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
what is the role of bronchioles
bronchi split into these and air moves in
what is the role of alveoli
bronchioles lead to the alveoli
air sacs where gaseous exchange occurs
what is the role of the diaphragm
separates the lungs from digestive organs
moves down casing inhalation
how does ventilation work
rib cage moves up and out and diaphragm moves down causing the volume of the chest to increase
increased volume results in low pressure
air is drawn into the chest as air moves from areas of high pressure (environment) to low pressure (lungs)
the opposite happens when enhaling
how does gas exchange work
upon inhalation, alveoli fill with oxygen
blood in capillaries surrounding alveoli is deoxygenated (comes from pulmonary vein) , has lots of carbon dioxide as it is a product of respiration
oxygen diffuses down its concentration gradient into the capillary bloodstream, which has a low concentration of oxygen
carbon dioxide diffuses down its concentration gradient from the blood to the alveoli
how are alveoli adapted for gas exchange
very small and arranged in clusters creating a large surface area for diffusion to take place
capillaries provide a large blood supply maintaining the concentration gradient
walls of alveoli are thin meaning there is a short diffusion pathway
how can you calculate breathing rate
number of breaths/ number of minutes
what is plasma
liquid that carries components in the blood such as
red blood cells, white blood cells, platelets, glucose, amino acids, carbon dioxide, urea, hormones, proteins, antibodies, antitoxins
what are red blood cells
carry oxygen molecules from lungs to body cells
bioconcave disc shape provides a large surface area
no nucleus allowing room for oxygen
contain red pigment haemoglobin which binds to oxygen and forms oxyhemoglobin
what are white blood cells
part of the immune system (bodys defence against pathogens)
have a nucleus
have types that=
produce antibodies
engulf and digest pathogens
produce antitoxins to neutralise toxins
what are platelets
help the blood clot form at the site of a wound
the clot dries and hardens to form a scab which allows new skin to grow underneath without microorganisms entering
small fragments of cells
no nucleus
without them ,cuts would result in excessive bleeding and bruising
when does coronary heart disease occur
when the coronary arteries that provide blood to the heart become blocked with a build up of fatty material , resulting in less blood flowing to the heart, reducing its oxygen supply and possibly leading to a heart attack
what do stents do for coronary heart disease
keep the arteries open to allow blood to flow through
what are stents
metal tubes inserted in arteries
what are the advantages of stents
effective in lowering risk of a heart attack
recovery time from surgery is quick
what are the disadvantages of stents
risk of a heart attack during the procedure or an infection following it
a change that blood clots can form near the stent called thrombosis
how do statins help coronary heart disease
decrease levels of ldl cholesterol which would lead to coronary heart disease
what are the advantages of statins
reduce the risk of strokes, coronary heart disease and heart attacks
increase the levels of hdl cholesterol
what are the disadvantages of statins
need to be taken continuously which may be inconvenient
can produce side effects
may not have an immediate effect as it only slows down the rate it is deposited
what is a faulty valve
when a heart valve becomes stiff so cannot open or it is damages so it leaks, blood flows in the wrong direction meaning the heart does not work as efficiently as it should
what are the solutions to fixing faulty valves
replacing with a biological valve (pigs or cattle)
replacing with a mechanical valve (man made)
what is an advantage of replacing faulty heart valve with biological valves
works very well
what is a disadvantage of biological valves
only last 12-15 years
what is an advantage of man made valves
lasts for a long time
what is a disadvantage of man made valves
constant medication is needed to stop blood from clotting around the valve
how can heart failure be solved
with a transplant
what does a heart transplant need
a donor who has recently died
not always available so an artificial one must be used whilst waiting
what are the advantages of man made heart transplants
less likely to be rejected by the immune system - metal and plastic are not recognised as foregin
what are the disadvantages of man made heart transplants
surgery temporarily leaves the body exposed to infection
as it is mechanical , parts could wear out and the motor could fail
blood clots could form leading to strokes
drugs are taken to prevent the above which thin the patients blood
what can extreme blood loss be solved by
giving artificial blood
what is artificial blood
a salt solution that can keep people alive even if they lose 2/3 of their red blood cells
what is the advantage of artificial blood
it means the patient has more time to produce new blood cells
what is the disadvantage of artificial blood
can only be used for short periods of time, then a blood transfusion has to take place
what is health
a state of physical, mental, social wellbeing
what is a communicable disease
infectious diseases caused by pathogens and are passed on from one person to another
what is a non communicable disease
not passed on from person to person
what happens if an immune system of an individual is poor
they are more likely to become infected with a communicable diseases as the body is less able to fight off pathogens.
