Urinary system

Functions of Urinary System

• Removes waste• Maintains acid-base

balance of body• Parts include:

– 2 KIDNEYS

– 2 URETERS

– BLADDER

– URETHRA

Kidneys

• 2 bean shaped organs• Protected by ribs and fat• Each kidney is found in mass of fatty tissue

(adipose capsule)• 2 main sections:

– Cortex: outer layer, contains most of the neurons that aid in production of urine

– Medulla: inner layer, contains most of tubes that carry urine from the nephrons through the kidneys

Nephrons• Microscopic filtering units• Over 1 million/kidney• Contains glomerulus

– Cluster of capillaries that filter waste

• Bowman’s capsule– Surround glomerulus picks

up filtered materials and passes it to the convoluted tubule

– Substances needed by the body are reabsorbed and returned to the capillaries

• At the end, most of the water, sugar, vitamins and salts have been reabsorbed

• Excess salts, water, wastes remain in the tubule and become urine

• Urine enters collecting ducts (tubes) in the medulla

• Collecting tubes empty into the renal pelvis (first section of the ureter)

Ureters• 2 muscular tubes 10-12

inches long

• One extends from the renal pelvis to the bladder

• Peristalsis: a wavelike motion of the involuntary muscle that moves urine through the ureter from the kidney to the bladder

Bladder

• Hollow muscular sac• Lining folds called rugae –

disappears as muscles of bladder allow it to expand and fill with urine

• 3 layers of visceral muscle• Urge to void occurs when

bladder contains 1 cup• Circular sphincter muscle

– Control bladder opening– Can’t be controlled by

infants

• FUNCTIONS:– Receives urine from

ureters

– Stores urine until eliminated from body

Urethra

• Tube carries urine from bladder to outside

• External opening called meatus

• Different in male/females– Females shorter– Opens in front of vagina or

passes through the penis– Male: carries both urine

from urinary system and semen from the reproductive system

• Liquid waste

• 95% water

• Excess useful products like sugar can be found, but usually indicates disease

• 1 ½ - 2 quarts produced daily

• 150 quarts filtered through kidneys

Urine

Key Terms

• Polyuria: excess urination• Oliguria: below normal urination• Anuria: absence of urination• Hematuria: blood in urine• Nocturia: urination at night• Dysuria: painful urination• Retention: inability to empty bladder• Incontinence: involuntary urination

Diseases

• Inflammation of the bladder

• More common in females due to shortness of urethra

Symptoms:

• Frequent urination

• Dysuria and burning

• Bladder spasm

• Hematuria

• ? Fever ?

Treatment:

• Antibiotics and increased fluid intake

Glomerulonephritis

• Inflammation of the glomerulus• Usually follows strep infection• Can be acute or chronic• Symptoms: hematuria, hypertension, edema,

fatigue, congestive heart failure, renal failure, death

• Treatment: treat symptoms– Low salt diet, high blood pressure medicine, dialysis,

transplant

Pyelonephritis

• Inflammation of kidney tissue and renal pelvis

• Usually caused by pus forming bacteria

• Symptoms: chills, fever, back pain, dysuria, hematuria and pyuria

• Treatment: antibiotics, increased fluid intake

Renal Calculi

• Kidney stone formed when salts in urine settle

• Small stones can be eliminated in urine• Large stones may become lodged• Symptoms: sudden pain, hematuria and

retention• Treatment: increase fluids, pain meds, strain

urine w/ gauze, lithotripsy, possible surgery

Renal Failure

• Kidneys stop functioning• Acute

– Caused by injury, poisoning, dehydration

– Prompt treatment leads to good prognosis

• Chronic– Progressive loss of kidney function caused by

glomerulonephritis, hypertension, toxins and endocrine disease.

– Waste accumulates and affects body systems

Uremia• Toxic condition where urinary waste is in

bloodstream• Caused from any condition that affects

proper function of kidneys• Symptoms: n/v, ammonia breath, anuria,

headache and confusion, coma/death• Treatment: restrictive diet, dialysis, transplant

Urethritis

• Inflammation of the urethra

• Caused by bacteria, viruses or chemicals

• Symptoms: painful urination, redness, itching at meatus, ?discharge

• Treatment: sitz baths or warm compresses, antibiotics, increased fluid intake

Identify parts of Urinary system

• Use handout to label all parts of the urinary system

• Use handout to trace flow of urine through the urinary system (name all parts as you go)