Gas exchange Flashcards
overall human diffusion pathway and gross structure
diffusion of oxygen in air in alveoli to blood
co2 in blood to air in alveoli
pathway of o2 from alveoli to blood
across alveolar epithelium to capillary endothelium
trachea - bronchi - bronchioles - alveoli
alveoli
-single layer of cells so short diffusion distance
-LSA 4 ge as lots of air sacs
-surrounded by network of capillaries so conc gradient
tidal volume
normal resting breath
vital capacity
max volume of air inhaled and exhaled
pulmonary ventilation
tidal volume times ventilation rate
total volume of air removed during 1 minute
lung disease
narrow lumen - inflammation so less air entering and leaving alveoli
reducing conc gradient so dont get enough o2
alveolar wall breakdowns reducing surface area so less o2 diffuses in
thicker wall so expand and recoil less so increases diffusion distance and reduced conc gradient
= less gas exchange
why does lung disease cause fatigue
cells receive less oxygen
so fall irate of aerobic respiration
so less atp made
fishes
small sA:V so require gas exchange surface - gills
obtain oxygen from water but water has 30% less oxygen than air
so need to maintain conc grad for diffusion to occur
stacks of gill filaments covered in lamellae so larger surface area
short diffusion distance as capillary network in ever lamellae maintain conc grad
thin lamellae wall
counter current flow
blood water flow in opposite directions so equilibrium not reached
o2 conc always higher in water than blood near
so once gradient along whole length of lamellae so diffusion along full length of lamellae
in fish blood leaving has more o2 than water leaving
human blood leaving has less o2 than air leaving
leaf structures and adaptations
thin so short diffusion distance
spongy mesophyll - spaces for gases diffuse in maintaining conc gradient and LSA
stomata - oxygen diffuse out
co2 diffuses in
reduces water loss by evaporation - stomata close at night so no photosynthesis
there’s lots of stomata so LSA 4 GE
xerophytes
sunken stomata traps moisture reducing WPG from leaf to air so less evaporates
thick cuticle increases DD less evap
hairs to trap moisture and curled leaves
spines and needless reduce SA:V
insect GE process
GE by diffusion - conc gradient from tracheoles to atmosphere
contracting and relaxing of abdominal mucles
when insect in flight respires anaerobically producing lactate and LWP so water moves from tracheoles into cells by osmosis so volume in tracheoles decrease
so more air from atmosphere drawn in
trachea and tracheoles
tracheoles - reach all tissues deliver oxygen to respiring cells
lots so short DD LSA and permeable
trachea - network of internal rings - tubes strengthen and provide tubes full of air so fast diffusion
insect adaptations to reduce water loss
exskeleton - lipid layer preventing water loss
tracheal system has thin walls so short diffusion distance to all cells
small SA V where water can evaporate from
spiracles can open and close to reduce water loss
spiracles are round valve like openings where co2 and o2 can leave and enter from here
why can o2 co2 diffuse across membranes
lipid part of membrane non polar
o2 co2 small non polar so diffuse in down conc grad
