IB Kidney & Excretion Study Guide
Read Pages (11.3 Section (pages 299-306)on the kidney ) and define the following vocabulary and address the following
learning objectives
Define the following Words:
Excretion
Ultrafiltration
Collecting duct
Cortex
Fenestrated blood capillaries
ADH
glomerular filtrate
Medulla
Osmosregulation
urine
Pelvis
Microvilli
proximal convoluted tubule
Ureter
Osmosis
Renal blood vessel
Active transport
Glomerulus
Loop of Henle
Nephron
Medulla
Learning Objectives
11.3.1 Define excretion.
11.3.2 Draw and label a diagram of the kidney. Include the cortex, medulla, pelvis, ureter and renal blood vessels.
11.3.3 Annotate a diagram of a glomerulus and associated nephron to show the function of each part.
11.3.4 Explain the process of ultrafiltration, including blood pressure, fenestrated blood capillaries and basement
membrane.
11.3.5 Define osmoregulation.
11.3.6 Explain the reabsorption of glucose, water and salts in the proximal convoluted tubule, including the roles of
microvilli, osmosis and active transport.
11.3.7 Explain the roles of the loop of Henle, medulla, collecting duct and ADH (vasopressin) in maintaining the
water balance of the blood. Details of the control of ADH secretion are required in option H (see H.1.5).
11.3.8 Explain the differences in the concentration of proteins, glucose and urea between blood plasma,
glomerular filtrate and urine.
11.3.9 Explain the presence of glucose in the urine of untreated diabetic patients.
Helpful Websites with Animations and Practice Quizzes
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter26/
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter26/animation__micturition_reflex.html
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter27/
http://www.sumanasinc.com/webcontent/animations/content/kidney.html
IB Practice Questions (optional)
1. Define excretion.
 “The removal from the body of waste products of metabolic processes .” (1)
2. Label and state the functions of the structures of the kidney.
Renal vein
a.
b.
c.
d.
Carries balanced blood away from the
kidney.
e.
f.
The nephron is the functional unit of the kidney.
3. Label and state the structures of the functions of the nephron.
a.
Structure
Function
Renal capsule
Ultrafiltration of blood.
b.
c.
d.
e.
f.
In (overly) simple terms, the kidney works by forcing everything out of the blood and then selectively
reabsorbing the components which are desirable. Waste products therefore continue to the pelvis and become part
of the urine.
4. Ultrafiltration is the first step, and takes place in the renal capsule.
a. Distinguish between the afferent and efferent arterioles.

b. Identify one component of the renal capsule which is an example of an extracellular component in animals.

c. Explain the process of ultrafiltration.




d. List three components of the blood which are not pushed into the glomerular filtrate and state the reason
why.

5. Selective reabsorption returns valuable molecules to the blood.
a. State the location of selective reabsorption in the kidney.

b. List three molecules that are recovered back into the blood by selective reabsorption.

c. Explain the significance of the following elements of selective reabsorption.
Convolutions of the
tubule
Microvilli
Mitochondria
Protein pumps and
channels
Osmosis
6. A major function of the kidney is to maintain the balance of water in the blood.
a. Define osmoregulation.

b. List three functions of water in animals.



c. State the location of osmoregulation in the kidney.

d. Distinguish between the descending and ascending parts of the loop of Henle.

e. Explain the role of the loop of Henle in osmoregulation.
Input:
Output:
f.
Explain the role of the collecting duct in osmoregulation.




g. ADH is a hormone used in negative feedback control of blood water balance.
i. State the two parts of the brain involved in osmoregulation and their functions.
o
o
ii. Describe the effects of ADH on:
The walls of
the
collecti
ng duct
Water uptake
into the
blood
Concentration
of the
urine
7. Consider this data table:
a. Calculate the concentration of urea in the urine.
b. Explain why such a large proportion of urea is removed from the blood.
c. Explain why no proteins and macromolecules are present in the filtrate or urine.
d. 100% of glucose is reclaimed. Explain how this occurs.
8. Consider the urinalysis for patient B:
a. Calculate the percentage of glucose which is reuptaken to the blood.
o
b. Explain the presence of glucose in the urine of patients with diabetes. You will need to consider two
processes in your answer: glucoregulation and osmoregulation.







c. Deduce, with a reason, the effective of taking an insulin shot on the urine glucose concentration of a
patient with Type I diabetes.


Intensity of
thirst / arbitrary
units
10
9
8
7
6
5
4
3
2
1
0
Plasma
ADH /
pmol dm–3
d. Deduce, with a reason, the effective of taking an insulin shot on the urine glucose concentration of a
patient with Type II diabetes.


9. The plasma solute concentration, plasma antidiuretic hormone (ADH) concentration and feelings of thirst
were tested in a group of volunteers. These graphs show the relationship between intensity of thirst,
plasma ADH concentration and plasma solute concentration.
(Question taken from the QuestionBank CDRom)
280 290 300 310 320
Plasma solute concentration / mOsmol kg –1
20
18
16
14
12
10
8
6
4
2
0
280 290 300 310 320
Plasma solute concentration / mOsmol kg –1
[Source: adapted from C T Thompson, et al ., (1986), Clinical Science London, 71, page 651]
(a)
Identify the plasma ADH concentration at a plasma solute concentration of 300 mOsmol kg-1
using the line of best fit.

(1)
(b)
Compare intensity of thirst and plasma ADH concentration.

(1)
(c)
Outline what would happen to plasma solute concentration and ADH concentration if a person
were to drink water to satisfy his/her thirst.


(2)
(d)
State two reasons why a person’s plasma solute concentration may increase.


(2)
(Total 6 marks)
10. The proximal convoluted tubule is a part of the nephron (kidney tubule). Its function is selective
reabsorption of substances useful to the body.
(a)
Outline how the liquid that flows through the proximal convoluted tubule is produced.


(2)
(b)
(i)
Water and salts are selectively reabsorbed by the proximal convoluted tubule. State the
name of one other substance that is selectively reabsorbed.

(1)
(ii)
State the names of the processes used to reabsorb water and salts.
Water:
salts:
(2)
The drawing below shows the structure of a cell from the wall of the proximal convoluted tubule.
(c)
The actual size of the cell is shown on the diagram. Calculate the linear magnification of the
drawing. Show your working.
Answer
(2)
(d)
Explain how the structure of the proximal convoluted tubule cell, as shown in the diagram, is
adapted to carry out selective re-absorption.


(2)
(Total 9 marks)
Works Cited
1. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l. : Oxford University Press, 2007. 978-0-19-915143-1.
2. Mindorff, D and Allott, A. Biology Course Companion. Oxford : Oxford University Press, 2007. 978-099151240.
3. Clegg, CJ. Biology for the IB Diploma. London : Hodder Murray, 2007. 978-0340926529.
4. Campbell N., Reece J., Taylor M., Simon. E. Biology Concepts and Connections. San Fransisco : Pearson Benjamin
Cummings, 2006. 0-8053-7160-5.
5. Taylor, Stephen. Science Video Resources. [Online] Wordpress, 2010. http://sciencevideos.wordpress.com.
6. Burrell, John. Click4Biology. [Online] 2010. http://click4biology.info/.
7. IBO. Biology Subject Guide. [Online] 2007. http://xmltwo.ibo.org/publications/migrated/productionapp2.ibo.org/publication/7/part/2/chapter/1.html.