Organisation and Transport in Plants + Animals Flashcards
catchy
What is blood
A tissue consisting of plasma, platelets, red blood cells and white blood cells
Plasma
Yellow liquid that transports all blood cells and other substances (glucose, antibodies, hormones) around the body
e.g Carbon dioxide to the lungs, urea to the kidneys from the liver, small soluble products of digestion from the small intestine to your cells
Red blood cells
Contains haemoglobin which binds to oxygen to transport it from lungs to tissues and cells, which need it for respiration.
oxygen and haemoglobin word equation
oxygen + haemoglobin <-> oxyhaemoglobin (reversible)
White blood cells
Bigger than red blood cells, wbc are part of the body’s defence system against harmful microorganisms
● Some produce antibodies
● Some form antitoxins
● Some ingest and digest bacteria and viruses
Platelets
Small fragments of cells which recognise damaged blood vessels and trigger blood clotting to prevent too much bleeding
How are red blood cells adapted to their function
● Biconcave disc shape – increased sa:v ratio which increases diffusion of oxygen
● Very small, can fit through tiny capillaries
● No nucleus – more space for haemoglobin.
● Packed with haemoglobin
Arteries
Take blood from heart to organs
Have thick walls made from muscle and elastic fibres
Small lumen
Veins
Take blood from organs to heart
Thinner walls and valves to prevent backflow
Large lumen
Capillaries
Allow substances needed by cells to pass out of the blood
Allow substances produced by the cells to pass into the blood
Allow exchange of oxygen, co2, hormones etc
Narrow, very thin walls a single cell layer thick, narrow lumen
Diffusion distances are short
Why is a transport system needed
To circulate chemicals around the body - oxygen and glucose are needed for respiration by every cell and cells need to get rid of waste products e.g carbon dioxide and urea
Double circulation system process
Oxygenated blood is pumped by the heart to the rest of the body
Oxygen leaves the blood in the body and the blood returns to the heart
Deoxygenated blood is pumped from the heart to the lungs
At the lungs, the blood receives oxygen and is pumped back to the heart
Pacemaker cells
Regulate natural resting heart rate, found in right atrium
Coronary heart disease
Layers of fatty material build up in coronary arteries and narrow them, reducing blood flow to the heart
Reduces supply of oxygen to the heart muscle, resulting in pain, heart attacks, even death
How do stents work
Small cut in thigh, tube carrying a balloon inserted
When in place, balloon will inflate to expand the stent
Balloon deflates, stent is in place, artery is widened
Stents pros and cons
Increases blood flow
Cheap
No general anaesthetic
Patients will recover well
Will not work on very blocked arteries
How do statins work
Prescribed tablets that reduce blood cholesterol levels, thin blood
Statins pros and cons
Slows down the rate of fatty material deposit
Non invasive
No surgery risk - no concern
Have to take for life
Side effects
Patients may forget/od
How does a bypass operation work
Vein is taken from thigh and attached to the heart
Vein placed underneath the blockage, making an alternative route for blood flow
Pros and cons of bypass operation
Effective if the blockage is severe
General anaesthetic involved (risky)
Expensive
Leaky valves
Over time heart valves can become leaky or stiff, making the heart less efficient - can result in death if not treated
Mechanical valves
Made of metal - titanium (blood does not react to) and polymer
Lasts a long time in the body
Requires open heart surgery
You need to take anti-clotting drugs for the rest of your life to prevent clotting around the artificial valve
Biological valve
Comes from pig or cattle hearts and sometimes human donors
Pigs/cattle have ethical and religious issues attached
Work extremely well, no need for medication
Need to take immunosupressant
Only last 12-15 years, need replacing
Artificial pacemakers
Electrical device which corrects irregularities in the heart rate, implanted into the chest
Sends strong, regular electric signals to heart to stimulate it to beat properly
Pacemaker cells stop working
Beats too slow - cells dont get enough oxygen
Beats too fast - cannot pump blood properly
