Section 3: Mass Transport Flashcards
(57 cards)
1
Q
Why is mass transport systems required?
A
- Most cells too far away from exchange surfaces for diffusion alone to maintain composition of tissue fluid
- Mass transport maintains final diffusion gradients bringing substances to and from cells
- Mass transport helps maintain relatively stable immediate environment of cells
2
Q
What is the double circulatory system?
A
- Pulmonary circulation: Deoxygenated blood in right side of heart pumped to lungs - oxygenated blood returns to side of heart - left side
- Systemic circulation: Oxygenated blood in left side pumped to tissues/ deoxygenated blood returns on right side
3
Q
Why is the double circulatory system important to animals?
A
- Prevents mixing of oxygenated and deoxygenated blood - so blood is saturated with oxygen - efficient delivery of oxygen and glucose for respiration
- Blood can be pumped at a higher pressure - substances taken to and removed from cells quicker and more efficient.
4
Q
What are the coronary arteries?
A
- Deliver oxygenated blood to cardiac muscle (heart)
5
Q
What are the names if the blood vessels entering and leaving the heart?
A
- Aorta - takes oxygenated blood from heart - respiring tissue
- Vena cava - takes deoxygenated blood from respiring tissue to heart
- Pulmonary artery - takes deoxygenated blood from heart to lungs
- Pulmonary vein - takes oxygenated blood from lungs to heart
6
Q
What are the names of the blood vessels entering and leaving the lungs?
A
- Pulmonary artery
- Pulmonary vein
7
Q
What are the names of the blood vessels entering and leaving the kidney?
A
- Renal artery - Takes oxygenated blood - kidneys
- Renal veins - take deoxygenated blood to the vena cava from the kidneys
8
Q
What are the different valves?
A
- Atrioventricular valves - prevent backflow of blood to ventricles from atria
- Semi-lunar valves - prevent backflow of blood from arteries to ventricles
9
Q
What is the adaptation of the left ventricle
A
- Has thicker muscular walls
- Generates high blood pressure
- For oxygenated blood has to travel greater distance around the body
10
Q
What is the structure of arteries related to their function?
A
- Thick smooth muscle layer - Contract pushing blood along and control blood flow/pressure
- Elastic tissue layer - stretch as ventricles contract and recoil as ventricle relaxes. Even out blood pressure and maintain high pressure
- Thick wall - Withstands high pressure and prevents artery bursting
- Smooth endothelium - reduces friction
- Narrow lumen - Increases and maintains high blood pressure
11
Q
What are arterioles and what is their structure related to their function?
A
- Division of arteries to smaller vessels directing blood to capillaries. Structure similar to arteries BUT…
- Thicker muscle layer - constricts to reduce blood flow and dilates to increase blood flow
- Thinner elastic layer as lower pressure
12
Q
What is the structure of veins related to its function?
A
- Wider lumen than arteries
- Very little elastic and muscle tissue
- Valves - prevents the backflow of blood
13
Q
Exam Question: The rise and fall in blood pressure in the aorta is greater than in the small arteries. Suggest why.(3)
A
- Aorta is close/directly linked to the heart/ventricle/ pressure is higher
- Aorta has elastic tissue
- Aorta has stretch and recoil
14
Q
Structure of capillaries related to its function
A
- Capillary wall is a thin layer (1 cell thick) - short diffusion pathway - rapid diffusion
- Capillary bed is made of a large network of capillaries - large SA - rapid diffusion
- Narrow lumen - reduces flow rate so more time for diffusion
- Capillaries permeate tissues - short diffusion pathway
- Pores - allows substances to escape
15
Q
What is tissue fluid?
A
- The fluid surrounding cells/tissues
- Provides respiring cells with water, oxygen, glucose, amino acids
- Enables waste substances to move back into blood e.g urea, lactic acid
16
Q
What is the formation of tissue fluid?
A
- Higher blood/ hydrostatic pressure inside capillaries than tissue fluid
- Forces fluid/ water out of capillaries
- Large plasm proteins remain in capillary
17
Q
What is the return of tissue fluid to the circulatory system?
