respiratory systems Flashcards
which factors affect rate of diffusion?
FICKS LAW
temperature p,p gradient length of diffusion pathway size of molecule s.a. of gas exchange surface its solubility in liquid
what is important about s.a:V
as organism gets larger its SA:V ratio gets smaller so it cannot rely on simple diffussion anymore
> so require specialised gas exchange surfaces
what structural features do larger organsims have to make gas echange more efficient?
(general)
> they have evagination and invaginations (folidng of exchange surface) which increases the s.a
thin surfaces to mimimise the diffusion pathway
they often are vascular or have access to fresh supply of substances
in gas, the internal tissue is moist so the gas can adjust to the bodies internal liquid enviroment.
True or false?
the dead zone is involved with gas exchange
False! the dead zone does not take part in gas exchange but helps with ventilation
what values can you get from a spirometer?
tidal volume
vital capacity
inspiritory capacity
resdiual volume - prevent complete collapse of lung
avian birds (comparative anatomy)
they have air sacs and unidirecional airflow
so all air can be used for gas echange and not wasted on ventilation
forgs (comparative anatomy)
they have a POSITIVE pressure pump
air forced into lungs when mouth cloese
Insects (comparative anatomy)
they have spiricles and can also do abdomnal pumping
fish (comparative anatomy)
water moves across gills
counter current system for max gas exhang
when mouth closes the pressure increases and forces water out
compare tidal breathing with unidirectional flow
flow is more efficient as incoming air NEVER mixes with the expired air so all air can be used for gas exchange.
It is optimised to MINIMISE the ‘dead space’
body reaction to hypercapnia (high co2)
Hypercapnia causes increase in minute ventilation so frequency and tidal ventialtion increases
> Body more responsive to hypercapnia than hypoxia but hypoxia has the same effects
All gas movement is…
active
passive
osmosis
passive process governed by diffusion
what DOESN'T make the Bohr shift occur? (shift to right) A increase of Co2 B decrease [H+] - more acidic C increase [H+] - more alkali D increase temperature E increase 2-3 BPG
option C decreasing H+/increaed pH a
> high carbon increases acidity, high temp and 2-3 bpg all contribute to Bohr
how does 2-3 bpg infulence haemoglobin///?
changes Hb from a high affnity to low affinity oxygen state
at rest intrapleural pressure is…
negative w.r.t atmospheric pressure
Alveolar pressure/ intrapleural pressure is lower than atmospheric pressure
A during inspiration
B during expiration
in INSPIRATION
quick deinitions of the pressures x3
- atmospheric
- intrapleural
- intraalveolar
Atmospheric pressure- pressure of the air outside the body.
Intrapleuralpressure- pressure within the pleuralcavity.
Intraalveolar pressure- pressure inside thealveoliof the lungs.
These three pressures are responsible for pulmonary ventilation.
which lung has less lobes?
left lung has 2 lobes (bicuspid valves winkywink)
‘‘left lung less lobes’’
surfacant is produced from which type of alveolar cell?
type 1 pneumocyte
type 2 pneumocyte
type 3 pneomocyte
type 2 pneumocytes secrete surfacant which reduces surface tension of the alveoli!
What is external respiration?
delivery and removal of gases to and from tissues and cells
which part of the respiratory tract is part of the respiratory zone and not the conducting zone?
transitional and respiratory zones = respiratory bronchioles, alveolar ducts, alveolar sacs
How do resistive forces affect airflow?
They oppose inspiration and assist expiration.
how does gravity affect pattern of ventilation and perfusion (blood flow)?
blood flow is more affected by gravity. at the top of the lungs we have the least volume of blood and ventilation.
when ventilation mathces perfusion we get the optimum gas exchange
what are the features of the pulmonary system?
ung to heart
high flow system as cardiac output flows thrug lungs low pressures and low resistance
arterial walls are thin to allow for high flow
how can ventilation be modified to reach optimum gas exchange?
you can vasoconstrict and divert blood away from poorly ventilated areas (e.g. low ppO2/ hypoxia)
which is the most efficient gas exchange system?
fish! the countercurrent system is around 905 efficient at extracting oxygen
how is oxygen transported arounf body?
via haemoglobin
how does cooperative binding occur?
conformational change