Self-test questions: Chapter 39

. The kidneys receive about 10% of the resting cardiac output

True

False

. Renal blood flow is maintained within narrow limits despite changes in arterial blood pressure

True

False

. Increased activity in the renal sympathetic nerves results in increased blood flow to the kidneys

True

False

. Which of the following statements regarding the glomerular filtration rate (GFR) are correct? Please select all that apply

The GFR depends on the pressure in the afferent arterioles

A substance that has a clearance less than the GFR must have been absorbed by the renal tubules

The glomerular filtration rate can be determined by measuring the clearance of insulin

The glomerular filtrate has the same composition as plasma

. Regarding the transport of glucose by the renal tubules:

In a healthy person, the distal tubules reabsorb all of the filtered glucose

Glucose is secreted into the urine in small quantities

The transport maximum for glucose is about 36 mg min^-1

Glucose transport by the renal tubules is linked to sodium transport.

. Concerning the excretion of acid by the kidneys:

The filtered bicarbonate is absorbed by anion transport

The intercalated cells of the distal tubule secrete hydrogen ions to reabsorb bicarbonate from the tubular fluid

All of the filtered bicarbonate is normally reabsorbed in the first half of the distal tubule.

Urine pH is normally greater than that of plasma

. Regarding the regulation of plasma sodium:

Juxtaglomerular cells secrete renin in response to low plasma sodium

Angiotensin II is formed from renin by the action of an enzyme found on the endothelium of the pulmonary blood vessels

The uptake of sodium ions is regulated by the proximal tubule

Sodium transport by the thick ascending limb of the loop of Henle occurs by the same mechanism as that of the proximal tubule

. The zona glomerulosa of the adrenal cortex secretes aldosterone in response to stimulation by angiotensin II .

True

False

. Which of the following statements regarding the control of water balance by the kidneys are correct?

The renal medulla has an osmotic gradient that increases from the border with the cortex to the renal papilla

ADH is secreted by the anterior pituitary in response to a decrease in the osmolality of the blood

A normal person cannot produce urine with an osmolality greater than 300 mOsmol.kg^-1

ADH acts on the P cells of the collecting ducts to increase their permeability to water

. Which of the following statements regarding normal urine are correct?

The concentration of potassium in the urine is greater than that in plasma

The plasma concentration of calcium is greater than that of urine

Urine normally contains about 2 mmol l^-1 of bicarbonate

Urine pH is normally greater than that of plasma

Urine normally contains no measurable quantity of protein

. Which of the following statements regarding the function of the renal tubules are correct? Please select all that apply.

Plasma potassium is regulated by the sodium pump activity of the proximal tubules.

Calcium absorption by the distal tubules is decreased by parathyroid hormone

Phosphate absorption by the proximal tubule is regulated by parathyroid hormone

The intercalated cells of the distal tubule secrete hydrogen ions to reabsorb bicarbonate from the tubular fluid

Without the buffering action of phosphate, the kidneys would not be able to excrete more than 1 mmole of hydrogen ions each day

. Following the intake of a large volume of water, a normal person may produce urine with an osmolality of less than 100 mosmol.kg^-1

True

False

. ADH acts on the collecting ducts to decrease their permeability to water

True

False

. Which of the following statements are correct given the following information:
Pressure in the glomerular capillaries = 60 mm Hg
Pressure in Bowman's capsule = 18 mm Hg
Plasma oncotic pressure = 32 mm Hg
Oncotic pressure of filtrate = 0 mm Hg
Plasma inulin = 0.25 mg ml^-1
Urine inulin = 12.5 mg ml^-1
Urine flow rate = 2.5 ml min^-1

The net filtration pressure is 7 mm Hg.

The net filtration pressure is 10 mm Hg

The net filtration pressure is 12 mm Hg

The net filtration pressure is 15 mm Hg

The glomerular filtration rate is 110 ml min^-1

The glomerular filtration rate is 115 ml min^-1

The glomerular filtration rate is 120 ml min^-1

The glomerular filtration rate is 125 ml min^-1

. A 45 year old woman is drinking large volumes of water and has become confused. She is passing copious amounts of dilute urine with an osmolality is 250 mOsm kg^-1. Blood glucose is 5.5 mg ml^-1. Nasal administration of desmopressin causes her to secrete a hypertonic urine. Which of the following statements is likely to be correct? Please select all that apply.

She is suffering from type 2 diabetes

Her pituitary is not secreting sufficient ADH

Her kidneys are not responding to pituitary ADH

Her kidneys are hypersensitive to ADH

She could be hyponatraemic.

Self-test questions: Chapter 39

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