Renal system

• The kidneys 


  • below the 11th/12th rib
  • retorperitoneal- behind the perineal membrane
  • one is lower than the other- right is lower as it is crowded by the liver
  • bean shaped
  • located in the superior lumbar region
  • on top of each kidney is an adrenal gland
• nephron 


  • approximately over 1 million nephrons in each kidney
  • produce urine
  • remove excess waste
• Glomerulus and bowmans capsule 


  • bowmans capsule covers the glomerulus
  • filters the kidney
• Urine 


  • 95% water
  • 5% solutes
  • uric acid
  • urea
  • creatine
  • ions
  • ph of 4.5-8
  • clear- yellow
• ureters 


  • transport urine from kidneys to bladder
  • lined by transitional epithelium (changes shape)
  • contains a smooth muscle- muscularis
• The bladder


  • composed of three layers
  • detrusor muscle- a muscular coat consists of three layers of smooth muscular fibres
  • subumucous coat- consisting a layer of areolar tissue
  • mucous coat- thin, smooth, loose texture, pale rose colour, thrown into folds or rugae when the bladder is empty
• The trigone


  • formed by three openings in the floor of the urinary tract
  • two are from the uterus and from the base of the trigone
  • small flaps of mucosa cover these openings and act as valves
• urethra


  • carries urine from the urinary bladder to outside the body
  • runs between the internal and external orifices
  • most lined by pseudostratified
• Micturition- passing urine


  • removes toxins and waste from the kidneys
• Fluid balance 


  principle- the amount of water lost from the body must equal the amount of water taken in
• regulating blood concentration and volume


  we can regulate blood concentration and volume by regulating urine concentration and volume

  we need to make sure our plasma has an osmolarity of about 300 milliosmoles

  • the more concentrated something is the higher its osmolarity vice versa
• How does ADH work


  • hypothalamus contains osmo-receptors that measure the plasma osmolarity
  • they adjust the release of ADH and this sends a message to the posterior pituitary to make changes in plasma osmolarity
• erythyropoiten 


  • hormone produced by the kidney
  • promotes the formation of red blood cells in the bone marrow
  • hypoxia- low oxygen
  • kidneys note this and release EPO that stimulates the production of rbcs
• where salt goes, water follows and chloride tags along
• Renal changes during pregnancy 


  • kidneys and ureters dilate
  • slow down in the flow
  • increases the risk of infection
  • internal urethral sphincter relaxes
  • to uriante more frequent
  • stress incontinence
  • increase blood volume and cardiac output
  • increase in renal flow and more filtration rate
  • increases urination
  • increases size of uterus and kidneys
  • decreases ureter motility