exchange and transport Flashcards
what do organisms need to live
oxygen-aerobic respiration
glucose-source of energy
proteins-growth and repair
fats-make membranes and a source of energy
minerals-maintain water potential and enzyme action
removal of waste products
effects of size on an organism
bigger the organism the more complex
small organism can do all their exchange through diffusion as they have a high SA:V
main factors affecting the need for a specialised exchange surface
size
SA:V
level of activity
affect of SA:V
the smaller the SA:V the more cells that need supplies and produce more waste
this means cells to deep for diffusion to occur quick enough
affect of level of activity
higher the level of activity the greater the demand for oxygen and other essential minerals
need a extremely specified surface as part of a bigger system
what are some examples of specialised exchange surfaces
walls of alveoli in the lungs
small intestine
liver
root hairs of plants
hyphae of fungi
why the lungs are a good specialised surface
large SA
lots of alveoli
thin barrier so small diffusion distance
good blood supply
good ventilation
features of alveoli
small (0.1mm-0.3mm)
lots of alveoli
thin layer of moisture
lungs produce a surfactant to reduce cohesive forces between water molecules
features of the exchange layer in the lungs
1 cell thick
squamous tissue
permeable to CO2 and O2
capillaries are close and narrow
total barrier is 0.001mm thick
features of a good blood supply in the lungs
concentration of oxygen is higher in the air than the blood
maintains the concentration gradient
features of the good ventilation in the lungs
replaces the air used
removes CO2
maintains a concentration gradient
what happens when you breath in
intercostal muscles contract
ribs raise
diaphragm muscles contract
diaphragm moves down
volume of chest increases
air pressure in the lungs is below the pressure of the air outside
air rushes into the lungs
what happens when breathing out
intercostal muscles relax
ribs fall
diaphragm muscles relax
diaphragm moves up
volume of chest decreases
air pressure in lungs is above the pressure of the air outside
air rushes out of the lungs
what do airways need to be
large
supportive
flexible
where is cartilage found
trachea and bronchus
what shape is the cartilage and is it flexible
c shape and is flexible
what is the role of ciliated cells
to move mucus to the back of the throat
where are ciliated cells found
in the trachea and the bronchus and some in the bronchioles
what is the role of elastic fibres
to allow the alveoli to recoil to allow o2 in and they help to also push air in and out of the lungs by stretching and recoiling when breathing
where are elastic fibres found
in all places of the circulatory system
what is the role of goblet cells
to produce mucus to help prevent against pathogens
where are goblet cells found
in the trachea, bronchus and some in the bronchioles
how does spirometry work
breathe into the tube connected to the chamber
breathing in takes air from the chamber so sinks
breathing out causes air to be pushed into the chamber so it rises
this movement is recorded with data loggers or a trace
do at different breathing rates like at rest, after doing exercise and with deep breaths
what is tidal volume
volume of air exchanged in a single normal breath
what is vital capacity
maximum volume of air that cam be breathed in and out
what is inspiratory reserve volume
volume of extra air that can be inhaled above tidal volume
what is expiratory reserve volume
volume of air that can be forced out after a normal expiration
residual volume
volume of air that remains in the lung tissue after forced expiration
what are the problems bony fish have with gas exchange
small SA:V
skin is impermeable so gases cant diffuse through
oxygen concentration in water is typically lower than the air
who does the fishes circulatory system work
the fish opens its mouth so water flows into the buccal cavity
the fish raises its buccal floor increasing pressure in buccal cavity forcing water over the gills
the fish opens its mouth again so the operculum bulges out increasing the volume of the opercula cavity to decrease pressure so water is drawn over the gills
opercula flaps open so operculum contracts forcing water out and then flaps close again
this cycle then repeats
how does counter current work
blood and water flow in opposite directions
blood with the lowest oxygen concentration pass over the water with the lower concentration of oxygen so there is a constant concentration gradient
what do spiracles do in an insects transport system
allow air to enter the tracheas where air is transported across the tracheoles
where is the main site of gas exchange in an insects respiratory system
between the tracheal fluid and the air in the tracheoles but also directly with the tracheole walls
what supports the trachea
chitin which are strengthened rings to stop them from collapsing
what does the movement of wings do to this system
it alter the volume of the thorax (upper body) so air is pushed out of the tracheal system
features of a good transport system
fluid/medium to catty oxygen and other essential nutrients
a pump to push fluid
exchange surfaces for oxygen to enter fluid
tubes/vessels to carry fluid
in some cases 2 circuits, one for oxygenated blood and one for oxygenated blood
what is the structure of arteries (inside to outside)
small lumen
thick endothelium
thick elastic fibres
thick smooth muscle
thick collagen fibres
what is the structure of veins (inside to outside)
wide lumen
thin endothelium
thin elastic fibres
thin smooth muscle
thin collagen fibres
what is the structure of capillaries (inside to outside)
narrow lumen
1 cell thick epithelial layer to reduce diffusion distance
function of artery
carry blood away from the heart
function of veins
carry blood back to the heart
function of capillaries
to exchange between blood and tissue fluid
adaptations of arteries
thick wall to withstand high pressure
lumen is small to maintain high pressure
inner wall folded to expand as blood flow increases
adaptations of arteriole
layer of smooth muscle to constrict the diameter to increase blood flow
constriction is used to divert the flow of blood to regions demanding more oxygen
adaptations of veins
lumen is large to ease the flow of blood
thinner layers as they don’t need to stretch
valves to prevent backflow