how can viruses cause cancers
infections by viruses in certain parts of the body can trigger the growth of cancer
how does diet affect health
eating too much or too little and not enough nutrients prevents a balanced diet which can effect mental and physical health
how can stress affect health
physical and mental stress puts strain on it bodies which can lead to heart disease, cancers and mental illnesses
how can life situations effect health
where you live, financial status , ethnic group, access to medical care and levels of hygiene can lead to communicable diseases or non communicable diseases
what is the casual mechanism for cardiovascular disease
diet containing lots of ldl cholesterol results in blocked arteries , increasing blood pressure
smoking damages the walls of arteries
exercise lowers blood pressure, reducing strain on the heart
what is the casual mechanism for type 2 diabetes
obesity affects the body’s metabolism - fat molecules are released into the blood which can effect the cells uptake of sugar
what is the casual mechanism for liver and brain function
alcohol causes fatty liver which can lead to liver failure
alcohol can damage nerve cells in the brain
what is the casual mechanism for lung disease and lung cancer
smoking damages the cells in the lining of the lungs
what is the casual mechanism for pregnancy
smoking and alcohol can cause damaging effects on the unborn child
what is the casual mechanism for cancer
carcinogens such as ionising radiation can lead to cancers
what is cancer
the result of changes in cells that lead to uncontrollable growth and division, causing a tumour
what is a benign tumour
growth of cells contained in one place, usually a membrane
not cancerous
it grows until there is no more room
it does not invade other tissues
if it causes pressure or damage to an organ it can be dangerous
what is a malignant tumour
tumour that grows and spreads to other tissues
cancerous
the tumour may split up, resulting in cells being carried in the bloodstream or lymphatic system
they can travel to and stay in another organ potentially causing secondary tumour
the cancer cells divide more rapidly and have a longer lifespan in comparison to normal cells
what are the lifestyle risks for cancer
smoking
obesity
uv light
viral infection
what are the genetic risks for cancer
you can inherit certain genes that increase likelihood of getting cancer
where is epidermal tissue found
covering the whole plant
what are the features of epidermal tissue
covered with a waxy cuticle
what is the function of epidermal tissue
helps to reduce water loss by evaporation , as the waxy cuticle prevents water from moving out
where is the palisade mesophyll tissue found
underneath the epidermal tissue
what are the features of palisade mesophyll tissue
has lots of chloroplasts
what is the function of palisade mesophyll tissue
having many chloroplasts means photosynthesis can happen rapidly
positioned at top of leaf so receive lots of light
where is spongy mesophyll tissue found
underneath the palisade mesophyll
what are the features of spongy mesophyll tissue
lots of air spaces
what is the function of palisade mesophyll tissue
allows gases to diffuse in and out of cells
where is the xylem found
roots, stems , leaves
what are the features of the xylem
made of dead cells joined together creating a continuous tube
strengthened with lignin but this has some holes in it along the tube called bordered pits
what is the function of xylem cells
allows movement of water, mineral ions from roots to stem and leaves where it evaporated (transpiration system)
lignin makes it strong and waterproof so water will not leave except and bordered pits, allowing minerals to go to specific places in the plant
where is phloem found
roots, stems , leaves
what are the features of phloem
elongated cells with hols in cell walls (end walls called sieve plates)
many organelles from cells are removed so cell sap can move through
what is the function of phloem
food substances can be moved in both directions , from the leaves where they are made or from storage to parts of the plant that need it (translocation
where is meristematic tissue found
the tips of shoots and roots
what are the features of meristematic tissue
able to differentiate into different types of plant cells
what is the function of meristematic tissue
allows the plant to grow
what is translocation
the movement of food substances made in the leaves up or down the phloem , for use immediately or storage
what is transpiration
the loss of water from the leaves and stems of the plant
consequence of gaseous exchange as the stomata are open so this can occur
why does water evaporate at the open stomata
water molecules are attracted to each other, when some molecules leave the plant the rest are pulled up through the xylem
results in more water being taken up from the soil resulting in a continuous transpiration stream through the plant
how does increase in temperature affect evaporation/ transpiration
molecules move faster resulting in faster evaporation and transpiration
rate of photosynthesis increases so more stomata are open for gaseous exchange , more water evaporates and transpiration increases
how does increase in relative humidity effect transpiration and evaporation
if it is high the concentration gradient between conc of water vapour inside and outside of leaf is reduced , resulting in a slower rate of diffusion which decreases the rate of transpiration
how does increased air movement affect evaporation and transpiration
if more air moves towards the leaf due to it being blown away, concentration of water vapour surrounding leaf is lower
steeper conc gradient
diffusion happens faster
increased rate of transpiration
how does an increase in light intensity affect evaporation and transpiration
increased rate of photosynthesis
more stomata open for gaseous exchange
more water can evaporate
increased rate of transpiration
what do you measure to indicate the rate of transpiration in a plant
uptake of water
how do you measure uptake of water
photometer
place plant in tube of water
measure distance travelled by a bubble
what do guard cells do
close and open stomata
what are the features of guard cells
kidney shaped
thin outer walls and thick inner walls
when lots of water available, fill and change shape opening stomata
allows gases to be exchanged and more water to leave the plant via evaporation
more stomata found on bottom of lead allowing gases to be exchanged whilst minimising water loss by evaporation as owner surface is shaded and cooler
