Ch. 26 Urinary

Question 1

Regulation of blood pH : List the two key ions, one excreted and one reabsorbed and conserved, that play a key role in regulating blood pH

Answer 1

H+ & HCO3-

Question 2

Maintenance of blood osmolarity: By separately regulating the loss of water and the loss of __________ the kidneys maintain the osmolarity of the blood at approximately 300 milliosmoles/liter (300 mOsm/l)

Answer 2

Solutes

Question 3

Production of hormones: The kidneys produce two hormones, ______________________, which stimulates the production of RBCs and _________________, which helps regulate calcium homeostasis (and is the active physiologic form of Vitamin D)

Answer 3

Erythropoietin; Calcitriol

Question 4

The primary reason for the reserve capability is the kidney’s ability to ___________the size of individual nephrons (since new nephrons cannot be created) through hypertrophy, such that after a person gives up a kidney as part of a kidney donation the remaining kidney can eventually perform at ____% capacity of the previous two kidneys.

Answer 4

Increase; 80

Question 5

The loop of Henle associated with the juxtamedullary nephrons consists of three segments or limbs: a descending limb followed by a thin ascending limb that turns into the ________ ascending limb.

Answer 5

Thick

Question 6

Each nephron also has a specialized group of cells, called the macula densa and the juxtaglomerular cells, which combine to form the juxtaglomerular apparatus (JGA), that helps the nephrons regulate ________________ _____________________ .

Answer 6

Blood Pressure

Question 7

The distal convoluted tubule also contains two specialized cells. The principal cells serve as receptors for both antidiuretic hormone (ADH), and ________________, which regulate the principal cell’s function for fluid balance and blood pressure.

Answer 7

Aldosterone

Question 8

Also found in the distal convoluted tubule are the specialized intercalated cells, which play a role in maintaining the ____ homeostasis of the blood.

Answer 8

Ph

Question 9

To produce urine the kidneys, at the level of the nephrons and collecting ducts, perform three sequential functions: glomerular filtration, tubular reabsorption, and tubular secretion. Basically how does reabsorption in the renal tubules differ from absorption in the GI tract?

Answer 9

Returns something into the blood that had been in the blood previously.

Question 10

It’s important to realize that of this glomerular filtrate volume, more than ______% returns to the blood stream via reabsorption, leaving only 1-2 liters to be excreted as urine.

Answer 10

99

Question 11

Generally the GBHP is around 55 mmHg; CHP is usually around 15 mmHg; BCOP averages about 30mmHg in glomerular capillaries. The formula summing all of these three pressures to produce the Net Filtration Pressure is : NFP (net filtration pressure) = GBHP – CHP – BCOP. Substituting the values given for each term in the above information what is the typical NFP that serves to cause filtration to take place in the nephron?

Answer 11

55 - 15 - 30 = 10mmHg = NFP

Question 12

What can happen in the body if GFR is too high possibly due to hypertension?

Answer 12

Urine excreted will increase.

Question 13

What can happen in the body if GFR is too low, possibly due to a weakened heart (for example, post-MI) unable to maintain normal blood pressures?

Answer 13

Urine excreted may decrease.

Question 14

What happens to the glucose transporter molecules (an example of symporters because they move two or more substances in the same direction across a membrane) in the nephrons when the blood glucose levels reach more than 200mg glucose/dl of blood plasma, as occurs in diabetes mellitus?

Answer 14

Transport maximum has been reached for glucose carriers.
Excess is excreted through urine.
Urine tastes sweet.

Question 15

What is the resulting condition of significant levels of glucose in the urine called?

Answer 15

Glucose Urea

Question 16

________________ is released in response to a decrease in blood levels of Ca++ ions, and stimulates the early distal convoluted tubules to reabsorb more Ca++.

Answer 16

Parathyroid Hormone

Question 17

___________________ is one of the most potent vasoconstrictor substances in the body, including causing vasoconstriction of the afferent arterioles with the subsequent decrease in GFR.

Answer 17

Angiotensin II

Question 18

The hormone ________________________can inhibit reabsorption of Na+ and water, eventually leading to an increase in urine output and a decrease in blood volume and blood pressure.

Answer 18

Atrial Natriuretic Hormone

Question 19

_____________________ is a hormone that stimulates the principal cells in the distal convoluted tubule and collecting duct to reabsorb more Na+ ions and water, while secreting more K+ ions, leading to an overall increase in blood volume and blood pressure.

Answer 19

Aldosterone

Question 20

The presence of the hormone _______________________________ causes the principal cells to insert water channel molecules into the principal cell membranes, increasing their ability to reabsorb water. Without this hormone, the water channels are not inserted and this part of the distal convoluted tubule is almost impermeable to water molecules. This hormone is released by the hypothalamus when there is as little as a1% decrease in water concentration of the blood plasma or interstitial fluid (i.e. the fluid outside the cells in the surrounding tissue).

Answer 20

ADH (Antidiuretic Hormone)

Question 21

Why can’t someone at sea who has used all available fresh water drink seawater since it’s content is mostly water?

Answer 21

Kidneys use water from the body’s own internal fluids.
Body loses 2L of water to excrete solutes per 1L of seawater water consumed.
Body experiences severe dehydration.

Question 22

What are some possible medical problems that could result in the following urinalysis results: Albuminuria

Answer 22

Protein lost through urine due to high BP (poorly managed) that has damaged the kidneys.
Unmanaged chronic Diabetes Mellitus.

Question 23

What are some possible medical problems that could result in the following urinalysis results: Ketonuria

Answer 23

Sign of poorly managed Type 1 Diabetes.

Question 24

What are some possible medical problems that could result in the following urinalysis results: Candida albicans organisms

Answer 24

Possible yeast infection.

Question 25

What is the role of erythropoietin in the body?

Answer 25

Stimulate production of RBC’s.

Question 26

Why are anticoagulant drugs such as Heparin added to the patient’s blood circulating through the hemodialyzer ?

Answer 26

Anticoagulants stop clotting and enable blood flow through circulation. Keeps things running smooth.