More Exchange & Transport Topic-3B Flashcards
Why is the circulatory system of mammals referred to as a double circulatory system?
There are two circuits, one taking blood from the heart to lungs and one back to the heart then to the rest of the body.
Name the part of the heart that provides it with its own blood supply.
The coronary arteries
Why are the pulmonary vein and artery different from usual?
As the vein carries oxygenated blood and the artery carries deoxygenated blood.
What does the aorta do?
Supplies oxygenated blood to the body
What does the vena cava do?
Supplies deoxygenated blood to the heart.
The ……. vein and …….. artery can be associated with the kidneys.
The renal vein and renal artery can be associated with the kidneys.
The hepatic vein and artery are associated with…?
The liver and gut
The hepatic portal vein can be found….
Between the liver and the gut.
Name adaptations of arteries
Walls are THICK and MUSCULAR
Walls have ELASTIC tissue to STRETCH and recoil as the heart beats (MAINTAINS HIGH PRESSURE)
endothelium is FOLDED allowing it to stretch.
Name the role of arteries
Arteries carry blood from the heart to the rest of the body.
Name the adaptations of veins
Wider lumen than arteries, have very little elastic or muscle tissue.
Valves to prevent backflow
Name the roles of veins
Take blood back to the heart under low pressure.
Name the roles of capillaries
Substances are exchanged between blood and body tissue at the capillaries.
Name adaptations of capillaries.
Found very near cells in exchange tissues (short diffusion pathway)
Walls only one cell thick
Large number to increase surface area (capillary beds=a network of capillaries in tissue.
What is tissue fluid?
The fluid that surrounds cells in tissues, made from small molecules that leave blood plasma(O2)
Name factors that increase the risk of cardiovascular disease.
High blood cholesterol and poor diet
Cigarette smoking
high blood pressure
genetic factors
Name the main stages of the cardiac cycle
Ventricles relax, atria contract
Ventricles contract, atria relax
Ventricles and atria relax
Name the main stages of the cardiac cycle in order
Ventricles relax, atria contract
Ventricles contract, atria relax
Ventricles and atria relax
How does blood get pushed into the ventricles?
The pressure increase due to volume decrease in the atria pushes the blood into the ventricles.
What happens when the pressure in the ventricles becomes higher than the atria?
The atrioventricular valves are forced shut and due to pressure in ventricles being higher than pulmonary artery and aorta the semi-lunar valves are forced open.
Why does the left ventricle have thicker muscular walls than the right ventricle?
Because it needs to contract powerfully to pump blood all the way round the body, not just to nearby lungs.
Why do the ventricles have thicker walls than the atria?
Because they have to push blood out of the heart but the atria just push blood a short distance into the ventricles.
Give the equation to calculate stroke volume
Stroke volume= cardiac output/heart rate
Give 4 ways the aorta structure is related to its function
Thick walls to withstand high pressure
Elastic tissue to allow recoil
Muscle for contraction
Semi-lunar valves to prevent backflow of blood.
Explain how tissue fluid is formed.
The overall hydrostatic pressure inside capillary is more than outside so small molecules are forced out of the capillary =tissue fluid.
Why does the hydrostatic pressure fall from the arteriole end to the venule end of the capillary?
Due to the loss of fluid through the capillary lining.
How does high blood pressure lead to an accumulation of tissue fluid?
High blood pressure=high hydrostatic pressure
Increases outward pressure of arterial end of capillary so more tissue fluid is formed.
Why is the water potential of the blood plasma more negative at the venule end than the arteriole end of the capillary?
Water has left capillary but the proteins in the blood are too large to leave so the concentration of blood proteins is higher and thus water potential.
Why would something be described as processed results?
Due to calculations being made from raw data
How would you use given data to find water potential?
Plot graph with conc on x axis and % change in mass on y axis.
Find where the curve crosses x axis
use calibration table to find wp of sucrose concentration.
Oxygen loads onto haemoglobin to form oxyhaemoglobin where there’s ….. ……
High pO2
pO2 means….
Partial pressure of oxygen
The greater the concentration of dissolved oxygen in cells = ….
Higher partial pressure
Haemoglobin has a high ….. for oxygen
High affinity for O2
When O2 leaves oxyhaemoglobinb(in lungs) it ……
dissociates
Oxyhaemoglobin …… it’s O2 where’s there’s ……. pO2
Oxyhaemoglobin unloads it’s O2 where there’s lower pO2
Where in the body does oxygen load onto haemoglobin and why?
O2 enters blood capillaries at alveoli due to high pO2.
When cells respire they …. .. …….. which lowers the ……
When cells respire they use up OXYGEN which lowers the pO2.
