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B2 - Organisation - Part 2 - Coggle Diagram
B2 - Organisation - Part 2
L12 - Cardiovascular Diseases
Faulty heart valves
cause some valves to
not fully open
; the heart
has to beat faster to equilibrize the slower rate of blood flow.
This means the heart is
less efficient
and this condition may cause
tiredness
,
nausea
, breathlessness and difficulty exercising.
Faulty heart valves can be replaced with an artificial or mechanical variation of a valve. A biological valve is often taken from a mammal such as a pig, these valves cannot last as long as mechanical valves (8 - 10 years). No anti-clotting drugs are required for this valve type.
-
Mechanical valves can last a longer amount of time (>20 years). They will not get rejected by the body but they will produce a clicking sound and may damage red blood cells or cause clotting so anticlotting drugs must be taken.
An
artificial heart
can be given to a patient that is
awaiting a heart transplant
, these artificial hearts are only a
temporary solution.
-
Issues with heart transplants:
major surgery,
anti-rejection drugs (
immunosuperessants
) must be taken,
shortage of donors.
An
artificial pacemaker
regulates
the
'beating' of the heart
via electrical impulses.
Major surgery is not required
for an artificial pacemaker to be given to a patient; this pacemaker
may need to be replaced
after a period of time however and there is a
risk of the body rejecting the device.
L13 - Lifestyle Factors
A diet that is high in salt can increase blood pressure; increasing the risk of developing cardiovascular diseases. Smoking can also increase the likelihood of cardiovascular diseases being developed. One disease that has an increased likelihood of being developed due to smoking is emphysema.
Carcinogens are substances that increase the risk of cancer developing due to expose or ingestion of the substance.
People infected with type two diabetes struggle to maintain a suitable level of glucose within the blood.
A correlation is a pattern within data, a correlation between the likelihood of developing a disease and a lifestyle factor does not necessarily mean that one factor causes the other. A causal mechanism does however, the causal mechanism of a disease is a factor that directly results in the disease being caused or developing.
L14 - Cancer
Cancer is the result of uncontrolled cell division (mitosis) and growth. Cancerous tissue is known as a tumour.
A benign tumour is a tumour constructed of cancerous cells that will not spread to or invade other bodily tissue. They are contained in one area. Benign tumours divide slowly so they can simply be cut off/ removed. A wart is an example of a benign tumour.
A malignant tumour is a tumour constructed of cancerous cells that are likely to invade/attack other cells or tissue. They spread to other parts of the body when some of the cancerous cells break off and travel to the other parts of the body through the lymph stream or blood stream; at which point secondary tumours are formed.
Some causes of cancer include:
Viruses
Smoking
Lifestyle choices
Carcinogens
Ionising radiation
L15 - Plant Tissue
Examples of plant tissue include:
Epidermal tissue
Palisade mesophyll
Spongy mesophyll
Xylem
Phloem
Meristem (tips of roots and shoots)
The function of the epidermal tissue is to allow light to pass through the upper epidermis through to the palisade cells. The lower epidermis is covered in stomata which are responsible for the exit and entry(diffusion) of gasses into the leaf.
The palisade mesophyll contains a large amount of chloroplasts which are required to carry out the function of the palisade cells (photosynthesis).
The spongy mesophyll contain large spaces between their cells, this allows for the diffusion of gasses into and out of the leaf.
Stomata open and close (due to expansion of the guard cells) to let gasses enter and leave the plant; they are concentrated on the bottom of the leaf to reduce water loss through them.
L16 - Transpiration and Translocation
Transpiration is the movement of water towards a leaf via the xylem. The water is extracted from the soil by the plant through osmosis; it then travels through the vascular bundle (the xylem) towards the leaf at which point the water evaporates and leaves the leaf through the stomata. This water is important because its evaporation cools the leaf. The water also carries dissolved mineral ions throughout the plant; makes cells turgid and is used as a reactant in photosynthesis.
Translocation is the movement of dissolved sugars from the leaf to the rest of the plant through the phloem tissue; these sugars are then used immediately or are stored by the plant. The phloem is adapted for translocation because of its wall, the phloem walls allow for the movement of sap through them.
Stomatal Density = Number of Stomata / Area of Sample
L17 - Rate of Transpiration
Several factors increase the rate of transpiration:
High temprature
Low humidity
High air movement
High light intensity
Anything that will increase the rate of photosynthesis will increase the rate of transpiration (more carbon dioxide in = stomata open more = more/faster water loss)
Water vapour difuses more easily into dry air as the concentration gradient is steeper.
A higher wind intensity results in water vapour being removed from the leaf much more quickly.
Plants can alleviate the rate of water loss via a waxy cuticle or by concentrating stomata on the underside of the leaves(unaffected by environmental factors).