organisation Flashcards
tissue
a group of specialised cells with similar structure and function, can be made of more than one type of cell e.g muscular tissue
organs
formed from a number of tissues working together to produce a specific function e.g stomach ( muscular and epithelial tissue)
organ systems
organs which work together to perform a certain function e.g the digestive system
digestive system
- several organs work together to break down food (large and insoluble) in order for it to be in a form that can be absorbed by cells
glands (ds)
- salivary glands and pancreas
- produce digestive juices which contain enzymes to break down food
stomach (ds)
- produce hydrochloric acid to kill bacteria
- provide optimum pH for protease to work
small intestine (ds)
- where soluble molecules are absorbed into blood
liver (ds)
- produces bile which is stored in the gall bladder
- helps with the digestion of lipids
large intestine (ds)
- absorbs water from undigested food to produce faeces
- passes out of body through rectum and anus
enzymes
biological catalysts / substances that increases the rate of reaction without being used up
4 facts about enzymes
- present in many reactions so they can be controlled
- can both break up large molecules and join small ones
- protein molecules and shape vital to its function
- each enzyme has its own uniquely shaped active site where the substrate binds
lock and key hypothesis
- substrate shape complementary to shape of active sit
- where they bond it forms an enzyme substrate complex
- once bound reaction takes place and products are released from the surface of the enzyme
since enzymes are proteins…
they require an optimum pH and temperature
optimum temperature of enzyme is…
37 degrees celsius
increase in temperature up to optimum = …
increased rate of reaction
but above the optimum temperature = …
rate of reaction rapidly decreases and eventually the reaction stops
when temperatures are too hot…
the bonds in the structure will break changing the shape of the active site -> substrate can no longer fit in and enzyme is denatured (no longer works)
carbohydrase
- convert carbs into simple sugars
- e.g amylase breaks down starch into maltose
- produced in salivary glands, pancreas and small intestine
protease
- convert proteins into amino acids
- e.g pepsin (in stomach)
- found in pancreas and small intestine
lipase
- convert lipids into fatty acids and glycerol
- produced in pancreas and small intestine
products of digestion are used to…
- build new carbohydrates, lipids and proteins
- some glucose for respiration
bile
- produced in liver stored in gall bladder
- released into small intestine
2 roles of bile
- alkaline to neutralise the hydrochloric acid from stomach - enzymes in the small intestine have a higher optimum pH than in stomach
- breaks down large drops of fat into smaller ones (emulsifies it). larger SA allows lipase to chemically break down the lipid into glycerol and fatty acids faster
circulatory system
- carries oxygen and nutrients to every cell in the body and removes waste products
heart
- organ in the cs
- pumps around the body in a double circulatory system
double circulatory system
- deoxygenated blood flows into the right atrium then the right ventricle then pumped to lungs to undergo gaseous exchange
- oxygenated blood flow into the left atrium the left ventricle which pumps oxygenated blood around the body
structure of heart
- muscular walls to prove a strong heartbeat
- muscular wall of left ventricle thicker as blood needs to be pumped all around the body
- 4 chambers separate oxygenenated blood from deoxygenated
- valves to make sure blood does not flow backwards
- coronary arteries cover the heart to provide its own oxygenated blood supply
heart process
- blood flow into right atrium through vena cava
- left atrium through pulmonary vein
- atria contract forcing blood in ventricles
- ventricles contract pushing blood in the right ventricle to pulmonary artery to be taken to lungs
- blood in left ventricle to aorta to be taken around the body
- as this happens, valves close to make sure blood does not flow backwards
natural resting heart rate is…
around 70bpm controlled by a group of cells in right atrium that act as a pacemaker
pacemakers
provide stimulation through small electrical impulses which pass as a wave across the heart muscle, causing it to contract
without pacemaker…
heart would not pump fast enough to deliver the required amount of oxygen to whole body
artificial pacemaker
- used if an individual has an irregular heartbeat
- an electrical device that produces a signal causing the heart to beat at a normal speed
3 types of blood vessel
- arteries
- veins
- capillaries
arteries
- carry blood away from the heart
- layers of muscle in walls make them strong
- elastic fibres allow them to stretch
- helps vessels withstand high pressure created by the pumping of the heart
veins
- carry blood towards the heart
- lumen (where blood actually flows through) is wide to allow low pressure blood to flow through
- valves to ensure blood flows in right direction
capillaries
- allow blood to flow very close to cells to enable substances to move between them
- one cell thick walls = short diffusion pathway
- permeable walls so substances can move across them
rate of blood flow calculation
volume of blood / number of minutes
lungs
- supply oxygen to blood and remove carbon dioxide
- found in thorax protected by ribcage
gas exchange system is made up by…
- trachea
- intercostal muscles
- bronchi
-bronchioles
alveoli
diaphragm
trachea
- windpipe, air moves through here
intercostal muscles
- contract and relax to ventilate lungs
bronchi
air from trachea move into bronchi, lead to each lung
bronchioles
- bronchi split into these and air moves in
alveoli
-bronchioles lead to alveoli , air sacs where gaseous exchange occurs
diaphragm
separates lungs from digestive organs, moves down causing inhalation
ventilation
- ribcage up and out diaphragm down causing volume of chest to increase
- increased volume results in lower pressure
- air drawn into the chest as air moves from areas of high pressure to low (lungs)
- opposite in exhalation
gas exchange
- upon inhalation alveoli fill with oxygen
- blood in capillaries surrounding alveoli is deoxygenated, has lots of carbon dioxide as it is a product of respiration
- oxygen diffuses down its conc gradient into capillary bloodstream, which has a low conc of oxygen
- carbon dioxide diffuses down its conc gradient from blood to alveoli
alveoli adaptations
- very small and arranged in clusters, creating a large SA for diffusion to take place over
- capillaries provide a large blood supply, maintaining the conc gradient
- thin walls, short diffusion pathway
breathing rate calculation
number of breaths / number of minutes
what is blood made up of?
