Transport In Animals Flashcards
(28 cards)
Hydrostatic pressure at arteriole end: 4.3kPa
Hydrostatic pressure at veinule end: 1.6kPa
Hydrostatic pressure of tissue fluid: 1.1kPa
Use this information to explain how tissue fluid is formed. (2)
- overall outward pressure is 3.2kPa
- forces small molecules out of capillary
Hydrostatic pressure falls from arteriole end to venue end of capillary. Explain why. (1)
- loss of water
- due to friction
High blood pressure leads to an accumulation of tissue fluid. Explain why. (3)
- increase outward pressure from arteriole end of capillary
- so more tissue fluid formed
- can’t be reabsorbed
Water potential of blood plasma is more negative at the venue end of the capillary than at the arteriole end of the capillary. Explain why. (3)
- water has left capillary
- proteins too large to leave capillary
- increasing conc of blood proteins and water potential
Explain four ways in which the structure of the aorta is related to its function. (4)
- elastic tissue to smooth out flow
- elastic tissue stretches when ventricles contact
- thick wall withstands pressure
- aortic valve prevents backflow
- smooth endothelium reduces friction
- muscle for contraction
An oxyhaemoglobin dissociation curve for 2 different species ( X= kPa of oxygen Y= % saturation of haemoglobin with oxygen) shows:
- species A is slightly to the left of species B but plateaus at the same point: just under 100%
- species B is slightly to the right of A but ends at the same pint: just under 100%
Species B is more active than species A. Use the info above to explain how the haemoglobin of species B allows a greater level of activity. (4)
- right so lower affinity
- haemoglobin unloads more readily
- more oxygen to tissues
- for faster/ more respiration
What’s cardiac output and how do you calculate it?
- cardiac output is the volume of blood pumped out the heart per unit of time
- cardiac output= heart rate * stroke volume
What is stroke volume?
The volume of blood pumped out of the left ventricle during one cardiac cycle
What’s heart rate?
The number of times a heart beats per minute
What’s Cardiac cycle?
The events that occur during one heart beat
Some people produce a much higher ventricular blood pressure than normal. This can cause tissue fluid to build up outside the blood capillaries of these people.
Explain why. (2)
-more fluid is forced out
- less return of fluid due to pressure
Some drugs used to reduce high ventricular blood pressure, cause widening of blood vessels.
Suggest how widening of blood vessels can reduce ventricular blood pressure. (2)
- larger lumen
- reduces blood pressure in vessels
- less friction
Explain the role of the heart in the formation of tissue fluid. (2)
- contacting of ventricles produces high hydrostatic pressure
- this forces water out of blood capillaries
Lymphoedema is a swelling in the legs which may be caused by a blockage in the lymphatic system.
Suggest how a blockage in the lymphatic system could cause lymphoedema. (1)
Excess tissue fluid builds up as can’t be reabsorbed
The graph shows the oxyhaemoglobin dissociation curves for fetal haemoglobin(HbF) and adult haemoglobin(HbA): ( X= kPa of oxygen Y= % saturation of haemoglobin with oxygen)
- HbF is slightly to left of HbA, it is an S-shaped (sigmoid) curve and plateaus at just under 100%
- HbA is slightly to the right of HbF, it is an S-shape (sigmoid) curve and plateaus at just under 100%
Explain how changes in the shape of haemoglobin result in the S-shaped (sigmoid) oxyhaemoglobin curve for HbA. (2)
- first oxygen struggles to bind but then causes changed shape
- allows more oxygen to bind more easily
The graph shows the oxyhaemoglobin dissociation curves for fetal haemoglobin(HbF) and adult haemoglobin(HbA): ( X= kPa of oxygen Y= % saturation of haemoglobin with oxygen)
- HbF is slightly to left of HbA and is an S-shaped (sigmoid) curve which plateaus at just under 100%
- HbA is slightly to the right of HbF, it is an S-shape (sigmoid) curve and plateaus at just under 100%
At birth 98% of the haemoglobin is HbF. By the age of 6 months, the HbF has usually completely disappeared from the baby’s blood and been replaced by HbA.
Use the graph to explain why this change is an advantage for the baby. (2)
- HbA has lower affinity for oxygen at lower partial pressures
- easier unloading of oxygen for respiration
Name the blood vessels that carry blood to the heart muscle. (1)
Coronary arteries
Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin. (2)
- affinity of oxygen lowers
- by decreasing blood pH
Use the info in figure 3 (seals are diving mammals, the graph shows curves for seal oxyhaemoglobin and seal myoglobin- an oxygen carrying protein fond in muscles: the myoglobin curve is the left whereas the oxyhaemoglobin curve is to the right) to explain how the seal’s myoglobin dissociation curve shows the seal is adapted for diving. (2)
- higher affinity of oxygen
- allows aerobic respiration when diving at lower partial pressures of oxygen
Explain how an arteriole can reduce the blood flow into capillaries. (2)
- vasoconstriction
- contracts muscles in walls so diameter of arteriole reduces
Figure 1 shows heart valves during one stage of a cardiac cycle. Ventricles are visible through open valves. ( the 2 valves between ventricles and arteries are closed, whereas the 2 valves between atria and ventricles are open)
What can you conclude from the appearance of valves in figure 1 about heart muscle activity and blood movement between:
1. Ventricles and arteries? (2)
2. Arita and ventricles? (2)
- VENTRICLE AND ARTERIES:
-ventricle muscles relaxed
- no blood movement in/ from arteries - ATRIA AND VENTRICLES:
- atria muscles contracted
- blood movement from atria into ventricles
Which blood vessel carries blood at the lowest blood pressure? (1)
Vena cava
Give the pathway a red blood cell takes when travelling in the human circulatory system from a kidney to the lungs.
Do not include descriptions of pressure changes in the heart or the role of heart valves in your answer. (3)
- renal vein
- vena cava to right atrium
- right ventricle to pulmonary artery
Tissue fluid is formed from blood at the arteriole end of a capillary bed.
Explain how water from tissue fluid is returned to the circulatory system. (4)
- plasma protein remain
- creates water potential gradient
- water moves to blood by osmosis
- returns to blood by lymphatic system
