2h - Transport Flashcards
How do unicellular organisms get their supply of oxygen and nutrients?
By diffusion through the membrane of their cell.
Because they are so small and have a large SA/vol ratio
How do bigger organisms get their supply of oxygen and nutrients to their cells?
They have to develop a system to deliver oxygen and nutrients to all cells quickly.
(small SA/vol ratio)
What does the phloem transport?
Sucrose and amino acids
What does the xylem transport?
Water and dissolved minerals
What is the phloem made of?
Sieve plates which have holes in the end of cell walls to allow an easy flow of substances
What is the xylem made of?
No cell wall at the end of the cells so forms continuous tubes
In which directions does phloem deliver sucrose and amino acids?
Two direction,
Up + down
In which direction does xylem deliver water and dissolved minerals?
One way only
Up ^
What does the xylem offer alongside transportation?
Supports the plant
What is the percentage of plasma in the blood?
55%
What is the percentage of all blood cells in the blood?
45%
Aside from transportation, what is another function of plasma?
Maintaining body temperature
What does plasma transport?
- Digested food to cells (for respiration or assimilation)
- Urea to the kidney (excreted as urine)
- Hormones (stimulate changes in body conditions)
- Waste CO2 (from respiring cells to the lungs for exhalation)
How can the shape of a red blood cell be described?
Biconcave
What is an advantage of the ‘biconcave’ shape of a red blood cell?
Large SA/ vol ratio for the most efficient rate of diffusion of oxygen
Why are red blood cells small and flexible?
So they can squeeze through narrow blood vessels and capillaries
What is the main function of a red blood cell?
Carry oxygen around the body
What are the two types of white blood cells?
- Lymphocytes
- Phagocytes
How do lymphocytes destroy bacteria?
Produces antibodies which attach to the antigens of a bacteria. This causes the bacteria to burst or stick together for phagocytes to detect them easily.
What is the function of a memory cell?
It remembers the antibodies for each type of pathogen
How do phagocytes destroy pathogens?
1) Directly engulfs pathogen
- -> Drawing them into the cytoplasm
2) The phagocyte then kills and digests the pathogen with its enzymes
Which side of the heart receives deoxygenated blood?
Right side
Where is deoxygenated blood pumped?
The lungs
Where is oxygenated blood pumped?
The body
What is the function of valves?
They prevent backflow of the blood
Why does the left ventricle have a thicker muscle wall than the right ventricle?
Because it pumps oxygenated blood which requires more pressure to pump around the body
What is the name of the vein which transports deoxygenated blood to the heart?
Vena cava
What is the name of the vein which transports oxygenated blood to the heart?
Pulmonary vein
What is the name of the vein which transports oxygenated blood away from the heart?
Aorta
What is the name of the artery which transports deoxygenated blood away from the heart?
Pulmonary artery
Why does the heart rate increase during exercise?
Muscle cells need more energy since they are contracting more, which makes the heart rate increase as the cells require more oxygen. (Meaning the heart has to pump more blood around the body faster)
Why does it take a couple minutes for the heart rate to restore after exercise?
Because it needs to repay the oxygen debt if anaerobic respiration took place
What happens when Adrenaline is secreted into the blood?
It causes the heart rate and stroke volume to increase and take blood away from non-essential areas.
Why is Adrenaline secreted?
When afraid, stressed or angry.
What happens when plaques block the coronary arteries?
No oxygen will be delivered and will cause a heart attack
What is the name given to the disease when plaque blocks coronary arteries?
Coronary heart disease
Which blood vessels carry blood away from the heart?
Arteries
Which blood vessels carry blood to the heart?
Veins
Which blood vessels have valves?
Veins
Normally arteries do not have valves, but which two arteries do have valves?
Aorta
Pulmonary artery
Why do arteries have thick walls?
Because they carry blood away from the heart under high pressure and speed.
How thick are capillaries?
One cell thick
Why are capillaries so thin?
So substances can diffuse across the capillary wall
Where are capillaries found?
Every tissue in the body
Why do arteries have elastic fibres in their walls?
So they can expand and recoil under high pressure
What are the names of the blood vessels which carry blood towards and away from the ‘Kidney’?
Towards –> Renal artery
Away –> Renal vein
What are the names of the blood vessels which carry blood towards and away from the ‘Lung’?
Towards –> Pulmonary artery
Away –> Pulmonary vein
What are the names of the blood vessels which carry blood towards and away from the ‘Liver’?
Towards –> Hepatic artery
Away –> Hepatic vein
What are the names of the blood vessels which carry blood towards and away from the ‘Heart’?
Towards –> Vena cava
Away –> Aorta
