Mass Transport In Animals Flashcards
What does haemoglobin consist of?
Consists of 4 polypeptide chains each containing a haem group including an iron ion
What type of structure is haemoglobin?
Quaternary
How many molecules of oxygen can each haemoglobin molecule transport?
4
What is another word for carbon dioxide or oxygen concentration?
Partial pressure
What does association mean?
When haemoglobin binds with oxygen
What does dissociation mean?
Haemoglobin releases oxygen
Where must haemoglobin readily associate or dissociate?
Readily associate where ppo2 is high in the lungs and readily dissociate where ppo2 is pow in respiring tissues
What is special about different haemoglobins?
Different affinity
What is the shape of the oxygen dissociation graph?
Curve
Why is the gradient at the start of the oxygen dissociation curve so shallow?
Shape of haemoglobin makes it hard for first o2 to bind as polypeptide subunits are very closed
What does the binding of the first oxygen molecule do?
Changes the quaternary structure
Why does the gradient steepen on the oxygen dissociation curve?
1st molecule changes quaternary structure so 2nd and 3rd can bind more easily called cooperative binding
Why does the gradient of the oxygen dissociation curve level off?
Harder to bind fourth oxygen molecule as less likely to find an empty oxygen site
What does it mean when the curve shifts right?
Lower affinity for oxygen loads o2 less readily but unloads more easily
What does it mean when the curve shifts to the left?
Higher affinity for oxygen loads oxygen more readily but unloads less easily
How is the heart supplied with oxygen?
Coronary arteries
What can happen if a coronary artery is blocked?
Cause myocardial infraction or heart attack
What are some risk factors of cardiovascular disease?
Smoking, high blood pressure, blood cholesterol has high density or low density lipoproteins, diet high salt or saturated fat
How can smoking cause cardiovascular disease?
CO combines with hb not o2
Nicotine stimulates adrenaline increases heart rate raises blood pressure
Makes platelets sticky higher risk of thrombosis
What are the 3 stages of the cardiac cycle?
- Relaxation of heart- diastole
- Contraction of atria - atria systole
- Contraction of ventricles- ventricular systole
What happens in diastole of the heart?
- Blood returns to the atria from the pulmonary veins and vena cava so pressure rises causing atrioventricular valve to open so blood flows into the ventricle
- Muscular walls and ventricle walls relax causing them to recoil reducing the pressure in the ventricle so semi lunar valve closes causing dub sound of heartbeat
What happens in atria systole?
- Contraction of atria walls recoil forcing remaining blood into ventricle from atria
- Muscle walls in ventricle remain relaxed