HUBS192 Lecture 31 - Renal Physiology: Urine Composition, Functions of the Kidney and the Basic Nephron Processes Flashcards
what 6 things do you expect to be in normal urine?
1) 95 - 98 % water
2) creatinine (metabolic waste product)
3) urea, uric acid (comes from protein degradation and purines, toxic part of the protein)
- H+, NH3 (degradation of proteins and acid)
4) Na+, K+ (to keep blood pressure constant)
5) drugs (anti-viral, diuretics that actively secreted)
6) toxins
what 6 things do you expect in pathological urine?
1) glucose (glucosuria, diabetes)
2) protein (proteinuria)
3) blood (erythrocytes, haematuria)
4) haemoglobin (haemoglobinuria)
5) leukocytes
6) bacteria (infection)
what should normal urine look like?
clear, light or a dark amber look
what should normal urine taste like?
acidic with a pH of 5-6
what does it mean if urine tastes sweet?
it means that the patient has diabetes mellitus
what is the pH of urine dependant on?
dependant on diet
what is the pH of urine of vegetarians?
pH up to 7.2 (slightly alkaline)
what is the pH of urine of meat eaters?
pH of 4.8
what should normal urine smell like?
should have no distinct smell
what should pathological urine look like?
golden, red, brown or blue
what should pathological urine taste like?
sweet: indication of diabetes mellitus
what should pathological urine smell like?
- like fruits: ketosis (fasting), diabetes, chronic alcohol abuse
- rotten: infection (bacteria), tumour
what are the 5 parameters of urinalysis?
1) blood
2) specific gravity (osmolarity)
3) glucose
4) protein
5) pH
is glucose present in the plasma or in the urine?
in the plasma, it should never be in the urine
is proteins present in the plasma or in the urine?
in the plasma, it should never be in the urine
is blood present in the plasma or in the urine?
not present in either
what is the normal range for the osmolarity of gravity in plasma?
285-300 mOsmol/L
what is the normal range for the osmolarity of gravity in blood?
50-1335 mOsmol/L
what are the possible diseases/conditions if the normal values for blood changed or became positive in urine?
- haematuria
- urinary tract infection
- damage to the filtration barrier
what are the possible diseases/conditions if the normal values for gravity (osmolarity) changed or became positive in urine?
- polyuria
- diabetes mellitus
- diabetes insipidus (concussion)
what are the possible diseases/conditions if the normal values for glucose changed or became positive in urine?
- glucosuria
- diabetes mellitus
what are the possible diseases/conditions if the normal values for protein changed or became positive in urine?
- proteinuria
- glomerulonephritis
- image to the filtration barrier
what are the possible diseases/conditions if the normal values for pH changed or became positive in urine?
- diet-dependant (athlete, vegetarian) conditions
- acidosis
- alkalosis
- asthma
- anxiety disorder
what is the volume of normal urine per day?
1.5 L per day
where are low oxygen levels detected by?
detected by the kidneys
what does the kidney release?
releases erythropoietin (EPO)
what does erythropoietin (EPO) stimulate?
stimulates the bone marrow to produce more red blood cells
what is chronic renal failure?
anaemia which is low levels of red blood cells/haemoglobin hah leads to low blood oxygen levels
what is the function of salt/ion homeostasis in terms of potassium ion concentration?
in all cells resting membrane potential is based on the potassium gradient (inside/outside) of cells
what does potassium ion homeostasis control in terms of neurons and cardiomyocytes?
- action potentials
- rhythm generation in pacemaker cells
- contractility
- signalling
what does potassium ion homeostasis control in terms of neurons and cardiomyocytes?
- action potentials
- rhythm generation in pacemaker cells
- contractility
- signalling
what is hyperkalemia?
kidney disease/failure that results in death in a build up of potassium levels
how much potassium is required per day from the diet?
5g of potassium per day based on dietary need
how are lipophilic compounds metabolised?
passed from the blood to the liver to be more hydrophilic, water soluble compounds and then are released again into the blood to be excreted by the kidneys
what is aspirin and where is it secreted?
a common pain killer that is highly water soluble (hydrophilic) and is excreted directly by the kidneys
what is equation for pH?
-log(H+)
what is the blood pH of alkalosis?
blood pH greater than 7.4
what is the blood pH of acidosis?
blood pH less than 7.4
what is the function of bicarbonate (HCO3-) in the blood?
bicarbonate (HCO3-) is the main buffer of the blood neutralising acids from metabolism, food and drinks, and maintaining a blood pH of 7.4
how is the bicarbonate (HCO3-) concentration controlled in the blood?
bicarbonate (HCO3-) concentration in the blood is controlled by the lungs through exhalation of CO2 and the kidneys reabsorbing bicarbonate (HCO3-) or the secretion of H+ ions
what are the 9 general functions of the kidney?
1) water homeostasis (hydration, blood pressure)
2) salt/ion homeostasis (Na+, K+, Ca2+, blood pressure)
3) re-absorption of nutrients (amino acids, glucose)
4) filters blood
5) pH regulation
6) excretion of drugs, endogenous metabolites and toxins
7) hormone production of EPO
8) metabolism
9) gluconeogenesis
what are the 3 basic nephron processes of the kidney?
1) filtration
2) secretion
3) re-absorption
what is the effect of filtration in the kidney?
creates a plasma-like filtrate of the blood
what is the effect of reabsorption in the kidney?
removes useful solutes from the filtrate and returns them to the blood
what is the effect of secretion in the kidney?
adds additional wastes from the blood to the filtrate
what is the process that occurs in the glomerulus of the nephron?
filtration
what is the process that occurs in the proximal tubule of the nephron?
bulk reabsorption of electrolytes (sodium, potassium), secretion of metabolites, drugs and toxins
what is the process that occurs in the distal tubule of the nephron?
fine-tuning of electrolytes/water reabsorption
what is the process that occurs in the collecting duct of the nephron?
fine-tuning of electrolyte/water reabsorption
how is glucose handed and where is it handled in the nephron?
glucose is only reabsorbed in the proximal tubule
how is potassium handed and where is it handled in the nephron?
potassium is reabsorbed or secreted in different parts of the tubule (depends on diet)
how is water handed and where is it handled in the nephron?
water is reabsorbed in most parts of the tubule
how are drugs and toxins handled and where is it handled in the nephron?
penicillin is mostly excreted by active secretion, not filtration
how are big molecules handed and where is it handled in the nephron?
big molecules are not even filtered
