1. Entry slip: None
Lesson 4.1- Examine the effect of exercise on the
heart and/or respiratory rate; the effect of
adrenalin on blood pressure; CO2 production as an
indicator of metabolism.
(pp315-318) of Biology-McGraw-Hill Ryerson)
I. Terms:
a.Exercise: when the body works harder
than it does “at rest” (i.e. running/ lifting).
i. This increase of movement requires
an increase of energy (glucose) to be
used, much like a car using more fuel
to travel at a faster speed. Due to the
increased energy consumption, more
CO2 is produced in the cells of the
body, much like how more exhaust
comes from the tail-pipe of a car that
is travelling faster.
b. Heart rate: how many times the heart
beats, in one minute (normal is about 72
2. beats per minute). Controlled by the “S.A.
node” – a part of the heart.
c. Respiratory rate: how many times you
inhale and exhale, in one minute (normal
for high-school aged children is 16-25
breaths per minute)
d.Feedback: communication between the
brain and the body.
e.Hormone: a chemical in the blood that
instructs specific organs to perform
specific tasks.
II. Effect of exercise of the heart rate and
respiratory rate:
a.Effect on heart rate:
i. As discussed above, exercise leads to
an increased amount of CO2 produced
in the cells.
ii. If we have a higher amount of CO2 in
the bloodstream, the heart will have
to pump faster to get it to the lungs
quickly to be exhaled.
3. iii. If this does not happen, the higher
amount of CO2 will build up in the
blood and will convert into an acid.
This change in pH is dangerous as
certain enzymes will not be able to
work properly anymore, like amylase
which breaks down CHO’s.
iv. Heart-rate increases due to the
following feedback mechanism:
A. Increased CO2 in the blood
stream will be sensed in the
brain.
B. The brain will send a signal to the
adrenal glands located on the
kidneys, to release two
hormones, called “noradrenaline”
and “adrenaline” into the
bloodstream
C. When noradrenaline comes into
contact with the SA node (a part
of the heart), the SA node will
cause the heart rate to increase.
4. b. Effect on respiratory rate.
i. Similarly to how exercise and
increased CO2 levels in the
bloodstream caused the heart rate to
increase, increased CO2 levels in the
bloodstream cause the respiratory
rate to increase.
A. Increased CO2 in the blood
stream will be sensed in the
brain.
B. The brain will send electrical
signals more quickly to the
diaphram and intercostals
muscles, causing your respiratory
rate to increase.
C. Demo: How long can you hold
your breath?
III.Effect of adrenaline on blood pressure:
a.Blood-pressure: the pressure your blood
exerts on the walls of blood vessels.
Normal is 120/80. The numbers represent
5. “millimetres of mercury” or “mmHg”, but
all you have to remember is that the
higher the number, the higher the
pressure.
b. As discussed above, increased CO2 levels
in the bloodstream lead to the brain
sending signals to the adrenal glands on
the kidneys to release the hormones
noradrenaline and adrenaline.
i. Noradrenaline causes the heart rate
to increase, to get the CO2 in the
blood to the lungs a quick as possible.
ii. Adrenaline, as well, has a purpose in
sending blood through to the lungs as
quickly as possible. It does this by
increasing blood pressure.
a.Adrenaline causes the blood
vessels to constrict, or
become smaller.
b.Since the same amount of
blood has to get through
these smaller vessels, the
6. blood is forced to move much
more quickly.
iii. Pressures:
a.“Systolic Pressure”- the top
number represents the
pressure from the heart beat.
b.“Diastolic Pressure”- the
bottom number represents
the pressure on the walls of
the blood vessels between
beats.
c. Demo: water hose
IV. Demos: Youtube search: “Understanding a
Blood Pressure Reading (Health Guru Tip)”
I. Homework Assignment:
a. On a piece of paper, create a concept map
to illustrate the effect of exercise on the
heart-rate, starting with exercise and
ending with increased heart-rate
