Biology Student Activities
Comes to Life
Homeostasis:
role of the cardiovascular,
respiratory and renal systems
The blood, circulatory, respiratory and renal systems have critical roles to play in maintaining homeostasis. They provide
cells with nutrients and oxygen (O2) required for metabolic processes, whilst also playing important roles in the removal
of metabolic waste products such as carbon dioxide (CO2) and nitrogenous waste. By using equipment from the UNE
biomedical science laboratory, you will be able to identify the body’s physiological responses to exercise and consider
why these changes occur. You will have the opportunity to participate in a number of tests, including vertical jump
performance, maximal aerobic uptake (VO2max), and maximal power. Each of these tests has been included to assist in
your understanding of the human body, see how you stack up against your friends, whilst also having a bit of fun!
Activity A: What impact does homeostasis have on my breath concentration?
Oxygen is important for ATP production in the human body, whilst carbon dioxide is a waste product and must be
removed. This activity is designed to demonstrate how breath concentration varies before and after high-intensity
exercise, and also indicate the importance of O2 and CO2 in the body.
IMPORTANT: If you wish to complete the 30-second exercise test, you must complete the Adult Pre-Exercise Screening
Tool. Follow the instructions from the UNE staff member and complete the table below:
Before Exercise
After Exercise
Heart Rate
O2% Saturation
CO2% Concentration (Breath)
O2% Concentration (Breath)
School of Science
and Technology
Activity A continued:
Bike
Running
Power Peak (W)
Split 1
m/s
Power Peak/Weight (W/kg)*
Split 2
m/s
Power Average (W)
Split 3
m/s
Power/Mass (W/kg)
Total Distance
m
* Power Peak/Weight (W/kg)= Power Peak divided by Weight
How did your peak velocity compare to Usain Bolt who was recorded at 12.4 m/s (approx 45 km/hr) between the
60th and 80th meter in the 2009 World Championships?
How do you compare: to the Number 1 Draft athlete from the National Hockey League (NHL) who achieved a
Power Peak/Weight of 15.6 watts/kg?
Question 1. What happened to the concentrations of O2 and CO2 in breath before and after the completion of
exercise? Use this information to identify which gas is valuable to the body, and which is a waste product which
needs to be removed?
Question 2. What is the role of a negative feedback loop in controlling the concentration of CO2 and H+ in the
blood?
With the help of your, teacher, friends and the UNE staff member complete the table below, with reference to the
homeostatic mechanism controlling CO2 concentration in blood (fill out as much as you can)
Stimulus
Receptor organ detects change
Coordinating organ eg hypothalamus
Effector organs bring about change
Response
Increased CO2
and [H+]
Decreased CO2
and [H+]
Question 3. Why must CO2 be removed from the body, and why does this become even more important during
high-intensity exercise? What occurs to performance if CO2 is not removed from the body quickly enough?
Activity B: How are nutrients/gases transported in the body, and how is core
temperature controlled during long duration exercise?
Oxygen is important for all processes occurring in the human body, in particular for ATP production. Sports scientists
use maximal aerobic uptake (VO2max) testing to determine fitness of an athlete. Your job is to collect data for one of
your class mates completing a VO2max test, and identify what the data is saying about the roles of the respiratory and
cardiovascular systems. You will also need to keep in mind how the body attempts to control body temperature during
high-intensity exercise.
4. Complete the equation to demonstrate the importance of O2 and CO2 in the body:
Glucose +
________ →
Water
+________
+ATP
Record the results from the VO2max test in the table below. If time permits, complete the graph:
Watts/Speed
Oxygen Uptake (VO2)
CO2 % of Breath
Heart Rate
How does your classmate compare: to the highest ever recorded VO2max of 92mL/kg/min?
Complete the table, by choosing from the following options¬(1):
(Carbon dioxide, oxygen, nitrogenous waste, water, fats, salts, products of digestion)
Substance
What it is carried by ...
Coordinating organ - eg hypothalamus
Red blood cells
Oxyhaemoglobin
Plasma
Red blood cells
Mostly as bicarbonate ions, with a small percentage
dissolved directly in plasma
Carbamate (combination of CO2 and haemoglobin)
Plasma
Water molecules
Plasma
Ions
Plasma
Chylomicron (a package of digested lipids,
phospholipids and cholesterol wrapped in protein)
Plasma
Mostly urea
Plasma
Whole molecules: eg glucose
5. Draw an arrow to demonstrate how substances (including O2 and CO2) follow a concentration gradient:
LOWHIGH
Complete the table from the following options (kidney, small intestine, lungs, and other body tissues) (1):
Tissue
Main change
Removal of CO2; Oxygenation of blood
Deoxygenation of blood; removal of glucose; increase in carbon dioxide
Removal of nitrogenous waste
Increase in digestive products (ie glucose)
Question 6. How do concentration gradients for CO2, O2 and glucose change in exercising muscle cells? Why does this
emphasise the importance of exercise in diabetic patients?