A
- Hydrostatic pressure reduces as fluid leaves
- An increasing conc of proteins lowers the WP in the capillary below the tissue fluid
- Water re-enters the capillaries from the tissue fluid by osmosis - down WP gradient
- Excess water taken up by lymph system and returned to circulatory system
18
Q
How does a low concentration of plasma proteins cause the accumulation of tissue fluid?
A
- Water potential in capillary not as low so WP potential gradient is reduced
- More tissue fluid formed at arteriole end
- Less/ no water absorbed into blood capillary by osmosis
19
Q
How does high blood pressure lead to the accumulation of tissue fluid?
A
- High blood pressure = high hydrostatic pressure
- Increases outward pressure from arterial end
- So more tissue fluid formed/ less reabsorbed
- Lymph cant drain fast enough
20
Q
What are the different stages of the cardiac cycle?
A
- Atrial systole
- Ventricular systole
- Diastole
21
Q
What is atrial systole?
A
- Atria contract - decreasing volume and increasing pressure inside atria
- AV forced open, semi lunar closed
- Blood pushed into ventricles
22
Q
What is ventricular systole?
A
- Ventricles contract from the bottom up - decreasing the volume and increasing pressure in ventricles
- Semi lunar valves are open
- AV valves shut
- Blood pushed out of heart through arteries
23
Q
What is diastole?
A
- Atria and ventricles relax - increasing volume and decreasing pressure inside chambers
- Blood from veins fill atria (increasing pressure slightly) and flows passively into ventricles
- AV valves open, SL valves closed
24
Q
How do you calculate cardiac output and what do the different parts of the equation mean?
A
- Cardiac output = stroke volume x heart rate
- Cardiac output = amount of blood pumped out of the heart per minute
- Stroke volume = volume of blood pumped by the ventricles in each heart beat
- Heart rate = number of beats per minute
25
How do you calculate heart rate from cardiac cycle data?
* 1 beat = 1 cardiac cycle
* Find the length of 1 cardiac cycle
* Heart rate in beats per minute = 60 seconds
26
What is cardiovascular disease and name an example of one?
* Conditions affecting structure or functions of the heart
* Coronary heart disease
27
How can an atheroma result in a heart attack
* Atheroma causes narrowing of coronary arteries
* Restricts blood flow to heart muscle supplying glucose or oxygen
* Heart anaerobically respires - less ATP produced - not enough energy for heart to contract - lactate produced - damages heart tissue
28
What are the common risk factors of cardiovascular disease (increase probability of getting disease)
* Age
* Diet - high in salt or saturated fat
* High consumption of alcohol
* Stress
* Smoking
* Genetic
29
Exam Question: Studies of CVD patterns between different countries suggest there is a link between CBD and diet. Suggest why such studies may not prove the link between CVD and diet (2)
* Other variables/ uncontrolled variables affect CVD
* Genetic differences
* Different countries have different lifestyles
* Data does not provide a causal link
30
What is haemoglobin?
* Is a group of chemically similar molecules found in many different organisms
* This structure may differ between organisms
31
Where is Haemoglobin found?
* In red blood cells
32
What is the structure of haemoglobin?
* No nucleus - contain more haemoglobin
* Biconcave shape - increase surface area for rapid diffusion
* Quaternary structure - 4 polypeptide chains
* Each polypeptide chain contains a haem group of Fe2+ which combines with oxygen
33
What is the structure of haemoglobin?
* No nucleus - contain more haemoglobin
* Biconcave shape - increase surface area for rapid diffusion
* Quaternary structure - 4 polypeptide chains
* Each polypeptide chain contains a haem group of Fe2+ which combines with oxygen
34
Where in the body does haemoglobin have a high and low affinity to oxygen?
* In lungs there is a high pO2, haemoglobin has a high affinity for oxygen - readily loads
* At respiring tissues, a low pO2 oxygen readily unloads. CO2 conc high increasing unloading
35
Explain the shape of the oxyhaemoglobin dissociation curve?
* Haemoglobin has a low affinity for oxygen as first oxygen binds
* After first binds the shape changes that makes 2nd and 3rd easier to bind
* After 3rd, haemoglobin starts to become saturated, shape changes and it is hard to bind
36
What is the effect of CO2 (bohr effect)
* Lowers the pH and reduces haemoglobin's affinity for oxygen as haemoglobin changes shape
* Oxygen rapidly unloads
* Advantageous - provides more oxygen for muscles for aerobic respiration. Curve shifts to the right
37
What is the effect of the curve being shifted to the left?
