Organisation Flashcards
what is a tissue
a group of specialised cells with a similar structure and function and can be made of more than one type of cell
what are organs
a number of different tissues working together to produce a specific function
what are organ systems
organs that work together to perform a certain function
why do we need the digestive system
food is large and insoluble and needs to be broken down in order for it to be in a form that can be absorbed by cells
what is the digestive system made up of
salivary glands
stomach
pancreas
small intestine
liver
gall bladder
large intestine
rectum
anus
what do salivary glands and the pancreas do?
produce digestive juices containing enzymes that break down food
what does the stomach do
produces hydrochloric acid to kill bacteria and provide the optimum ph for the protease enzymes to work
what does the small intestine do?
where soluble molecules are absorbed into the blood
what does the liver do
produces bile which helps with digestion of lipids
what does the gallbladder do
stores bile
what does the large intestine do
absorbs water from undigested food to produce faeces
how do faeces pass out of the body
rectum and anus
what are enzymes
biological catalysts (that increase the rate of reaction without being used up)
what can enzymes do
present in so many reactions that they can be controlled
can break up large molecules and join small ones
protein molecules and have a special shape
what is the lock and key hypothesis
shape of substrate complimentary to active site
binds to form an enzyme substrate complex
once bound a reaction takes place and products are released from the surface of the enzyme
what do enzymes require to work
an optimum ph and temperature because they are proteins
what is the optimum temperature for enzymes
37 degrees (body temp)
how does rate of reaction in enzymes change with temperature
increases up to the optimum
after this temperature rapidly decreases until reaction stops
when temp is too hot the bonds in the structure break
this changes the shape of the active site so the substrate can’t fit
the enzyme is now denatured
what is the optimum ph for enzymes
7
some produced in acidic conditions have a low optimum ph
how do enzymes work dependent on ph
if ph is too high or low the forces that hold amino acid chains that make up the protein are affected
this changes the shape of the active site so the substrate can’t fit
the enzyme is denatured and cannot work
what do carbohydrases do
convert carbohydrates into simple sugars
eg amylase breas down starch into maltose
where are carbohydrases found
produced in salivary glands , pancreas and small intestine
what do proteases do
convert proteins into amino acids
eg pepsin
where are proteases found
produced in stomach, pancreas and small intestine
what do lipases do
convert lipids into fatty acids and glycerol
where are lipases found
produced in pancreas and small intestine
how do enzymes build new carbohydrates , lipids and proteins and sometimes glucose use in respiration
soluble glucose, amino acids, fatty acids and glycerol pass into the bloodstream ro be carried to all the cells around the body
which tests can be used to determine whether a solution is a sugar and which colour does it turn
benedict’s
turns brick red
which test identifies starch and which colour does it turn
iodine
blue/black
which test identifie protein and which colour does it turn
biuret
turns purple
which tests cna be used to identify lipids and how can it be identified
emulsion test - add ethanol and cloudy layer appears if a lipid is present
sudan III test - red layer forms on top
where is bile produced, stored and released into
produced in the liver
stored in the gallbladder
released into the small intestine
what are the two roles of bile
alkaline - neutralises hcl from stomach, enzymes in small intestine have a higher optimum ph than those in the stomach
emulsifies fat- larger sa allows lipase to chemically break down the lipid into glycerol and fatty acids faster
what does the circulatory system do?
carries oxygen and nutrients to every cell in the body and removes the waste products
which system does the heart pump blood in
a double circulatory system
what are the two circuits of the double circulatory system
deoxygenated blood flows into the right atrium then right ventricle which pumps it into the lungs to undergo gaseous exchange
oxygenated blood flow into the left atrium then left ventricle which pumps oxygenated blood around the body
what is the role of the muscular walls of the heart
provide a strong heartbeat
why is the muscular wall of the left ventricle thicker
blood needs to be pumped all around the body rather than to just the lungs
what is the role of the 4 chambers in the heart
separate oxygenated blood from deoxygenated blood
what is the role of the valves in the heart
make sure blood does not flow backwards
what is the role of the coronary arteries in the heart
cover the heart to provide its own oxygenated blood supply
what is the process of the heart
blood flows into right atrium through vena cava, left atrium through pulmonary vein
left and right atrium contract forcing blood into the ventricles
ventricles contract pushing blood from right v into pulmonary artery and blood from left v to the aorta
as this happens valves close to make sure blood does not flow backwards
what is the natural resting heart rate controlled by
cells in the right atrium that act as a pacemaker and provide stimulation through small electrical impulses that pass as a wave across the heart muscle causing it to contract
when is an artificial pacemaker used
if someone has an irregular heartbeat, an electrical device that produces a signal causing the heart to beat at a normal speed
what do arteries do
carry blood away from the heart
layers of muscle in the walls make them strong
elastic fibres allow them to stretch
this helps the vessels withstand the high pressure of the pumping of the heart
what do veins do
carry blood towards the heart
the lumen is wide to allow the low pressure blood to flow through
have valves to ensure the blood flows in the right direction
what do capillaries do
allow blood to flow very close to cells to enable substances to move between them
one cell thick walls to create a short diffusion pathway
permeable walls so substances can move across them
how is rate of blood flow calculated
volume of blood/number of minutes
where are the lungs found
in the thorax protected by rib cage
what do the lungs do?
supply oxygen to blood and remove carbon dioxide
what are the parts of the gas exchange system
trachea
intercostal muscles
bronchi
bronchioles
alveoli
diaphragm
what is the role of the trachea
windpipe, air moves through there
what is the role of the intercostal muscles
contract and relax to ventilate the lungs
what is the role of the bronchi
air from the trachea move into these , lead to each lung