Mass Transport Mamals And Plants Flashcards
Name the four Chambers of the heart
Left and right atrium and ventricle
Name the vessels coming in and out of the right side on the heart
In: vena cava
Out:pulmonary artery
Name the vessels coming in and out of the left side on the heart
In:pulmonary vein
Out:aorta
What seperate the 2 sides of the heart?
Septum
Name the valve between the ventricle and atrium and func
Atrioventricular valve
Prevent back flow into atrium from ventricle in ventricular systole
Name valve between arteries and ventricle and function
Semilunar valves
Prevent back flow into ventricle from artery
Name valve between ventricle and atrium on right side of heart
Tricuspid
3 cusps
Name valve between ventricle and atrium on left side of heart
Bicuspid
Two cusps
What prevents the AV valves from inverting?
Tendons attached to papillary muscles
What is the largest artery in the body?
Aorta
Why is the max pressure in the ventricle larger than that of the atrium?
Ventricle has thicker muscular wall because needs larger force to pump blood at higher Pa to travel further
Why is the left side of the heart more muscular?
More muscle means larger contraction force means larger Pa means blood is pumped further (Systemic VS pulmonary)
Where does the blood that supplies the heart come from?
The coronary arteries that branch off the aorta
What is the name for a heart attack and what does it mean?
Myocardial infarction
Heart+ tissue death
What are risk factors?
Factors that increase the liklihood of an individual getting the disease
What are the risk factors of cardiovascular disease?
Smoking High blood pressure Blood cholesterol(diet) Age Sex Genetics
How does smoking affect the risk of CHD?
Nicotine makes platelets more sticky increasing risk of thrombosis + stimulates adrenaline production (increase blood Pa and heart rate
CO irreversibly binds to haemoglobin to form carboxyheamoglobin displacing oxygen = heart works harder to get enough O2 to tissue.
Define thrombosis
Blood clot near heart
How does high blood pressure increase risk for CHD?
Heart has to work harder to increase pressure of ventricles above arteries to pump blood out
Can cause aneurysms as walls weaken
Walls may thicken and harden restricting flow of blood
How does blood cholestetol increase risk for CHD?
LDL cholesterol promotes fatty material depositing in tissue such as arteries = narrow arteries = thrombosis
What’s the difference between HDL And LDL?
HDL = remove cholesterol from tissue to liver
LDL= remove cholesterol from liver to tissue
Define atheroma
Fatty deposits
How is cholesterol Transported in the blood?
Lipoproteins
How does diet affect risk for CHD?
High salt= high BP
High saturated fat=high cholesterol
Antioxidants and dietary fibre (non-starchy polysaccharides) = decreased risk
Define myocardial infarction
Heart - tissue death
Outline the treatments for CHD
Statins
Stents
Aspirin (makes platelets less sticky)
Why is the heat cycle a cycle?
Continuous
Name the main stages of the heart cycle
Atrial systole
Ventricular systole
Diastole
Describe diastole
Heart muscles are relaxed
Ventricle walls recoil so SL valves close
Blood trickles into atrium untill pressure exceeds that of the ventricle so AV valves open
Describe atrial systole
Atrial walls contract simultaneously
Blood forced into ventricles which are relaxed
SL valves and AV valves are open
Describe ventricular systole
After a short delay after strial systole
Simultaneous contraction of ventricle walls
SL valves open
AV valves close (prevent back flow into atrium)
What makes the lub dub sound of the heart beat?
AV then SL valves snap shut
Why are there pressure variations in the heart?
Due to a closed system
When do the SL valves close?
Diastole
When do the SL valves open?
Ventricular systole
When do the AV valves close?
Ventricular systole
When do the AV valves OPEN?
atrial systole
Why does aortic Pa never fall below 12 KPa?
Recoil of elastic fibres increase Pa
Why does the pressure in the ventricle increase during diastole?
Blood trickles in from the atrium as the heart fills with blood
Why is atrial Pa always low?
Thin walls= less force when contracting = less Pa
Why does the atrial Pa increase and then decrease during diastole?
Increases as blood fills atrium but then decresease once AV valves open
How is cardiac output calculated?
Stroke volume X heart rate
Define cardiac output
Volume of Blood pumped by one ventricle in a min
Define stroke volume
Volume of Blood pumped by a ventricle per contraction
Give units for cardiac output
Dm3min-1
State effect of strenuous exercise on heart rate and why
Decrease
so potential for greater cardiac output
State effect of strenuous exercise on heart rate and why
Decrease
so potential for greater cardiac output
State effect of strenuous exercise on stroke volume and why
Increased
Heart muscle increases so contraction force is greater
Volume in heart increases
Name the types of blood vessels
Arteries
Arterioles
Veins
Capillaries
Name the tissues found in blood vessels
Endothelium
Smooth Muscle
Elastic fibres
Tough fiborous outer layer
Sate the function of the tough fiborous outer layer
Resist Pa changes inside and outside
What is the tough fiborous outer layer made of?
