Golden points from Urinary system (anatomy)

 

Urinary system

Major organs :-

1)  Kidneys - 2

2)  Ureters - 2

3)  Urinary bladder - 1

4)  Urethra - 1

 

Kidneys :

Ø The structural and functional unit of kidney is nephron.

Ø Kidney is bean shaped organ and brown in colour.

Ø The dimension of kidney is length - 11cm, breadth - 6cm and width - 3cm.

Ø It is extended from thoracic 12­­­^th vertebra to 3^rd lumber vertebra.

Ø Right kidney is slightly lower in level than left kidney due to presence of liver in right side.

Ø Kidney filters the whole blood in 4 minutes.

Ø Outer part of kidney is called cortex and inner part is medulla.

Ø Hormones secreted by kidney are Vitamin D₃, Renin Erythropoietin

Ø 25% blood of cardiac output goes in kidney.

 

Nephrons :

·      Each kidney consists of 1-3 million nephrons.

·      One nephron is 6cm.

·      Parts of nephrons (4) :

1.  Bowmen's capsule (Glomerular capsule)

2.  Proximal convoluted tubule (PCT)

3.  Loop of Henle (LoH)

4.  Distal convoluted tubule (DCT)

 

Steps in urine formation :

1)  Simple filtration

2)  Selective/tubular reabsorption

3)  Secretion

 

vDrugs are eliminated by the process of secretion.

vNet filtration pressure of Glomerulus is 10 mm of Hg.

vGlomerular filtration rate (GFR) is 125 ml/min. or 180 litre/day.

vAverage production of urine in healthy person is about 1000 ml to 1500 ml per day.

vComposition of urine :

o  Water - 96%

o  Urea - 2%

o  Others - 2% (uric acid, creatinine, ammonia, sodium, potassium, chlorides, phosphorus, oxalates etc.)

vpH value of urine is 6 (4.5-8) normally slightly acidic.

vDrug Rifampicin can cause red urine (orange colour).

 

§  Length of ureter is 25 cm and diameter is about 3 mm

§  Capacity of urinary bladder is 500 ml.

§  But when 200-300 ml of urine is collected, we feel to urinate.

 

Some useful terms :

ü Pyelonephritis - inflammation of kidney

ü Cystitis - inflammation of urinary bladder

ü E. coli - most common cause of UTI

ü Calcium oxalates - most common urinary stone

ü Anuria - absence of urine or less than 100 ml

ü Chyluria - chyle in urine

ü Hematuria - blood in urine

ü Dysuria - difficulty or pain during urination

ü Polyuria - more than 3000 ml urine per day

ü Oliguria - urine output less than 400 ml/day

ü Pyuria - pus in urine

ü Nocturia - passing more urine during night time

ü Enuresis - Bed wetting/urination in bed

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