Exchange - Mass Transport In Animals Flashcards
What is the evidence that haemoglobin has a quaternary structure
Contains 4 polypeptide chains
What is made when haemoglobin combines with oxygen
Oxyhaemoglobin
Explain the term partial pressure
The amount of a particular gas in a mixture of gases or solution
Where is the partial pressure of oxygen highest in the body
In the alveoli capillaries in the lungs
Why is the partial pressure of oxygen lower in the tissues
Because of respiring tissues
Explain why the oxygen dissociation curve s sigmoid shaped
- Oxygen is complementary to the haemoglobin group
- Each time a molecule of oxygen attaches, haemoglobin changes shape
- This exposes ore of the next oxygen binding site
- This makes it easier for the next oxygen molecule to attach
What happens when the disassociation curve is shifted to the left
- Haemoglobin has a higher affinity or oxygen
- At the same partial pressure of oxygen, there is a greater percentage saturation of haemoglobin with oxygen
- So haemoglobin associates oxygen more readily and can be transported to tissues for aerobic respiration
What happens when the disassociation curve is shifted to the right when there is an increase in CO2 / active organism / increased respiration
- There is an increased rate of respiration
- This produces more carbon dioxide
- The curve shifts to the right (Bohr shift)
- This causes haemoglobin to have a lower affinity for oxygen
- At the same partial pressure of oxygen, there is a lower percentage of saturation of haemoglobin with oxygen
- So haemoglobin dissociates oxygen more readily at tissues for faster aerobic respiration
What happens when the dissociation curve is shifted to the left and altitude is present in the question
- Haemoglobin has a higher affinity or oxygen
- At the same partial pressure of oxygen, there is a greater percentage saturation of haemoglobin with oxygen
- So haemoglobin associates oxygen more readily and can be transported to tissues for aerobic respiration
- At altitude there is lower partial pressure of oxygen in the atmosphere
- So there will be a lower partial pressure of oxygen in the lungs
State the function of the valves
Prevents backflow of blood
Describe the three stages of the cardiac cycle
- Diastole (muscles are relaxed
) - Atrial Systole (atrial muscles contract)
- Ventricular Systole (ventricular muscles contracts)
Define the term cardiac output and what are the units
- The volume of blood pumped by one ventricle out of the heart in one minute
- dm3 min-1
Define the term heart rate
The rate at which the heart beats
Define the term stroke volume
Volume of blood pumped with each beat
What is the equation for cardiac output
Cardiac output = heart rate x stroke volume
Define mass transport
The bulk movement of liquids (and gases) use to a pressure difference
Why do large,active,multicellular organisms need a blood transport system
They have a low surface area to volume ratio and therefore require a specialised transport system
State why a double circulatory system is required
To ensure that oxygenated blood can be pumped efficiently at a higher pressure around the body
Name the blood vessels entering and leaving the kidney
- Renal artery - takes oxygenated blood to the kidney
- Renal vein - takes deoxygenated blood away from the kidney
Describe the structure of the arteries and arterioles
- High level of muscular tissue (arterioles)
- High level of elastic tissue (elastic tissue)
- Narrow lumen
Relate structure of the arteries and arterioles to their function
- High level of muscular tissue (arterioles) - To control blood flow by restricting or dilating (thickest in arterioles)
- High level of elastic tissue (elastic tissue) - To allow recoil during to pressure of systole (thickest in arteries)
- Narrow lumen - To maintain high pressure
Describe the structure of the veins
- Less elastic tissue
- Less muscular tissue
- Overall thickness less than arteries
- Valves
Describe the structure of the capillaries
- One cell thick (epithelium)
- Many & highly branched
- Narrow diameter
- Narrow lumen
- Spaces between
Relate structure of the veins to their function
- Less elastic tissue - Blood under less pressure returning to heart.
- Less muscular tissue - Blood returning to heart so less need to control flow to tissues
- Overall thickness less than arteries - Pressure too low to burst walls Allows flattening allowing compression by muscles
- Valves - Prevents back-flow of blood due to low pressure
Relate structure of the capillaries to their function
- One cell thick (epithelium) - Short, rapid diffusion pathway
- Many & highly branched - Large SA for diffusion
- Narrow diameter - Permeates tissue, close to all cells
- Narrow lumen - Red blood cells squeezed flat , reduces diffusion path for oxygen
- Spaces between - cells allows white blood cells to leave blood & enter lymph cells
Explain why arteries and veins are classified as organs
There are different types of tissues within them such as muscle and elastic tissue
What is tissue fluid
Made up of water, small organic molecules, mineral ions, gases and other substances
Describe how tissue fluid is formed and returned to the blood
- High hydrostatic pressure at the arterioles end of the capillary bed forces out wall soluble molecules and water
- Soluble proteins remain in the blood plasma because these molecules are too large to pass through the capillary walls
- The proteins create a more negative water potential at the venule end of the capillary
- Water enters the capillary by osmosis
- Some/excess fluid is also returned to the blood by the lymphatic system
Describe the order in which blood flows through the double circulatory system
- Vena cava
- Right atrium
- Right ventricle
- Pulmonary artery
- Lungs
- Pulmonary veins
- Left atrium
- Left ventricle
- Aorta
Explain the term association (loading)
When oxygen is taken up by haemoglobin, normally in the lungs
Explain the term dissociation (unloading)
When oxygen is released from haemoglobin, normally to be used in respiring tissues
Describe the structure of haemoglobin
- Quaternary protein
- Haemoglobin is made up of 4 polypeptide chains
- There is a haem group at the centre of each chain containing an iron ion to which one oxygen molecule binds
What happens during diastole phase
- Ventricle pressure is lower than the aorta/pulmonary artery
- Semi lunar valve is forced shut
- Atrium pressure is lower than veins and os blood flows into the atrium
What happens during atrial systole phase
- Blood enters the atrium and the increase in blood volume increases pressure
- Atrium pressure is higher than ventricular pressure
- Atrioventricular valve opens
- Atrium muscles contract, forcing blood into the ventricles
What happens during ventricle systole phase
- Ventricular pressure is greater than the pressure in the atrium
- Atrioventricular valve shuts
- Contraction of ventricles causes pressure in the ventricles to rise above that of the arteries
- Semi lunar valves are forced open and blood flows into arteries
Where does blood flow when atrioventricular valves are open
From the atrium to the ventricle
Where does blood flow when the semi lunar valves are open
From the ventricles to the aorta
