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Short Term Responses of
Cardiovascular and
Respiratory System
Recap of last lesson…
1. Structure of the Respiratory System
2. Function and Mechanics of the Respiratory
System
3. Respiratory Volumes
1. Structure
1. Structure
2. Function and Mechanics of
Respiratory System
Function
• The primary function of the respiratory
system is to supply the blood with oxygen
in order for the blood to deliver oxygen to
all parts of the body. It also removes waste
products such as Carbon Dioxide from the
body.
• The respiratory system does this through
breathing. When we breathe, we inhale
oxygen and exhale carbon dioxide
Inspiration - Breathing In
When inhaling…

The intercostal muscles contract
and pull the rib cage up and out.

The diaphragm contracts
causing it to flatten.

The chest cavity gets
larger causing pressure
in the lungs to fall.

Air moves into the lungs
from the higher outside
pressure.
Air
flowing
in
Expiration - Breathing Out
When exhaling…
Air
flowing
out

The intercostal muscles relax
and so the rib cage returns
to normal.

The diaphragm relaxes
pushing it up.

The chest cavity gets
smaller and so pressure
in the lungs increases.

Air flows out of the lungs.

During periods of exercise, expiration becomes an active process,
involving the forced expulsion of air.
The Exchange of Gases within the Lungs

The 2 bronchi, which lead to each lung divide into many bronchioles.

