B4-Organising Animals and Plants Flashcards
what does phloem transport
Phloem transports dissolved sugars to storage organs, where it provides an energy store for the winter
define translocation
Translocation = movement of dissolved sugars from leaves to the rest of the plant
what do Aphids feed from
Aphids feed from phloem and suck its sugary fluids out
what does Xylem transport
Xylem tissue transports water and mineral ions
what are mineral ions used for
Mineral ions are used for the production of proteins and other molecules within cells
what are the guard cells
Guard cells = cells on either side of the stomata (holes on the underside of a leaf), that opens and closes the stomata by changing its shape
what is transpiration
Transpiration = when water vapour diffuses out of the air spaces in the leaf, through the stomata into the atmosphere
what is the transpiration stream
Transpiration stream = the constant movement of water being pulled up through the xylem to replace the water vapour lost
why does transpiration occur
Transpiration occurs due to the evaporation of water in the leaves, SO the factors that affect evaporation are also going to affect transpiration
what does the blood do
Blood is a connective tissue that transports substances around the body
why is blood needed to transport substances around the body
Organisms that have a small SA:V require specialised transport systems
what is blood based on
Blood is based on a yellow liquid called plasma
what is the average amount of blood
An average person has 4.7-5L of blood
what does blood transport
It transports cells and:
Waste CO2 produced by cells to lungs
Urea formed in the liver from the breakdown of excess protein and is taken to the kidney to form urine
Small soluble products of digestion to cells that need it (glucose, amino acids)
what are adaptations of red blood cells
Adaptations of red blood cells:
No nucleus - more space for more haemoglobin to carry more oxygen
Red pigment called haemoglobin which binds to oxygen in a reversible reaction
Biconcave disc - increased SA:V ratio for a higher rate of diffusion
what are phagocytes
Phagocytes = engulf and digest invading bacteria and viruses
what is blood clotting
Blood clotting = a series of enzyme controlled reactions in converting fibrinogen into fibrin (the thing that is used in blood clots
what size are capillaries
Capillaries are the smallest and thinnest blood vessel
what do arteries do
Arteries carry oxygenated blood AWAY from the heart TO the body cells
why do arteries pulse
Arteries pulse as they carry high pressure blood, so whenever the heart pumps, the artery stretches as the blood goes through, and then returns to its normal shape
how can arteries stretch
Arteries have elastic tissue in their walls which allow them to stretch and then return to their shape
what do veins do
Veins carry deoxygenated blood IN to the heart
what do veins have
Veins have valves
what do valves do
Valves prevent backflow of blood
how is blood squeezed back to the heart
Blood is squeezed back to the heart by skeletal muscles
what kind of lumen do veins hav000e compared to arteries
Veins have a larger lumen, and arteries have a more narrow lumen (as they carry higher pressure blood)
where does the blood enter the heart from
Blood enters the heart through the veins into the atria (pl. atrium = singular)
what is the sound of the heartbeat
Sound of heartbeat = sound of the valves closing
Why is the muscle of the LEFT ventricle a lot thicker than the muscle of the right?
The left ventricle is pushing blood through the aorta to the entire rest of the body, whilst the right ventricle is only pushing blood to the lungs. So, the left ventricle needs to push with a lot more force and pressure, so it needs a lot more muscle.
what is coronary heart disease
Coronary Heart Disease = when coronary arteries that supply blood to heart become narrower
what are coronary arteries
Coronary arteries = blood vessels that take blood to the heart muscle to give it oxygen, glucose etc
what is a common cause of CHD
Common cause: fatty material building up on the lining of vessels
what is a stent
Stent = a metal mesh tube placed in the artery
balloon is inflated –> the stent widens with the balloon –> balloon is deflated and removed –> stent holds the blood vessel open –> blood flows freely
how can blood clot travel
A blood clot can travel in the bloodstream and block a narrower artery down the path, or travel to the brain and cause damage
what is the method when stents arent effective
For badly blocked arteries that stents cannot open, doctors can do bypass surgery
what is bypass surgery
Bypass surgery = take veins from other parts of the body and replace the narrow or blocked coronary artery
what type of disease is coronary heart disease
- Coronary heart disease is a type of cardiovascular disease
what are statins
Stains reduce the rate at which fat builds up in coronary arteries
what happens if heart valves start to become stiff and what can they be replaced by
If the heart valves start to become stiff, and don’t open up properly, the person can become breathless, and eventually die –> not enough blood (oxygen) reaching the cells
These can be replaced with mechanical valves made of titanium and polymers –> lasts a very long time
1 disadvantage of mechanical valves
you need to take medication for the rest of your life to stop the blood from clotting around it
what is an alternative instead of biological valves
Biological valves - taken from cows or pigs - very good and don’t require meds, BUT they only 12-15 years
what is the resting rate of the heart
Resting rhythm of a healthy heart is 70bpm - this is controlled by a natural pacemaker
what happens when the pacemaker is faulty and how can it be solved
If the pacemaker doesn’t work properly, are heart rhythm can be:
too slow –> person won’t get enough oxygen
too fast –> blood won’t pump properly
This problem can be solved with artificial pacemakers –> an electrical device planted in the chest to correct irregularities of the heart rate
what happens when the heart fails
When the heart fails, a donor heart or heart lungs must be transplanted
where are lungs located?
The lungs are located in the ribcage in the thoracic cavity
(chest = thorax, cavity = space)
what are the three muscles involved in breathing
Three muscles involved in breathing: diaphragm, internal intercostal and external intercostal muscles
what is the corelation between pressure and volume
As volume increases pressure decreases - they are indirectly proportional
how does the process of breathing occur
To breathe in:
1.Diaphragm contracts (it flattens)
2. internal intercostal muscles contract - pulls the ribcage up and out
3. external intercostal muscles relax
Diaphragm flattening, and internal intercostal muscles pulling the ribcage up and out, BOTH increases the volume in the thoracic cavity
how is the sucking effect formed in the lungs?
As volume increases, pressure decreases
Pressure in the thoracic cavity decreases below atmospheric pressure
This creates a sucking effect (air moves from high pressure to low)
This is how you breathe in.
what does epidermal tissue do
Epidermal tissue = covers the surfaces and protects them
what does the upper epidermis do
The epidermis at the top of the leaf (upper epidermis) secretes a waxy substance that forms a waterproof surface of the leaf
what does the palisade mesophyll layer contain
Palisade mesophyll tissue = has palisade cells which contain lots of chloroplasts and carry out photosynthesis (palisade cells are the cells you draw when asked to draw a ‘plant cell’)
what does the spongy mesophyll layer have
Spongy mesophyll tissue has some chloroplasts, big air spaces and a large surface area to make diffusion of gases easier (think of it as it is has lots of air spaces which makes this layer spongy)
where are xylem and phloem found
Xylem and phloem, found in a vascular bundle
what is in the lower epidermis
Where the stomata and guard cells are found
