Renal - Function 1/2 Flashcards
What are the functions of the kidney?
(Know 4)
Regulate water and electrolyte balance
Regulate arterial pressure
Excrete metabolic waste/foreign chemicals
Regulate blood pH
Regulate erythrocyte production
Regulate hormone production (vitamin D)
Regulate blood glucose
How does the regulation of water and electrolyte balance affect the arterial pressure? What is its impacts on the body?
Controlling water and electrolyte removal/retainership over the long term lower/increases blood pressure
How does the kidney regulate pH?
It removes/retains HCO3- and H30+
What is the overarching role of the kidney?
To maintain the homeostasis
What happens when the kidney doesn’t function?
Swelling, high blood pressure, shortness of breath, fatigue, nausea
What is the role of the kidney in the cardiovascular system?
It controls how much blood goes into the heart
How does water move within the body?
By osmosis
What is osmosis?
The movement of water through a selectively permeable membrane form an area of lower solute concentration (i.e. high water concentration) to an area to higher solute concentration (i.e. lower water concentration)
What is osmotic pressure?
The pressure required to prevent net water movement (i.e. pressure required to stop water moving through selectively permeable membrane)
What is osmolarity?
A measure of the osmotic pressure exerted by the individual solution across a selectively permeable membrane compared to pure water per volume (i.e. 150mM NaCl into 1L of water = 150mML-1 of Na+ and Cl- therefore ~300mOsmL-1)
What is osmolarity dependent on?
The number of particles in solution (not the nature of the particles)
What are the three types of relative osmalrity? What do they mean?
Hyperosmotic - A solution with a higher relative osmolarity than another solution (i.e. it has a higher concentration of solutes)
Isosmotic - Where two solutions have the same osmotic pressure (i.e. both solutes have the same concentration of solutes)
Hyposmotic - Where a solution has a relatively lower osmotic pressure (i.e. it has a lower concentration of solutes)
What is tonicity?
The combine effects of the osmotic pressures and a cells permeability to a solute
If a cell was put into an isotonic solution of NaCl, what would the affect be? Why?
There would be no cell expansion because the osmolarity is the same so there is not net water movement and cells are relatively impermeable to NaCl so it can’t diffuse across
If a cell was put into an isotonic solution of urea, what would the affect be? Why?
There would be cell expansion because, even though they are isosmotic meaning no movement of water from osmosis, there is a lower concentration of urea in the cell than outside the cell and urea is highly permeable. This means that urea can diffuse into the cell which causes water to follow it to maintain osmolarity
What are the three types of relative tonicity? What do they mean?
Hypertonic (high POsm) - A solution with a higher partial osmotic pressure (POsm), i.e. the water will move into the solution as it has a higher concentration of solutes
Isotonic (same POsm) - the two solution have the same POsm, i.e. same concentration of solutes so no water movement
Hypotonic (low POsm) - a solution has a lower POsm than another, i.e. the solution has a lower concentration of solutes/higher concentration of water so water moves out of it
How do relative POsm interact?
When one solution has a higher POsm it exerts a greater pressure on the lower POsm solution so water moves down the pressure gradient
What is the percent of fluid in males and females? Why are they different?
55% fluid for female, 60% for males
Less for females because they have more fat cells
What is the intracellular and extracellular distribution of fluid?
Intra = 2/3, extra = 1/3
What is the distribution of extracellular fluid?
Interstitial = 4/5, Blood plasm = 1/5
If you were to drink 1L of isotonic fluid, where would this go in the body? Why?
1L would go into the extracellular fluid, of that 200ml into the blood, 800ml into the interstitial fluid and NONE into the intercellular fluid
This is because the osmotic pressure (POsm) of the isotonic fluid is the same as the intercellular fluid (hence isotonic) so its equal concentration gradient doesn’t allow for water movement
I you were to drink 1L of water (hypotonic solution), where would this go in the body? Why?
1L would be distributed throughout the body; 2/3 into the intracellular fluid, 1/3 into the extracellular fluid (4/5 of this into the interstitial fluid, 1/5 into the plasma)
The water is hypotonic (high water concentration, low solute). As the membranes are selectively permeable the solutes of the cell cannot pass through into the hypotonic solution, however water from the hypotonic solution by osmosis can move into the cells
What are the major sources of water intake?
Metabolism (8%), food (28%) and beverages (64%)
What are the major sources of water output?
Faeces (4%), lungs (12%), skin (24%) and urine (60%)
What are the sources of water input that are controlled and uncontrolled?
Controlled: Beverages and food
Uncontrolled: Metabolism
What are the sources of water output that are controlled and uncontrolled?
Controlled: Urine
Uncontrolled: Feces, lungs and skin
What are the three main ion in the body fluid?
K+, Na+, Cl-
Where is the concentration of Na+ high or low in the bodies fluid?
High: Blood plasma, interstitial fluid
Low: Intracellular fluid (inside the cell FYI)
Where is the concentration of K+ high or low in the bodies fluid?
High: Intracellular fluid
Low: Blood plasma, interstitial fluid
Where is the concentration of Cl- high or low in the bodies fluid?
High: Blood plasma, interstitial fluid
Low: Intracellular fluid (inside the cell FYI)
How much blood is filtered every day?
~180L
