6.4 GAS EXCHANGE Flashcards
ESSENTIAL IDEA
the lungs are actively ventilated to ensure that gas exchange can occur passively
VENTILATION
movement of air into and out of the lungs in two stages
inspiration and expiration
WHAT IS VENTILATION CONTROLLED BY?
the movement of the diaphragm and ribcage
GAS EXCHANGE
the exchange (diffusion) of oxygen and CO2 to and from the blood at the alveoli and the respiring tissue
CELL RESPIRATION
this is production of ATP at the cellular level (mitochondria)
aerobic respiration uses oxygen
anaerobic does not
LARGER ORGANISMS HAVE
adaptations that reflect their environmens
SMALLER ORGANISMS CAN
exchange gases directly with their surroundings through diffusion
LAND BASED ANIMALS HAVE EVOLVED AN
internal ventilation system which allows for gas exchange with the blood
WHY DO WE NEED AN INTERNAL VENTILATION SYSTEM?
to maintain a large concentration gradient with the alveoli and the blood
WHAT IS OUR CONCENTRATION GRADIENT?
high CO2 conc and low O2
BREATHING OUT
increases the conc gradient of CO2 between the blood and alveolus so CO2 will diffuse out
BREATHING IN
increases the conc gradient of O2 between the alveoli and blood
so it diffuses into the blood
VENTILATION
maintains concentration gradients of O2 and CO2 between air in alveoli and blood flowing in adjacent capillaries
FOR GAS EXCHANGE TO BE EFFIECIENT
high concentration gradient must be maintained in the alveoli
IF ALVEOLI WERE NOT VENTILATED
equilibrium would be reached and no gas exchange would occur
INTERCOSTAL MUSCLES
control the movement of the ribcage
THE VENTILATION SYSTEM DIAGRAM
https://image.slidesharecdn.com/biok6-160301001719/95/bioknowledgy-presentation-on-64-gas-exchange-9-638.jpg?cb=1457352468
INSPIRATION
PRESSURE CHANGE
decrease
INSPIRATION
VOLUME CHANGE
increase
INSPIRATION
RIBCAGE MOVEMENT
up and outward
INSPIRATION
EXTERNAL INTERCOSTAL MUSCLES
contract
INSPIRATION
INTERNAL INTERCOSTAL MUSCLES
relax
INSPIRATION
DIAPHRAGM
contract
flattens
moves downwards
INSPIRATION
ABDOMINAL MUSCLES
relax
EXPIRATION
PRESSURE CHANGE
increase
EXPIRATION
VOLUME CHANGE
decreaes
EXPIRATION
RIBCAGE MOVEMENT
down and inward
EXPIRATION
EXTERNAL INTERCOSTAL MUSCLES
relax
EXPIRATION
INTERNAL INTERCOSTAL MUSCLES
contract
EXPIRATION
DIAPHRAGM
relax
EXPIRATION
ABDOMINAL MUSCLES
contract
MECHANICS OF VENTILATION OVERVIEW
https://image.slidesharecdn.com/biok6-160301001719/95/bioknowledgy-presentation-on-64-gas-exchange-10-638.jpg?cb=1457352468
ANTAGONISTICALLY
internal and external intercostal muscles
diaphragm and abdominal muscles
USE OF ANTAGONISTIC MUSCLES
relaxation is a passive process
relaxing of a muscle group is aded by the contraction of the other
ADAPTATIONS OF ALVEOLI
increase surface area for gas exchange
network of capillaries
high concentration gradient
membranes are very thin
surfaces are wet
TYPE I PNEUMOCYTES
single layer of cells from the walls of an alveolus
extremely thin- short diffusion distance
permeable- aids diffusion
TYPE II PNEUMOCYTES
secrete fluid to moisten the inner surface of the alveolus
fluid aids diffusion of gases
fluid contains surfactant to prevent the wall sticking together- maintains the lumen
can divide to form type I pneumocytes- repair damage
EMPHYSEMA CAUSES
smoking
chest infections
air pollution
= inflammatory response in the lungs
EMPHYSEMA PROCES
protease is released by leukocytes and inflamed lung tissue
protease breaks down connective tissue of the lungs
destruction of small airways and alveoli
formation of large air pockets and breakdown of capillaries
EMPHYSEMA CONSEQUENCES
large air pockets have much lower S.A: VOL than alveoli
when combined with the reduced blood supply
= inefficient gas exchange
low blood O2 levels
LUNG CANCER
cancer that starts in the trachea , bronchus or the lung tissue
LUNG CANCER CAUSES
> smoking
< second hand smoke
< air pollution
< exposure to radon gas
LUNG CANCER SYMPTONS
being short of breath
having a constant cough
coughing up phlegm
ache or pain in chest
loss of appetite
tiredness/ fatigue
losing weight
LUNG CANCER CONSEQUENCE
if untreated = death
MONITORING VENTILATION
independent variable: intensity of exercise
dependent variable: measure of ventilation (frequency of breath/T)
controlled variables
data analysis: calculating rate of…
ethical and safety concerns
