Vanders Renal Questions and Key Comments Flashcards
Ch 1 Key Concept. In addition to excreting waste, the kidneys perform many necessary functions in partnership with other body organ systems.
Ch 1 Key Concept. The kidneys regulate the excretion of many substances at a rate that balances their input, thereby maintaining appropriate body content of those substances.
Ch 1 Key Concept. A major function of the kidneys is to regulate the volume and osmolality of extracellular fluid volume.
Ch 1 Key Concept. The kidneys are composed mainly of tubules and closely associated blood vessels.
Ch 1 Key Concept. Each functional renal unit is composed of a filtering component (glomerulus) and a transporting tubular component (the nephron and collecting duct).
Ch 1 Key Concept. The tubules are made up of multiple segments with distinct functions.
Ch 1 Key Concept. Basic renal mechanisms consist of filtering a large volume, reabsorbing most of it, and adding substances by secretion, and, in some cases, synthesis.
1-1 Renal corpuscles are located
a. along the cortico-medullary border.
b. throughout the cortex.
c. throughout the cortex and outer medulla.
d. throughout the whole kidney.
1�1. (b) Renal corpuscles are distributed throughout the cortex, which
includes the region just above the cortico-medullary border
(i.e., the juxtamedullary region). None are in the medulla.
1-2 Relative to the number of glomeruli, how many loops of Henle,
and how many collecting ducts are there?
a. Same number of loops of Henle; same number of collecting
ducts.
b. Fewer loops of Henle; fewer collecting ducts.
c. Same number of loops of Henle; fewer collecting ducts.
d. Same number of loops of Henle; more collecting ducts.
1�2. (c) Each glomerulus is associated with a nephron, which includes a
loop of Henle. Each collecting duct is formed from the
coalescence of several nephrons.
1-3 It is possible for the body to be in balance for a substance when
a. the amount of the substance in the body is constant.
b. the amount of the substance in the body is higher than normal.
c. the input of the substance into the body is higher than normal.
d. in all of these situations.
1�3. (d) Balance implies that input equals output, which can occur at
normal or abnormal levels of amounts in the body, or normal or
abnormal input, so long as the inputs are matched by equal
outputs.
1-4 The macula densa is a group of cells located in the wall of
a. Bowman�s capsule.
b. the afferent arteriole.
c. the end of the thick ascending limb.
d. the descending thin limb.
1�4. (c) The macula densa cells are located in the tubule where it passes
between the afferent and efferent arterioles. This location is at
the end of the thick ascending limb of the loop of Henle just
before it becomes the distal tubule.
1-5 The volume of fluid entering the tubules by glomerular filtration
in one day is typically
a. about three times the renal volume.
b. about the same as the volume filtered by all the capillaries in
the rest of the body.
c. about equal to the circulating plasma volume.
d. more than the total volume of water in the body.
1�5. (d) A healthy young 70-kg person contains about 42 L of water
(~60% of body weight), and filters up to 180 L of plasma each
day.
1-6 In the context of the kidney, secretion of a substance implies that
a. it is transported from tubular cells into the tubular lumen.
b. it is filtered into Bowman�s capsule.
c. it is present in the final urine that is excreted.
1�6. (a) Secretion implies transport from tubular cell to the lumen. Most
often the substance entered the cell from the blood, but it could
also be synthesized and then transported.
Ch 1 Key Note. We use the term �reabsorption� to describe the movement of filtered substances
back into the blood because they are re-entering the blood. �Absorption� describes
the original entrance of consumed substances from the GI tract into the blood.
Ch 2 Key Concept. The kidneys have a very large blood flow relative to their mass that is regulated for functional reasons rather than
metabolic demand
Ch 2 Key Concept. Glomerular capillary pressure is determined by the
relative resistances of afferent arterioles, which precede
the glomerulus, and efferent arterioles, which follow it.
Ch 2 Key Concept. Glomerular filtration proceeds through a three-layered
barrier that restricts filtration of large macromolecules
such as albumin.
Ch 2 Key Concept. Negative surface charge on the filtration barrier restricts
filtration of negatively charged solutes more than positively
charged solutes.
Ch 2 Key Concept. The glomerular filtration rate (GFR) is determined by the
permeability of the filtration barrier and net filtration
pressure (NFP).
Ch 2 Key Concept. Net filtration pressure (NFP) varies mainly with
hydrostatic and oncotic pressures in the glomerular
capillaries.
Ch 2 Key Concept. Control of the resistances of the afferent and efferent
arterioles permits independent control of glomerular
filtration rate and renal blood flow.
Ch 2 Key Concept. Autoregulation of vascular resistances keeps GFR within
limits in the face of large variations in arterial pressure.
2-1. Blood enters the renal medulla immediately after passing through
which vessels?
a. Arcuate arteries
b. Peritubular capillaries
c. Afferent arterioles
d. Efferent arterioles
2�1. (d) Most efferent arterioles feed peritubular capillaries, but those
associated with juxtamedullary glomeruli feed vascular bundles
that descend into the medulla.
2-2. Which cell type is the main determinant of the filterability of
plasma solutes?
a. Mesangial cell.
b. Podocyte.
c. Endothelial cell.
d. Vascular smooth muscle.
2�2. (d) While various factors affect how much plasma is filtered, the
glycocalyx, basement membrane, and particularly the slit
diaphragms bridging the foot processes of podocytes, all of
which are extracellular, are the key determinants of what is
filtered.