skeletal muscles applies pressure to force the blood in the direction of the valves
adaptations of the venule
thin layers of muscle to slow down the blood flow entering the capillaries
adaptations of capillaries
thin walls to increase diffusion
lumen narrow to help with transfer of oxygen
single layer of squamous epithelial cells to reduce diffusion distance
walls are leaky to allow blood plasma and dissolved substances to leave the blood
how diffusion occurs into tissue fluid
the arteriole end has a high hydrostatic pressure
ultrafiltration then occurs to allow oxygen and other small minerals through the micro pores
venule side has a low hydrostatic pressure so oxygen and other minerals taken up by the tissue fluid
what can not be found in the tissue fluid
erythrocytes, most leucocytes, large proteins and platelets
what happens at the venule end of the capillaries
90% of the tissue fluid returns back into the capillaries carrying waste product e.g. carbon dioxide however 10% of the fluid goes into the lymphatic system
what can be found in the lymph vessels
proteins that were too large to be in the capillaries
lots of white blood cells
what happens to the lymph vessels
they all join back up and empty themselves into the 2 large veins in the neck
what is the role of lymph nodes
the are part of the immune system and contain large numbers of white blood cells which screen the lymph looking for infections
what is the hearts function
a muscular pump
left side pumps oxygenated blood to the body and the right side pumps deoxygenated blood up to the lungs
what is blood pressure
cardiac muscle contracts to create pressure
both atria have thin walls to have a low blood pressure as they don’t need to pump the blood far
why is the left ventricle thicker than the right
blood from right ventricle has less distance to travel and less resistance caused by the pulmonary circulation
the alveoli is so delicate so blood pressure must be low in the pulmonary artery to protect them
what are the 3 stages of the cardiac cycle
diastole
ventricular systole
atrial systole
why is the cardiac cycle so important
all chambers of the heart must be co-ordinated otherwise it would lead to insufficient pumping
what is the cardiac cycle
all events involved in one heat beat
what happens at atrial systole
atria contracts pushing blood into the ventricles, ventricles remain relaxed
what happens at ventricular systole
atria relaxes, short delay, ventricles fill with blood
walls of ventricles contact this creates pressure opening the atrio ventricular valves
blood pushed away from the heart through pulmonary artery and the aorta
what happens at diastole
blood returns to atria from pulmonary vein and vena cava
atria increases in pressure forcing atrio ventricular valves open
pressure is lower than in the aorta than pulmonary vein so semi lunar valves close
how does pressure change in the blood vessels
-blood enters aorta and pulmonary artery quickly however tissues require blood in an even flow
-artery walls close to the heart have lots of elastic tissue that stretch and recoil
-further the blood flows the less pressure and fluctuations
-pressure gradient between arteries and arterioles keep blood flowing
how is the heart co-ordinated
muscle in the heart is known as myogenic
muscle responds to changes in electrical charge
don’t require impulse simulation from brain
if contractions aren’t synchronised then it can lead to insufficient pumping
what does myogenic mean
contact thymically
what does the Sino-atrial node do
it creates a wave of excitation which spreads across the walls of both atria causing the cardiac muscle to contract. this forces blood through the bicuspid and tricuspid valves into the ventricles
what does the atrio-ventricular node do
after a short delay it sends a wave of excitation down from the top of the septum through the bundle of his. The tissue at the base of the heart (purkyne tissue) this then causes the ventricles to contract.
what is the function of haemoglobin
to transport oxygen and carbon dioxide
what type of protein is haemoglobin
globular protein
how many subunits does haemoglobin have
4 subunits
how many haem iron molecules does each haemoglobin gave
4 (Fe2+)
what does affinity mean
the ability to attract oxygen
how many oxygen atoms can each haemoglobin bind to
8 atoms (4 molecules)
what is created when haemoglobin binds to oxygen
oxyhaemoglobin
what is used to measure the relative amount of O2
partial pressure of oxygen or oxygen tension
what happens when there is a relatively low amount of O2
the haemoglobin doesn’t readily take up O2
what happens to the haemoglobin shape when binded to oxygen
there is a slight formational change to allow more haemoglobin to react
what happens when haemoglobin has 3 molecules
oxygen isn’t likely to bind so it is difficult to reach 100% saturation
what is the difference in affinity in a mammalian fetus compared to adult haemoglobin and why
the affinity is greater as the placenta allows the foetal haemoglobin to absorb oxygen from the surrounding fluid
what are the 3 ways CO2 can be transported
5% dissolved in the plasma
10% associated with the haemoglobin to create carbaminohaemoglobin
85% is transported as H+ ions
what is formed when CO2 is dissolved in water
it creates carbonic acid
what is the catalyst of the reaction between water and CO2
carbonic anhydrase
what happens to carbonic acid
it releases H+ ions
what happens to the H2CO3-
it diffuses out of the erythrocyte
why does chloride move into the erythrocyte
to balance the charges, this is called the chloride shift
what happens the H+ ions
they bind with the haemoglobin to create haemoglobinic acid
what does the erythrocyte do to prevent it becoming acidic
the haemoglobinic acts as a buffer by binding to the H+ ions
what does a change in pH do to affect the haemoglobin
it reduces the affinity of the haemoglobin and can affect its tertiary structure
what happens in respiring tissues
more CO2 released
more carbonic acid formed
more H+ ions dissociate
more competition for haemoglobin
more oxygen dissociation
what is the affect of the Bohr affect
the oxygen dissociation curve shifts to the right
what happens to the H+ ions in terms of competition
they compete for space taken up by the oxygen on the haemoglobin molecule
what happens to the oxygen when CO2 is present
hydrogen ions displace the oxygen so the oxyhaemoglobin releases more oxygen into the tissues
