5- The Kidney in Acid Base Balance Flashcards
What are the functions of the kidneys
Remove waste products/drugs from
the body.
Balance the body’s fluids.
Help maintain blood pH.
Release hormones that regulate
blood pressure.
What is a normal blood pH
7.4
What are the symptoms of Acidosis
Central Nervous System
Headache
Sleepiness Confusion
Loss of consciousness
Coma
Respiratory System
Shortness of Breath
Coughing
Heart
Arrhythmia
Increased heart rate
Muscular System
Seizures
Weakness
Digestive System
Nausea
Vomiting Diarrhea
Symptoms of Alkalosis
Central Nervous System
Confusion Light-headedness Stupor
Coma
PNS
Hand tremor
Numbness in the face hands or feet
Muscular System
Twitching Prolonged spasms
Digestive System
Nausea Vomiting
What does the law of mass action state
The rate of a chemical reaction is proportional to the product of the concentration of the reactants.
What is the relationship between blood concentration of HC0-3 and CO2
pH= 6.1 + Log ([HCO3]/0.02 x pCO2)
What are sources of H+ gain
- CO2 in blood
- Non-volatile acids from metabolism (e.g. lactic acid)
- Loss of bicarbonate in diarrhoea
What are the sources of H+ Loss
Use of H+ in metabolism of organic anions
* Loss of H + in vomit (stomach acidic!)
* Loss in urine
* Hyper-ventilation
What are the two main ways the kidneys maintain acid-base balance
cells reabsorb bicarbonate HCO3 from the urine back to the blood and they secrete hydrogen H+ ions into the urine.
How does the law of mass action explain the acid-base balance
Low molecular weight
compounds are filtered into the lumen of the nephron.
This includes bicarbonate ions which will then be lost in urine unless the body can reabsorb the bicarbonate.
This is achieved by the tubular epithelial cells.
HCO3- in interstitial fluid then gets into capillary
Bicarbonate ions are synthesised
in the tubule cells, as long as a“sink” for hydrogen ions(hereHPO42-) is available.
What are the major hormones involved in the kidneys regulation of blood pressure
Angiotensin II
* Antidiuretic hormone (ADH)
* Aldosterone
* Atrial Natriuretic peptide (ANP)
What do juxtaglomerular cells do
They are smooth muscle cells in afferent arteriole wall detect changes in blood pressure
Secrete the enzyme renin to trigger RAS if blood pressure fails.
What do macula densa cells do
Cells in the wall of the distal tubule in this area monitor the osmotic potential in the filtrate in the distal tubule
stimulate JG cells to release renin if filtrate is too dilute
What is ADH release stimulated by
Angiotensin II
Drop in BP
Increase in plasma solute concentration
What does ADH release result in
increased water permeability at DCT and collecting duct
Stimulates thirst center in hypothalamus
Changes water permeability by moving intracellular
aquaporins - water channels -to plasma membrane
