Topic 1

Created by

Bicepking

Cards (98)

Describe an open circulatory system
Blood is not contained in blood vessels but circulates in large spaces
Define a closed circulatory system
Blood is enclosed within vessels/diffusion of substances only takes place within vessels
Define a single circulatory system
"Blood flows through the heart once for each complete circuit of the body
Blood is pumped at a low blood pressure. Suitable for organisms with a low metabolic rate"
Define a double circulatory system
"Blood flows through the heart twice for each complete circuit of the body (i.e simultaneously pumps to lungs and heart)
Maintains a high blood pressure to meet demands of a high metabolic rate"
Why cant complex multi cellular organisms rely on diffusion to transport substances around the body?
They are too large for diffusion to transport substances quickly enough (small SA:V)
How does blood circulate in an open circulatory system?
A simple heart pumps blood out into the cavities surrounding the organs. The heart muscle relaxes so the pressure decreases and blood is drawn from the cavity back into the heart through open valves
Why is a closed circulatory system more efficient?
The blood is forced through fairly narrow tubes so it travels faster and under pressure.
What are the benefits of a mass transport system?
Carries raw material from specialised exchange organs to the body cells to remove metabolic waste
Why is water a polar molecule? Oxygen is more electronegative than Hydrogen so there is a slight difference in charge between the atoms.
Why is water a polar molecule?
Oxygen is more electronegative than Hydrogen so there is a slight difference in charge between the atoms.
Why does water remain a liquid over a wide range of temperatures?
Hydrogen bonding holds water molecules together and collectively they make water very stable
Why is water cohesive?
the delta positive H is attracted to the delta negative O. This helps water to flow so it is good at transporting substances
Why is water a good solvent?
Polar molecules and ionic substances dissolve in water because water is dipolar. The forces of attraction between the delta positive H and the delta negative O are stronger than the ionic bonds so the ions become hydrated and completely surrounded by water molecules
Describe the structure of capillaries
Very narrow lumen for short diffusion distance, single layer of cells so it can lie very close to the cells. joins the arteries and venues together, medium pressure, large surface area - Structure of the capillaries
What is the function of the capillaries?
Where metabolic exchange occurs so substances are exchanged between cells and the capillaries -
Describe the stretch and recoil in arteries
Heart contracts and blood is forced into the arteries. The elastic walls stretch a little to accommodate the blood. The heart relaxes and the elasticity of the walls causes them to recoil a lot behind the blood pushing it forward. This causes a pulsing flow through the arteries
Describe how blood flows in veins
Blood flow is assisted by the contraction of skeletal muscles during movement of limbs and breathing. Low pressure in thorax when breathing draws blood back into the heart from veins -
State the four chambers of the heart
Left atria/left ventricle/right atria/right ventricle
State the four vessels entering/exiting the heart
aorta/vena cava/pulmonary artery/pulmonary vein
How is the left side of the heart identified?
Presence of a thicker muscular wall
What is present inside the heart to prevent backflow?
AV valves (tricuspid = right, bicuspid = left) and semi-lunar valves.
Why are the ventricle walls thicker than atria walls?
Blood needs to be under higher pressure to travel a further distance
Why are valves important?
Prevent backflow/allow build up of pressure
State what happens to the heart during ventricular diastole and atrial systole
Ventricles are relaxed/atria contract/increases pressure in atria/AV valves open/blood flows into ventricles
State what happens to the heart during ventricular systole and atrial diastole
Atria relax/ventricles contract/increase pressure in ventricle/AV valves shut/SL valves open/blood forced into arteries (pressure currently lower in arteries)
State what happens to the heart during cardiac diastole
Atria and ventricles relax/higher pressure in arteries causes SL valve to shut/atria begin to fill again/as pressure in ventricles drops, AV valves begin to open
What valves are open during ventricular systole?
SL valves
Why are daphnia a good model organisms?
Simple nervous system - feel no pain/transparent so can see heart beat/open circulatory system so substances can easily diffuse/invertebrate
CPAC 1 - Daphnia heart rate: State the IV/DV/CV
IV: Conc. Of caffeine/DV: Heart rate (min)/CV: volume/time/species/age/light intensity
What can damage the endothelial lining?
High blood pressure/smoking
What is atherosclerosis?
The hardening of arteries due to build up of plaque which blocks/narrows the arteries
What happens during the inflammatory response?
White blood cells leave the blood vessel and move into the artery wall
How does an atheroma form?
White blood cells accumulate chemicals especially cholesterol and this deposit builds up
How does a plague form?
Calcium salts and fibrous tissue also build up forming a hard swelling called a plaque on the inner artery wall. This build up of fibrous tissue causes the artery wall to lose some elasticity so it hardens.
How can an atheroma increase the risk of thrombosis in arteries?
An atheroma can rupture the endothelium of an artery, damaging the wall and leaving a rough surface. This triggers thrombosis at the rupture site
Where is thromboplastin released from?
It is a protein released from the damaged blood vessel and from platelets which have stuck to the damaged blood vessel wall
What do thromboplastin and calcium ions from plasma do?
The trigger the conversion of prothrombin into thrombin.
What does thrombin do?
Catalyses the conversion of fibrinogen into fibrin.