Urinary System

Ch. 21

Kidney Overview

Parts of the Urinary System

2 Kidneys

2 Ureters

Urinary Bladder

Urethra

The Kidney

Kidney bean shaped organs below the rib cage on the dorsal side of the body.

The left kidney is higher than the R.

Kidneys have two layersOuter layer: Cortex (not salty)

Inner Layer: Medulla (salty)Blood is transported to the kidney via the

renal arteries

More on the Kidney’s• Blood is transported to the Nephrons of the

Kidney.

• Job and parts of the Nephron

– Removes waste (urea) from blood

– Regulates water

– Electrolyte balance

Kidney and Nephron Fuction

What else does the Kidney Do?

– Makes Vitamin D Usable

– Stimulates Red Blood Cell Production in the bone Marrow.

– Regulates Blood Pressure

How is BP regulated?

• ADH- antidiuretic hormone secreted from the posterior pituitary prevents excess water loss.– If not functioning: Diabetes Insipidus. 25L/day lost

• Aldosterone- regulates Na+ ions. Water follows salt. Na+Cl- increase H2O in blood & Ions.

• Renin- regulates aldosterone and increases vaso-constriction.

More on the Nephron– The Glomerous: 1st part. High pressure

area which pushes out waste and returns good blood to the body via the efferent arteriole. This blood will later be transported to the Inferior Vena Cava and returned to the heart.

– The Loop of Henley: 2nd part. High salt content. Pulls excess water out of the tube and into the kidney thereby increasing the urine concentration.

!!! Go to

Fig. 21.4!!

Where does it all go?

• From the Distal tubule of the nephron urine leaves through the collecting duct. More NaCl, H2O are absorbed.

• It collects in the Calyces and finally the Renal Pelvis. Fig. 15.2

• Ureter collects urine from the kidneys and transports it to the bladder.

Where does it all go? continued• Bladder is a small walnut shaped, heavily

folded, hollow organ. Expands when water enters it. Pressure increases as the bladder expands.

• Urine exits the body through the Urethra. See Fig 15.10.

• People produce .6-2.5 liters of urine a day depending on how much a person drinks.

Micturition Reflex

Diseases of the Urinary System

• UTI- Urinary Tract Infection. Occurs when bacteria goes up the urethra. Characterized by frequent urge to urinate. Antibiotics cure.

• Kidney Transplant- must have histocompatibility. Old kidney not removed. Reinal vein and artery are connected first, than ureter is connected to bladder.

Kidney Transplant

UTI

Diseases Galore….• Problems of SHOCK. Arterial blood pressure

drops causing glomerous not to filter wastes. The tubes of the kidney don’t receive enough nutrients and they die (tubular necrosis). Chronic renal failure or kidney loss may ensue.

• What can be done?

Peritoneal Dialysis

Another one.

• Proteinurea: from glomerulonephritis. Glomerous is inflamed. Increasing its permeability to proteins which are excreted in the urine. This causes a reduction in the protein percentage in a persons blood plasma or hypoproteinemia . Blood pressure drops. Fluid can’t move out of the capillaries = edema (fluids are traped in the cell=bloating).

And still more

• Glucoseuria- glucose in the urine. From IV’s of glucose or Diabetes melitus (Type 1), insulin dependent diabetes. Cause: Insufficient insulin released from the pancreas.

• Gout- uric acid concentration in the blood is high. Crystallizes in the joints and tissues. Causes inflammation and extreme pain.

Gout

The last of them…

• Kidney stones: composed of uric acid, calcium oxalate, calcium phosphate, or magnesium phosphate. Form in the collecting ducts and renal pelvis. Pass into the ureter causing pain. Use sound waves to break them up.

• Urine control: ADH (pituitary) concentrates urine by increasing the permeability of the distal tubule of the Nephron.

Kidney Stones