The urinary system maintains the state of homeostasis by
regulating water and solutes in the human body.
The Urinary System: The Kidneys,
the ureters, the bladder and urethra.
THE KIDNEYS are a pair of organs located in the retroperitoneum/back (Posterior wall) of the abdomen. The main function is to
filter the blood. They create urine (Urine is composed of components like urea,
water, ions and toxic wastes) as the end product which drains down to the
bladder by a tube-like structure called ureters.
Cortex is the outer region and medulla is the inner area of the
kidney. Renal pyramids are triangular structures that are found within the
medulla.
The minor calyces are a funnel-shaped structure that surrounds the
tip of each pyramid. The minor calyx integrates to constitute the major calyx.
The renal pelvis is the large collecting funnel that is formed by
a bunch of major calyx.
Nephrons - Functional unit of the kidney produces urine in the process
of removing waste and excess substances from the blood. There are about 1
million units in each kidney.
A. Glomeruli: Cluster/ball of capillaries, with the filtering membrane forms
Bowman’s capsule.
B. Renal tubules
- Proximal convoluted tubule (PCT)
- Descending and ascending - loop of Henle
- Distal convoluted tubule (DCT)
- Collecting tubule
URETERS: Carry urine from renal pelvis to the bladder. Two tubes about 15-18
inches long ½ inch diameter. Ureteral orifice (at bladder), prevents
reflux of urine in ureters and the renal pelvis.
BLADDER: Muscle sac in the pelvis, just behind the pubic
bone that receives and stores urine, approximately 250 ml. of urine until
excreted from the body through the urethra. It is called voiding or micturition (emptying bladder).
Bladder has
Internal sphincter (involuntary) & External sphincter (voluntary by
training). Apex (trigone top) and Neck (lower part supported by
ligaments).
URETHRA: It is a tube that connects the bladder to genitals for
the expulsion of urine, semen etc out of the body. In a female, it is located just
above the vaginal opening.
For a female it is about 1 to 1 ½ inches long; urinary meatus located between the
clitoris and the vagina.
Male it is about 8 inches long, passes from bladder through the prostate gland
and the penis to the meatus located at the end of the penis carries both urines
and semen.
Common
Diseases of Excretory System:
1. Pyelonephritis - Inflammation of the
kidney due to a bacterial infection.
2. Glomerulonephritis - is inflammation
of the glomeruli, which are structures in your kidneys that are made up of tiny
blood vessels.
3. Nephrolithiasis – Kidney stones is a
disease affecting the urinary tract. Kidney stones are small deposits that
build up in the kidneys, made of calcium, phosphate and other components of
foods. Kidney stone formation may result when the urine becomes overly
concentrated.
4. Acute renal failure - A condition in
which the kidneys suddenly can't filter waste from the blood that develops
within 7 days.
5. Chronic renal failure - is a progressive loss in kidney function over a period of months or years
6. End-stage renal disease - is the
final stage of chronic kidney disease in which the kidneys no longer function
well enough to meet the needs of daily life.
7. Diabetic nephropathy - is damage to
your kidneys caused by diabetes.
8. Hypertensive nephropathy - is a
kidney disease that occurs as a result of high blood pressure.
9. Renal cyst - are sacs of fluid that
form in the kidneys.
10. Urinary
Tract Infection - An infection in any part of the urinary system, the
kidneys, bladder or urethra
11. Cystitis -
is inflammation of the bladder, usually caused by a bladder infection
12. Bladder
cancer – Is an abnormal growth of cells in the bladder.
Common signs and symptoms:
1.
Anuria
2. Dysuria
3. Oliguria
4. Nocturia
5. Hematuria
MEDICAL TERMINOLOGY:
1.
Kidney
- Nephro / Reno
2.
Bladder
- Cysto / Vesico
3. Renal pelvis - pyel/o
MEDICAL ABBREVIATIONS:
1. ARF -
Acute renal failure
2. ESRD - End-stage renal disease
3. ESWL - Extracorporeal shockwave lithotripsy
4. GFR - Glomerular filtration rate
5. GU - Genitourinary
6. KUB - Kidneys, ureters, bladder
7. UA - Urinalysis
8. UPJ - Ureteropelvic junction
9. UTI - Urinary tract infection
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