Collagen
Sate the function of Smooth muscle
Control bloid flow by narrowing lumen
Sate the function of endothelium
Reduce friction to aid blood flow
Provide SDP
Sate the function of elastic fibres
Maintain Pa
Smooth out Pa changes
Name function of arteries
Transport oxygenated blood from heart to Arterioles and Capillaries at high Pa
Describe and explain adaption of arteries
Thick muscular walls= alter flow and maintain high Pa
Thick elastic fibres= smooth out Pa changes, maintain high Pa, resist bursting
Thick wall= resist rupture
Folded endothelium= allow diameter to increase to reduce Pa
State func of Arterioles
Regulate flow of blood to capillaries (lower Pa than arteries)
Describe and explain adaptions of Arterioles
More muscle than arteries
Regulate flow of blood to capillaries by reducing diameter of lumen
Less elastic fibre = blood at lower Pa
State func of veins
Carry blood at low Pa from tissue to heart
Describe and explain adaptions of veins
Thin muscle = low blood Pa, contraction won’t alter Pa
Thin elastic fibres= Pa too low to allow recoil to change flow, won’t burst
Thin walls= allow compression by skeletal muscle to aid flow
Extended shape = no structure
Large lumen= increase blood flow (ensure same vol of blood enters heart as leaves)
Pocket valves= prevent back flow when compressed
What are venules
Blood vessels connecting capillaries to veins
Where along veins are pocket valves found?
Regular intervals
Describe the structure of valves
Flaps of tough fiborous tissue in cusp (bowl) shape
State the function of capillaries
Exchange metabolic materials with tissues
Connect arteries to veins
Describe and explain how capillaries are adapted
Only endothelial tissue = SDP
Spaces between cells= allow white blood cells to permeate
Many + branched = large SA:vol = increased rate of diffusion
Narrow diameter= compress red blood cells= SDP and slow flow of blood (more time for diffusion to occur across), allow capillaries to permeate tissue.
What is tissue fluid?
The liquid that bathes cells in tissue and is their immediate environment
Same as plasma but no plasma proteins
Why is tissue fluid necessary?
Allows constant environment
Allows all cells to get metabolic materials
Name the main stages of tissue fluid formation and where they occur
Ultrafiltration (Arterioles end of capillary)
Reabsorption (venule end of capillary)
Drainage (at lymph vessel)
Describe how tissue fluid forms
At Arteriole end of capillary:
Hydrostatic Pa of blood > hydrostatic Pa of tissue fluid = water and dissolved substances forces out (plasma proteins too large to fit through)
Osmotic Pa of plasma< osmotic Pa of tissue fluid = resistance
State the two ways tissue fluid is reabsorbed
Through capillary
Through lymph vessel and then joins blood at vena cava
Describe and explain how tissue fluid is reabsorbed into the capillaries
At the venous end the HPa of the tissue fluid is > the blood plasma so small molecules are forced in
Osmotic Pa of plasma < tissue fluid due to plasma proteins (lowering WP) to water moves into capillaries via Osmosis down water potential GRADIENT.
What the difference between lymph and tissue fluid?
Lymph has more fatty material
What the difference between plasma and tissue fluid
Plasma proteins
State the function of the xylem
Transport water and dissolved ions
Describe the structure of the xylem
Dead cells strengthened with lignin
Hollow (no organelles) with no end walls
Pits in walls
Why is the xylem Hollow and have no end walls
To aid flow (no obstruction)
Why does the xylem have Pits in its walls?
To allow lateral movement of water
Why is the xylem strengthened with lignin?
They are dead cells so have no support
Lignin prevents collapse under tension
How is lignin distributed within the xylem
In helical rings
How is the xylem adapted to allow a continuous column of water to form
No end walls
Pits in walls
No organelles
What are the main stages of the movement of water through the xylem?
Evaporation
Transpiration
Tension and cohesión
How is water uptake by the root?
Mineral ions are actively Transported into the xylem
Lowers WP causing water to move in via Osmosis
Outline the first stage of movement of water in xylem
Water evaporates from mesophyll cells due to energy of sun into air space and then diffuses out of stomata via transpiration.
This lowers the water potential of the cells neighbouring the xylem
Outline the second stage of movement of water in xylem
Water moves via Osmosis into adjacent mesophyll cells with lower WP
Cohesion of water molecules creates continuous column due to H bonds between molecules
Creates tension in xylem causing water to be drawn up via transpiration pull
Explain how water moves across the leaf
Water evaporates from mesophyll near stomata into air spaces then diffuses out via transpiration
Lowers WP of cell causing water to move from neighbouring cells, lowers WP of that cell and cycle continues.
Water moves down WP gradient
Is transpiration active or passive
Passive
No ATP
Energy of Sun
What evidence is there for the Cohesion-tension theory
Diameter of trees in small during day (more transpiration= greater tension= pull in walls of xylem)
Water does leak out of xylem (under tension)
If xylem broken transpiration stops (air bubble into xylem breaks continuous column)
Why does the flow of water in xylem increase during day
Increased light intensity=stomata open= more transpiration
Warmer = more energy for evaporation
What is used to measure the rate of transpiration and what must be assumed and why is it not always true?
