Urinary System Flashcards
Kidney functions:
• removal of waste
• water balance
• salt balance
• blood pressure homeostasis
• acid/base balance of blood
How are the kidneys held in place
By fat
Where are the kidneys
Retroperitoneal (back of the abdomen, behind the peritoneum)
Kidneys bear the major responsibility of:
Eliminating nitrogenous wastes, toxins and drugs
The kidneys filter gallons of?
Fluid from the bloodstream
How does the kidneys regulate blood volume
Maintains proper balance between water and salts, between acids and bases
What do the kidneys produce
• enzyme renin to regulate BP
• hormone erythropoietin to stimulate red blood cell production in bone marrow
The kidney cells convert:
Vitamin D produced in the skin to its active form, calcitriol
How much blood is filtered through the kidneys
One-quarter of the total blood supply every minute
What supplies the kidney with blood
The renal artery
What is the functional unit of the kidney
Nephron
Function of the nephron within the kidneys
• filter that forms urine
What is glomerular filtration
• non-selective, passive process
• fluid passes from the blood to the glomerular capsule & part of the renal tube
• filtrate (blood plasma without blood proteins)
• proteins and blood cells are normally too large to pass through the filtration membrane
• normal systemic BP allows filtrate to form
• low BP = low glomerular pressure and filtrate formation stops.
What is tubular reabsorption
• reclaims useful substances like water, glucose, amino acids, ions and return to blood
• active transport - uses membrane carriers, requires ATP and is selective
• some passive transport of water via osmosis
• mostly occurs in DCT
What is tubular secretion?
• elimination of substances that remain in the blood through peritubular capillary
• additional means for controlling blood pH
What are the 3 processes resulting in urine formation?
- Glomerular formation
- Tubular reabsorption
- Tubular secretion
Glomerular filtration rate (GFR):
• glomerular hydrostatic pressure: ~55mm Hg - blood pressure
• blood colloid osmotic pressure: ~30mm Hg - proteins in blood
• capsular hydrostatic pressure: ~15mm Hg - tubule resistance
• net outward pressure: 55-30-15 =10 mm Hg
What is GFR
GFR depends on the amount of blood flowing through the kidneys and the proportion of the plasma leaving the capillary
What can GFR be measured by
Creatinine clearance rate
The kidneys filters how much blood plasma
• 150-180 litres through their glomeruli into the tubules
• only about 1.0-1.8 litres of urine is produced - urine and filtrate are quite different
The normal yellow colour of urine is due to:
Chrome, a pigment that results from the body’s destruction of haemoglobin - solute urine is pale, straw colour.
• urine can be different colour due to certain foods eaten or the presence of bile or blood
Urine is denser than water because:
Of the solutes
Substances not normally found in urine
• glucose
• blood proteins
• red blood cells
• haemoglobin
• white blood cells (pus)
• bile
The pH of urine is usually
6
Kidney problems
• Chronic kidney diseases
• Kidney stones
• Inflammation
What are kidney stones disease (urolithiasis)
The form of crystals (renal calculi) from substances in the urine.
Calculi may stay in the kidney or move into the urinary tract, irritating and damaging it. Causing pain and dysfunction
Symptoms of Renal Calculi
• pain (resulting from inflammation, stretching and spasms of urinary tract
• blood in urine
• Raised temperature
• nausea and vomiting
• Painful urination
• cloudy urine
• urine changes - smell, more or less than usual
• crystals in urine
• fever and/or chills
Types of kidney stones
• crystine stones
• calcium stones
• uric acid
• struvite stones
Risk factor of kidney stones
• age
• male gender
• family history
• dehydration
• calcium supplements
• high diet in animal proteins
• oxalate - rich vegetables
• Coca Cola (contains phosphates)
• hyperparathyroidism (increase calcium concentration)
• recurrent urinary tract infections (struvite)
• other diseases or medical conditions
• obesity
• physical in-activity (bed-bound or inactive)
Diagnosis of kidney stones
• blood in urine
• pH indicate type of stone
• urinalysis dipstick
• imaging studies
Treatment of kidney stones
• high fluid intake for 24 hours to flush stone out
• promote dissolving crystals
• avoid phosphoric acid
• removal of the stones
What is renal failure?
• kidneys are unable to filter waste
• the organ is failing to perform its primary function
• leads to disruption in endocrine and metabolic function, fluid, electrolyte and acid-base disturbances
What is AKI (acute kidney injury)
• sudden damage to the kidneys that causes them to not work properly. It can range from minor loss of kidney function to complete kidney failure.
• normally a complication of another serious injury
• usually reversible if treated quickly
What is CKD (chronic kidney failure)?
• slow, chronic decline of renal functions. >75% of kidney function lost.
Symptoms of AKI (acute kidney injury)
• nausea
• vomiting
• confusion
• high BP
• abdominal/back pain
• oedema
