blood to the lungs. the aorta had branches that carry 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 then begins again as the atria starts to fill with blood
how is the heart adapted to its function?
- it is divided into a left and right side, with a wall of muscle called the septum dividing it. the wall of the left ventricle is much thicker than the right ventricle because it has to pump blood to all other parts of the body and requires more pressure
- the valves ensure the blood can only flow in one direction through the heart
- the walls of the atria are thin so that they can be stretched to receive blood as it returns to the heart but can contract with enough force to push blood through the bicuspid and tricuspid valves into the ventricles
-the wall of the heart is made of cardiac muscle, which can contract and then relax continuously without becoming fatigued - the cardiac muscle has its own blood supply - the coronary circulation so blood reaches the muscle via coronary arteries. it is then returned via the coronary vein through the right atrium
how is the ventricle adapted to its function?
- it is divided into a left and right side, with a wall of muscle called the septum dividing it. the wall of the left ventricle is much thicker than the right ventricle because it has to pump blood to all other parts of the body and requires more pressure
how are the valves adapted to its function?
- the valves ensure the blood can only flow in one direction through the heart
how is the atria adapted to its function?
- the walls of the atria are thin so that they can be stretched to receive blood as it returns to the heart but can contract with enough force to push blood through the bicuspid and tricuspid valves into the ventricles
how is the wall of the heart adapted to its function?
-the wall of the heart is made of cardiac muscle, which can contract and then relax continuously without becoming fatigued
- the cardiac muscle has its own blood supply - the coronary circulation so blood reaches the muscle via coronary arteries. it is then returned via the coronary vein through the right atrium