module 8 review
Describe the location of the hilus and its significance. - Answer The hilus is a concave
cleft, and it is at this point where the ureters, blood vessels, and nerves enter the
kidney.
Describe the functions of the nephron. - Answer The function of the nephron is to
control the concentration of water and soluble materials by filtering the blood,
reabsorbing needed materials and excreting waste products as urine. The nephron
thereby eliminates wastes from the body, regulates blood volume, pH and pressure, and
controls the levels of electrolytes.
Name the structures of the nephron and describe their individual functions. - Answer
Each nephron consists of two parts, the glomerular capsule (renal corpuscle) and the
renal tubule. These two structures are connected (through the tubule) to the associated
collecting ducts. The glomerular capsule (renal corpuscle) filters the blood, while the
renal tubule reabsorbs needed materials, and the collecting ducts carry the remaining
material away as urine to be excreted.
Compare and contrast the renal cortex and renal medulla. Discuss the structures found
in each. - Answer The outer cortex houses the glomeruli and convoluted tubules
(proximal and distal) of the nephron as well as blood vessels. The inner medulla is
comprised of the Loop of Henle of the nephron and cone-shaped masses also known as
the renal pyramids.
Explain the difference between cortical nephrons and juxtamedullary nephrons. -
Answer Cortical nephrons make up 85% of all nephrons. They originate superficially in
the cortex and have shorter loops of Henle that extend only a short distance into the
medulla. Juxtamedullary nephrons make up the remaining 15% of all nephrons. They
originate deeper in the cortex, and their loops of Henle are thinner and extend into the
medulla entirely.
Explain the differences in the two systems providing the blood supply to the nephron.
How does their structure determine their role? - Answer Nephrons receive their blood
supply from 2 systems known as the glomerulus and peritubular capillary network. The
glomerulus is a unique system in that it is located between 2 arterioles, afferent and
efferent. Arterioles are high resistance vessels resulting in an extremely high-pressure
system which can easily force fluid and solutes out of the blood into the glomerular
capillary along its entire length. The peritubular capillaries are low-pressure vessels
better suited for reabsorption as opposed to filtration. These capillaries surround the
tubules in their entirety allowing rapid movement of solutes and water.
Name two specialized structures of the glomerular capillaries that contribute to the
filtration of blood. - Answer Fenestrations and podocytes
, List the 4 segments of the nephron tubule. - Answer (1) the proximal convoluted tubule
(highly coiled) which drains Bowman capsule; (2) the loop of Henle; (3) the distal
convoluted tubule; and (4) the collecting tubule which joins with other nephron tubules
to collect the filtrate.
What are the 3 processes involved in urine formation? Describe where they occur. -
Answer (1) filtration (2) reabsorption and (3) secretion. Filtration takes place in the renal
corpuscle; reabsorption and secretion occur in the renal tubules.
What is the norm value for the GFR? Discuss why maintenance of this value is
important. - Answer A normal glomerular filtration rate (GFR) is 120-125 ml/min or 180
L/day. Maintenance of a relatively constant GFR is important for adequate reabsorption
of water and other needed nutrients from the filtrate.
List the 3 regulatory mechanisms of the GFR. - Answer (1) renal autoregulation, (2)
nervous system control, and (3) hormonal control.
List 3 ways that the kidney acts as an endocrine organ. - Answer (1) through the renin-
angiotensin-aldosterone system (RAA) (2) through the regulation of red blood cell
production through the formation of erythropoietin, and (3) through calcium metabolism
by the activation of vitamin D.
Describe the action of ADH. - Answer ADH acts on the collecting tubule to increase
water absorption. ADH inhibits urine output by increasing the number of water channels
in the cell membrane of the collecting ducts.
Describe the action of Aldosterone. - Answer Aldosterone acts to place several types of
ion channels inside the cells of the collecting ducts. One type of ion channel is a
sodium-hydrogen ion channel. Aldosterone increases Na+ reabsorption through the
excretion of H+ ions. Na+ ions are pumped out of the filtrate while hydrogen ions are
pumped inside and then excreted. Because water follows salt, Na+ reabsorption will
cause water reabsorption. Aldosterone will also increase K+ secretion through Na+/K+
pumps. Na+ is pumped out of the filtrate to be returned to the blood while potassium
(K+) is excreted in urine. The main action of aldosterone is to increase the blood volume
and, therefore, blood pressure when needed.
Define hyponatremia using blood values. - Answer Hyponatremia occurs when plasma
concentration falls below 135 mEq/L.
Define hypernatremia using blood values. - Answer Hypernatremia occurs when plasma
Na+ levels rise above 145 mEq/L with a serum osmolality greater than 295 mOsm/kg.
Define hypokalemia using blood values. - Answer Hypokalemia occurs when plasma K+
levels fall below 3.5 mEq/L.
