Urinary system

⮚ The renal pelvis continuous running and form a funnel like structure that leads to descends from hilum called ureter.
⮚ Both the ureter runs paralarlly with each other in the form of narrow tube (20-30 cm) which opens into the urinary bladder.
⮚ It is having 3 layers of tissue i.e., outer fibrous tissue, middle muscular tissue and inner epithelium tissue
it propels the urine from kidney into the bladder by peristaltic movement of the smooth muscle.
Urinary bladder:
⮚ It is a hollow, ballon like muscular sac which act as the reservoir for the urine received from the kidney.
It is made up of 3 layers of t tissue
-Outer layer
● loose connective tissue
-middle layer
● smooth muscle (called as detrusor muscle) and elastic fibres
-inner layer
● lined with transitional epithelium
⮚ The mean capacity of the bladder is 220 ml, filling beyond 220 ml causes a desire to micturate.
⮚ When smooth muscle is contracted and the sphincter is relaxed the urine can be released.
Function: it can temporarily store the urine till micturation and released the urine by reflex action.
Urethra: urinary bladder opens in a membraneous tube called urethra which is having the opening for passage of urine.
It is having 3 layers of tissues

  1. Outer elastic tissue and smooth muscles
  2. Middle submucosal layer
  3. Inner mucosal layer
    ⮚ It is about 4 cm long in female which opens separately called urethral orifice above the vaginal aperture
    ⮚ Incase of male it is about 18-20 cm long which opens as urinogenital aperture and it is the common passage for urine and spermatic fluid.
    Function : it act as a passage for urine.
    Disorders of urinary system
  4. Renal stone/ renal calculi:
    It is the formation of stone in the urinary tract which is due to the precipitation of salts (mainly calcium oxalate or calcium phosphate) in urine
    ⮚ Mostly it originate in collecting duct and papillae then pass into the pelvis which may increase in size and become too large to pass through the ureter , thus obstruct the outflow that leads to kidney failure
    ⮚ Sometimes it may arise in bladder and increase in size due to which they obstruct the urethra.
    Cause: it may cause due to dehydration, impairment of buffer system, due to some infection or due to abnormal metabolic condition(mainly hyperparathyroidism)
  5. Uremia:
    it is a condition in which the toxic substances like urea, uric acid, and creatinine are accumulate in blood and the concentration of these are more than normal.
    Cause: it may cause due to the abnormal functioning of kidney.
  6. Renal failure:
    it is occure when there is sudden and severe reduction in kidney function.
    ⮚ It may be acute or chronic
    The acute failure may be 3 stages
    ● Pre-renal
    ● Renal
    ● Post-renal
    Pre-renal: this results when there is reduced in renal blood flow
    Renal: damaged to the kidney itself due to ATN(acute tubular necrosis) and glomerulonephritis (inflammation in nephron)
    ATN: it occurs when there is severe damage to the epithelial cells due to ischaemia that results into oligouria ( 400 ml/day), severe oligouria(100 ml/day) and anuria (absence of urination)
    ⮚ It may last for few weeks
    Glomerulonephritis: it is mainly due to inflammation of glomerulus
    ⮚ It may be acute or chronic. Acute is characterized by the presence of oligouria, uremia, haematuria, proteinuria, hyperlipidaemia, hypertension etc.
    ⮚ Chronic occurs when nephrons are irreversibly damaged after the renal reserve is lost
    ⮚ Due to reduced in glomerular filtration, reabsorption and secretion leads to ‘oedema’ (accumulation of fluid inside ) body
    Post- renal : it occurs due to obstruction of outflow of urine either due to tumour in bladder or uterus or cervix or due to renal calculi.
    Chronic renal failure: this occurs when there is irreversible damage to the nephron (70 %)
    Cause: Glomerulonephritis, diabetes mellitus, hypertension etc.
  7. UTI (urinary tract infection): it is an infection which is due to microbes mainly bacteria or fungi ( mainly E. coli or S. faecalis)
    ⮚ It can be occure anywhere in the urinary tract . when it occurs in the upper tract i.e., in kidney and ureter it is called pyelonephritis but when it occurs in the lower tract i.e., in bladder and urethra then it is called cystitis.
  8. Acid base imbalance:
    Normally the buffer system, respiratory system, and kidney can do their work in coordination to maintain the PH of blood (7.35-7.45) . but under abnormal circumstances there may be a decrease in PH (<7.35) cause acidosis and increase in PH (>7.45) cause alkalosis.
    ⮚ This acidosis and alkalosis is 2 types that is
    ● Respiratory acidosis and alkalosis
    ● Metabolic acidosis and alkalosis
    Note : incease in CO2 level- acidosis
    Decrease in CO2 level- alkalosis

Urinary incontinence (involuntary urination):
This is a condition in which there is loss of urine involuntarily.
⮚ This is more common in young children due to undeveloped neuron during childhood. Incase of adult it may be due to UTI, calculi, injury, emotional stress, incase of older person it is due to enlargement of prostate gland.

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