Prolonged exercise causes an increase in core temperature. Can you complete the following table, demonstrating the role
of the homeostatic control mechanism under prolonged exercise? (1)
Stimulus
Receptor organ detects change
Coordinating organ
Effector organs bring about change
Response
Increase in core
temperature
7. During prolonged exercise, the body attempts to control body temperature by sweating, and vasodilating blood
vessels near the skin allowing for heat transfer to the external environment. Why might athletes performing prolonged
exercise in hot environments show signs of fatigue earlier than during competitions in cooler environments?
Activity C:
What is the role of anti-diuretic hormone (ADH) and aldosterone in the
human body?
Water and electrolyte balance is a critical consideration for the body to maintain homeostasis. If the correct concentration
of electrolytes is not maintained, individual cells may swell and shrink and have a negative impact on processes occurring
in the human body. The kidney has a very important role in maintaining the correct fluid/electrolyte balance. The goal of
this activity is to review kidney function, and consider how the hormones aldosterone and ADH impact on fluid electrolyte
balance during exercise. You will need to follow instructions from the UNE staff member, complete 1 minute worth of
vertical jumps on the specialised jump mate, before entering your results into the computer program which will reflect on
your kidney function. It is important to know that these results are only “hypothetical”, designed to help you learn in a fun
and interactive way!
Complete the following table to identify the main metabolic waste products and how they are excreted (1):
Metabolic Waste
Product
Carbon dioxide
Excess water
Excess salts
Nitrogenous waste (urea,
ammonia, uric acid)
Excreted in ....
Question 8. What is the primary role of the kidney and what is the name of the functional unit of the kidney?
Question 9. Briefly outline each of the three stages of nephron function?
Filtration:
Reabsorption:
Secretion:
Complete the jump protocol according to instructions from the UNE staff member and fill out the table using the autogenerated results from the central computer:
JUMP PERFORMANCE TABLE
Jump #
Watts
Jump #
5
35
10
40
15
45
20
50
25
55
30
60
Average Jump Power =
Person
A
B
C
D
Average
Jump
Power
(watts)
Sweat
volume
(mL)
Height (cm)
Watts
ADH Conc.
(mmol/L)
Aldosterone %
Conc.
Reabsorb
(mmol/L)
Volume
urine (mL)
Urine
Conc.
(mmol/L)
Blood
Blood
Vol (mL) Pressure
(mm/Hg)
How did your best vertical jump score compare to the Number 1 Draft Athlete in the National Hockey
League (NHL) who achieved a score of 83 cm?
What is the impact of the hormone ______________ on nephron function?
Aldosterone-
ADH-
Question 10. Performing high-intensity exercise for long periods of time causes sweating and results in a loss of
blood volume. How would this impact upon the release of aldosterone and ADH, and what impact would it have on
kidney function? (Feel free to draw a diagram to represent this process)
Glossary:
Adenosine triphosphate (ATP): energy source for all muscular contractions in the human body. Without ATP, we
cannot live, let alone exercise!
Carbonic Acid (H2CO3): forms when CO2 combines with H2O, causing acidity of blood
Cellular respiration: process where the chemical bonds of energy-rich molecules such as glucose, are converted
into ATP
Glucose
+
Oxygen →
Water+ ATP
Carbon Dioxide
+
Rate of ATP production: increases with increasing exercise intensity
Aerobic ATP production: occurs more slowly than anaerobic, but can be sustained for long periods. Oxygen must be
present for aerobic ATP production to occur.
Waste product: produced during ATP production, and has a negative effect on athlete performance. Examples
include carbon dioxide, nitrogenous waste and lactic acid.
Reference:
Jeffery, C. and Ross, P. (2007) NSW BIOLOGY- “Maintaining a balance”, Macmillan Education Australia, South Yarra,
Australia.
School of Science
and Technology
Produced by Marketing and Public Affairs UNE, April 2016.
Information correct at time of printing. CRICOS Provider No. 00003G.