Climbing a mountain involves strenuous activity that places increased demands on the circulatory and respiratory systems. When climbing, the heart rate increases to deliver more oxygenated blood to the working muscles. Deeper breathing also occurs to expel more carbon dioxide. Upon reaching high altitudes, the lower oxygen levels trigger faster breathing and heart rate to compensate. Hypoxia results from too little oxygen reaching tissues and can cause symptoms ranging from inattentiveness to coma. Treatments for hypoxia include breathing assistance, controlling heart function, raising blood pressure, and managing seizures. The body's response is similar in males and females during strenuous activity.

1. Animal Physiology
Assigment 4 & 5

2. Question 1 :
Changes in circulatory and respiratory
system when a man :
a) is climbing the mountain
(hint: strenuous activity)
b) when he reached the highest peak
(hint: altitude)

3. a) Climbing the
mountain
(strenous activity)

4. What are strenous activities?

5. O involve heavy cardiovascular exercises as well as
aerobic exercises.
O get the heart pumping (increase the heart rate)
instantly, and peak at a 80-85 percent of
maximum heart rate
O Example : swimming, sprinting, running, sports
activities, weightlifting and others

6. Effects of strenous activity
(climbing the mountain)
O Circulatory System
O Repiratory System

7. Circulatory System
O Substrate & O2 requirements of working skeletal
O
O
O
O
O
O
O
muscles above resting requirements.
Produce more CO2 and more lactic acid
heart rate and stroke volume = limiting factor for O2
delivery to the tissues
Increase in cardiac ouput > increase in O2 consumption
> increase in blood flow to muscle
Muscles have a higher metabolic rate
pH and body temperature shift the oxygen
dissociation curve for haemoglobin to the right
More O2 unload into muscle.
When muscle contract, blood flow restricted
briefly, but overall it is enhanced by the pumping action
of the muscle.

8. Respiratory System
O At submaximal intensities, ventilation & O2
O
O
O
O
consumption linearly with in work rate
tidal volume and respiratory rate
O2 uptake and CO2 output.
pulmonary ventilation
Haemoglobin continues to be fully saturated
with O2 throughout the climbing

9. b) reached the
highest peak
(altitude)

10. Circulatory System
O High altitudes = low O2 levels
O Heart beats faster, higher tidal volume in lungs
O O2 is in demand CO2 need to be expelled.
O Blood pressure slightly increased temporarily
O No change in stroke volume
O The resting cardiac output
O O2 delivery to the tissues remained unchanged

11. Respiratory System

12. Respiratory System
O O2 demand
O CO2 must be expelled.
O Faster, deeper breathing (a higher tidal
volume in the lungs)

13. c) Hypoxia.
(Symptoms & Treatments)

14. Hypoxia
O Lower than normal PO2 in environment or blood
O condition in which the body or a region of the
body is deprived of adequate oxygen supply.
O Divide into 2 :
 Generalised hypoxia (affecting the whole body)
 Local hypoxia (affecting a region of the body)

15. Symptoms
O Symptoms of mild hypoxia include:
• Change in attention (inattentiveness)
• Poor judgement
• Uncoordinated movement
O Symptoms of severe hypoxia include:
• Complete unawareness and unresponsiveness (coma)
• No breathing
• No response of the pupils of the eye to light

17. Treatments
O Breathing assistance (mechanical ventilation)
O Controlling the heart rate and rhythm
O Fluids, blood products, or medications to raise
blood pressure if it is low
O Medications including phenytoin,
phenobarbital, valproic acid, or general
anesthetics to calm seizures.

18. Bonus Question :
Would it make any difference
if the climber is a female?
No. The overall response of the cardiovascular
system and respiratory system in doing
strenuous activity is similar in male and
female.