51 Renal blood flow and glomerular filtration

Question 1

T/F. The kidneys are responsible for regulation of arterial blood pressure

Answer 1

True

Question 2

T/F. The kidneys are responsible for regulation of acid-base balance

Answer 2

True

Question 3

T/F. The kidneys are responsible for synthesis of vitamin D

Answer 3

False. The kidneys are responsible for synthesis of the active form of vitamin D

Question 4

T/F. The kidneys are responsible for synthesis of erythropoietin, prostaglandins, and bradykinin

Answer 4

True

Question 5

What is the function of bradykinin?

Answer 5

It is a vasodilator

Question 6

A vasodilator. Vasodilates the afferent more than the efferent arterioles

Answer 6

Prostaglandins

Question 7

T/F. The kidneys are capable of gluconeogensis

Answer 7

True

Question 8

Filtration, reabsorption, secretion, and metabolism

Answer 8

Four main processes of the nephron

Question 9

The volume that a given substance occupies in the plasma appearing in the urine in a period of time. C=(excretion rate)/(concentration in plasma)=V/P. Units are ml/min

Answer 9

Clearance

Question 10

Secretion and reabsorption occur b/t the ___ capillaries and the convoluted tubule

Answer 10

Peritubular capillaries

Question 11

T/F. Filtration is the non-selective process by which about 40% of the renal plasma flow is filtered

Answer 11

False. Filtration is the non-selective process by which about 20% of the renal plasma flow is filtered

Question 12

delP/R = ?
delP = P renal artery - P renal vein
R = total renal vascular resistance

Answer 12

Renal blood flow

Question 13

(1-Hct)*RBF = ?

Answer 13

Renal plasma flow

Question 14

Three layered components –the fenestrated capillary endothelium, the glomerular basement membrane (GBM), and filtration slit diaphragms b/t pedicels.

Answer 14

Glomerular filtration barrier

Question 15

T/F. • The Glomerular filtration barrier is responsible for determining what is filtered from plasma according to size only

Answer 15

False. • The Glomerular filtration barrier is responsible for determining what is filtered from plasma according to size and net charge:

Question 16

Component of glomerular filtration barrier that excludes large blood components (mainly lipoproteins and RBCs)

Answer 16

Capillary endothelium

Question 17

Component of glomerular filtration barrier that is composed of glycosaminoglycans (GAGs), which are negatively charged. Functions to repel molecules w/ large negative charges (primarily proteins)

Answer 17

Basement membrane

Question 18

Component of the glomerular filtration barrier that forms filtration slit pores. These mainly exclude remaining large blood components

Answer 18

Podocytes

Question 19

T/F. Cells, proteins, and lipids (b/c they are bound to proteins) are not filtered

Answer 19

True

Question 20

The glomerular filtration barrier loses is lost (any of the three components of the basement membrane). Symptoms: Hypoproteinemia, albuminuria, generalized edema, and hyperlipidemia

Answer 20

Nephrotic syndrome

Question 21

T/F. TF/P = 0 for a substance that is freely filtered

Answer 21

False. If TF/P= 1 (in bowman’s space): the substance is freely filtered

Question 22

T/F. Major electrolytes (including bicarbonate), waste products (urea, creatinine), AAs, ketone bodies, non-natural substances (inulin, PAH), and low MW proteins and peptides (insulin & myoglobin) are all freely filtered

Answer 22

True

Question 23

T/F. TF/P > 1 in bowman’s space for a substance that is not freely filtered

Answer 23

False. TF/P s space for a substance that is not freely filtered

Question 24

T/F. Plasma proteins (e.g. albumin) and lipid soluble substances bound to proteins (e.g. TAG, cholesterol, FS-vitamins, hormones) are not freely filtered

Answer 24

True

Question 25

T/F. Filtration is an active process

Answer 25

False. Filtration is a passive process

Question 26

T/F. Nephrons are connected in series

Answer 26

False, nephrons are connected in parallel

Question 27

This is the most important factor affecting glomerular filtration rate (GFR)

Answer 27

Glomerular hydrostatic pressure

Question 28

T/F. Increasing afferent arteriolar resistance: decreases renal blood flow and decreases GFR

Answer 28

True

Question 29

T/F. Increasing efferent arteriolar resistance: decreases renal blood flow and decreases GFR.

Answer 29

False. o Increasing efferent arteriolar resistance: decreases renal blood flow and increases GFR.

Question 30

(strong activation) via catecholamines [alpha-1 receptors]: serves as a vasoconstrictor of the arterioles of the kidney. E.g. severe hemorrhage. Afferent arterioles are constricted more than efferent arterioles (however, resistance is increased in both)

Answer 30

Sympathetic NS

Question 31

Low doses preferentially constrict the efferent arteriole. However, high doses lead to constriction of the afferent arteriole, which results in no change in the GFR. Release during: low sodium diet, blood volume depletion, renal artery stenosis

Answer 31

Angiotensin II

Question 32

A vasodilator that protects against excessive vasoconstriction. Patients w/ endothelial dysfunction (e.g. atherosclerosis) may have greater risk for excessive decrease in GFR in response to stimuli such as volume depletion

Answer 32

Nitric oxide (endothelium-derived)

Question 33

This parameter can be used to measure: Renal function (decreased GFR is a marker for progression of disease), Evaluation of risk of kidney failure, Evaluation for kidney donation, Dose and monitoring for medications cleared by the kidney, Determine safety of diagnostic tests or procedures, Renal insufficiency (25-30% of normal ___), Renal failure (10-25% of normal ___)

Answer 33

GFR

Question 34

GFR/RPF = ?

Answer 34

Filtration fraction (FF)

Question 35

Clearance of ___ is clinically used to measure GFR

Answer 35

Creatinine. However, Creatinine is excreted in higher amounts than inulin b/c it is secreted as well as filtered (inulin is only filtered). Therefore, Creatinine clearance is higher, and therefore overestimates the GFR

Question 36

What increases from afferent to efferend ends of the glomerulus? What decreases?

Answer 36

colloid osmotic pressure increases from the afferent to the efferent ends. GFR therefore decreases from afferent to efferent ends