These are less than 1mm in diameter and terminate in grape-like
clusters of tiny sacs called alveoli.
Thorax
Section of
lung
Single alveolus
The Difference between Inhaled
and Exhaled Air
Inhale
air into the lungs (%)
Exhale
air out of the lungs (%)
Oxygen 20.95 %
Oxygen 16%
Nitrogen 79%
Nitrogen 79%
Carbon Dioxide 0.04%
Carbon Dioxide 4.0%
Water vapour 0.01%
Water vapour 1%
2. Function and Mechanics of the Respiratory
System
•
3. Respiratory Volumes
• Inspiratory Reserve Volume
Tidal Volume
• The volume of air inspired
or expired per breath
(Approx 500ml at rest)
– The amount of space that is
available to draw in more air
• Eg; Breathe in normally, then
breathe in more. This extra
capacity is your IRV
• Expiratory Reserve Volume
– The amount of space that is available to breathe out, once you have exhaled
normally
• Eg: Breathe out normally, then force out more air. This is your ERV.
•
Total Lung
Capacity
•
• Residual Volume
– Breathe out as much as
possible
• There is always
some air left in
your lungs
• This is your RV
(Approx 1200ml)
•
• Vital Capacity
– Breathe in as much as you can,
and then force as much air out of
your lungs as possible.
• This is your IRV+ERV+TV,
and is your Vital Capacity
•
Take in as
much breath
as possible
This is your
total lung
capacity
ERV+IRV+TV
+RV (Approx
6000ml)
3. Respiratory Volumes
Todays Aims & Objectives
Aim
Understand the short term effects of exercise
on the Cardiovascular and Respiratory System
Objectives
1.Describe 4 responses to exercise by the Cardiovascular
System.
2. Describe 2 responses to exercise by the Respiratory
System
Word Salad
Reminder of the Cardiovascular
System
1. Structure and Function of the Heart
2. Pulmonary and Systemic Circuits
3. Blood Vessels
1. Structure
Aorta
Vena cavae
Semilunar valves
Right atrium
Tricuspid valve
Right ventricle
Septum
(dividing wall)
Pulmonary artery
Pulmonary veins
Left atrium
Bicuspid valve
Left ventricle
Cardiac muscle
1. Function
• This system has three main functions:
Transport of nutrients, oxygen, and
hormones to cells throughout the body and
removal of metabolic wastes (carbon
dioxide
2. Pulmonary and Systemic Circuits
Retention
http://www.youtube.com/
Success
watch?v=7XaftdE_h60
Blood Pressure
What is it?
It is the strength of your blood
pushing against the arterial walls
of your blood vessels
Systole: contracting phase of the
heart (blood forced out of
ventricles)
Diastole: relaxing phase of the heart
(atria fill with blood)
Components of Cardiac Cycle
Cardiac Output:
Stroke Volume:
Heart Rate:
Blood vessels
3 types of blood vessel
Arteries
Retention
Left
Atrium
Veins
Left
Ventricle
Capillaries
Right
Ventricle
Complete questions 1,2 and 3
Objective 1
• Describe 4 responses to exercise by the
Cardiovascular System
Effects of exercise on the cardiovascular system 11
Short-term effects of exercise on
the cardiovascular system
Increase in Blood
Pressure
Heart rate
increases
Blood vessels
dilate at the skin’s
surface to release
heat, causing skin
to redden
Blood is
pumped to the
working
muscles
Stroke
volume
increases
Systems, such
as the digestive
system, are
bypassed
Waste products
exit the body via
pores and
capillaries at the
skin’s surface
Cardiac
output
increases
Heart beats
harder
Arteries
automatically widen
Heart Rate Anticipatory Response.
• Occurs before the start of
exercise (nervousness).
• Increases Heart Rate above
normal resting levels.
• The greatest AHR response
is higher prior to sprint
events.
• Nerves supplying the heart
with Adrenaline (chemical
released).
The effect of exercise on heart rate
Approximated by:
• HRmax= 220-age
or
• HRmax = 208(0.7 x age)
Components of the
Cardiac Cycle
What are the components?
1. Cardiac Output
2. Stroke Volume
3. Heart Rate
Cardiac Output = Stroke Volume x Heart Rate
Increased venous return (preload) (the muscle pump help
with venous return during exercise):
extent to which ventricle fills with blood and stretches and
subsequently contracts more forcefully: Frank-Starling
mechanism
1.
3.
Blood is returned
through the veins to
the heart and enters
the atria
The greater the venous return
the more blood that enters the
ventricles, the greater the
myocardium is stretched. The
further it is stretched the
stronger and more
forceful the contract will
be
2. Blood then moves from the atria
to the ventricles causing the
myocardium (cardiac muscle) in
the ventricles to stretch
You can mimic preload
by stretching an elastic
band, the further the
stretch the elastic band
the greater the distance it
will travel when you
release it!!!
The Muscle thoracic Pump Helps Venous Return
 During exercise the muscle
pump functions to return
blood to the heart, or
increase venous return; the
muscles contract and
squeeze the veins to push
blood back up to the heart
Immediate effects on the circulatory
system
In response to exercise, the heart beats not only faster,
but stronger.
Heart rate increases from around 70 bpm to up to 200 bpm.
Stroke volume (the volume of blood pumped per beat)
increases from around 50 ml to around 120 ml. In highly
trained athletes, stroke volume can reach 200 ml.
The arteries respond to the body’s increased demands by
dilating slightly to allow more blood to pass through them.
Blood is also diverted away from systems that are not
involved in the activity, for example, the digestive system.
Write a paragraph explaining how the roles of the
heart and lungs in supporting exercise are connected.
Increased Blood Pressure.
Pressure of blood against Artery walls, can
be calculated via two methods:
1. By the Heart through Arteries in the
Circulatory system.
2. Force of Arteries as they resist back
flow.
Systolic Blood Pressure
Diastolic Blood Pressure – Same
Redistribution of blood
During exhaustive
exercise the working
muscles may receive up
to 80% of cardiac output.
This increased blood flow
to the muscles results
from restriction of blood
flow to the kidneys, liver
and stomach
Shunting
• Blood flow changes
dramatically once
exercise commences.
• At rest, only 15-20%
of cardiac output is
directed to skeletal
muscle (the majority
of it goes to the liver
(27%) and the
kidneys (22%).
• Blood is redirected to
areas where it is
needed most.
• This is known as
Shunting.
How is this achieved?
Vasodilation – takes place in the coronary blood vessels
that surround your heart, and in your skin and the blood
vessels of your muscles.
Vasoconstriction - blood vessels in non-active tissue to
constrict, or narrow, reducing blood from the inactive
tissues of your body, such as your abdomen and kidneys
Normal
Vasoconstriction
Vasodilation
The immediate effects: heat loss
The body has two main ways of getting rid of the extra
heat produced by muscles during exercise.
1. Vasodilation
The capillaries close to the surface of the
skin dilate, allowing more blood to flow into
them. Because the blood is closer to the
skin, more heat is lost to the environment.
2. Sweating
Sweat glands in the skin excrete
sweat – a mixture of water, salts and
urea. As the sweat evaporates, it
takes heat away with it.
The immediate effects of exercise
Immediate effects of exercise
Objective 1: Describe 4 responses
to exercise by the Cardiovascular
System
Complete question 4
Objective 2
• Describe 2 responses to exercise by the
Respiratory System
Effects of exercise on the cardiovascular system 11
Short-term effects of exercise on
the Respiratory system
Increase Tidal
Volume
Increase in
Breathing Rate
Breathing rate
• Lungs must work harder and faster to
keep the body supplied with oxygen and
also to exhale the carbon dioxide that is
produced.
• Breathing rate increases from around
18 breaths per minute to up to 80!
• The amount of air inhaled and exhaled
in each breath also increases from
around 0.5 litres to up to 4.5 litres.
• During aerobic exercise, the lungs are able to work fast
enough to supply the muscles with oxygen.
• During anaerobic exercise, the lungs can’t supply
enough oxygen. Once the exercise is over, breathing
remains fast to repay the ‘oxygen debt’.
Increase in Tidal Volume
Lung Volume
Resting Volume
Change due to exercise
Tidal Volume (X)
500ml per breath
Increases up to 4 times
Frequency
12-15
Increases up to 60
Minute Ventilation (VE)
6l/min
Inspiratory reserve Volume
3000ml
Up to 175l/min in large aerobically
trained athletes
Decreases
Expiratory reserve Volume
1200ml
Decreases
Vital Capacity
4700ml
Slight decrease
Residual Volume
1200ml
Slight decrease
Total Lung capacity
5900ml
Slight decrease
Mechanics of breathing - Inspiration
• During exercise, More
muscles are involved.
• The sternocleidomasoid,
sclanes and pectoralis major
are now involved as well as
the diaphragm and
intercostal muscle
• This means that the sternum
lifts further and faster than it
does at rest
Mechanics of breathing - Expiration
• During exercise Becomes an
active process
• intercostal muscles now
contract
• They pull the rib cage down
• More muscles are involved
• Rectus abdominus/obliques
now contract as well
• The diaphragm pushes up
harder into the thoracic cage.
Why does our rate of breathing get faster
and deeper
• Breathing is controlled by the Respiratory
control centre
• Located in the medulla oblongata
• Controls the respiratory
muscles that initiate breathing
• They are under
involuntary neural control
– We don’t normally
consciously control our
breathing rate
Humoral Influence
• A number of things stimulate the
Respiratory Control Centre to work
harder
– Chemoreceptors located in Carotid
bodies and Aortic bodies
– send information to the RCC
– Detect the increased content of Carbon Dioxide in
the blood and the decrease in Oxygen
– This stimulates the RCC to increase the rate and
depth of breathing.
Respiratory Responses.
• Your body is extremely sensitive to rising levels
of CO2.
• The more intense the exercise, the greater
concentration of CO2 in the blood.
• Therefore our breathing rate must increase to
balance the concentration of O2 to CO2.