Mass Transport in animals Flashcards
Describe the structure of Haemoglobin.
consists
each carrying.
Globular, water soluble. Consists of four polypeptide chains, each carrying a haem group (quaternary structure).
Describe the role of Haemoglobin
Something binds to .. to the ..
carried… to …
Oxygen molecules bind to the haem groups and are carried around the body to where they are needed in respiring tissues.
Present in red blood cells.
Name three factors affecting oxygen haemoglobin binding.
- Partial pressure/ concentration of oxygen
- Partial pressure/ concentration of carbon dioxide.
- Saturation of haemoglobin with oxygen
How does partial pressure of oxygen affect oxygen haemoglobin binding?
↑ the affinity of … for .. also
tightly
What happens to oxygen when PP is low.
As partial pressure of oxygen increases, the affinity of haemoglobin for oxygen also increases, so oxygen binds tightly to haemoglobin.
When partial pressure is low oxygen is released from haemoglobin.
How does partial pressure of carbon dioxide affect oxygen haemoglobin binding?
What happens to the conditions?
What happens to the shape
What happens to the affinity of o2.
What is this known as.
- As partial pressure of CO2 increases, the conditions become acidic causing haemoglobin to change shape.
- The affinity of haemoglobin for oxygen therefore decreases, so oxygen is released from haemoglobin. This is known as the Bohr effecting.
How does saturation of haemoglobin with oxygen affecting haemoglobin binding?
It hard does what?
Once it does what changes? it makes it for the..
What is this known as?
What about the 4th and why?
low chance od..
- It is hard for the first oxygen molecules to bind.
- Once it does, it changes the shape to make it easier for the second the third molecules to bind, known as +VE cooperativity.
- It is then slightly harder for the fourth oxygen molecules to binds because there is a low chance of finding a binding site.
Explain why oxygen binds to hemoglobin in the lungs.
PP is what?
high or low c of so what so what does this mean?
- Partial pressure of oxygen is high
- Low conc of CO2 in the lungs, so affinity is high +VE cooperativity (after the first oxygen molecules binds, binding of subsequent molecules is easier)
Explain why oxygen is released from haemoglobin in respiring tissues.
PP is what?
High..
so..
- Partial pressure of oxygen is low
- High conc of Co2 in respiring tissues, so affinity decreases
How does Co2 affect the position of an oxyhaemoglobin dissociation curve?
Shifts left or right?
and why.
affinity
Curve shifts to the right because haemoglobin’s affinity for oxygen has decreased
Name 3 common features of a mammalian circulatory system.
- Transport
- Maintaing
- Means of controlling
- Suitable medium for transport, water based to allow substance to dissolve.
- Means of moving the medium and maintaining pressure throughout the body, such as the heart
- Means of controlling flow so it remains unidirectional such as valves.
Describe what happens during atrial systole.
what controls and how?
The atria contract, pushing any remaining blood into the ventricles.
Describe what happens during ventricular systole.
The ventricles contract. The pressure increases, closing the atrioventricular valves to prevent backflow, and opening the semilunar valves. Blood flows into the arteries.
Name the nodes involved in heart conc and where they are situated.
- Sinoatrial node (SAN)= wall of right atrium
- Atrioventricular node (AVN)= in between the two atria
What does myogenic mean?
The heart’s contraction is initiated from the within the muscle itself, rather than by nerve impulses
Explain how the heart contracts.
- SAN initiates and spreads impulse across the atria, so they contract.
- AVN receives, delays and then conveys the impulse down the bundle of His
- Impulse travel into the Purkinje fibres which branch across the ventricles, so they contract from the bottom to top.
Why does the impulse need to be delayed?
If the impulse spread straight from the atria into the ventricles, there would not be enough time for all the blood to pass through and for the valves to close.
How is the structure of capillaries suites to their function?
- Walls are only one cell thick therefore, short diffusion pathway
- Very narrow, co can permeate tissues and red blood cells can lie flat against the wall, affectively delivering oxygen to tissues
- Numerous and highly branched, providing a large surface area.