Describe the location of the hilus and its significance. - Answer The hilus is a concave
cleft, and it is at this point where the ureters, blood vessels, and nerves enter the
kidney.
Describe the functions of the nephron. - Answer The function of the nephron is to
control the concentration of water and soluble materials by filtering the blood,
reabsorbing needed materials and excreting waste products as urine. The nephron
thereby eliminates wastes from the body, regulates blood volume, pH and pressure, and
controls the levels of electrolytes.
Name the structures of the nephron and describe their individual functions. - Answer
Each nephron consists of two parts, the glomerular capsule (renal corpuscle) and the
renal tubule. These two structures are connected (through the tubule) to the associated
collecting ducts. The glomerular capsule (renal corpuscle) filters the blood, while the
renal tubule reabsorbs needed materials, and the collecting ducts carry the remaining
material away as urine to be excreted.
Compare and contrast the renal cortex and renal medulla. Discuss the structures found
in each. - Answer The outer cortex houses the glomeruli and convoluted tubules
(proximal and distal) of the nephron as well as blood vessels. The inner medulla is
comprised of the Loop of Henle of the nephron and cone-shaped masses also known as
the renal pyramids.
Explain the difference between cortical nephrons and juxtamedullary nephrons. -
Answer Cortical nephrons make up 85% of all nephrons. They originate superficially in
the cortex and have shorter loops of Henle that extend only a short distance into the
medulla. Juxtamedullary nephrons make up the remaining 15% of all nephrons. They
originate deeper in the cortex, and their loops of Henle are thinner and extend into the
medulla entirely.
Explain the differences in the two systems providing the blood supply to the nephron.
How does their structure determine their role? - Answer Nephrons receive their blood
supply from 2 systems known as the glomerulus and peritubular capillary network. The
glomerulus is a unique system in that it is located between 2 arterioles, afferent and
efferent. Arterioles are high resistance vessels resulting in an extremely high-pressure
system which can easily force fluid and solutes out of the blood into the glomerular
capillary along its entire length. The peritubular capillaries are low-pressure vessels
better suited for reabsorption as opposed to filtration. These capillaries surround the
tubules in their entirety allowing rapid movement of solutes and water.
Name two specialized structures of the glomerular capillaries that contribute to the
filtration of blood. - Answer Fenestrations and podocytes
, List the 4 segments of the nephron tubule. - Answer (1) the proximal convoluted tubule
(highly coiled) which drains Bowman capsule; (2) the loop of Henle; (3) the distal
convoluted tubule; and (4) the collecting tubule which joins with other nephron tubules
to collect the filtrate.
What are the 3 processes involved in urine formation? Describe where they occur. -
Answer (1) filtration (2) reabsorption and (3) secretion. Filtration takes place in the renal
corpuscle; reabsorption and secretion occur in the renal tubules.
What is the norm value for the GFR? Discuss why maintenance of this value is
important. - Answer A normal glomerular filtration rate (GFR) is 120-125 ml/min or 180
L/day. Maintenance of a relatively constant GFR is important for adequate reabsorption
of water and other needed nutrients from the filtrate.
List the 3 regulatory mechanisms of the GFR. - Answer (1) renal autoregulation, (2)
nervous system control, and (3) hormonal control.
List 3 ways that the kidney acts as an endocrine organ. - Answer (1) through the renin-
angiotensin-aldosterone system (RAA) (2) through the regulation of red blood cell
production through the formation of erythropoietin, and (3) through calcium metabolism
by the activation of vitamin D.
Describe the action of ADH. - Answer ADH acts on the collecting tubule to increase
water absorption. ADH inhibits urine output by increasing the number of water channels
in the cell membrane of the collecting ducts.
Describe the action of Aldosterone. - Answer Aldosterone acts to place several types of
ion channels inside the cells of the collecting ducts. One type of ion channel is a
sodium-hydrogen ion channel. Aldosterone increases Na+ reabsorption through the
excretion of H+ ions. Na+ ions are pumped out of the filtrate while hydrogen ions are
pumped inside and then excreted. Because water follows salt, Na+ reabsorption will
cause water reabsorption. Aldosterone will also increase K+ secretion through Na+/K+
pumps. Na+ is pumped out of the filtrate to be returned to the blood while potassium
(K+) is excreted in urine. The main action of aldosterone is to increase the blood volume
and, therefore, blood pressure when needed.
Define hyponatremia using blood values. - Answer Hyponatremia occurs when plasma
concentration falls below 135 mEq/L.
Define hypernatremia using blood values. - Answer Hypernatremia occurs when plasma
Na+ levels rise above 145 mEq/L with a serum osmolality greater than 295 mOsm/kg.
Define hypokalemia using blood values. - Answer Hypokalemia occurs when plasma K+
levels fall below 3.5 mEq/L.
