circulatory system + water Flashcards
why do larger organisms need a circulatory system
This is because they have too large of a diffusion distance and they have higher energy requirements and so need reactants delivered quickly for metabolism.
what is mass transport?
It is the bulk movement of gases or liquids in one direction usually via a system of tubes or vessels.
what is cohesion?
It is the attraction of water molecules to each other and it allows water molecules to pull each other along.
what is adhesion?
It is when water forms hydrogen bonds to other molecules which allow it to stick to the sides of the vessel
how is water a solvent?
Since it is polar in nature it is able to react with many ions and also covalently bonded substances like glucose. The water molecules surround the the charged particle and then the positively charged ends of the water molecule are attracted to the negatively charged ends of the particles and vice versa. The surrounded molecules then break apart ad the ions have now been dissolved.
what is a closed circulatory system?
This is where blood is transported through blood vessels and pumped around the body
what is an open circulatory system?
This is where the blood moves freely in the body cavity and it bathes the organs.
what is a double circulatory system?
This is where the blood passes through the heart twice and has two different circuits on to the lungs and one to the body.
what is a single circulatory system?
This is where the blood only passes through the heart once and the there is only one circuit to the lungs
Basic: what is the path of blood in the human heart?
The right side of the heart pumps deoxygenated blood to the lungs for gas exchange and is known as the pulmonary circulatory system and the left side pumps blood from the heart to the rest of the body at high pressure which is oxygenated blood and this is the systemic circulatory system.
What is the heart protected by
The pericardium which is a tough and fibrous sack.
What are the four chambers in the heart and what makes sure that blood doesn’t mix inside the heart
The left and right atrium and the left and right ventricle and the septum ensures the blood doesn’t mix inside the heart.
What is the pathway of the blood in detail?
-Deoxygenated blood flows into the heart from the superior vena cava
-Then into the right atrium which is then pumped into the right
ventricle through the tricuspid valve (atrioventricular valve)
-Then out the pulmonary artery to the lungs through the semilunar valves known as the pulmonary valve
On the left side:
-Oxygenated blood comes into the heart from the lungs via the pulmonary vein
-Then into the left atrium where is it then pumped through the bicuspid valve into the left ventricle
-Then pumped through to the aorta through the semilunar valve (aortic valve) to the rest of the body.
What are the valves in the heart attached by?
They are attached to the wall of the heart by valve tendons and prevent the valves from flipping inside out under high pressure
What is the purpose of the valves and how do they work?
They prevent the backflow of blood and they open when the pressure behind them is greater than the pressure in front of them and then close when when the pressure in front of them is greater than the pressure behind them.
Adaptation of the left ventricle?
It is thicker than the right since the right ventricle only needs to pump blood to the lungs which is a shorter distance compared to the left which needs to pump blood around the body.
Why are the ventricles thicker than the atria?
The atria only need to pump blood into the ventricle whilst the ventricles need to pump blood around the whole body
What are AV valves?
They prevent the backflow of blood from the ventricles back into the atria
What are the semilunar valves?
They prevent the backflow of the blood from the aorta and the pulmonary artery.
Vena cava
Superior brings blood from above the heart and inferior brings blood from blow the heart.
pulmonary vein
Brings blood from the lungs
pulmonary artery
Takes blood to the lungs
aorta
Takes blood to the rest of the body
What supplies blood to the muscles of the heart itself?
THE coronary arteries which run along the surface of the heart
Atrial systole (also ventricular diastole)
The walls of the atria contract
Atrial volume decreases
Atrial pressure increases
The pressure in the atria rises above that in the ventricles, forcing the atrioventricular (AV) valves open
Blood is forced into the ventricles
There is a slight increase in ventricular pressure and chamber volume as the ventricles receive the blood from the atria
The ventricles are relaxed at this point; ventricular diastole coincides with atrial systole
Ventricular systole (atrial diastole)
The walls of the ventricles contract
Ventricular volume decreases
Ventricular pressure increases
The pressure in the ventricles rises above that in the atria
This forces the AV valves to close, preventing back flow of blood
The pressure in the ventricles rises above that in the aorta and pulmonary artery
This forces the semilunar (SL) valves open so blood is forced into the arteries and out of the heart
During this period, the atria are relaxing; atrial diastole coincides with ventricular systole
The blood flow to the heart continues, so the relaxed atria begin to fill with blood again
cardiac diastole
The ventricles and atria are both relaxed
The pressure in the ventricles drops below that in the aorta and pulmonary artery, forcing the SL valves to close
The atria continue to fill with blood
Blood returns to the heart via the vena cava and pulmonary vein
Pressure in the atria rises above that in the ventricles, forcing the AV valves open
Blood flows passively into the ventricles without need of atrial systole
The cycle then begins again with atrial systole
