Urinary System

Can you hold it long enough for me to get through this lecture?

QUICK REVIEW OF ELIMINATION

• Lungs eliminate CO2• Sweat glands

eliminate excess heat, salt

• Digestive tract- indigestible solids, bacteria

• Urinary tract is the main system of elimination

A little vocab

• Uria or Ur- urine

• Cyst- bladder

• Nephr or Ren- kidney

• Dys- painful

• Anuria– Without urine

• Cystitis– Inflammation of the bladder

• Dysuria– Painful urination

• Hematuria– Blood I urine

• Hydronephrosis– > water in kidney

• Renal– Pertaining to kidney

The Urinary Tract• Urinary tract consists of 2

kidneys, 2 ureters, one bladder and one urethra.

• Kidney location:– Retroperitoneal– Dorsal wall of abdominal cavity– 12th thoracic and 3rd lumbar

vertebrae

• Urethra– 1.5 inches in women, 8 inches

in men

• Outer layer- Cortex

• Inner layer- Medulla

• Calyx- collects urine as it is formed, join together to form the ureter

• Kidneys filter blood- 2, 000 L/day (500 gal)– remove waste products and reabsorb water, other

valuable substances.– 1.5 L of urine/day

• Metabolism produces toxic substances- esp nitrogen containing waste as a by-product of protein breakdown

• We eliminate nitrogen as urea- water soluble

• The main functional unit of the kidney is called the NEPHRON.

• 1 million per kidney

• Most of nephron located in renal cortex

• Loop of Henle is located in the renal medulla

• Capillaries in glomerulus filter blood- Bowman’ capsule collects ultra filtrate

• Through passive and active diffusion, 95% of water is reabsorbed, along with K, Na, Ca

• Other things are actively excreted, like drugs.

• Excretion is controlled by hormones such as ADH from hypothalamus

• Urine is made in 4 steps

1. Filtration

2. Reabsorption

3. Secretion

4. Excretion

A urinalysis is the most common non-invasive medical test

ordered

Diseases of the Kidney

• Acute Kidney failure- sudden loss of function– Causes: nephritis, shock, injury, heart failure or

poisoning– Symptoms: anuria or oliguria. Uremia, nausea,

coma, death

• Chronic Kidney failure- gradual loss of function due to hypertension (high blood pressure) or endocrine disease

• Cystitis- inflammation of the urinary bladder

Dialysis, Kidney transplant

• Hemodialysis- serves as an “artificial kidney” 2-3x/week for 2-4 hours

• Peritoneal dialysis- uses patient’s own peritoneal lining to filter blood

• Kidney transplant- need suitable donor. Only need one, but must take anti-rejection drugs for the life of the patient