Heart failure
Donor heart can be transplanted, but requires a donor heart to be available and many die waiting
Artificial hearts
Can be used to keep patients alive while waiting for a heart transplant or to allow the heart to recover
Respiratory system what goes on
Heart sends blood to lungs via pulmonary artery
Air obtained by breathing reaches lungs through trachea
Trachea divide in two tubes - bronchi
Bronchi divide forming bronchioles, then tiny air sacs alveoli
Alveoli - site of gas exchange
Blood taken back to lungs through pulmonary vein
Alveoli
MAke gas exchnage more efficient, well adapted:
Rich supply of capillaries maintaining a concentration gradient
Close to capillaries so short diffusion distances
Spherical shape - large sa:v
Inspiration (lol)
Diaphragm contracts, moves downwards
Intercostal muscles contract, moving ribcage up and out
Vloume of the thorax is increased
Pressur in the chest decreases, is now lower than air pressure outside, so air is drawn into the lungs
Expiration
Diaphragm muscle relaxes and moves upwards
Intercostal muscles relax and ribcage falls down
Volume of thorax is decoreased
Pressur in the chest increases, is now greater than air pressure outside, so air is forced out of teh lungs
Waxy cuticle
Stops water loss due to photosynthesis
Epidermis
Covers the outer surfaces of the plant for protection
Palisade layer
COntains lots of chloroplasts for photosynthesis
Spongy mesophyll layer
Air spaces between cells allow gases to diffuse through the leaf
Xylem vessels
Transports water and minerals up through the plant, from roots to leaves
Phloem vesseks
Transports sugars made in photosynthesis from leaves through the rest of the plant
Stomata
Allow diffusion of gases in/out of the leaf, can be open and closed by guard cells.
What do leaves need to photosynthesise?
Large surface area to absorb light, many chloroplasts containing chloropyll, a supply of water and co2, a system for carrying away the products of photosynthesis to other parts of the plant
Stomata conditions
Found in lower epidermis which is shaded and cooler; open during the day when carbon dioxide is needed for photosynthesis and excess oxygen can leave. AT night, stomata closes to prevent water vapour being lost when the plant can’t photosynthesise, can also close when the plant loses more water than it can replace
Translocation
the movement of dissplved sugars from the leaves to the rest of the plant; these sugars are needed for respiration to release energy and provide materials for growth
Xylem vs phloem
Dead vs alive
Lignin vs none
No end plates vs some
Water and mineral ions vs sugars and water
Up only vs up and down
Water and mineral ions obtained
Water absorbed into roots via osmosis, carried by vascular bundle to leaves where it is used for photosynthesis
Mineral ions are obtained from the soil by plant roots via active transport and transported by xylem upwards to wherever needed
Root hair cells adaptions
Large Sa:V ratio to increase rate of osmosis
Contains lots of mitochondria which release energy to provide energy needed for active transport
Transpiration
Evaporation/loss of water in the leaves
Process of transpiration
Water diffuses out of the stomata, replaced by other water through osmosis, this has a knock on effect through whole plant therefore water constantly enters the roots and is drawn up the xylem
Rate of transpiration measure
Can be measured from a cut shoot by estimating the rate at which the shoot takes up water (only an estimate as some water is used in the leaf)
Transpiration stream
Movement of water through the plant from the roots up to the leaves - driven by loss of water vapour from the leaves
Temperature effect on transpiration
Higher temp = higher rate as more energy is transferred to the water to allow it to evaporate quicker
Air flow rate effect on transpiration
Faster air flow = higher rate as wind will blow away water vapour allowing more to evaporate, if air is still moist air stays close to stomata so the concentration gradient is low
Light effect on transpiration
Lighter = faster rate as stomata will open so more water can escape
Humidity effect on transpiration
Less humidity = faster rate as air contains less water vapour so the concentration gradient for diffusion is higher
