organisms exchange substances Flashcards
when surface area increases what happens
sa:vol ratio decreases
where does gas exchange occur for single celled organisms
through the membrane
what are adaptations for diffusion
steep concentration difference
good blood supply
large surface area (alveoli)
thin membrane (short diffusion distance)
what is flick’s law of diffusion
rate of diffusion = sa x concentration difference/diffusion distance
what sa:vol ratio do fishes
small
what type of membrane do fishes have
impermeable membrane (gases can’t diffuse through membrane)
what is the lamella in fish
main site of gas exchange
what are adaptations for fish
counter current flow (opposite of parallel flow) of water & blood maintains steep concentration gradient along whole length of gill
large number of gills, filaments, lamellae and capillaries which increases sa
what are the steps for fish gas exchange
fish opens mouth so water can flow in, then closes it to increase pressure
water passes through lamella, oxygen diffuses into bloodstream (capillaries)
waste co2 diffuses into the water & flows back out of the gills
what are the features in insects for gas exchange
spiracle
trachea
tracheoles
insects: what is the spiracle
pore
controls water loss
insects: what is the trachea
large tube kept open by rings of chitin
prevents collapse
insects: what is the tracheoles
smaller tubes
gas exchange occurs here
insects: what is an air sac
stores some air so they can respire quicker when required
insects: how are spiracles opened and closed
by a valve
to control gas exchange and water loss
at rest what do insects have in their tracheoles
liquid
plants: what do air spaces create
high sa : vol ratio
plants: what does the stomata do
controls water loss and gases entering and leaving
how does the stomata work
guard cells close stomata when there’s a low water potential
this causes water to diffuse in, making it turgid and opening
how do plants control water loss
thick waxy cuticle
decreased sa:vol ratio
leaf rolling
hairy leaves
sunken stomata
stomata can open and close
what is the equation for respiration
glucose + oxygen -> carbon dioxide + water
why are lungs internal
it has a high sa so there would be lots of water loss if it was external
humans: what is the trachea
muscular airway strengthened w/ cartilage
lined w/ ciliated epithelial cells
what are bronchioles
highly branched
muscle contracts and relaxes to regulate airflow into the alveloi
where does gas exchange take place for mammals
epithelial of alveoli
why is diffusion rapid in humans
red blood cells slowed, more time for diffusion
thin membrane
cells are flattened -> decreases distance
large sa
breathing ventilates lungs & heart (gradient)
what are the blood vessels on the right side of the heart and where do they go to
pulmonary artery to the lungs
vena cava from the body
what are the blood vessels on the left side of the heart and where do they go to
aorta to the body
pulmonary vein from the lungs
what blood is in the right and left side of the heart
right - deoxygenated
left - oxygenated
what valve is between the atria and ventricles
atrioventricular valves
what valve is between the ventricles and arteries
semi lunar valves
what wall is inbetween the 2 sides of the heart and what does it do
septum
separates deoxygenated and oxygenated blood
what are the strings of tissue attached to atrioventricular valves and what do they do
cordae tendinae
supports the valve, prevents backflow
what is systole
period of ventricular contraction
what is diastole
period of ventricular relaxation
what are the three stages of the cardiac cycle
diastole (all chambers relaxed)
atrial systole (atria contract)
ventricular systole (ventricles contract)
what happens in diastole
ventricles and atria relax
blood enters atria
elastic recoil of atrial walls generate low pressure
initially atrioventricular valves are closed
as ventricles relax, blood falls back from the aorta & pulmonary artery causing semi lunar valves to close
what happens in atrial systole
ventricles relax, atria contract
as blood enters atria, pressure increases in atria
atrioventricular valves pushed open
blood flows into ventricles
atria contract simultaneously forcing remaining blood into ventricles
what happens in ventricular systole
ventricles contract, atria relax
after slight delay ventricles contract
this increases pressure in ventricles causing atrioventricular valves to close
blood is forced into aorta & pulmonary artery, semi lunar valves open
what is the diaphragm
muscle separating the thorax and abdomen
what is the internal intercostal muscles
in between ribs, leads to expiration
what is the external intercostal muscles
in between ribs, leads to inspiration
describe inspiration
external intercostal muscles contract
ribs pulled up and out, increases volume of thorax
diaphragm contracts & flattens
increased thorax volume reduces air pressure within lungs
atmospheric pressure is greater than lung and pulmonary pressure
