52R. Gas transport in the blood Flashcards
where is oxygen carried to from where
from the lungs to the tissues
where is carbon dioxide carries to from where
the tissues to the lungs
is oxygen soluble in water
no
what does oxygen transport require
a carrier
what molecule binds and transports oxygen
haemoglobin in RBCs
what shape is haemoglobing (use its proper name)
tetramer
what does tetramer mean haemoglobin can do
bind 4 oxygen molecules
what shape is myoglobin
monomer
what does myoglobin being a monomer mean
it can only bind to one oxygen molecules
what kind of curve shows the relationship between oxygen binding and partial pressure of oxygen (pO2).
dissociation curves
what shape is the haemoglobin dissociation curve
sigmoidal (S shape)
what are the two haemoglobin states and what are their respective affinities for oxygen
T state - Low affinity For Oxygen
R state - High affinity For Oxygen
oxygen combines reversible/irreversible
revesible
where is myoglobin present
muscle cells
what does the myoglobin dissociation curve show
how much oxygen myoglobin binds at different oxygen pressures (pO2)
The curve demonstrates that oxygen binding to myoglobin is reversible.
As pO2 increases, more oxygen binds to myoglobin until it reaches saturation.
Total oxygen content includes both bound and dissolved oxygen.
The curve saturates (levels off) because there is a limited amount of myoglobin available to bind oxygen
The Bohr Effect Explained Simply:
Oxygen Delivery:
Haemoglobin carries oxygen to different parts of your body
When you play or run around, your muscles work hard and produce more waste (carbon dioxide and acid).
The waste (carbon dioxide and acid) tells the haemoglobin to drop off oxygen in those busy areas.
How It Works:
The haemoglobin changes shape when it senses the waste, making it easier to unload the oxygen.
is arterial blood got high or low oxygen pressure in the alveoli
high
what is the normal haemoglobin amount in your blood
2.2mmol/L
EXTRA NOTE:
Normal Haemoglobin Amount: If you have a normal amount of haemoglobin in your blood, it’s about 2.2 mmol/L.
Oxygen Binding: Each haemoglobin molecule can carry four oxygen molecules.
Total Oxygen: So, the total amount of oxygen in your blood is:
2.2 mmol/L x 4 = 8.8 mmol/L
explain anaemia in relation to haemoglobin
Normal Haemoglobin Amount: If you have a normal amount of haemoglobin in your blood, it’s about 2.2 mmol/L.
Oxygen Binding: Each haemoglobin molecule can carry four oxygen molecules.
Total Oxygen: So, the total amount of oxygen in your blood is:
how much oxygen is still bound to haemoglobin in venous blood when its on its way back to the heart
half
what is the lowest tissue pO2 can get
3kPa
Do tissues, such as the heart muscle, have a high or low capillary density
HIGH.
pO2 can be lower because oxygen doesn’t have to travel as far to reach cells.
This is particularly important in metabolically active tissues, which require more oxygen and thus have a denser capillary network
when pH of the blood is low, what does the Bohr graph do
shift to the right
what happens when the blood is more acidic/lower pH (in relation to Hb)
releases oxygen more easily
promotes T state (tense)
in metabolically active tissues is pH higher or lower
lower
what 3 things make Hb give up oxygen more readily (shift the curve)
temperature, Low pH, 2,3 Bisphosphoglycerate
How much of the oxygen in arterial blood is used by the body under normal conditions.
27%
what is 2,3 Diphosphoglycerate
a metabolite produced during glycolysis
when do 2,3 Diphosphoglycerate levels increase
anemia or at high attitude
what does 2,3 Diphosphoglycerate allow
more O2 to be given up to the tissues
It binds to hemoglobin, reducing its affinity for oxygen, which promotes oxygen release in tissues that need it most.
in CO poisoning Carbon monoxide binds to hemoglobin (Hb) to form…?
Carboxyheamoglobin (COHb)
Binding to Hemoglobin: Carbon monoxide binds to hemoglobin in red blood cells much more strongly than oxygen does. This forms a compound called carboxyhemoglobin (COHb).
Blocking Oxygen: When CO binds to hemoglobin, it prevents oxygen from binding. This means less oxygen is carried in the blood.
Increased Affinity: The presence of COHb also makes the remaining hemoglobin hold onto oxygen more tightly, so it doesn’t release oxygen to the tissues as easily
what percentage does CO poisoning become fatal
> 50%
what is hypoxaemia
low pO2 in arterial blood
what is hypoxia
low oxygen levels in body or tissues
if pO2 levels are low - not all the Hb will be …………?
If Hb levels are low, not enough oxygen will be present in the …..?
Saturated
Blood
what can cause peripheral hypoxia
peripheral vasocontriction
what are the diseases when tissues are using O2 faster than it is delivered
Peripheral Arterial Disease
Raynaud’s
what is Cyanosis
bluish colouration due to unsaturated haemoglobin
Deoxygenated haemoglobin is less red than oxygenated haemoglobin
where can you see cyanosis
Can be peripheral (hands or feet) due to poor local circulation
Or central (mouth, tongue, lips, mucous membranes) due to poorly saturated blood in systemic circulation
when is cyanosis difficult to see
○ Poor lighting
○ Skin colouration
what is pulse oximetry and what does it do
small device that measures how much oxygen your Hb is carrying.
how do pulse oximeters work
uses light to detect the difference between oxygenated and deoxygenated haemoglobin
where do pulse oximeters detect
- Only detects pulsatile arterial blood
