Transport In The Blood Flashcards
What is tissue fluid?
A watery substance that contains oxygen, goucose and other nutrients. It bathes cells of tissues so the nutrients can diffuse into the cells. It provides cells with nutrients they require
Explain how tissue fluid is formed
At the arteriole end lf capillary, hydrostatic pressure is higher than the opposing water potential gradient.
Water and other small soluble substances are forced out of the capillary via its pores, down a pressure gradient
This forms tissue fluid outside the capillaries which can now bath cells around it.
Substances inside the fluid diffuses into cells
Explain How is tissue fluid returned into the capillaries
The hydrostatic pressure decreases along the capillaries die to the loss of water and increases concentration of plasma proteins
At the venule end, the inward water potential gradient is higher than the hydrostatic pressure, so water reenters the capillaries via osmosis. It now contains high carbon dioxide concentrations and lower pxugen concentrations.
Any excess tissue fluid is drained into the lymphatic system, then back to the circulatory system.
What is the hearts role in the formation of tissue fluid?
The left ventricle contracts to increase the hydrostatic pressure in the arterioles, which forces water down a pressure gradient out of the capillaries.
What is mass transport?
The movement of substances to and from exchange surfaces over large distances. Due to pressure differences
What is blood and what are the main components of blood?
Blood is a tissue, it transports substances during mass transport.
Compondnts- red blood cells, white blood cells, platelets and plasma
What is the role of red blood cells?
They trabsport oxygen from the kungs to the rest of the body, using haemoglobin
Describe three things that blood plasma transports (where from and where to)
Carbon dipxide from organs to lungs
Soluble products of digestion from the small intestine to other organs
Urea from lover to kidneys
Describe snd explain three adaptations lf red blood cells
Very small, meaning all RBCs are nearer to plasma membranes, which decreases the diffusion oathway for oxygen and increases the surface area to volume ratio
Biconcave shape, incraeses surface area to volume ratio even more, so rate of diffusion of oxygen is quicker.
No organelle, so there is more space for haemoglobin so more oxugen can be loaded and trabsported to respiring cells
Red blood cells lack organelles, suggest what cellular processes they cannot go through
No cell division due to no nucleus or chromosomes
No active transport due to no mitochondria
No protein synthesis due to no dna for prptein coding
What is haemoglobin and its characteristics?
It is the blood pigmant
It has a high affinity for oxygen
It is conjugated
It has a quaternary structure, as it contains 4 polypeptide chains
It contains haem groups that bind to 4 oxygen molecules
What is the role of haemoglobin?
It has a high affinity for oxygen
Itreadily loads oxugen when in high oxugen partial pressures
Transports oxygen around the body in the blood
It then unloads oxygen when in low oxugen partial pressures, allowing oxugen to diffuse into cells
What is percentage saturation of haemoglobin?
The amount of pxugen carried by haemoglobin
What is the name for haemoglobin once it has binded to oxygen?
Oxyhemoglobin
What is partial pressure of oxygena nd its units?
The pressure exerted by oxygen in a mixture of gases, it is a measure of oxygen’s concentration
Measured in pO2
Ehat is an oxugen dissociation curve and what shape does oxygen show?
It is the grapgical reprisentation of the behaviour of haemoglobin when subjected to different partial pressures
It shows a sigmoidial shape (S shape)
State Why does the oxugen dissocistion curve has a sigmoidial shape?
Due to cooperative binding.
Explain what cooperative binding is
It is where the binding of the first oxugen molecule onto haemoglobin changes the tertiary and wuaternary structure of the haemoglobin, which can create other binding sites or uncover other haem groups.
This allows another oxugen to be loaded
How does paryial pressure of oxugen effect haemoglobin
At higher pO2, haemoglobin has a higher affininity for oxugen, so oxugen is more readily loaded. Therefore percentage saturation in haemoglobin increases
At lower pO2 concentrations, haemoglobin has a lower affinity for oxygen, so oxygen is more readily unloaded. Percentage saturation in haemoglobin decreases
Where in the body will haemoglobin have a high or low affinity for oxygen, and how can this be shown on a dissociation curve?
High affinity at the lungs, where pO2 is higher (shown at the top right of curve)
Lower affinity near respiring tissues, where pO2 is lower and oxygen is needed for aerobic respiration (shown at the bottom left lf curve)
What is the Bohr effect?
Where the oxygen dissociation curve shifts to the right, meaning haemoglobin has a lower affinity for oxygen and unloads more readily
What factprs can cause the bohr effect?
An increased temperature
An increased carbon dioxide concentration
A decreased pH
In what type lf tissues is the Bohr effect most likely to take place?
In more active tissues, with higher metabollic rates. They will have a higher demand for oxygen, so due to the bohr effect haemoglobin can unload oxugen more readily to allow it to diffuse into respiring cells
What hapoens when the dissociation curve shifts to the left, and why may this happen?
Haemoglobins affinity for oxygen increases, so it is more readily loaded.
This may happen in animals that live areas of very low pO2 condidtioms, so they can still load enough oxygen ti transport around the body to maintain a high metabollic rate.
What is hydrostatic pressure?
The pressure of any fluid in an elcosed space
Why does an increased carbon dioxide concentration cause the bohr effect?
It causes the pH to decrease, which causes haemoglobin to release their load of oxygen
How can the lxugen dissociation curve moving to the right be beneficial?
As it means haemoglobin has an increased affinty for oxygen, so aerobic respiration can still take place even at very low pO2s
