Urinary system

5 urinary system functions

• filtration

• reabsorption

• sectretion

• maintain arterial blood pH

• homeostasis

filtration

• water and solutes out of blood

reabsorption

• water and solutes needed into blood

secretion

• wastes in the form of urine

maintain arterial blood pH

• pH of 7.4 is normal

homeostasis

• water balance of our bodies

• maintain BP 

the urinary system is made up of

• 2 kidneys

• 2 ureters

• 1 bladder

• 1 urethra

kidneys

• 2 bean-shaped organs located on either side of the vertebral column, behind the upper part of the abdominal cavity. Separated from this cavity by the peritoneum. RETROPERITONEAL ORGAN

• Protected by the ribs and a heavy cushion of fat.

• Connective tissue helps hold the kidneys in position.

• Each is enclosed in a mass of fatty tissue- adipose capsule.

• Covered externally by a tough, fibrous tissue- renal fascia or fibrous capsule.

cortex of kidney

1. Outer section

2. Contains most of the nephrons (aid in the production of urine).

medulla of kidneys

1. Inner section

2. Contains most of the collecting tubules, which carry the urine from the nephrons through the kidneys.

Hilum

= ROOT of kidney

•  each kidney has one.

• Notched/indented area through which the ureter, nerves, blood vessels and lymph vessels enter and leave the kidney.

anatomy of kidney

1. Renal cortex

2. Renal Medulla

3. Renal Calyces

4. Renal Pelvis

5. Renal Artery

6. Renal Vein

7. Renal Papilla

8. Renal Pyramid

9. Ureter

10. Renal Capsule

ureters

• 2 muscular tubes approx. 10-12 inches long

• One extends from the renal pelvis of each kidney to the bladder.

• Peristalsis (rhythmic, wave-like motion of the muscle) moves the urine through the ureter from the kidney to the bladder.

collecting urine

• The urine then enters the collecting ducts (tubules) located in the medulla.

• These collecting ducts empty into the renal pelvis (renal basin)

1. Funnel-shaped structure

2. First, widest, section of the ureter that starts in the kidney.

Calyx

1 collecting duct/tube that joins renal pelvis which is the widest part of the ureter 

Calyces

more than 1 calyx (pleural)

bladder

• Hollow, muscular sac

• Lies behind the symphysis pubis and at the midline of the pelvic cavity

• Has a mucous membrane lining arranged in a series of folds (rugae)

• The walls of the bladder contain 3 layers of visceral (smooth) muscle

• receives urine from the ureters

• Stores urine until eliminated from the body.

• Urge to void when bladder has 250 mls urine (1 cup), the bladder can hold much more.

• Circular sphincter muscle controls the opening to the bladder to prevent emptying

• When the bladder is full, receptors in the bladder wall send out a reflex action, which opens the muscle. Infants cannot control this action. As children age, they learn to control the reflex.

urethra

• The tube that carries the urine from the bladder to the outside.

Urinary meatus

external opening of urethra

female urethra

1. Approx 3.75 cm long

2. Opens in front of the vagina

3. Carries only urine to the outside

male urethra

1. Approx 20 cm long

2. Passes through prostate gland and out penis

3. Carries both urine and semen 

Vascular Structures

Aorta branches to left and right renal artery.

Right and left renal veins join with the inferior vena cava.

renal artery

• carries blood to the kidney. Branches of the renal artery pass through the medulla to the cortex, where the blood enters the first part of the nephron –the glomerulus.

renal vein

carries blood away from the kidney.

nephrons

• Microscopic filtering units located in the kidneys

• More than 1 million/kidney

• Each consists of a glomerulus, Bowman’s capsule, a proximal convoluted tubule, a distal convoluted tubule and a collecting duct (tubule).

glomerulus

• A cluster of capillaries.

• Blood passes through the glomerulus and water, mineral salts, sugar, metabolic products and other substances are filtered out of the blood.

• RBC’s and proteins are not filtered out.

• Filtered blood leaves the glomerulus and eventually makes its way to the renal vein, which carries it away from the kidney.

Which vessel take blood out of the glomerulus capsule?

 Efferent arteriole

bowman capsule

• Substances filtered out in the glomerulus enter

• C-shaped structure that surrounds the glomerulus

• The start of the convoluted tubule

• Picks up the materials filtered from the blood in the glomerulus and passes them into the convoluted tubule.

• As these materials pass through the various sections of the tubule, substances needed by the body are reabsorbed and returned to the blood capillaries.

• Most of the water, sugar, vitamins and mineral salts have been reabsorbed by the time the filtered material pass through the tubule.

• Excess sugar and mineral salts, some water and wastes (including urea, uric acid and creatinine) remain in the tubule and become known as the concentrated liquid- urine.

cystitis

• Inflammation of the bladder.

• Usually caused by pathogens entering the urinary meatus.

• More common in females because of the shortness of the urethra.

