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