Organisation Flashcards
give the definition for tissue
a group of similar cells working together to carry out a particular function
give the definition for organs
a group of tissues working together to perform a specific function
give the definition for an organ system
a group of organs that work together to form whole organisms
what is an enzyme
a biological catalyst
- *something that speeds up the rate of reaction without being changed or used up in the reaction
what is the lock and key method?
every enzyme has a substrate that fits perfectly with it
- once the enzyme is in place, the enzyme and substrate bind together to form a substrate-enzyme complex; the reaction takes place rapidly; the products are released from the surface of the enzyme; enzyme is free to use again
what are the three digestive enzymes?
carbohydrase enzymes, protease enzymes, lipase enzymes
what is an example of a carbohydrase enzyme?
amylase
what does a carbohydrase enzyme break down?
carbohydrates (starch)
what does starch break down into?
simple sugars
where is amylase found?
salivary glands, small intestine, pancreas
what do protease enzymes break down?
proteins
what do proteins break down into?
amino acids
where is protease found?
stomach, small intestine, pancreas
what do lipase enzymes break down?
lipids
what do lipids break down into?
glycerol and fatty acids
where is lipase found?
small intestine, pancreas
what are the two roles of bile?
NEUTRALISES the stomach’s ph 2 into a ph 7.5 ready for enzymes made in the pancreas and small intestine
EMULSIFIES large molecules of lipids into smaller pieces of lipids (droplets) so the enzymes have a larger surface area to work with
how is the small intestine adapted to gas exchange? (4)
- covered in millions and millions of villi which increase the surface area
- villi covered in microvilli which further increases the surface area
- villi has a network of capillaries = good blood supply
- villi have a thin membrane = ensures a shorter diffusion path
what is the route the blood takes through the heart? (6)
- de-oxygenated blood comes back to the heart through the vena cava
- passes through the right atrium, through the tricuspid valve and into the right ventricle
- leaves the heart through the pulmonary artery to go to the lungs
- oxygenated blood returns to the heart through the pulmonary vein
- passes through the left atrium, through the bicuspid valve and into the left ventricle
- leaves the heart through the aorta to be taken to the body cells
repeats
what is the purpose of the coronary arteries?
- to provide oxygen to the muscle cells of the heart
how is resting heart rate naturally controlled?
a group of cells in the wall of the right atrium that act as a pacemaker, they send electrical impulses to the muscle cells of the heart so that it contracts
what is an artificial pacemaker?
can be inserted beneath the skin and has a wire leading to the heart that sends the electrical impulses to the muscle cells
in what case would an artificial pacemaker be needed?
if the group of cells in the atrium aren’t working and someone has an irregular heartbeat
what are the features of an artery? (3)
- thick walls to support the high pressure blood
- small lumen
- thick layer of elastic fibres that expand and spring back into place when there’s surges of blood
what are the features of a vein? (3)
- relatively thin walls because the blood is only at low pressure
- large lumen
- valves to stop back flow of blood
what are the features of a capillary? (3)
- walls one-cell thick to allow for a faster rate of the diffusion of gases
- walls are permeable
- narrow lumen
how are red blood cells adapted for carrying oxygen? (3)
- biconcave shape gives it a larger surface area to speed up the diffusion of oxygen into it
- no nucleus gives it more space for the oxygen to fill
- contains haemoglobin which binds to oxygen to create oxy-haemoglobin that can then be carried to the body tissues
what is plasma? (4)
- 90% water
- carries virtually everything in the body
- carries waste products like urea + carbon dioxide
- can be separated from the other components of blood using a centrifuge
what are platelets?
tiny fragments of cells that help blood to clot in the face of an injury
what are white blood cells? (2)
- fight infection by creating antibodies
- contain a nucleus with dna that codes the instructions the white blood cells need to do their jobs
what is chd?
coronary heart disease
where the coronary arteries that supply blood to the muscles of the heart get blocked by layers of fatty material
how can chd cause a heart attack?
blocking the coronary arteries means reducing the flow of blood through them which results in a lack of oxygen for the heart muscle
this results in a heart attack, where the heart is starved of oxygen
how can stents be used to help chd?
stents can be inserted into a coronary artery to stretch it open and restore and maintain blood flow
how can statins help with chd?
statins are drugs that help to lower the cholesterol by lowering its production in the liver
the ‘bad’ cholesterol in the blood is what makes the fatty material that causes coronary heart disease
what are the advantages (3) and disadvantages (3) of using stents?
ADVANTAGES
- recovery after surgery is usually quick; lower the risk of a heart attack; effective for a long time
DISADVANTAGES
- risk of complications during the operation; risk of infection from the surgery; thrombosis (a blood clot around the stent)
what are the advantages (3) and disadvantages (2) of using statins?
ADVANTAGES
- reduces chances of a stroke, chd, and heart attacks; increase ‘beneficial’ cholesterol; may prevent other diseases
DISADVANTAGES
- have to take the drugs regularly and so the body can start to rely on them; effect isn’t immediate
what are the two types of artificial valve?
mechanical valve
biological valve
why might an artificial heart be better than a donor heart?
an artificial heart is less likely to be rejected by the patient because it’s made from metal/plastic that the body won’t see as foreign and attack it in the same way it would with living tissues in a donor heart
why might an artificial heart be worse than a donor heart? (4)
- surgery to fit it can lead to bleeding and/or infection
- parts of the heart could wear out or the electrical motor could fail
- blood doesn’t flow as smoothly, possibly causing blood clots
- patients have to take drugs to ensure this won’t happen, which can cause problems with bleeding if they’re hurt
how are the lungs adapted for gas exchange? (3)
- millions of alveoli give them a large surface area
- alveoli have thin walls to shorten the path for diffusion
- alveoli surrounded with capillaries which means they have a good blood supply
what produces a tumour?
uncontrolled cell division and mitosis
what are the two types of tumour?
benign
malignant
what is a benign tumour? (3)
- growths of abnormal cells which are found in one area
- contained within a cell membrane
- benign cells do not invade other parts of the body
what does a malignant tumour do? (3)
- cells invade neighbouring tissues
- cells move into the bloodstream
- cells are transported through the bloodstream and invade other healthy tissues in the body
what do malignant tumours form?
secondary tumours
examples of cancers that link to lifestyle: (4)
smoking: lung cancer
obesity: bowel, liver, and kidney cancer
uv exposure: skin cancer
viral infection: liver cancer
how are communicable diseases spread?
pathogens
what are the different types of pathogens? (4)
- bacteria
- viruses
- fungi
- protists
what are the three ways a pathogen is spread?
- Air
- Water
- Direct Contact
how do bacteria make us ill?
they produce toxins that damage our cells and tissues
how do viruses make us ill?
they invade a host cell and reproduce inside of it; continues to reproduce until the cell bursts, damaging that cell and releasing all the new viruses
how are viruses different to bacteria?
viruses need a host cell to reproduce in whereas bacteria can reproduce on their own
what causes cardiovascular disease?
what type of people is cardiovascular disease increased an decreased in?
- a high in fat and low in vegetables diet increases certain types of cholesterol in the blood which increases the amount of fatty material in the arteries
- increased in people who smoke
- decreased in people who exercise
who is more likely to develop type 2 diabetes? (2)
- people with obesity
- drinking excess alcohol can lead to obesity which, again, increases the risk of developing type 2 diabetes
