b2 organisation Flashcards
what are the basic building blocks of all organisms?
cells
what is a tissue?
a group of cells with a similar function and structure
what are organs?
aggregations of tissues performing specific functions
what is an organ system?
a group of organs working to create an organism
what is the digestive system?
an organ system which works to digest and absorb food
what is the role of enzymes?
to break down food into smaller, soluble molecules, which can be absorbed in the blood stream
what breaks down carbohydrates and what does it break down to?
carbohydrase breaks carbs into simple sugars.
amylase breaks down STARCH into simple sugars
what breaks down proteins and what does it break to?
protease breaks proteins into amino acids
what breaks down lipids and what does it break down to?
lipase breaks down lipids into glycerol and fatty acids
where is carbohydrase made?
salivary glands
pancreas
small intestine
where is protease made?
stomach (called pepsin there)
pancreas
small intestine
where is lipase made?
pancreas
small intestine
what are products of digestion used for?
to build new carbohydrates, proteins and lipinds. also to make glucose for respiration
what are the functions of bile?
1) it is alkaline and used to neutralise the hydrochloric acid from the stomach
2) also emulsifies fat to form droplets to increase the surface area. the alkaline conditions and large surface area increase the rate of fat breakdown by lipase
where is bile made and stored?
made: liver
stored: gall bladder
what is the heart?
an organ which pumps blood around the body in a double circulatory system
what happens in the first part of the double circulatory system?
1) the vena cava brings in the deoxygenated blood brings it to the right atrium
2) the right atrium contract to push the blood through the valve and into the right ventricle
3) where the right ventricle’s muscular walls pump to push the blood up to the pulmonary artery and into the lungs for oxygenation
what happens in the second half of the double circulatory system?
1) oxygenated blood comes into the pulmonary vein and goes into the left atrium
2) the left atrium then contracts to push the blood into the left ventricle
3) the left ventricle then contracts to push the blood up to the aorta and out of the body
why are valves essential in the heart?
they only push open in one direction to prevent backflow of blood in the heart
why does the left ventricle have a thicker wall?
to provide it with more muscle to contact more. therefore pumping the blood further. this is because the oxygenated blood has to go to the rest of the body, not just the lungs
why are the coronary arteries important?
to branch off the aorta and surround the heart to supply it with oxygenated blood for respiration and energy
how is the pulse of the heart controlled?
by a group of cells in the right atrium wall that acts as a pacemaker. these cells produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract
what is an artificial pacemaker?
it can be used to control the heartbeat when the natural pacemaker cells dont work properly.
— it is a little device thats implanted under the skin and has a wire going to the heart. ii produces an electric current to keep the heart beating regularly
what can a pacemaker fix?
1) irregular heartbeat
2) heart failure
3) syncope
what are the three types of blood vessels?
arteries
capillaries
veins
what is the function of the arteries?
to carry the blood away from the heart
features of arteries?
1) strong and elastic walls- to withstand high blood pressures
2) thick walls compared to the lumen- to withstand high blood pressures
3) contain thick layers of muscle- for strength
4) elastic fibres- so the walls can stretch and spring back
function of capillaries?
they carry the blood really close to the cells to exchange substances with them
features of capillaries?
1) permeable walls- so substances can diffuse in and out
2) walls are one cell thick- to increase the rate of diffusion by providing a short pathway
function of veins?
to take the blood back to the heart
features of veins?
1) thinner walls- there is lower blood pressure so the walls do not need to be as thick
2) bigger lumen- to help the blood flow despite the lower pressure
3) valves- to make sure the blood is flowing in the right direction
how do you calculate the rate of blood flow?
rate of blood flow= volume of blood // number of minutes
what is blood?
a tissue consisting of plasma, red blood cells, whire blood cells and platelets
function of plasma?
pale straw-coloured liquid which carries almost everything:
- CO2 from organs to lungs
- urea from liver to kidneys
- hormones
- proteins
function of red blood cells?
to carry oxygen from the lungs to all the cells of the body for respiration
adaptations of red blood cells?
1) shaped like a bioncave disk- to give a higher surface area for absorbing oxygen
2) no nucleus- to allow more room to carry oxygen
3) contain haemoglobin- to bind to oxygen and become oxyhaemoglobin. in the cells, the opposite happens
functions of white blood cells?
to defend against infection, they HAVE a nucleus
what are the white blood cells defence mechanisms?
1) phagocytosis (engulfing the unknown microorganism)
2) production of antibodies (to eliminate unknown microorganism)
3) production of antitoxins (to neutralise the microorganism)
functions of platelets?
small fragments of cells to help the blood clot at a wound. to stop blood pouring out and microorganisms from entering. they HAVE a nucleus
what causes coronary heart disease?
layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle
how can coronary heart disease be solved?
stents and statins
what are stents?
they are tubes inserted inside the arteries to widen the lumen so more blood can flow
advantages of stents?
