Urinary System Flashcards
Principal organs of the urinary system
Kidneys
Regulates the content of blood plasms to maintain “dynamic constancy” or homeostasis, of the internal fluid environment within normal limits
Urinary System
- Roughly oval with a medial indentation
- Approximately 11cm x 7cm x 3cm
- Lie on either side of the vertebral column between T12 & L3
- Renal fasciae anchor to surrounding structures
Kidney
Heavy cushion of fat the surrounds each kidney
Perirenal Fat Capsule
Renal Fat Pad
Outer region of the kidney
Renal Cortex
Inner region of the kidney
Renal Medulla
Make up much of the medullary tissue
Renal Pyramids
Areas where cortical tissue dips into the medulla between the pyramids
Renal Columns
Cuplike structure at each renal papilla that collects urine
Calyx
Narrows as it exits the kidney to become the ureter
Acts as a collection basin to drain urine from the kidney
Renal Pelvis
Tube running from each kidney to the urinary bladder
Ureter
- Composed mostly of smooth muscle tissue
- Can distend considerably
- Reservoir for urine before it leaves the body
- Aided by the urethra, expels urine from the body
Urinary Bladder
- Small tube lined with mucous membrane (urothelium) that extends from the base of the urinary bladder to the exterior of the body
- In females, lies posterior to the pubic symphysis & anterior to the vagina; approximately 3cm long
- In males, after leaving the bladder, passes through the prostate gland, where it is joined by 2 ejaculatory ducts; from the prostate, it extends to the base of the penis, then through the center of the penis & ends as the urinary meatus; approximately 20cm long
Urethra
- As bladder volume increases, contractions increase & the internal urethral sphincter relaxes
- The external urethral sphincter muscle contracts at first, then at the appropriate time, it relaxes to release urine
Micturition
Process blood & forms urine
Chief Function of Kidney
Urine is formed through 3 processes
1 Filtration
2 Tubular Reabsorption
3 Tubular secretion
Basic functional unit of the kidney
Nephron
Influences water reabsorption
It reduces water loss
ADH (Anti-diuretic Hormone)
Increases absorption of sodium, raising the sodium concentration of the blood & thus promoting reabsorption of water
Aldosterone
Promotes loss of sodium via the urine
Atrial Natriuretic Hormone (ANH)
Result of protein metabolism
Include urea, uric acid, ammonia & creatinine
Nitrogenous Wastes
Mainly the following ions:
Sodium, Potassium, Ammonium, Chloride, Bicarbonate, Phosphate & Sulfate
Electrolytes
During disease, bacterial poisons leave the body in the urine
Toxins
- Pigments
- Hormones
- Abnormal constituents (i.e. blood, glucose, albumin)
Urine Composition
