31 :D Flashcards
Why do we need kidneys?
To control WHAT is in our blood and HOW MUCH blood we have
Major functions of the kidney
To control WHAT is in our blood and HOW MUCH blood we have
Endocrine function of the kidney
➤ low blood oxygen levels are detected by the kidneys
➤ the kidneys release EPO
➤ EPO stimulates the bone marrow to produce more red blood cells
What happens when Chronic kidney/renal failure
➤ the kidneys cannot make enough EPO
➤ reduced red blood cell production
➤ ANAEMIA: low blood oxygen levels (dont have enough haemoglobin)
Function of the kidney - metabolic: gluconeogenesis
During fasting, or when our body is under stress:
- The kidneys make glucose (from lactate)
What is ph?
pH is a measure of how acidic or alkaline a solution is:
- pH = -log[H+]
- pH is the inverse (opposite) of H+ ion concentration
The more _____ ions there are the lower the _____
= more _____
The more H+ ions there are the lower the pH
= more acidic
The _______ H+ ions there are the _________ the pH
= more basic/alkaline
The fewer H+ ions there are the higher the pH
= more basic/alkaline
What happens when pH is not regulated tightly?
Acidosis vs alkalosis
- urine has a wider pH range as it allows us to pee out the extra acid or extra base
Two main sources of acid in the body:
- Acids coming from metabolism, food and drink
• direct sources of H+ (Non-volatile acids) - Carbon dioxide from metabolism
- more carbon dioxide you have the more you will shift the below equilibrium thus making more H+
Two systems The pH of the blood is controlled by:
- Lungs: exhalation of carbon dioxide (CO2)
- Kidneys: by reabsorption and secretion of bicarbonate (HCO3-) and hydrogen ions (H+)
Function of the kidney - Salt/ion homeostasis: what is it important for?
Potassium (K+) concentration is vital for many processes!!
Importance in all cells: the resting membrane potential is based on K+ gradient (inside/outside) of cell
Neurons and cardiomyocytes: APS, rhythm generation is pacemaker cells, contractiltiy, signalling
Too much potassium =
Death❌
In terms of ion homeostasis, what happens if the kidneys stop working?
hyperkalemia (death) - too much potassium
Major functions of the kidney: excretion of medications - which two in particular?
- Lidocaine is a commonly used local anaesthetic
- excreted by the kidneys AFTER metabolism in the liver due
to its fat soluble (lipophilic) nature (travel bound to a
protein which is too big to be filtered so goes via the liver
to be metabolised and be able to travel in the blood)
- excreted by the kidneys AFTER metabolism in the liver due
- Aspirin is a common pain killer
- excreted directly by the kidneys due to its high water
solubility (hydrophilic)
- excreted directly by the kidneys due to its high water
- medications are filtered and secreted by the kidneys to be excreted from the body in the urine
Major functions of the kidney: Body water balance
- Total body water remains relatively constant
- Intake and loss of water must balance
- Urine output is adjusted to maintain balance
Practice calculating
Volume of fluid in the body water compartments can change due to:
- how much water there is in the body
- the osmolarity of the body water compartments (water moves to where the osmolarity is the highest)
Why does it matter how much water there is in our body?
Increase in plasma = increase in BP
Decrease in plasma = decrease in BP
Increase in ICF = swelling of cells
Decrease in ICF = shrinking of cells
What is Osmolarity
The total number of solute molecules in a solution
Normal osmolarity:
Extracellular fluid (including plasma):
- 275-300 mosmol/L
Intracellular fluid:
- 275-300 mosmol/L
What does Isosmotic mean?
- same amount of solute molecules per litre
- same osmolarity
A change in the amount of ____ in the _____ changes the ______
A change in the amount of water in the ECF changes the osmolarity