Red blood cells deliver ……….. to respiring tissues
Red blood cells deliver oxyhaemoglobin to respiring tissues where it unloads oxygen
What does a dissociation curve show?
How saturated the haemoglobin is with oxygen at any partial pressure
What does 0% saturation mean
None of the haemoglobin molecules are carrying oxygen.
100% saturation means….
Every haemoglobin molecule is carrying the maximum of 4 molecules of oxygen.
Where pO2 is high haemoglobin has a ….. affinity for oxygen
High affinity= pO2 high
Where is pO2 expected to be high and where is it low?
High in the lungs
Low in respiring tissues
Where pO2 is low haemoglobin has a ….. affinity for oxygen so it …… it
Low affinity for oxygen so it releases it
Why is the dissociation curve S shaped?
After first O2 molecule combines, shape changes to make it easier for other molecules to bind. But as Hb gets saturated it’s harder for oxygen molecules to join.
How are organisms adapted to live in low concentration of oxygen environments
The dissociation curve moves left—> have higher affinity for oxygen than human
How are organisms adapted that are very active and have high oxygen demand?
Haemoglobin with a lower affinity for oxygen so curbs is to the right.
Oxygen dissociates more readily at …….. partial pressures of CO2
Higher partial pressure of CO2= readily dissociates oxygen
Why does the dissociation curve shift right at higher pCO2? What is this effect?
The rate of dissociation of oxyhaemoglobin increases so curve shifts right.
The Bohr effect.
Give the formula for calculating the percentage saturation of haemoglobin with oxygen
(oxygenated haemoglobin/
maximum saturation ) *100
The oxygen dissociation curve of the fetus is to the left of that for its mother. Explain the
advantage of this for the fetus.
Oxygen loads more readily at lower pO2, therefore oxygen moves from mother to fetus.
After birth, fetal haemoglobin is replaced with adult haemoglobin. Use a graph to
suggest the advantage of this to the baby.
oxygen dissociates to respiring tissues
What does diastole mean?
Cardiac relaxation
What does systole mean?
Cardiac contraction
What makes the binding of the 2nd and 3rd oxygen easier?
The change in shape of the haemoglobin caused by the binding of the first oxygen.
The two sets of intercostal muscles are said to be….
antagonistic.
What type of process is Transpiration?
A passive on as the energy for the process comes from the sun.
How can plants control the rate of transpiration?
By changing the size of their stomatal pores
What is the main factor for movement of water up the xylem?
Cohesion and Tension (cohesion-tension theory)
Haemoglobin with high affinity for oxygen takes it up more readily but also ….
releases it less readily.
Haemoglobins affinity for oxygen varies depending on
the partial pressure of oxygen.
Why is the 4th O2 molecule difficult to associate with Hb
Because the Hb has started to become saturated so it’s harder for more oxygen molecules to join
Why are the 2nd and 3rd O2 molecules easiest to associate with Hb
Because after the 1st O2 shape of Hb alters its shape so it’s easier for other molecules to bind
What is the xylem?
water transport tissue in plants composed of dead cells.
What is translocation
the movement of materials (particularly sucrose) from the leaves to other parts of a plant.
What is transpiration?
the loss of water from the leaves of a plant by evaporation.
What is a sieve-tube element?
cellular structure in the phloem of plants that transports the products of photosynthesis throughout the plant by mass flow
What 4 factors affect the transpiration rate?
Light
Temperature
Wind
Humidity
When a wave of electricity reaches the atrioventricular node there’s a short delay before a new wave leaves. Explain the importance of this delay.
Allows Atria to empty before the ventricles contract.
How to calculate stroke volume?
Cardiac output /beats per minute
What causes the lumen of arteries to narrow in the formation of an atheroma?
Fibrous Plaques
During a potometer experiment why do you cut the shoot underwater?
To prevent water entering the xylem
How is the Xylem adapted for continuous flow of water?
No end walls for vessel elements so forms a continuous tube
What does the potometer experiment calculate?
The rate of transpiration.
List the things that result in uptake of water in a plant?
Transpiration (evaporation of water from leaves) which creates Tension (Hydrogen bonds between water and xylem vessels) Cohesion (H bonds between H2O) And diffusion of water into the roots via osmosis due to decrease in wp
The Bohr effect means that oxygen….
dissociates at lower PO2
Function of coronary arteries
Carry oxygen to heart muscle.
What causes the increase in pressure of the heart
CONTRACTION
How does ringing affect translocation
-Phloem removed when ring of bark taken so high conc of solute above ring as none can travel down phloem
What is an atheroma?
fatty materials/cholesterol in artery wall
Name 4 adaptations of capillaries
Pores in walls=faster filtration
endothelium is one cell thick=shorter diffusion pathway
narrow lumen=more time for diffusion
small diameter=large SA/V ratio
