1. The Urinary System

2. System Overview
Consists of:
Kidneys
Ureters
Urinary bladder
Urethra

3. System Functions
Removes certain salts and nitrogenous wastes from blood
Helps maintain normal concentrations of water and electrolytes within body fluids
Regulates the pH and volume of body fluids
Helps control red blood cell (RBC) production and blood pressure

4. Kidneys - Function Remove substances from the blood Form urine
Help regulate some metabolic processes by secreting hormones:
Erythropoietin-RBC
Renin-Blood Pressure

5. Kidneys - Location Either side of the vertebral column
In a depression on the posterior wall of the abdominal cavity
Between 12th thoracic and 3rd lumbar vertebrae
Left kidney is usually higher
Behind the parietal peritoneum
Held in place by CT and adipose

6. Kidney Structure Hilium Renal pelvis Renal papillae Renal medulla
Calyces
Renal papillae
Renal medulla
Renal cortex
Nephrons

7. Kidney Blood Supply Renal arteries Renal veins From abdominal aorta
Branches in kidney to form afferent arterioles
Renal veins
Join the inferior vena cava

8. Nephron Structure Renal corpuscle Renal tubules Glomerulus
Glomerular (Bowman’s) capsule
Renal tubules
Nephron loops (loop of Henle)
Dump filtrate into collecting ducts  calyces

9. Blood/Urine Pathways

10. Urine Formation Urine is a product of nephron activity.
It is formed by 3 processes:
Glomerular filtration
Tubular reabsorption
Tubular secretion

11. Glomerular Filtration
Produces filtrate (mostly water)
Pressure for filtration comes from blood pressure
Filtrate is similar to blood plasma

13. Urine Composition
Reflects the amounts of water and solutes that the kidneys must eliminate or retain to maintain homeostasis
Contains urea, uric acid, electrolytes, traces of amino acids
Average urine volume L/day
Volume depends on fluid intake, temperature, relative humidity, emotional state, respiratory rate, body temperature
Abnormal components:
Glucose, proteins, hemoglobin, ketones, and blood cells

14. Urine Elimination
Nephron  collecting ducts  calyces  renal pelvis  ureter  urinary bladder  urethra  outside of the body

15. Ureters
About 25 cm long
Extend from renal pelvis to the underside of the urinary bladder
Muscular walls propel urine by peristalsis
Flap-like fold acts as valve into the bladder

16. Urinary Bladder Hollow, distensible, muscular organ Stores urine
Forces urine into the urethra
Behind the symphysis pubis
Trigone

17. Bladder Stone Removal (Rough)

18. Bladder Stone Removal (Smooth)

19. Bladder Location in Females

20. Male and Female Bladder

21. Micturition Aka urination
Reflex triggered by stretching of the bladder:
Detrusor muscle contracts.
Abdominal wall and pelvic floor muscles contract.
Voluntary relaxation of external urethral sphincter
Reflex center located in the spinal cord.
Reflex accompanied by sense of urgency.
Bladder holds 600 ml,but urge begins at ml.

22. Urethra
Tube that conveys urine from the bladder to the outside of the body
Contains urethral glands that secrete mucus into the urethral canal
Incontinence

23. Dialysis Treatment