Week 1 - Introduction to urinary system Flashcards
Where are the top of the kidneys located?
T11/T12
Name the sections of the kidney from outside to inside?
Cortex, medulla
What connects kidney to uterer?
Renal pelvis
What are the main functions of the kidneys?
Regulation - controls concentrations of key substances in ECF
Excretion - removes waste products
Endocrine - synthesis of renin, erythropoietin and prostaglandins
Metabolism - active form of Vitamin K, catabolism of insulin, PTH calcitonin
What is osmolality?
Solute per kg of solvent
What is osmolarity?
Number of osmoles of solute per litre
What is the osmotic force due to proteins called?
Oncotic force
What is the osmolality determined mainly by in the ECF and ICF?
ECF - Na and Cl (80%) - in clinical practise, estimated by doubling serum Na
ICF - K (50%)
What is the normal range for osmolarity in ICF?
280-310 mmol/L
What effect will failure to control extracellular electrolytes cause?
Affect transport and electrical functions
What is the relationship between kidneys, ECF and ICF?
Directly affects ECF, indirectly affects ICF
What happens if fail to control ECF volume?
Changes in blood pressure, tissue fluid and cell function
What happens if fail to control osmolarity of ECF?
Cell shrinks or swells
How much does a kidney filter a day?
180L
What is the average amount of urine produced a day?
1.5L
What is the structure of a nephron in order?
Glomerulus, proximal convoluted tubule, loop of henle, distal convoluted tubule, collecting duct
What are the functions of epithelium in kidney?
Excrete waste products from body
Reabsorb needed materials from filtrate
What percentage of cardiac output do the kidneys at rest?
22%
What is the function of the glomerulus?
Filtration
Water, electrolytes and small molecules forced through by pressure in capillaries
What is the function of proximal convoluted tubule?
Major site of reabsoption
What is the importance of sodium pumps?
Energy from sodium movement drives reabsorption of other substances
Water follows electrolytes osmotically
What is the function of the loop of henle?
Further reabsorption of salts
Creates gradient in increasing osmolarity in medulla which allows formation of urine if water has been conserved
What is the function of the distal convoluted tubule?
Reabsorption
Fluid leaving is hypotonic
Actively secretes H ions
Water may or may not follow reabsorption of electrolytes
What is the function of the collecting duct?
Water may or may not leave urine depending on osmotic gradient in medulla