Potometer
Rate of uptake = rate of transpiration
Used in reactions (hydrolysis)
Describe how to set up a potometer
Submerge shoot in water and cut end
Submerge and fill potometer
Fit shoot to potometer underwater using rubber tube
Remove potometer from water keeping capillary tube in water
Seal joints with jelly
Remove capillary tube briefly to introduce air bubble
Full reservoir and close tap
Align ruler with capillary tube
Describe how to use a potometer in an investigation into temperature and transpiration rates
Set up potometer
Place potometer into room at 10°c and record distance travelled by bubble in 2hours
Open reservoir tap to reset bubble
Place plant in hotter room and repeat
Repeat for other temperature
Define translocation
Movement of nutrients around the plant
By what mechanism does sucrose get Transported around the plant
Translocation
Describe the phloem
Living cells
Sieve tube elements and companion cells
Sieve plates and pores
Very thin walls
Few organelles and cytoplasm
Describe and explain the adaptions of companion cells
Lots of large mitochondria= aerobic Respiration= ATP for active transport
Many ribosomes=synthesis enzymes for Respiration
How is the cytoplasm of Sieve tubes and companion cells linked?
Plamsodesmata
What does plamsodesmata mean
Via cell walls
Define a source
A cells that produces excess glucose and so excess sucrose
Define a sink.
A cells that is sucrose deficient
Site of sucrose use or storage
Give examples of sources
Leaves
Give examples of sinks
Seeds
Root
Fruit
Potatoes
What is the main difference between translocation and transpiration
Translocation is bidirectional whereas transpiration is unidirectional
What is carried in the Phloem
Cells sap:sucrose and dissolved Inorganic ions (chloride, magnesium, potassium
Describe the substances uptake and released by the roots
Up taken
Oxygen
Water
Mineral ions
Released
Carbon dioxide
Water
Where are the phloem and xylem found?
In vascular bundles around the outer edges of the stem
Which is bigger, the xylem or phloem
Xylem
What is the theory of how translocation. Occurs called?
Mass flow hypothesis
What are the main stages of translocation
Movement of sucrose into phloem from source
Mass flow
Active transport of sucrose into sink from phloem
Describe how the sucrose gets from the source to the phloem
H+ ions are actively Transported out of the companion cell creating a H+ concentration gradient.
Sucrose molecules are co-transported down the H+ ion conc gradient via co transport protein into companion cell from source
Sucrose conc in cell increases
Sucrose moves via facilitated diffusion from companion cell to Sieve tube element
Describe how mass flow occurs in the Phloem
As sucrose conc increases at source the WP decreases below that of the xylem
Water moves by Osmosis down WP gradient from xylem to Sieve tube elements increasing hydrostsic Pa
Sap moves down Pa gradient towards source
Describe how sucrose is Transported into sink cells from STE
By active transport using ATP and a carrier protein
Why is the HPa of the phloem near the sink lower than at the source?
At source water moves in from xylem as sucrose is Transported into STE decreasing WP
at sink sucrose conc decreases as its actively Transported into companion and then sink cells so WP increases so water moves into xylem
What evidence supports the mass flow hypothesis
Increase in sucrose conc in leaves follows increase in phloem
Sap flows out of phloem when cut showing Pa inside
Metabolic inhibitors or lack of oxygen prevents translocation occuring
Ultrastructure of companion cells (many large mitochondria)
At night or in sahde downward flow of sap ceases
Sucrose conc in leaves > roots
Translocation occurs faster than diffusion should allow
What evidence disproves the mass flow hypothesis
Not all solutes move at the same speed
Sucrose arrives to all parts of plant at sane time despite differing needs
Sieve plates seem to obstruct flow
Name the main methods of investigating transport in plants
Ringing
Tracer
Aphids
Describe how ringing experiments work
A layer of bark is removed around the whole of a stalk to remove the phloem but leave the xylem intact
After some time the area above the ring swell and cells further down die
Explain how ringing provides evidence of the phloem being used in translocation
Analysis of fluid is swollen part shows high conc of sucrose and Amino acids (contains same as phloem)
Non-photosynthetic Cells die further down due to lack of sucrose so lack of glucose so less Respiration so less ATP synthesised so less energy available for metabolic processes
Only phloem removed so must be due to phloem
Describe and explain how aphids can be used to prove the phloem carries sucrose
Let aphid insert stylet
Anaesthetise aphid and cut off body fromm stylet leaving stylet inside phloem
Drain off phloem and analyse content
Contains high conc of Amino acids and sucrose
What can aphids be used to prove
The increase sucrose conc in leaves is followed by and increase in sucrose conc in phloem
How can Tracers be used to investigate transport in plants?
Radioactive carbon is introduced into plant
Incorporated in glucose in Respiration and then sucrose
Movement can be traced by cutting the stem above and below leaf and exposing an x-ray film to it. Darker areas show radioactivity in phloem
Can also be used to calculate rate of flow of sap in phloem.
What is autoradiography
A technique that uses X-ray film