plasma, red blood cells, white blood cells and platelets
plasma
liquid that carries components in the blood: rbc, wbc, plateletss, glucose, amino acids, carbon dioxide, urea, hormones, proteins, antibodies and antitoxins
red blood cells
- carry oxygen molecules from lungs to all cells in the body
- bioconcave shape = large SA
- no nucleus allowing more room to carry oxygen
- red pigment (haemoglobin), binds to oxygen to form oxyhaemoglobin
white blood cells
- part of the immune system (body’s defence against pathogens)
- have a nucleus
- some produce antitoxins to neutralise toxins produced by microorgansims
phagocytes
engulf and destroy pathogens that enter the blood through phagocytosis
lymphocytes
produce antibodies(small proteins that clump them together) when a foreign body such as a microorganism enters the body
platelets
- cell fragments produced by giant cells in the bone marrow
- help blood clots form at site of a wound
- clot dries and hardens to form a scab which allows new skin to grow underneath whilst preventing microorganism from entering
- without = cuts = excessive bleeding and bruising
how do platelets stop bleeding?
- have proteins on their surface that enable them to stick to breaks in a blood vessel and clump together
- secrete proteins that result in a series of chemical reactions that make blood clots, which plug a wound
coronary heart disease
- when coronary arteries that provide blood to the heart become blocked with the build up of fatty material (certain types of cholesterol)
- results in less blood flowing to the heart, reducing oxygen supply
- may lead to a heart attack
- chest pain, fatigue, fatal
non-communicable
non-infectious
stents
- metal mesh tubes inserted in arteries
- keep arteries open to allow blood to flow
stents advantages
- effective in lowering risk of heart attack
- recovery time from surgery is quick
stents disadvantages
- risk of heart attack during procedure of infection following it
- chance that blood clots can form near stent (thrombosis)
statins
drugs that decrease the levels of LDL (bad cholesterol) which would otherwise lead to CHD (lowers production in liver)
statins advantages
- reduce risk of strokes, CHD and heart attacks
- increase levels of HDL (good cholesterol)
statins disadvantages
- needs to be taken continuously and long term
- can produce side effects (headaches and memory loss)
- may not have an immediate effect as it only slows down that rate it is deposited (stops taking = cholesterol will rise)
- not suitable for everyone e.g pregnant
faulty valves
- when a heart valve becomes stiff so cannot open or it is damaged so it leaks
- blood flows in the wrong direction = heart does not work as efficiently as it should
faulty valve solutions
- replacing it with a biological valve (pigs or cattle) = works well but only lasts 12-15 years
- replacing it with a mechanical valve = lasts a long time but medication needed to stop clotting around valve
heart failure solution
- heart transplant = requires donor who has recently died, not always available
- artificial heart may be used while waiting
artificial heart advantages
- less likely to be rejected by immune system
- metal and plastic are not recognised as foreign
artificial hearts disadvantages
- surgery leaves body temporarily exposed to infection
- mechanical parts could wear out and motor could fail
- blood clots could form = stroke but drugs are taken to thin patients blood
extreme blood loss solution
- giving artificial blood
- salt solution that can keep people alive even if they lose 2/3 of their red blood cells
artificial blood advantages and disadvantages
- patient has more time to produce new blood cells
- only can be used for short periods of time - then a blood transfusion has to take place
health
state of physical, mental and social well-being, not merely the absence of disease
communicable diseases
- infectious as they are caused by pathogens
- passed on e.g flu
reduction in physical health prevents…
individual to carry out tasks or reducing life expectancy can lead to mental illness
non-communicable diseases
- not passed on e.g CHD
infections by viruses in certain parts of the body can…
trigger the growth of cancers e.g liver cancer from hepatitis virus
poor immune system…
more likely to be infected with a communicable disease as body is less able to fight off any pathogens
infection by pathogen, leading to immune response can ->
trigger allergic reactions to things in the environment e.g rashes
factors that affect health
- diet - too little / much food, not enough nutrients, can cause type 2 diabetes or obesity
- stress - physical and mental, put strain on bodies, lead to heart disease, cancers and mental illness
- life situations - hygiene, financial status, access to medical care, can lead to communicable disease e.g malaria or non e.g heart disease
risks factors are linked to an increased rate of disease and can either…
- be aspects of a person’s lifestyle
- substances in the person’s body
- environment
causal mechanism has been proven for some risk factors