• Symptoms: frequent urination, dysuria, burning sensation during urination, hematuria, bladder spasm, fever

• Treatment: antibiotics, increased fluid intake

GLOMERULONEPHRITIS/
NEPHRITIS

Inflammation of the glomerulus of the kidney

ACUTE
GLOMERULONEPHRITIS 

• usually follows a streptococcal infection (strep, scarlet fever, rheumatic fever)

• Symptoms: chills, fever, fatigue, edema, oliguria, hematuria, albuminuria (protein in the urine).

• Treatment: rest, restriction of salt, maintenance of fluid and electrolyte balance, antipyretics (for fever), antibiotics as needed. With treatment kidney function is usually restored and prognosis is good.

CHRONIC
GLOMERULONEPHRITIS

• Can be caused by repeated attacks of acute glomerulonephritis

• Progressive disease that causes scarring and sclerosing of the glomeruli

• Early symptoms: hematuria, albuminuria and hypertension

• Late symptoms: additional glomeruli are destroyed, edema, fatigue, anemia, hypertension, congestive heart failure which leads to renal failure and death

Tx FOR GLOMERULONEPHRITIS

• Treatment: treating the symptoms

1. Low-sodium diet

2. Antihypertensive drugs

3. Maintenance of fluids and electrolytes

4. Hemodialysis (removal of the waste products from the blood by a hemodialysis machine)

• When both kidneys are severely damaged, a kidney transplant can be performed.

Pyelonephritis

• Inflammation of the kidney tissue and renal pelvis (upper end of the ureter)

• Usually caused by pyogenic (pus-forming) bacteria

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

• Treatment: antibiotics, increased fluid intake

acute pyelonephritis

Real kidney with pus pockets and destruction of normal anatomy

chronic pyelonephritis

MRI imaging of kidney & cavitations in the kidney from pus pockets

RENAL OR URINARY CALCULUS
(KIDNEY STONE)

• Nephrolithiasis

• Formed when salts in the urine precipitate (settles out of solution).

• Some small calculi may be eliminated in the urine, but larger stones often become lodged in the renal pelvis or ureter

• Symptoms: sudden, intense pain (renal colic), hematuria, possibly urinary retention

• Initial treatment: increase fluids, pain medication, straining urine to see if stones being eliminated

• Also called: NEPHROLITHIASIS

TX FOR RENAL CALCULI

• Lithotripsy- shock waves used to crush the stones so that they can be eliminated through the urine

• Ureteroscopy - uses a special camera device inserted thru the urethra, passed the bladder and up into the ureters to remove stones. 

• Surgery is the last resort to remove the calculi.

Renal failure

When the kidneys stop functioning

ACUTE RENAL FAILURE (ARF)

• Can be caused by hemorrhage, shock, injury, poisoning, nephritis, dehydration

• Symptoms: oliguria or anuria, headache, and ammonia odor to the breath, edema, cardiac arrhythmia, uremia

• Prompt treatment involving dialysis, restricted fluid intake and correction of the condition causing renal failure results in a good prognosis

3 types of ARF

• intrinsic

• prerenal

• postrenal

Intrinsic ARF

damage to structures within the kidney

prerenal ARF

marked decrease in renal blood flow

postrenal ARF

obstruction of urine outflow from the kidney

CHRONIC RENAL FAILURE (CRF)

• Results from the progressive loss of kidney function

• Can be caused by chronic glomerulonephritis, hypertension, toxins and endocrine disease

• kidney damage

• GFR - glomerular filtration rate less than 60 ml/min for at least 3 months

• develops slowly

• Waste products accumulate in the blood and affect many body systems

• Symptoms: nausea, vomiting, diarrhea, decreased mental ability, convulsions, muscle irritability, ammonia odor to the breath, perspiration; later stages lead to coma and death

Tx for CKD

• Treatment: dialysis, diet modifications and restrictions, careful skin and mouth care, control of fluid intake.

• Kidney transplant is only cure.

causes of CKD

• diabetes

• high blood pressure

• heart problems or stroke

• obesity

• family history

• tobacco use

• 60+ years old

uremia

• Toxic condition that occurs when the kidneys fail and urinary waste products are present in the bloodstream

• AKA: azotemia

• Can result from any condition that affects the proper functioning of the kidneys, such as renal failure, chronic glomerulonephritis and hypotension.

• Symptoms: headache, nausea, vomiting, an ammonia odor to the breath, oliguria or anuria, mental confusion, coma and eventually, death.

• Treatment: restricted diet, dialysis until a kidney transplant can take place

urethritis

• Inflammation of the urethra

• Usually caused by bacteria (such as gonococcus), viruses or chemicals (such as bubble bath solutions). more common in females.

• Symptoms: frequent and painful urination, redness and itching at the urinary meatus, and a purulent discharge

• Treatment: sitz baths or warm, moist compresses; antibiotics; and/or increased fluid intake