exchange and digestion Flashcards
where in a cell has highest CO2 conc and lowest O2 conc and why
mitrochondria
to maintain diffusion gradient
why do small and inactive organisms not require specialised gas exchange surfaces
they have a low surface area to volume ratio
so gas can exchange across a thin membrane
why do large organisms require a circulatory system
because of their large surface area to volume ratio
why do specialised exchange surfaces have large surface area to volume ratio
increases rate of exchange
why do specialised exchange surfaces have very thin membranes
to decreases diffusion pathway
why do specialised exchange surfaces have selectively permeable membrane
allows only certain materials across
why do specialised exchange surfaces have movement of environmental medium in them
maintain diffusion gradient
why do specialised exchange surfaces have movement of internal medium
maintain diffusion gradient
what is ficks law
diffusion = SA x conc difference /length of pathway
describe the relationship between size of microorganism and SA;V
as the size of something increases the surface area to volume ratio decreases
what are the two ways terrestrial insects prevent water loss
exchange system has a small surface area to volume ratio
waterproof covering on exposed exoskeleton
name the parts of an insects tracheal system
spiracle
trachea
muscle tissue
tracheoles
what happens when insects respire anaerobically
lactic acid is produced which is solute and lowers the water potential of water in the tracheoles
the water is then moved via osmosis from trachea to cells.
air is drawn into tracheoles creating a lower pressure to increase rate of diffusion because muscle cells are swollen so closer to tracheoles
how are spiracles adapted to help maintain humidity
body segments pull skeleton plates together
air squeezes into the sacs to limit gas exchange
how are spiracle hairs used to reduce water loss
trap water molecules which maintains the hummidity around the spiracles to reduce conc gradient so less water is lost
what is the function of chitin in the trachea
also what is chitin
nitrogen containing polysaccharide
maintain trachea shape even at low pressure
name the parts of a fish gill
gill arch
gill
operculum
operculum opening
gilll filament
lamella
how do fish get oxygen from the water/
describe its structure
water is taken in the through the mouth and passed over the gills and out the operculum
gills comprise of filaments which increase the surface area
on the fillaments are lamella which also increase surface area
counter current flow - oxygen and water flow in opposite directions to maintain conc gradient
why do fish die in air
lamella stick together in air so decrease surface area and gas exchange cant happen so quick
by what process does water move out of the stoma
diffusion
what are stoma
pores on the underside of leaves which are surrounded by guard cells which control their opening and closing
what are the guard cells when stoma is open
turgid
what are the guard cells when stoma is closed
plasmalised
because water moves down water potential gradient and into the mesophyll
how do plants prevent water loss
closing the stoma
waterproof cuticle on leaves
rolling up leaves creates a high water potential so does hairs on leaves
reduced SA:V (pines)
name the parts of the human exchange system
nasal cavity
trachea
bronchi
bronchiole
alvioli
capillaries
why do humans need to respire aerobically
to have regular supplies of oxygen to make ATP during respsiration in the mitrochondira which also produces CO2 as a waste product
describe the specific qualities of the trachea
C shaped rings of cartalige
ciliated epithelial cells which waft rythmically
smooth muscle cells
elastic tissue
describe the specific qualities of the bronchus
small sections of cartalige
ciliated epithelial cells which waft rythmically
smooth muscle cells
elastic tissue
describe the specific qualities of the bronchioles
ciliated epithelial cells which waft rythmically
smooth muscle cells - contract t control air movement in the lungs
elastic tissue
describe the specific qualities of the alvioli
squaremous epithelial cell
elastic tissue - allows them to stretch and fill with air
what is the difference between bronchioles and bronchus by appearance
bronchioles have rough felled inner surface whereas bronchus are less likely to and will have chunks of cartilage
in what direction does gas move
from an area of high pressure to low pressure
what is inspiration
air pressure inside the lungs is reduced so air moves in
what is expiration
air pressure inside lungs is increased so air moves out
describe the steps of inspiration
- external intercostal muscles contract
- internal intercostal muscles relax
- ribs and sternum move up and out
- diaphragm contacts and flattens
- volume of thorax increases
- elastic tissue of lungs os streched
- lunges expand
- pressure in lungs is reduced
- air is forced into alvioli
describe the steps of expiration
1.external intercostal muscles relax
2. internal intercostal muscles contract
3. ribs and sternum move down and in
4. diaphragm relaxes and returns to dom shpe
5. volume of thorax decreases
6. elastic tissue recoils
7. lung size decreases
8. pressure inside the lungs increases
9. air is forced out of the alvioli
what is pulmonary ventilation
volume of air moved into the lungs in one minute
what is ventilation rate
number of breaths in one minute
what is tidal volume
resting breathing rate
what is vital capacity
max inhale + max exhale
what is the formula for pulmonary ventilation
tidal volume / ventilation rate
what is the formula for cardiac output
stroke volume ( volume of blood per beat) x heart rate
how does large surface area influence rate of gas exchange in the lungs
large area for diffusion so is quicker
how does very thin walls influence rate of gas exchange in the lungs
short diffusion pathway so is quicker
how does movement of medium influence rate of gas exchange in the lungs
maintain diffusion gradient
