lecture 31 - renal / urinary physiology Flashcards
what do kidneys balance in our body
- water
- ions (sodium)
- pH
what are things that we consume that kidneys remove from our blood
drugs / medicines and toxins
what are things our cells produce that the kidneys remove from the blood
- from metabolism
- from breaking down old cells
what are the endocrine functions of the kidney
- kidney detects low EPO, which stimulates the release of EPO
- bone marrow then produces more red blood cells and therefore more oxygen can be carried
what is gluconeogenesis
during fasting or when the body is under stress : the kidneys make glucose from lactate
what are the two main sources of acid in the body
- acids coming from food + drink and metabolism
- acids coming from CO2 = more CO2 leads to more H+ production because of equilibrium equation
how is the pH of the blood controlled
- lungs = exhalation of carbon dioxide
- kidneys = by reabsorption and secretion of bicarbonate and hydrogen ions
how are hydrophilic drugs and toxins excreted from the body
excreted directly by the kidneys
how are lipophilic drugs and toxins excreted from the body
excreted by the kidneys after they have been metabolised ( as they are fat soluble )
what percentage of our total body water is extracellular fluid
1/3 (33%)
what percentage of our total body water is intracellular fluid
2/3 (67%)
what percentage of our ECF is plasma
1/5 (20%)
what percentage of our ECF is interstitial fluid
4/5 (80%)
what does an increase in the ICF fluid do in terms of cell size
swelling of cells
what does an decrease in the ICF fluid do in terms of cell size
shrinking of cells
what is osmolarity
the total number of solute molecules in a solution
what is the normal osmolarity of both the ECF and ICF
275-300 mosmol/L
what is a isosmotic solution
same amount of solute molecules per litre
- some osmolarity
what is a hyposmotic solution
increase in water
- less solute molecules per litre
- decrease in ECF/ plasma osmolarity
what is a hyperosmotic solution
decrease in water
- more solute molecules per litre
- increase in ECF/ plasma osmolarity
where will water initially enter when you drink water
the ECF
what occurs if there is a loss of WATER ONLY
- water will be lost from the ECF
- ECF osmolarity increases = so water moves from the ICF to the ECF until balanced
- loss of water from both ICF and ECF = cells shrink
what occurs if there is a gain of WATER ONLY
- water gain to the ECF
- ECF osmolarity decreases = so water moves from the ECF to the ICF until balanced
- gain of water to both ICF and ECF = cells swell
what occurs if there is a loss of isosmotic fluid
- loss of isosmotic fluid in the ECF
- osmolarity in ICF and ECF still the same
- no water movement = decrease in ECF volume only
what occurs if there is a gain of isosmotic fluid
- gain of isosmotic fluid in ECF
- osmolarity in the ICF and ECF still the same
- no water movement = increase in the ECF volume only
where does filtration occur
- occurs in the renal corpuscle / glomerulus
what is filtration
movement of plasma from the glomerulus capillaries into the glomerular capsule
what substances are not filtered
large proteins e.g albumin and substances bound to proteins
what is secretion (nephron)
movement of solutes from peritubular capillaries into the tubular fluid
where does secretion occur
proximal tubule
where does reabsorption occur
proximal tububle, nephron loop and distal tubule and collecting duct
what is reabsorption
movement os solutes from the tubular fluid into the peritubular capillaries
what occurs in the proximal tubule
bulk reabsorption and secretion
what happens in the distal tubule and collecting duct and what is it regulated by
fine tuning / regulated by hormones reabsorption of ions (sodium) and water
