Chapter VII: Urinary System

Urinary System

A body system that removes waste from the body, help govern acid-base balance by retaining and excreting hydrogen ions, regulate electrolyte balance, and assist in blood pressure control.

• 2 Kidneys

• 2 Ureters

• 1 Urinary Bladder

• 1 Urethra

(6) Organs in the Urinary System

Urinary Bladder

One collective chamber the ureters connect to.

Kidney

A collapsible, reddish-brown, bean shaped, hollow organ.

• 12cm Long

• 6cm Wide

• 3cm Thick

Dimensions of the Kidneys

T12 - L3 (Superior Lumbar Region)

Location of the Kidneys

Renal Column

A part of the kidney’s cortex that extends down into the medulla, separating the renal pyramids; helps anchor the renal cortex in place.

Renal Pyramids

Cone-shaped tissues in the renal medulla that contains tubules responsible for carrying urine from the cortex to the calyces.

Renal Capsule

A tough fibrous layer that covers the outer surface of each kidney, protecting it form injury and providing support.

Renal Cortex

The outermost part of the kidney responsible for filtering blood and producing hormones.

Renal Medulla

The innermost part of the kidney responsible for regulating urine concentration and reabsorbing water and salts.

Renal Arteries

Blood vessels that supply the kidneys.

Ureters

Muscular and tubular structures that transport urine from the kidneys to the bladder.

Renal Pelvis

The central part of the kidney where urine collects before it is sent to the ureters.

Major Calyx

A large funnel-shaped structure within the kidney that transports urine from the minor calyces to the renal pelvis.

Minor Calyx

A small funnel-shaped structure within the kidney that transports urine from the renal medulla to the major calyces.

Amber

The neutral color of urine.

• Drugs

• Disease

• Water Intake

• Food Intake

(4) Things That Can Affect Urine Color

Drugs

These substances are highly hepatoxic and nephrotoxic.

Epoetin Alfa

A synthetic hormone used to treat anemia by stimulating the production of RBC.

Erythropoietin

A hormone produced by the kidney to stimulate the production RBC in the bone marrow.

Renin

Both a hormone and an enzyme that is produced by the kidney which causes blood vessels to constrict when released into the bloodstream.

Vasopressin

A hormone produced by the hypothalamus that helps control the body’s water balance, blood pressure, and sodium levels by regulating how much water the kidneys reabsorb.

Anterior Pituitary

The region in the hypothalamus that is responsible for producing antidiuretic hormones.

Diuresis

A medical term to describe an excessive production of urine.

Sodium

An essential electrolyte that helps regulate fluid balance, nerve function, and muscle function; attracts water.

Serum Sodium

A blood test that measures the concentration of sodium in the blood.

Aldosterone

A steroid hormone produced by the adrenal gland that regulates blood pressure by managing the body’s salt and water balance; separates sodium from the water and into the blood.

Bicarbonate Ions

Ions secreted by the kidney in response to acidosis.

Hydrogen Ions

Ions secreted by the kidney in response to alkalosis.

Nephrons

The structural and functional units of the kidneys, responsible for forming urine.

Renal Tubule

A part of the kidney’s nephron that is a long thin tube that modifies filtered fluid to become urine.

Renal Corpuscle

The blood-filtering unit of a kidney’s nephron, responsible for initiating urine formation by filtering blood.

Glomerulus

A part of the renal corpuscle that is a knot of capillaries that cover the nephron’s blood vessels and is a key structure, acting as the primary blood filter.

Podocytes

High specialized epithelial cells located in the kidney; essential for the blood filtration process.

Bowman’s Capsule

A cup-shaped sac in the kidney’s nephrons that encloses glomerulus.

• Filtration

• Reabsorption

• Secretion

(3) Processes of Urine Formation

Filtration

A process in urine formation where water and solutes are forced through the capillary walls and pores of the glomerulus into the renal tubule.

Reabsorption

A process in urine formation where water and other crucial ions are transported out of the filtrate and into the peritubular capillaries and then enter the bloodstream.

Secretion

A process in urine formation where hydrogen, potassium, creatinine, and drugs are removed.

Osmosis

The movement of water across a selectively permeable membrane from a region of high to low water concentration.

Jaundice

The pigmentation of the skin when uremic wastes are reabsorbed and delivered to the liver.

Uremia

A medical condition of having high levels of urea in the blood.

Glomerular Filtration Rate

The volume of fluid filtered from the kidney’s small blood vessels into the bowman’s capsule each minute; the main measure of kidney function.

• Urea

• Uric Acid

• Creatinine

(3) Nitrogenous Waste Products

Urea

A nitrogenous waste product formed by the liver and is the end product of protein breakdown when amino acids are used to produce energy.

Uric Acid

A nitrogenous waste product released when nucleic acids are metabolized.

Creatinine

A nitrogenous waste product from muscle use and is associated with metabolism in the muscle tissue.

Creatine

A natural compound found in the body that supplies energy to the muscles and brain.

• Hydrogen

• Oxygen

(2) Ions Necessary for Cellular Metabolsim

50%

Normal amount of water in the body for young adult females.

60%

Normal amount of water in the body for young adult males.

75%

Normal amount of water in the body for babies.

45%

Normal amount of water in the body for old age.

• Babies

• Old Age

(2) Age Groups Dehydration Can be Fatal to

Urochrome

The yellow pigment that gives urine its color, resulting from bilirubin and breakdown of proteins in the body.

6

Normal pH level of urine.

1.001 to 1.035

Urine’s specific gravity.

Bilirubin

A yellowish pigment formed when old red blood cells break down.

Concentrated

Characteristic of urine lower than a specific gravity of 1.001.

Hyperhydrated

Characteristic of urine higher than a specific gravity of 1.035.

~95%

Percentage of water in urine.

0.6 - 2.5L

The volumetric range of urine produced in a day.

1.8L

Average volume of urine produced in a day.

30 - 60mL/hour

The normal output of urine production per hour.

Urinary Catheter

A tube placed into the bladder to drain urine into a collection bag.