more movement = more diffusion
how many cells does a gas cross from alvioli to lungs
2
epithelial of alveoli and capillary
what does the line in a spirometer mean
down = inhale
up = exhale
what does the line in a lung capacity graph mean
down = exhale
up = inhale
what are the symptoms of pulmonary fibrosis
chronic dry cough
pain in chest
short breath
weakness/fatigue
what are the causes of pulmonary fibrosis
pollutants ( common among minners)
ideopathic - unknown cause
what is pulmonary fibrosis
scar tissue in the lungs causing less diffusion and less elasticity which causes difficulty breathing because alvioli cant recoil or fully inflate
what are the symptoms of asthma
tight chest
difficulty breathing
wheezing
coughing
what are the causes of asthma
family history
allergens ( fur , cold air , anxiety)
what is asthma
inflamation of the linng of the bronchi
more mucus is produced
so there is a resistance to air flow and oxygen conc decreases so less diffuses into the blood
what are the symptoms of emphysema
short breath
chronic cough
bluish skin colour
what are the causes of emphysema
smoking
what is emphysema
damage to elastin proteins ins the lungs so they loose elasticity so cant force air out or in so decreases diffusion into blood
diffusion pathway is increased because walls of alvioli are broken down
what are the risk factors for COPD
smoking
air pollution
genetics
frequent infections
occupation
what is a casual link in data
direct cause and effect relationship
what are the 3 stages of the scientific process
establish hypothesis
design and perform experiments
establish casual link and formulate theories to explain this
why do lipids lubricate the lungs
prevent alvioli being stuck together after a large inhalation
how does the digestive system work
glands produce enzymes that hydrolyse macromolecules into simple molecules ready for absorption
why are your intestines not technically part of your body
molecules and ions only truley enter your body when they are absorbed in the epithelial cells
your intestines are an outside environment
what does the salivary gland do
secret amylase via a duct to the mouth
which catalyses the hydrolysis of starch into maltose
what does the oesophagus do
carries food from the mouth to the stomach
made up of thick muscular walls
what does the stomach do
inner layer produces enzymes
stores and digests food especially proteins
glands produce digestive proteins
other glands produce mucus which prevents self digestion of its own enzymes
what does the pancreas do
a large gland below the stomach
secrets protease to digest proteins
lipase to digest lipids and amylase for the hydrolysis of starch
what does the small intestine do
long muscular tubes where food is digested
inner walls are folded into villi for large SA and covered in micro villi
absorbs products into the bloodstream
what does the large intestine do
reabsorbs water
food becomes thicker and drier making faeces
what does the rectum do
faeces is stored here before being removed via egestion
what is absorption
moving soluble molecules into the cell from the small intestine
what is assimilation
absorbed amino acids that are used to make new proteins
what is physical breakdown
breaking large food into smaller foods via chewing and muscular contractions in the stomach
to increase SA
what is chemical breakdown
using enzymes to hydrolyse molecules
name 2 membrane bound enzymes
sucrase and lactase
summaries starch digestion
amylase
from salivary gland and pancreas
not membrane bound
makes maltose
summaries maltose digestion
maltase
from the ileum
membrane bound
makes alpha glucose
summaries sucrose digestion
sucrase
from the small intestine
membrane bound
makes alpha glucose and fructose
summaries lactose digestion
lactase
from the ileum
membrane bound
makes alpha glucose and galactose
summaries proteins digestion
endopeptidase - from the pancreas- not membrane bound - makes amino acids
exopeptidase - from pancreas - not membrane bound - makes amino acids
dipeptidase - from the ileum - membrane bound - amino acids
summaries lipids digestion
lipase
from pancreas
not membrane bound
glycerol +fatty acid (monoglyceride)
what is the role of bile salts in lipid digestion
emulsifies large fat droplets into small ones
what is lactose intolerance
when your body doesn’t digest lactose because it cannot produce lactase
why does lactose intolerance lead to diarrhea
because solutes have not been absorbed are in the faeces so the water potential is lower so cannot be drawn out in the large intestine
How are amino acids absorbed into the blood stream
Co transport from ileum to epithelial cell
Facilitated diffusion through carrier proteins from epithelial cell to blood stream
Steps of Lipid digestion
1 bile salts produced in the liver emulsify lipids into Micelles to increase surface area
2ester bonds in the triglycerides are hydrolysed by pancreatic lipase the fatty acids and monoglycerides produced are packaged into micelles
3micelles come into contact with epithelial cells of villi and release monoglycerides and fatty acids
4they diffuse into epithelial cells and move towards the endoplasmic reticulum where they form triglycerides
5 these triglycerides in the chlymicrons are hydrolysed and fatty acids diffuse into tissue
6 they move out of epithelial cell via exocytosis and into lacteals
7chlyomicrons move from lacteals into blood stream
Are chlycomircons water soluble
Yes they can pass from lacteals to capillaries
Describe carbohydrate digestion
1 saliva enters mouth from salivary gland and mixes with food during chewing
2 hydrolysis of glycosidic bonds in starch by amalayse to form maltose
3 food is swallowed and enters the stomach
4 food moves to ileum where is mixes with pancreatic amylase
5 pancreatic amylase continues hydrolysis of starch to maltose
6 epithelial lining of the ileum produces the disaccharide maltase
Which is membrane bound and hydrolysed maltose into alpha glucose
7molcules are absorbed via co transport of sodium
