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RENAL SYSTEM WORK SHEET
List six key functions of the renal system.
1. ____________________________________
2. ____________________________________
3. ____________________________________
4. ____________________________________
5. ____________________________________
6. ____________________________________
The Nephron is the Functional Unit of the Kidney
The medulla is the (inner/outer) layer and the cortex is the (inner/outer) of the kidney. (Fig. 19-1c)
What is a nephron? ____________________________________________________________________.
Approximately how many nephrons are there in each kidney? ____________________.
Describe the portal system of the nephron (p 602) ____________________________________________
____________________________________________________________________________________.
What are the three major components of the renal corpuscle? (see Fig. 19-4a)
1.
2.
3.
What takes place at the glomerulus? _______________________________________________________.
What are the three major components of the renal tubule? (see Fig. 19-2)
1.
2.
3.
The three processes in the Nephron are Filtration, Reabsorption and Secretion
Name the three processes of the kidney and briefly describe them:
1)
2)
3)
Compare a cortical nephron to a juxtamedullary nephron:
In the human kidney, about _____% of the nephrons are cortical and _____% are a juxtamedullary.
How much plasma if filtered per day by the kidneys? __________ L/day.
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How much urine (on average) leaves the body per day? __________L/day.
What happens to the fluid that does not leave in the urine? _____________________________________.
Volume and Osmolarity Change as Fluid flows through the Nephron
Fluid leaving the Bowman’s capsule is nearly ________ osmotic with plasma. (p 604)
At the end of the proximal tubule _____% of the filtered fluid remains in the tubule. The osmolarity of
this fluid is _______ mOsM. Based on these numbers, it is said that the proximal tubule is the primary site
of (filtration/reabsorption/secretion).
Fluid leaving the loop of Henle is usually (isosmotic/hyperosmotic/hyposmotic) to plasma, so it is said
that the loop is the primary site for production of (concentrated/dilute/salty) urine.
By the end of the collecting duct, the fluid in the tubule has a volume of _________ L/day and an
osmolarity that can range from _________ to _________ mOsM. Both the volume and the osmolarity of
urine depend of the body’s need to conserve or excrete ____________ and ____________.
Filtration
What % of the plasma volume that enters the glomerulus is actually filtered? _______ %.
How much of that filtered plasma is becomes urine and is excreted? _______%
Filtration occurs because of Hydrostatic Pressure in the Capillaries of the Glomerulus
The driving force for glomerular filtration is: ________________________________________________.
1) The _________________ pressure of blood forces fluid out through leaky endothelium of capillaries.
2) The _________________ pressure inside glomerular capillaries is higher that that of fluid within the
Bowmans capsule.
The hydrostatic pressure (HP) of the glomerulus is ______ mmHg. This force (opposes/enhances) fluid
movement into the Bowman’s capsule, i.e., (opposes /enhances) filtration. The HP of the Bowman’s
space (or capsule) is ______ mmHg. This force (opposes/enhances) fluid movement into the capsule. The
colloid osmotic pressure (COP) of the blood in the glomerulus is ______ mmHg. This force
(opposes/enhances) fluid movement into the Bowman’s capsule?
If you summate these 3 forces that influence fluid movement across the glomerulus, the net force is
______ mmHg. The net direction of fluid movement is from the _____________ to the _____________.
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Glomerular Filtration Rate Averages 180 Liters a Day
Define glomerular filtration rate (GFR):
Briefly describe which two factors influence GFR the most.
1)
2)
An average value for GFR is _________ liters/day or _________ ml/min.
The total body plasma is _______ L, which means the kidneys filter the plasma ________ per day!
GFR is Subject to Autoregulation
What is autoregulation? _________________________________________________________________
____________________________________________________________________________________.
What is a myogenic response? ____________________________________________________________
____________________________________________________________________________________.
Why is a decrease in GFR when blood pressure falls below normal an adaptive response? _____________
____________________________________________________________________________________.
How does the distal tubule communicate with the arterioles? (see Fig. 19-9)
____________________________________________________________________________________.
What does the abbreviation “JG” stand for? _______________________________. The JG cells secret an
enzyme called ____________, which has a role in _________ and _________ balance.
Hormones and Autonomic Neurons also Influence GFR
In neural control of GFR (sympathetic/parasympathetic) neurons release (Ach/NE) onto (, 1, 2,
nicotinic or muscarinic) receptors, causing (vasodilation/vasoconstriction) of renal arterioles.
Vasoconstriction of the afferent arteriole will (increase/decrease) its resistance, will (increase/decrease)
hydrostatic pressure in the glomerulus and will (increase/decrease) GFR.
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Vasoconstriction of the efferent arteriole will (increase/decrease) its resistance, will (increase/decrease)
hydrostatic pressure in the glomerulus and will (increase/decrease) GFR.
Hormones that influence arteriole resistance and GFR include _______________________, which is a
potent vasoconstrictor and a group of regulators called ____________________ which are vasodilators.
Reabsorption
The bulk of reabsorption in the nephron takes place in the _____________________________________.
Which ion plays a key role in bulk reabsorption in the proximal (convoluted) tubule? _________.
List some molecules that are transported using Na+-linked secondary active transport:
____________________________________________________________________________________.
Saturation of Renal Transport plays an Important Role in Kidney Function
List the three properties of mediated transport seen in all protein-substrate interactions:
____________________________________________________________________________________.
Define saturation: _____________________________________________________________________.
Below saturation point, the rate of transport is proportional to ________________ _________________.
Should glucose normally be found in the urine? ____. The term for glucose in urine? ________________.
Should protein normally be found in the urine? ____. The term for protein in urine? _________________.
Secretion and Excretion
By what mode of transport is most of secretion accomplished? _____________________.
How is secretion different from excretion? __________________________________________________.
Table 1. Fill in the following table for the signal molecules that regulate the renal system.
Molecule
Source
Action
Renin
Angiotensinogen
Angiotensin I
Angiotensin II
Vasopressin (ADH)
Aldosterone