What is tissue fluid?
A watery substance containing glucose, amino acids, oxygen and other nutrients. It supplies these to the cells, while also removing any waste material.
How is tissue fluid formed?
- As blood is pumped through increasingly small vessels, this creates hydrostatic pressure which forces fluid out of the capillaries.
- It bathes the cells and then returns to the capillaries when the hydrostatic pressure is low enough.
How does Oxygenated blood enter through the kidneys?
The renal artery
How does Deoxygenated blood leave the kidneys?
The renal vein
Why is oxygenated blood higher in the aorta?
To ensure blood is pumped to all tissues in the body
Which artery transports deoxygenated blood from the heart to the lungs?
Pulmonary artery
Coronary arteries
The blood vessels that supply blood to the heart.
Vena cava
The blood vessel that carries deoxygenated blood from the body into the heart.
Renal artery
The blood vessel that oxygenated blood flows through to enter the kidneys.
Aorta
The blood vessel that oxygenated blood flows out of the heart through and to the rest of the body.
Pulmonary vein
The blood vessel that carries oxygenated blood from the lungs to the heart.
What is the only artery that carries deoxygenated blood?
Pulmonary arteries
Where is deoxygenated blood carried from?
The heart to the lungs
What is the only vein that carried oxygenated blood?
Pulmonary vein
Where is oxygenated blood carried from?
The lungs to the heart
What is Carbon dioxide partial pressure?
The concentration of carbon dioxide in the cells.
What does it mean when the Oxygen partial pressure is high? (pO2)
Haemoglobin has a high affinity for oxygen and oxygen binds to haemoglobin.
What does it mean when Oxygen partial pressure is low?
Haemoglobin has a low affinity for oxygen and oxygen dissociates from haemoglobin.
What is the name given to haemoglobin that has bound to oxygen?
Oxyhaemoglobin
What is cardiac output?
The volume of blood pumped by one ventricle of the heart in one minute
How do you calculate cardiac output?
Cardiac output = heart rate x stroke volume
What is cardiac output measured in?
Measured in dm3/min
What does it mean when the Oxygen partial pressure is high? (pO2)
Haemoglobin has a high affinity for oxygen and oxygen binds to haemoglobin.
What does it mean when Oxygen partial pressure is low?
Haemoglobin has a low affinity for oxygen and oxygen dissociates from haemoglobin.
Primary strcture
Sequence of amino acids in the four polypeptide chains
Secondary structure
In which each of these polypeptide chains is coiled into a helix
Tertiary structure
In which each polypeptide chain is folded into a precise shape - an important factor in its ability to carry oxygen
Quaternary structure
All 4 polypeptides are linked togethet to form almost spherical molecule.
- Each polypeptide is associated with a haem group that contains a ferrous
Loading or associating
The process by which haemoglobin binds with oxygen.
In humans it takes place in the lungs
Unloading dissociating
The process by which haemoglobin releases its oxygen
Takes place in the tissues
What must haemoglobin do to be efficent at transporting oxygen:
- Readily associate with oxygen at the surface where gas exchange takes place
- Readily dissociate from oxygen at those tissues requiring it.
Explain how DNA leads to different haemoglobin molecules having different affinities for oxygen.
Different base sequences in DNA - different amino acid sequences
different teritary /quaternary structure and shape = different affinities of oxygen
When the body is at rest, only one of the 4 oxygens molecules carried by haemoglobin is normally released into the tissues.
Suggest why this could be an advantage when the organim becomes more active
If all O molecules were released, there would be none in reserve to supply tissues when they were more active
CO occurs in car exhaust fumes, It binds permantley to haemoglobin in prefrence to oxygen.
Suggest a reason why a person breathing in car-exhaus fumes might lose consciousness.
CO will gradually occupy all the sites on haemoglobin instead of Oxygen.
No O will be carried to tissues such as the brain , these will cease to respire and to function making the person lose consciousness.
