Module 4 - Fluids & pH Flashcards
What are isotopes
Version of a element that is dependent on its mass number
Mass number =
Number of protons + number of neutrons
How do polar water molecules keep ions and small polar molecules in solution
They form hydration spheres
What are electrolytes
Inorganic ions that conduct electricity in solution
What’s a colloid
Solution of very large organic molecules eg blood plasma
Where does the exchange amoung subdivisions of extra cellular fluid occur
Primarily across endothelial lining of capillaries
The body composition from most to least in Kg
Proteins, lipids, minerals, carbohydrates, miscellaneous
What’s the difference between the osmotic concentration of ICF and ECF
They’re identical due to osmosis
Do homeostatic mechanisms response to changes in the ECF or ICF
ECF
Three hormones effecting fluid and electrolyte balance
Antidiuretic hormone, aldosterone, natriuretic peptides
What two things does antidiuretic hormone stimulate
Water conservation in the kidneys and thirst
What causes antidiuretic hormone production
When osmoreceptors in the hypothalamus pick up a change in osmotic concentration in the ECF, then neurons secrete ADH
Where in the hypothalamus is antidiuretic hormone released
Axons of neurons in anterior hypothalamus near fenestrated capillaries during neurohypophysis
What does the rate of release of antidiuretic hormone depend on
Osmotic concentration, higher concentration = increased release
What happens to plasma volume and electrolyte concentration when the body loses water
Plasma volume decreases, electrolyte concentration rises
What happens when water is lost but electrolytes remain
ECF osmotic concentration rises and water moves from the ICF to ECF
What are the results of severe water loss
Excessive sweating, inadequate water consumption, vomiting, diarrhoea
What are two physiologic mechanisms to water loss
ADH and Renin secretion
If ECF volumes rises, blood volume goes ….
Up
If ECF volume drops, blood volume …
Goes down
What is hyponatremia
When body water content rises (over hydration)
What is hypernatremia
Body water content declines (dehydration)
Two steps of potassium balance
Rate of gain across digestive epithelium, rate of loss into urine
What regulates potassium loss in urine
Ion pumps
Acids are proton ,,, and bases are proton ,,,
Donor, acceptor
What do buffers do
Neutralise either strong acids or bases
Important buffer in humans
Sodium bicarbonate
What are antacids
Basic compounds that neutralise acid and form a salt
Equilibrium equation for carbonic acid
H2CO3 H^+ + HCO3^-
What is acidosis
Physiological state resulting from abnormally low plasma pH
What is alkalosis
Physiological state resulting from abnormally high plasma pH
What body systems in particular do acidosis and alkalosis effect
Nervous and cardiovascular system
Three types of acids in the body
Fixed acids, organic acids, volatile acids
What are fixed acids
Acids that do not leave solution, once they’re produced they remain in body fluids until eliminated by kidneys
Two most important fixed acids in the body
Sulfuric acid and phosphoric acid
What are organic acids
There are two types, those produced by aerobic metabolism and those produced by anaerobic metabolism
What is carbonic acid
A volatile acid that can leave solution and enter the atmosphere
What happens to carbonic acid in solution with peripheral tissues
Interacts with water to form carbonic acid
What is released when carbonic acid dissociates
Hydrogen ions and bicarbonate ions
What is carbonic anhydrase
Enzyme that catalyses dissociation of carbonic acid
What is the most important factor affecting pH in Body tissues
Pco2
What happens to pH when CO2 levels rise
pH goes down as H+ and bicarbonate ions are released
How does process at the alveoli effect pH
Blood pH rises as CO2 diffuses into the atmosphere
How are H+ ions gained and eliminated
Gained - at digestive tract, through cellular metabolic actives
Eliminated - at kidneys and in urine, at lungs
Why must H+ ions be neutralised
To avoid tissue damage
List the three major buffer systems
Protein buffer systems, carbonic acid-bicarbonate buffer system, phosphate buff system
What does the protein buffer system do
Helps regulate pH in ECF and ICF,
What does the phosphate buffer system buffer
pH of ICF and urine?
What does the protein buffer system depend on
Amino acids
How does the protein buffer system work if pH rises
If pH rises causes carboxyl group of amino acids to dissociate acting as a weak acid releases a hydrogen ion chases the group to become a carboxylate ion
How does protein buffer system work if pH drops
Carboxylate ion and amino group act as weak bases and accept H+ ion which forms a carboxyl group and amino ion
