Urinary system

Question 1

Kidneys dispose of waste products in urine.

Answer 1

• Nitrogenous waste
• Toxins
• Drugs
• Excess ions

Question 2

Kidneys regulatory Functions:

Answer 2

-Regulate volume and chemical makeup of blood.
(Water, salts; Acids and bases)
-Production of renin to maintain blood pressure.
-Production of erythropoietin to stimulate red blood production.
-Conversion of vitamin D to its active form.

Question 3

• Kidneys
• Ureters
• Urinary Bladder
• Urethra

Answer 3

Organs of the Urinary system

Question 4

urine formation is the result of three processes:

Answer 4

• Glomerular filtration
• Tubular Reabsorption
• Tubular secretion

Question 5

. Glomerular filtration

Answer 5

• The glomerulus is a filter
• Filtration is a nonselective passive process
• Water and solutes smaller than proteins are forced through glomerular capillary walls into the glomerular capsule.
• Filtration is dependent on blood pressure in the arteries.
• Proteins and blood cells are normally too large to pass through the filtration membrane.
• Once in the glomerular capsule, fluid is called filtrate (basically blood plasma without blood proteins)
• Filtrate leaves via the renal tubule

Question 6

Tubular reabsorption

Answer 6

The peritubular capillaries reabsorb useful substances from the renal tubule cells, such as:

• Water
• Glucose
• Amino acids
• Ions
• Some reabsorption is passive; but most is active (requires ATP) and very selective.
• There are membrane carriers for substances that need to be reabsorbed; few or none for substances that don’t
• Most reabsorption occurs in the proximal convoluted tubule

Question 7

Tubular secretion

Answer 7

• Reabsorption in reverse.
• Some materials move from the blood of the peritubular capillaries into the renal tubules to be eliminated in filtrate.
• Hydrogen and potassium ions
• Creatinine
• Secretion is important for:
• Getting rid of substances not already in the filtrate.
• Removing drugs and excess ions
• Maintaining acid-base balance of blood
• Materials left in the renal tubule move toward the ureter

Question 8

Kidneys have four roles in maintaining blood composition.

Answer 8

.Excreting nitrogen-containing wastes

• Maintaining water balance of the blood
• Maintaining electrolyte balance of the blood
• Ensuring proper blood pH

Question 9

Urinary Hormone;

Anti-diuretic hormone (ADH)

Answer 9

• Released by posterior pituitary gland if blood volume is too low.
• Travels to kidney’s collecting ducts
• Causes duct cells to reabsorb more water
• Water is returned to the blood

Question 10

Urinary Hormones;

Aldosterone

Answer 10

• Regulates concentration of sodium ions (Na+) in the extracellular fluid (ECF)
• If there are relatively more Na+ ions in the ECF than in the blood, water leaves the blood and enters the ECF
• The rule is … water follows salt
• Leads to low blood volume and low blood pressure
• Low blood pressure causes cells in the juxtaglomerular (JG) apparatus to release the enzyme renin (not rennin) into the blood
• Renin causes adrenal cortex to release aldosterone
• Aldosterone acts to increase reabsorption of Na+ ions in the DCT and collecting ducts
• As Na+ ions return to blood, water follows
• Blood volume and blood pressure return to normal