exchange surfaces Flashcards
what does a peak flow meter do
measures the rate at which ir can be expelled from the lungs
how does a vitalograph work
patient breathes out as quickly as they can
what is a spirometer
used to measure different aspects of lung volume
define tidal volume
volume of air that moves into and out the lungs at rest
define vital capacity
volume of air breathed in when the strongest possible exhalation is followed by the deepest intake of breath
define inspiratory reserve volume
maximum volume of air you can breathe in over and above a normal inhalation
define expiratory reserve volume
extra amount of air you can force out
define residual volume
volume of air left in the lungs when you’ve exhaled as hard as possible
can’t be measured directly
define total lung capacity
sum of vital capacity and the residual volume
how do we find the ventilation rate
tidal volume x breathing rate
what stops gaseous exchange in insects
their exoskeleton
where are spiracles
along the thorax and abdomen
how can water loss be minimised in insect tracheal system
closed spiracles using sphincters
what lines the trachea
why
chitin
keeps them open if bent or pressed
impermeable so gaseous exchange doesn’t take place here
what’s towards the end of tracheoles
tracheal fluid
limits the penetration of air for diffusion
how does less moisture affect the tracheal system in insects
exposes more surface area for gaseous exchange
describe the mechanisms of mechanical ventilation of the tracheal system
air is actively pumped into the system by muscular pumping movements of the thorax and/or abdomen
these movements change the volume of the body which changes the pressure
describe collapsible enlarged trachea or air sacs
act as air reservoirs
used to increase the amount of air moved through the gas exchange system
how are gills adapted to be an efficient gaseous exchange system
large SA
good blood supply
thin layers
what is the operculum
covers the gills
what does a the efferent blood vessel do
carries blood leaving gills in the opposite direction of water
maintains a steep conc gradient
describe the processes of water moving into the fish
mouth opens and floor of buccal cavity lowers
increases the vol (decrease pressure)
so water moves into the b. cavity
the opercular valve shuts and the opercular cavity expends (lowers the pressure)
floor of buccal cavity moves up so water moves over the gills
the mouth closes and the operculum opens and the sides of the opercular cavity move inward
(increases the pressure)
forcing water out the gills
the floor of the buccal cavity moves steadily up to maintain flow of water
what are features of efficient gaseous exchange in water
tips of adjacent gill filaments overlap
which increases the resistance to water flow, so more time for g. exchange
blood and water flow in opposite directions (countercurrent) (maintain steep conc gradient)
what is the open body cavity called
what is low here
haemocoel
low pressure
what is insect blood called
what does it carry
haemolymph
transports food and nitrogenous waste products
what is the heart’s structure in an insects
extends along the length of the thorax and abdomen
what is a downside to the open circulatory system in insects
steep diffusion rates can’t be maintained
amount of haemolymph flowing cannot be varied to meet changing demands
describe a single circulatory system
blood travels once through the heart for each complete circulation
what is a downside to single closed circulatory system
blood passes through two sets of capillaries before returning to the heart
after the second, blood pressure drops so blood returns to the heart slowly
describe a double circulatory system
blood travels to twice through the heart for each circuit of the body
describe the proportion of elastin, smooth muscle and collagen in arteries
lots of elastin and smooth muscle
less collagen
describe the proportion of elastin, smooth muscle and collagen in veins
more collagen, then muscle then elastin
these proportions decrease as you go further away from the heart
how do substances in the plasma pass through capillary walls
through fenestrationsn
define oncotic pressure
what is its value
tendency of water to move into the blood
-3.3 kPa
at the arterial end of the capillary, what is present and what is its value
hydrostatic pressure
4.6 kPa
what is higher at the arterial end
what does this result in
hydrostatic pressure is higher than oncotic pressure
so fluid is squeezed out the capillaries
what happens as the venous end
hydrostatic press down to ~2.3 kPa as fluid has moved out and pulse is lost
oncotic pressure is still -3.3 kPa so it is stronger than hydrostatic pressure
so water moves into capillaries by osmosis
what happens to the 10% of tissue fluid that doesn’t return to capillaries
becomes lymph
contains fatty acids
the fluid is transported by squeezing of the body muscles
has valves
eventually lymph returns to the blood flowing into the right and left subclavian veins
what happens in lymph nodes
lymphocytes build up which pass into the blood
lymph nodes intercept bacteria and other debris
enlarged lymph nodes are a sign the body is fighting off an invading pathogens
what are adaptations of the nasal cavity
hairy lining - traps pathogens trapped in mucus
moist lining - increases humidity
high surface area with good blood supply - warms air to body temperature
what are adaptations of the trachea
incomplete rings of strong and flexible cartilage - stops trachea from collapsing
lined with cillia with goblet cells
what are adaptations of bronchioles
no cartilage – smooth muscle
contract and constrict to change volume of air reaching lungs
thin layer of flat epithelium making gas exchange possible
what are adaptations of alveoli
layer of flattened epithelial cells
some collagen, elastic fibres
allows stretching as air drawing in and then recoil to squeeze air out
what does elastic fibres do
composed of elastin and stretch and recoil, providing flexibility
what do smooth muscle do
contracts + constriccts to change size of lumen
what do collagen do
provide structural support and maintain shape of vessel
what do arterioles have a higher and lower proportion of
high smooth muscle and lower elastin
prevent blood flowing into capillary bed
what is an adaptation of capillaries
cross sectional area is higher than arteriole supplying them
so a low rate of flow gives more time for exchange of materials by diffusion
what is composition of veins
mostly collagen, less smooth muscle and very little elastic fibres
what are adaptations of venules
bigger veins run between bigger muscles
when muscle contract they squeeze veins, forcing blood quicker to the heart
breathing movement of chest acts as a pump
the changes in pressure in the blood in the veins of the chest and abdomen toward the heart
