Fluid compartments and Solutes Flashcards
Which cation is found in much higher concentrations extracellularly than intracellularly
Sodium ions are found in much higher concentrations extracellularly than intracellularly
Which cation is found in much higher concentrations intracellularly than extracellularly
Potassium ions are found in much higher concentrations intracellularly than extracellularly
How is the intracellular high potassium neutralised
By anions like negatively charged large molecules like DNA and proteins, phosphorylated proteins etcetera
What is the main intracellular and what the main extracellular anion
The main extracellular anion is chloride and the main intracellular anion is phosphate (bound to organic compounds)
How much more protons are found intracellularly than extracellularly and what is difference in pH
The difference in pH between blood plasma and cytoplasm is 0.3 (7.1 in cells, 7.4 in plasma) which is equivalent to approximately twice the protons in cells compared to extracellularly
What is the exception to identical osmolarity intracellularly and extracellularly
Identical osmolarity seen between cells and extracellular fluid is not seen in the kidneys where the excreted fluid is much more concentrated than intracellular osmolarity
What is the unit for osmolarity and is its definition
Osmol/L is the unit for osmolarity and it is defined as the number of moles of particles dissolved into a solution
Why is tonicity much more determinant than osmolarity in biological systems
Because in biological system permeability of membranes plays a role, osmolarity does not appropriately account for the outcomes of differences in osmolarity
How is the cell prevented from bursting despite higher intracellular concentration of impermeant solutes
The Na/K-pump actively pumps out sodium ions that flow down their concentration gradient to establish no net movement of sodium ions that therefore maintain a dynamic equilibrium in which there is higher intracellular concentration of impermeant solutes
When organs are donated, to what temperature is the organ cooled
Organs for donation are cooled to around 4 degrees Celcius
What is the function of the University of Wisconsin solution
The University of Wisconsin solution prevents organ cells from hypothermic swelling and enhance the preservation for transplantations
What three main factors in the UW-solution reduce swelling
The absence of sodium of chloride ions in the solution prevent an influx of sodium that can make membrane lose integrity, impermeant solutes like lactobionate and raffinol equalise osmolarity and starch acting as colloids to maintain high osmolarity in vascularity to prevent oedema
What is the function of allopurinol and glutathione in UW-solution
Allopurinol and gluathione serve as antioxidants to prevent against damage from reactive oxygen species that are released in hypothermic state
What happens to cell when Na/K-pump stops functioning
When Na/K-pump stops functioning, sodium ions start entering the cell and potassium starts the leaving the cell and water will follow the inward flow of sodium and this causes the membrane to lose its integrity and burst and this results in cell death
How does fluid leak out of vascular endothelium
Fluid can leave the capillaries through small pores between endothelial cells
How do lipid-soluble substances pass the vascular endothelium
Lipid-soluble substances pass through the endothelial cells to leave the capillary
How do certain proteins pass the vascular endothelium
Exchangeable proteins are transported through endothelial cells in vesicles that are transported from the luminal side of endothelial cell to outside into the tissue
What is colloid osmotic pressure
The osmotic pressure created in blood plasma by large insoluble plasma proteins that increase the blood plasma osmolarity such that only limited amounts of fluid leave capillary
By what force are molecules pushed out of capillary pores
By hydrostatic pressure that is caused by pumping of the heart, fluid and molecules are pushed out of capillary pores
What does the term oedema describe
Excess loss of fluid from a capillary into the interstitial space, due to loss of colloid osmotic pressure
How can increased permeability of capillary walls lead to oedema
In increased permeability plasma proteins that maintain the colloid osmotic pressure are lost, which means there is less resisting force of fluid leaving the capillary and the blood and this leads to excess fluid loss to the interstitial space
Why does interstitial fluid flow into lymphatic capillaries
Lymphatic capillaries have a lower internal pressure than the interstitial fluid, which leads to a net movement of the fluid into the capillaries
What is the order of the lymphokinetic motion
The blood flows into interstitial fluid, which flows into lymphoid capillaries, which flows into lymphoid veins, which flows into lymphoid ducts which empties in the bloodstream in large veins
In what two ways can lymph fluid be returned to the blood circulation
Lymphoid fluid can be returned to the blood circulation via lymphatic ducts emptying in large veins or via lymph nodes where lymphoid fluid can be returned through capillaries
In what two places do lymphatic ducts release lymphatic fluid into blood circulation
The thoracic duct empties lymph into the left subclavian vein and the right lymphatic duct empties lymph into the right subclavian vein
How can high blood pressure lead to oedema
High blood pressure leads to higher hydrostatic pressure in capillaries and because this is pushing fluid out, the same colloid osmotic pressure cannot counteract this and there is excess fluid loss to interstitial space and tissues
How can treatment of breast cancer lead to oedema
In carcinomas tumours often spread via the lymphatic system, so breast draining axillary lymph nodes are often removed and because the lymphoid fluid can then not be removed this leads to build up of lymphoid fluid and oedema in the arm
What is the cause and the consequence of elephantiasis
In elephantiasis parasitic worms block the lymphatic veins and this leads to build up of lymphoid fluid and this results in expansion of the tissue that cannot be drained
