1. THE URINARY SYSTEM
ITEC Exam
2 questions

2. Functions Waste Disposal Filters Blood Produces Urine Regulates Salts
Regulates Water Levels

3. Structure of the Kidney
Two, bean shaped, 11cm long
25% blood passes through to remove toxins
2 distinct parts
cortex (outside)
medulla (middle - inside)
Known as Renal Pelvis (funnel)
Hilum – point of entry for blood and lymphatic vessels, nerves and the ureters
Function – filter blood, reabsorption, form urine

5. Ureters 2 Tubes connecting kidneys to bladder 10 - 12 inches long
Function
Take urine to bladder
Urine stimulates mechanical contraction to move fluid forward

6. Renal Pelvis Structure – A funnel Connects medulla to ureter Function
Collects urine in tubules & passes onto ureter
Renal Pyramids with collecting Ducts
Renal Calyces
Renal Pelvis
Ureters

7. The Bladder Sac like organ in pelvic cavity Function
a reservoir for urine
Collection 200ml urine
walls contract
sphincter relaxes
empties into the urethra
Autonomic nervous system stimulates nerve endings to make bladder contact
Average human excretes between 1 to 2 litres of urine a day

8. The Urethra
Structure
A narrow tube passing from bladder to outside the body
Voluntary controlled external sphincter
Shorter in women – 4cm men – 20cm
Function – take urine from bladder out of body
In men also passage for semen

9. 3 Stages of Filtration & Urine Production
Each Kidney has 1 million filtration or Nephron’s
Filtration in the Bowman’s Capsule
Re-absorption in the Convoluted Tubules
Collection in the Pelvic Calyces

10. Stage 1 – Blood Filtration
Afferent arterioles turn into the Glomerulus
Water & salty substances only pass from the capillary through the Bowman’s Capsule wall
Bowman’s Capsule collects these waste products
Collects water, glucose, salts, ions – reabsorbed passing through Nephron

11. Stage 2 – Re-absorption
Filtered substances pass from Bowman’s Capsule into
Proximal Convoluted tubules which straightens into
“The Loop of Henle” and then into Distal Convoluted Tubule
Re-absorption of water, glucose, salts and ions take place in the tubules
1% of fluid filtered by Bowman’s Capsule is excreted as urine the rest is re-absorbed

12. Stage 3 Collection
Fluid passes into collecting tubes in Medulla known as
Pyramids which are in the renal pelvis
Collected waste liquid is
Funnelled through and emptied into ureter
2 Ureters that connect kidneys to the bladder

13. Keeping Balance
Secretion
Micturition
Electrolyte

14. Urine 96% water Salts excreted to maintain balance
2% urea 2% other
(ammonia, sodium, potassium, etc
Salts excreted to maintain balance
Colour from – bilirubin,
Normally acidic
1.5 litres produced daily
Increases - intake, cold, stress
Decreases - sweating, drinking less
Need 0.5 litres of water per day for waste disposal
NORMAL
Drink a glass of water
Drink ¼ -1/2 litre
Bilirubin – bile pigment
Drink 1/2 litre +
Drink 2 litres

15. Osmosis & Urine System Antidiuretic Hormone (ADH) / Vasopressin
Diffusion of water through a semi-permeable membrane
Reabsorption

16. Diseases & Disorders
Cystitis – inflammation of bladder – can be caused by infections – common in women (shorter urethra)
Diabetes Insipidus - a condition characterized by excessive thirst and excretion of large amounts of severely diluted urine

17. Diseases & Disorders Cancer Glomemlonephritis
can affect ureter, bladder, renal pelvis and kidney
Glomemlonephritis
inflammation of the filtering units of the kidney glomeruli – is often related to an autoimmune disorder

18. Dysuria – painful urination Enuresis – bed wetting
Incontinence – Inability to control reflex emptying the bladder
Nephroblastoma – Cancer of the kidneys in infancy
Renal Failure – failure to function adequately
Renal Colic – Intermittent pain
Uraemia
– Excess of urea in the blood 4 5

19. Interrelationships with other systems
Circulatory - purify blood
Endocrine - produce Renin – regulates blood pressure
Skeletal - help stimulate production of bone marrow
Skin - removes waste as does other excretory system - skin