an explanation of how one influences another
cardiovascular disease
- diet containing lots of LDL, blocks arteries and increasing blood pressure
- smoking damages artery walls
- exercise lowers blood pressure, reducing strain on heart
type 2 diabetes
- obesity affects body’s metabolism - fat molecules released into blood which can affect cells uptake of sugar
liver and brain function
- alcohol causes fatty liver -> liver failure
- alcohol can damage nerve cells in brain
lung disease and lung cancer
- smoking damages cells in lining of lungs and cilia
pregnancy
- smoking and alcohol can cause damaging effects on unborn baby
cancer
- carcinogens e.g ionising radiation can lead to cancers
cancer
result of changes in cells that lead to uncontrollable growth and division forming a tumour
benign tumour
- growth of cells contained in one place usually within a membrane
- not cancerous
- grows until no more room
- does not invade other tissues
- if it causes damage or pressure to organ can e dangerous
malignant tumour
- tumour grows and spreads to other tissues
- cancerous
- tumour may split up resulting in cells carried in the bloodstream or lymphatic system
- can travel to and stay in another organ, potentially causing secondary tumours
- cancer cells divide more rapidly and have a longer life span in comparison to normal cells
lifestyles risk factors for cancer
- smoking (lung, mouth)
- obesity (liver, kidney)
- UV light (skin)
- viral infection (liver (hepatitis B and C or cervical (HPV))
genetic risk factors for cancer
- inheriting certain genes
epidermal tissue function
- covers whole plants and has waxy cuticle (prevents water from moving out)
- helps to reduce water loss by evaporation
palisade mesophyll tissue
- found under epidermal tissue
- has lots of chloroplasts so photosynthesis can happen rapidly
- position at top of leaf so they receive lots of light
phloem
- found in roots, stems and leaves
- elongated with holes in cell walls (end walls = sieve plates)
- translocation = food substances can be moved in both directions
- organelles from cells are removed so cell sap can move through
spongy mesophyll tissue
- found under palisade mesophyll
- lots of air spaces allowing gases to diffuse in and out of cells
transpiration
- loss of water of water vapour from the leaves and stems of the plant
- consequence of gaseous exchange as stomata open so it can occur
meristematic tissue
- found at tips of roots and shoots
- can differentiate into different types of plant cell
- allows plant to grow
factors that effect rate of transpiration/evaporation
- temperature
- relative humidity
- air movement
- light intensity
xylem
- found in roots, stems and leaves
- made up of dad cells joined together creating a continuous tube
- transpiration stream - allows movement of water and mineral ions
- strengthened by lignin but has holes in it along tubes called bordered pits
- lignin makes it strong and waterproof, so water will not leave except at bordered pits, allowing minerals to go to specific places in the plant
guard cells
- surround the stomata and control the opening and closing of them depending on water availability
translocation
movement of food substances made in the leaves up or down the phloem for use immediately or storage
increase in temp
- molecules move faster = evaporation happens at a faster rate = rate of transpiration increases
- rate of photosynthesis increases = more stomata open for gaseous exchange = more water evaporates = rate of transpiration increases
transpiration stream
- water also evaporates and leaves at the open stomata
- as 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
measuring the uptake of water by plant…
gives indication to the rate of transpiration as water is only taken up if water leaves the plant
increase in relative humidity
high relative humidity = reduced concentration gradient between concentrations of water vapour inside and outside the leaf = slower rate of diffusion = rate of transpiration decreases
relative humidity
the measure of the concentration of water vapour in the air in comparison to the total concentration of water air can hold
increase in light intensity
increase rate of photosynthesis = more stomata open to allow gaseous exchange to occur = more water can evaporate = rate of transpiration increases
increase air movement (wind)
more air moving away from leaf due to it being blown away = concentration of water vapour surrounding leaf is lower = steeper concentration gradient = diffusion happening faster = rate of transpiration increases
potometer
- placing a plant in a tube of water
- measuring distance travelled by bubble
- used to measure rate of transpiration
guard cells (more)
- kidney shaped
- thin outer walls, thick inner walls
- lots of water availability = cells fill and change shape opening stomata
(also light sensitive) - allows gases to be exchanged and more water to leave the plant via evaporation
why are most stomata found on bottom of leaf?
- allow gases to be exchanged whilst minimising water loss by evaporation as the lower surface is shaded and cooler
