D6 gas transport Flashcards
identify pneumocytes, capillary endothelium cells and blood cells in this light micrograph
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identify a pneumocyte, capillary enodthelium cell and red blood cells in this electron micrograph
-
oxygen dissociation curves show the relationship between… (hint: refer to the x and y axes)
the partial pressure of oxygen and haemoglobin’s affinity to oxygen
at different partial pressures of oxygen, haemoglobin’s affinity to oxygen _________
changes
what is partial pressure? (understanding)
the pressure exerted by a gas in a mixture of gases
what’s the concept of cooperative binding (understanding)
the more oxygen bound to haemoglobin, the more higher the O2 affinity of haemoglobin
where does the haemoglobin become saturated with O2?
at O2 rich areas
at O2 rich areas, % O2 saturation of haemoglobin is [low/high]
high
at O2 deficient areas, % O2 saturation of haemoglobin is [low/high]
low
oxygen _____ from haemoglobin at O2 deficient areas
dissociates
the shape of the oxygen dissociation curve is _____-shaped
S
what are the factors that affect haemoglobin’s oxygen affinity?
- partial pressures
- temp
- pH
adult haemoglobin has [higher/lower] oxygen affinity than fetal haemoglobin at the same partial pressure
lower
why does fetal haemoglobin have higher oxygen affinity than adult haemoglobin at the same partial pressure
to ensure that maternal oxyhaemoglobin dissociates to release O2 for binding to fetal haemoglobin
where is myoglobin formed
muscle cells
what protein in the muscle cells stores oxygen?
myoglobin
what is the function of myoglobin?
it stores oxygen
myoglobin has [lower/higher] oxygen affinity than haemoglobin at the same partial pressure
higher
how does myoglobin function as an oxygen-storing molecule?
- it has a high affinity for O2
- it is saturated with oxygen at low partial pressures of O2
- it only releases oxygen rapidly at very low partial pressures of O2
what type of curve is the oxygen dissociation curve for myoglobin?
logarithmic
what is the function of myoglobin in intense exercise?
- during intense exercise, when O2 levels drop
- it releases O2 stores
- the slow release delays anaerobic respiration in muscles and lactic acid formation
how is CO2 transported in blood? (3)
- as dissolved CO2 in plasma
- as hydrogen carbonate ions in plasma
- bound to haemoglobin as carbaminohaemoglobin
when CO2 binds to haemoglobin it forms…
carboaminohaemoglobin
what is the enzyme involved in converting CO2 to HCO3-?
carbonic anhydrase
CO2 is converted by carbonic anhydrase into…
H+ and HCO3- (aka carbonic acid)
where is carbonic anhydrase found in?
RBC
where is HCO3- found in?
blood plasma
what ion causes blood to become more acidic?
H+
HCO3- ions are transported [out/into] the RBC at respiring tissues
out
HCO3- ions are transported out of RBC by… (process)
facilitated diffusion
___ is taken in when HCO3- exits RBC
Cl-
a [incr/decr] in pH causes haemoglobin to release O2
decr
what is another function of haemoglobin other than transporting O2?
- it functions as a pH buffer protein by absorbing H+
- this prevents a drop in pH
H+ in plasma comes from the ________ of carbonic acid
H+
what does carbonic acid dissociate to form?
HCO3- and H+
why must the pH of blood be regulated?
for optimal enzymatic activity!
____________ detect changes in blood pH
chemoreceptors
what is the function of chemoreceptors?
they detect changes in blood pH
chemoreceptors send _____________ to the ________
nerve impulses, medulla oblongata
which part of the brain controls ventilation?
the respiratory control centre in the medulla oblongata
where are chemoreceptors found?
- in the medulla oblongata
- in the aorta and carotid arteries
how is CO2 released from blood into the lungs for exhalation? (3)
- dissolved CO2 in blood plasma directly enters alveoli
- carbaminohaemoglobin dissociates to release CO2 from haemoglobin
- HCO3- from plasma is exchanged for Cl- ions in RBC –> forms carbonic acid with H+ in RBC
- carbonic acid is converted to H2O and CO2 by carbonic anhydrase to be released into plasma
carbonic acid catalyses a ________ reaction (think about the rxn it catalyses!)
reversible
give a possible scenario that would cause pH in blood to drop
exercise
how can one improve lung vital capacity?
regular exercise
how does the body react to a drop in blood pH
- ventilation rate incr + heart rate incr
- for quicker removal of CO2
- and for increased O2 uptake to support cell resp
what muscles are involved in ventilation? (recap of core)
intercostal muscles, diaphragm and abdominal muscles
to increase ventilation rate, where nerve impulses will be sent to?
intercostal muscles, diaphragm and abdominal muscles
what is the regulated range of blood pH?
pH 7.35-7.45
blood pH is regulated by…
homeostatic control
when blood pH <7.35, __________ occurs
acidosis
at what pH does alkalosis occur?
pH >7.45
what components in blood act as pH buffers?
plasma proteins and RBC
what is the Bohr shift? (defin.)
it is when the oxygen dissocation curve shifts right reflecting a decr oxygen affinity as a result of incr acidity
a decr in pH causes oxygen affinity in haemoglobin to [incr/decr]
decr
what causes the oxygen dissociation curve to shift right?
- when cells actively respire –> release more CO2 into blood
- CO2 converted into carbonic acid by carbonic anhydrase
- lowers the pH of blood
- causes O2 affinity of RBC to decr –> haemoglobin releases O2 at same partial pressures
when the oxygen dissociation curve shifts right, haemoglobin releases [more/less] O2 at ________ partial pressures
more, the same
how do RBCs know when to release more oxygen?
- at O2 deficient regions, CO2 conc is high –> pH decr
- haemoglobin’s affinity to O2 decr –> releasing O2
why is the Bohr shift important?
it ensures that respiring tissues get enough oxygen
at higher altitudes, there is [more/less] O2 in atmosphere
less
the partial pressure of O2 in atmosphere in the mountains is ________
lower
under what conditions is haemoglobin not fully saturated?
at high altitudes
how does the respiratory system respond in high altitudes?
- incr ventilation rate
- incr heart rate
if you climb a mountain and you haven’t climbed any mountain before what kind of illness will you get
mountain sickness
what are some symptoms of mountain sickness
nausea, dizziness, headache, fatigue
how does the body acclimatise to high altitudes? (apply) (5)
- incr production of RBC
- incr haemoglobin in RBC
- muscles produce more myoglobin
- vital capacity of lungs incr
- incr in capillaries in muscles and lungs
