Comparative Anatomy and Physiology of Animals
Lecture 8 Oxygen Transport and Blood Acid-Base Balance 03/11/20
Respiration in Vertebrates
- Principles of gas exchange by active ventilation
- Rate of oxygen uptake depends on 1) volume flow of air or water per unit time, and 2)
amount of O2 removed from each unit volume
Red blood cells (erythrocytes)
- Vary in size and shape in vertebrates.
- All species except mammals have nucleated red blood cells
- All contain haemoglobin
- Produced in bone marrow under hormonal control (haemopoietin produced in kidneys)
Oxygen transport
- Only one O2 molecule can bind to a haem group at a time
- 20mL O2 per 100 mL blood
- Oxygen saturation = % of binding sites filled
Oxygen transport and release
Oxygen transport during exercise
- pO2 of the blood leaving a particular tissue (venous reserve) depends on: Rate of blood flow
through the tissue, arterial pO2, amount of haemoglobin per unit of blood volume, and
tissue’s rate of oxygen consumption
- Blood passes through lungs faster reducing the time for equilibrium between air and blood
so blood pO2 leaving the lungs decreases but O2 content is hardly affected
Oxygen transport
- Binding capacity is enhanced by the presence of oxygen that is already bound –
cooperativity. This shifts the line to the right.
- Oxygen equilibrium curves vary: in shape because of various molecular forms of
haemoglobin in different species, and in height which reflects the amount of haemoglobin
present in the blood.
, Oxygen affinity
- P50 is an index of the affinity of a
respiratory pigment to O2
- P50 is the partial pressure in the blood
at 50% oxygen saturation
- A shift to the right leads to a reduced
O2 affinity
Bohr effect
- Decrease in pH reduces oxygen affinity and shifts oxygen equilibrium curve to the right.
Oxygen affinity
- An increase in temperature decreases oxygen affinity and shifts oxygen equilibrium curve to
the right.
- Blood at high temperatures can carry more oxygen at saturation.
- A decrease in pH reduces the oxygen-carrying capacity of haemoglobin in eels.
CO2 transport
- Dissolved in the blood plasma as CO2 molecules but is only a fraction is as a dissolved gas.
- Forms carbonic acid when dissolves in aqueous solution. Bicarbonate ions can also dissociate
into a hydrogen ion and a carbonate ion
- CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller chloegalvin. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £6.99. You're not tied to anything after your purchase.