* Haemoglobin has a higher affinity for oxygen
* More oxygen associates with haemoglobin more readily at low pO2 and dissociates less readily
* Advantageous - for those living in high altitudes, underground
38
What is the effect of the curve being shifted to the right?
* Oxygen dissociates from haemoglobin more readily to respiring cells
* Advantageous to organisms with a high rate of respiration
39
What is the function of the xylem?
* Is the tissue that transports water in the stem and leaves of plants
40
What is the cohesion tension theory?
* How water moves up the xylem against transpiration via transpiration stream
41
What is the process of the cohesion tension theory?
* Water evaporates from the leaves via the stomata due to transpiration
* Reducing WP in the cell and increasing WP gradient
* Water drawn out of xylem
* Creating tension
* Cohesive forces between water molecules pull water up as a column
42
What are some adaptations of the xylem?
* Elongated cells arranged end to end to form a continuous column
* Hollow
* End walls break down for flow
* Thick cell walls
* Rigid - less likely to collapse under low pressure
* Waterproof
43
What is the process of transloaction?
* Movement of solutes from source to sink
44
What is the mass flow hypothesis at the source?
* High conc of solute
* Active transport loads solutes from companion cells to sieve tubes of the phloem
* Lowering WP inside sieve tubes
* Water enters sieve tubes by osmosis from xylem and companion cells
* Increasing pressure inside sieve tubes at the source end
45
What is the mass flow hypothesis at the sink?
* Low conc of solute
* Solutes removed to be used up
* Increasing WP inside sieve tubes
* Water leaves by osmosis
* Lowering pressure inside sieve tubes
46
What is the mass flow in the mass flow hypothesis?
* Pressure gradient from source to sink
* Pushes solutes from source to sink
* Solutes used/stored at sink
47
What are the adaptations of the phloem?
* Sieve tubes have no nucleus and few organelles
* Companion cell for each sieve tube carry out important functions - provide ATP
48
What are some of the ways to investigate transport in plants?
* Use of tracers and ringing experiments
* Aphid
* Metabolic inhibitor
49
How do you use tracers to investigate transport in plants?
* Supply plant with C14
* This is incorporated into organic substances produced by the leaf and undergo translocation
* Plant killed and placed in autoradiography and turns black when radioactive substance is present
50
How do you use aphids to investigate transport in plants?
* Aphids pierce the phloem using mouthpiece
* Releasing sap from plants
* Flow of sap higher at leaves than at sink
* Evidence of pressure gradient - higher near source
51
How do you use of metabolic inhibitors to investigate transport in plants?
* Add a metabolic inhibitor to phloem
* Translocation stops
* Proves active transport is involved - as it requires ATP against conc gradient
52
What does a potometer do?
* Estimates the transpiration rate by measuring water uptake
53
What is the method of using a potometer?
* Cut shoot underwater - prevent air entering
* Assemble potometer and insert shoot underwater
* Dry leaves and allow time to acclimatise
* Shut off tap reservoir
* Remove the end of the capillary tube from water beaker until 1 bubble has formed
* Record position of air bubble and record time
* Rate of air movement = estimate transpiration rate can change variables
54
How does light affect the rate of transpiration?
* Higher light intensity - faster transpiration
* Because stomata open in light to let CO2 in for photosynthesis
* Allowing more water to evaporate faster
* Stomata close when it is dark - low transpiration rate
55
How does temperature affect the rate of transpiration?
* Higher temperature = faster transpiration rate
* Water molecules gain K.E and move faster
* Water evaporates faster
56
How does humidity affect the rate of transpiration?
* Lower humidity - faster transpiration rate
* Because as humidity increases, more water is in the air so has a higher WP potential
* Decreasing WP gradient - water evaporates more slower
57
How does wind affect the rate of transpiration?
* Windier = faster transpiration rate
* Wind blows away water molecules from around stomata
* Decreasing WP of air around stomata
* Increasing WP gradient
* Water evaporates faster
