topic 3 Flashcards
describe the relationship between a small organism and its surface area to volume ratio
small organisms have a very large surface area in comparison to their volume.
this means that there is a big surface for exchanging substances but also there is a small distance from the outside of the organism to the middle of it.
so small organisms can simply exchange substances across their membranes using simple diffusion.
describe the relationship between a large organism and its surface area to volume ratio
the larger an organism, the smaller its surface area compared to its volume and the larger the distance from the middle to the outside.
larger organisms typically have a higher metabolic rate, which demands efficient transport of waste out of cells and reactants into the cells.
they have adaptations that help make the exchange across surfaces more efficient.
describe the cardiac muscle
the walls of the heart have a thick muscular layer.
this muscle is called the cardiac muscle.
what are the properties of the cardiac muscle?
its myogenic meaning it can contract without nervous or hormonal stimulation.
it never fatigues as long as it has a supply of blood.
describe the coronary arteries and its role and what will happen to it if its blocked
they supply the cardiac muscle with oxygenated blood.
these branch off from the aorta.
if they become blocked the cardiac muscle wont receive oxygen, therefore it will not respire and the cells will die. This results in myocardial infarction (a heart attack).
what are the four chambers of the heart?
left and right atrium.
left and right ventricles.
describe the atria
thinner muscular walls.
do not need to contract as hard as not pumping blood far only to ventricles.
elastic walls to stretch when blood enters.
describe the ventricles
thicker muscular wall to enable bigger contraction.
this creates a higher blood pressure to enable blood flow to flow to longer distances (to lungs and rest of the body).
describe the role of the right ventricle
pumps blood to the lungs.
at low pressure to prevent damage to the capillaries in the lungs and so blood flows slowly to allow time for gas exchange.
therefore thinner muscular wall in comparison to the left ventricle.
describe the left ventricle
pumps blood to the body.
at a higher pressure to enable blood reaches all the cells in the body.
therefore much thicker muscular wall in comparison to the right ventricle to enable larger contractions of the muscle to create higher pressure.
describe the role of the vena cave
carries deoxygenated blood from the body into the right atrium.
describe the role of the pulmonary vein
carries oxygenated blood from the lungs to the left atrium.
describe the role of the pulmonary artery
carries deoxygenated blood from the hearts right ventricle to the lungs to become oxygenated.
describe the aorta
carries oxygenated blood from the left ventricle to the rest of the body.
where is the semi-lunar valve found?
in the aorta and pulmonary artery.
where is the atrioventricular valves found?
between the atrium and the ventricles.
where is the bicuspid and tricuspid valve?
bicuspid is on the left side.
tricuspid is on the right side.
when do valves open?
when the pressure behind the valve is high.
when do valves close?
when the pressure infront of the valve is high.
what is the role of the vavles?
they prevent the backflow of blood.
what is the role of septum?
separates the oxygenated blood and deoxygenated blood.
maintains high concentration of oxygen in oxygenated blood to maintain concentration gradient to enable diffusion at respiring cells.
what are the three stages of the cardiac cycle?
diastole.
atrial systole.
ventricular systole.
what is meant by diastole?
the atria and ventricular muscles are relaxed.
this is when blood will enter the atria via the vena cava and pulmonary vein.
the blood flowing into the atria increases the pressure within the atria.
what is the cardiac output?
the volume of blood which leaves one ventricle in one minute.
what is meant by atrial systole?
the atria muscles walls contracts increasing the pressure further.
this causes the atrioventricular valves to open and blood to flow into the ventricles.
the ventricular muscular walls are relaxed (ventricular diastole).
what is meant by ventricular systole?
after a short delay the ventricle muscular walls contract, increasing the pressure beyond that of the atria.
this causes the atrioventricular valves to close and the semi-lunar valves to open.
the blood is pushed out of the ventricles into the arteries (pulmonary and aorta).
how do you calculate the cardiac output?
cardiac output= stroke volume x heart rate.
when do the atrioventricular valves open?
when the pressure is higher in the atria compared to the ventricles.
when do the atrioventricular valves close?
when the pressure is higher in the ventricles compared to the atria.
when do the semi lunar valves open?
when the pressure in the ventricles is higher compared to in the arteries.
when do the semi lunar valves close?
when the pressure in the arteries is higher compared to in the ventricles.
what is meant by a closed system?
the blood remains within the blood vessels.
what is a double circulatory system?
the blood vessels pass through the heart twice in each circuit.
there is one circuit which delivers blood to the lungs and another circuit which delivers blood to the rest of the body.
why do mammals require a double circulatory system?
to manage the pressure of blood flow.
the blood flows through the lungs at low pressure.
this prevents damage to the capillaries in the alveoli.
and also reduces the speed of blood flow enabling more time for gas exchange.
why is oxygenated blood from the lungs pumped out at a higher pressure?
to ensure all the blood reaches all the respiring cells in the body.
what is the roles of the arteries?
arteries carry blood away from the heart and into arterioles.
describe the arterioles.
they are smaller than arteries and connect to the capillaries.
describe the capillaries.
they connect arterioles to the veins.
describe veins.
they carry blood back into the heart.
describe the muscule layer of arteries.
thicker than veins so that constriction and dilation can occur to control the volume of blood.
describe the muscle layer of veins.
relatively thin so it can control the blood flow.
do capillaries have a muscle and elastic layer?
no.
describe the muscle layer of arterioles.
thicker than in arteries to belp restrict blood flow into the capillaries.
describe the elastic layer of arteries.
thicker than in veins to help maintain blood pressure.
the walls can stretch and recoil in response to the heart beat.
describe the elastic layer of veins.
relatively thin as the pressure is much lower.
describe the elastic layer in arterioles.
thinner than in arteries as the pressure is lower.
describe the wall thickness of arteries.
thicker walls than veins to help prevent the vessels bursting due to the high pressure.
describe the wall thickness of veins.
thin as the pressure is much lower as there is a low risk of bursting.
the thinness mean the vessels are easily flattened which means the vessels are easily flattened, which helps the flow of blood up to the heart.
describe the wall thickness of capillaries.
one cell thick consisting of only a lining layer.
this provides a short diffusion distance for exchange materials between the blood and cells.
describe the wall thickness of arterioles.
thinner as pressure is slightly lower.
which blood vessel has valves?
veins.
describe the importance of capillary beds.
this is how gases and nutrients are supplied to the body’s cells. At the venule end of the capillary, carbon dioxide and wastes are reabsorbed into the blood.
what is haemoglobins?
haemoglobin are groups of globular protein found in different organisms.
haemoglobin is a protein with a quaternary structure.
haemoglobin and red blood cells transport oxygen.
what is meant by the affinity of haemoglobin for oxygen?
the ability for haemoglobin to attract or bind to oxygen.
what is meant by the saturation of haemoglobin with oxygen?
when haemoglobin is holding the maximum oxygen it can bind.
what is loading/association of haemoglobin?
the binding of oxygen to heamoglobin.
what is unloading/dissociation of haemoglobin?
when oxygen detaches or unbinds to haemoglobin.
describe the oxyhaemoglobin curve.
oxygen is loaded in regions with a high partial pressure of oxygen (e.g. alveoli).
oxygen is unloaded in regions with a low partial pressure of oxygen.
what is meant by cooperative nature?
the cooperative nature of oxygen binding to haemoglobin causes the haemoglobin to change shape when the first oxygen binds.
this makes it easier for further oxygen to bind.