1) lowers the risk of heart attack
2) are effective for a long time
3) recovery time from surgery is relatively quick
disadvantages of stents?
1) risk of complications during the operation
2) risk of infection from surgery
3) risk of patients developing blood clots near the stent
4) does not solve the issue of the fat build-up
what are statins?
drugs that can reduce the amount of ‘bad’ cholesterol present in the bloodstream. this slows down the rate of fatty deposits forming
what is cholesterol?
an essential lipid that the body needs to function properly. however too much of LDL cholesterol can cause fatty deposits to form inside the arteries
advantages of statins?
1) reduces the risk of strokes, coronary heart disease and heart attacks
2) can increase the amount of beneficial cholesterol in the bloodstream
3) could also help to prevent other diseases
disadvantages of statins?
1) long-term drug that must be taken regularly, so someone may forget to take them
2) negative side effects such as headaches, liver damage or memory loss
3) their effects arent instant, it takes time
what are the consequences of faulty valves?
1) backflow of blood
2) stiffening might block blood from flowing smoothly
how can faulty valves be fixed?
mechanical heart valve or biological heart valves
advantages of artificial hearts?
1) less likely to be rejected as they are made from metal so the immune system wont view it as foreign tissue
2) can get them in shorter notice
disadvantages of artificial hearts?
1) not long term
2) surgery to fit them can lead to bleeding and infection
3) dont work as well as biological ones
4) blood doesnt flow as smoothly
5) patient has to take anti-clotting drugs
what is health?
the state of physical and mental wellbeing
what can cause disease?
1) lifestyle choices
2) inherited disease
3) could be caught (if communicable)
how can different types of diseases interact?
1) defects in the immune system could lead to an increase in suffering from a communicable disease as the body is less likely to defend itself from the pathogen
2) some types of cancer can be triggered by infection by certain viruses inside the cells
3) mental health issues could be triggered by severe health problems
4) Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma
what are risk factors?
thinks that are linked to an increase in the likelihood that a person will develop a certain disease in their life
list different risk factors
1) lifestyle choices (how much exercise they do)
2) presence of certain substances in the environment (air pollution)
3) substances in your body (abestos fibres)
4) smoking or drinking
how can lifestyle factors have impacts locally, nationally and globally?
LOCALLY- non communicable diseases are more common as people with higher incomes can buy high-fat food
NATIONALLY- people from deprived areas are more likely to smoke, have a poor diet and not exercise, increasing the incidence of obesity and cardiovascular disease
what are some risk factors which is linked to the increased rate of getting a disease?
1) aspects of person’s lifestyle
2) substances in the person’s body
3) environment
specific risk factors?
1) smoking - cardiovascular disease
2) obesity - type 2 diabetes and coronary heart disease
3) alcohol - brain and liver damage
4) inhaling carcinogens - high ionising radiation and cancerous
what is cancer?
the result of a cell undergoing uncontrollable mitosis
what is a benign tumour?
a tumour which is contained within a membrane and therefore can not be spread to the rest of the body
what is a malignant tumour?
these are cancers. they travel and invade other body parts via the bloodstream where they form secondary tumours
risk factors for cancer?
smoking
obesity
uv exposure
viral infections
structure of the epidermal tissue and how its related to its function?
covered with a waxy cuticle
– prevents water loss by evaporation
structure of the upper epidermis and how its related to its function?
transparent
– light can pass through to the palisade layer
structure of the palisade layer and how its related to its function?
has lots of chloroplasts at the top
– so the chlorophyll can absorb light more so more photosynthesis occurs
structure of the phloem and xylem and how its related to its function?
form a network of vascular bundles
– which deliver water and other nutrients to the entire leaf and take away the glucose produced from photosynthesis
– also helps support the structure
structure of the tissues and how its related to its function?
– stomata on the lower epidermis
which open and close to let CO2 diffuse into the leaf
– controlled by guard cells in response to environmental conditions
– air spaces in the spongy mesophyll tissue increase the rate of gas diffusion
structure of the meristem tissue and how its related to its function?
found in the tips of the shoots and roots
– can differentiate into any plant cell
what is the function of xylem cellls?
transports water and mineral ions from the roots to the stems and leaves. It is composed of hollow tubes strengthened by lignin adapted for the transport of water in the transpiration stream
what is the function of phloem cells?
transports dissolved sugars from the leaves to the rest of the plant for immediate use or storage. The movement of food molecules through phloem tissue is called translocation.
It is composed of tubes of elongated cells. Cell sap can move from one phloem cell to the next through pores in the end walls
