Lecture 21

Question 1

Why are we gasping for air after we do exercise?

Answer 1

we are trying to replenish the O2 debt that you have paid during the onset of exercise

Question 2

At the start of exercise, your ______ requirement _________ what is available so you have an O2 _______

Answer 2

O2
exceeds
deficit/debt

Question 3

As you continue to exercise and the O2 consumption is _________ by the O2 ________, we are in the _______ state O2 consumption.

Answer 3

balanced
requirement
steady

Question 4

When you end your exercise, you continue to have a high O2 __________ that slowly returns to ________ ________ O2 _______ levels even though you ended your exercise. This time to recovery is the __________ ________-_______ _______

Answer 4

consumption
normal resting
consumption
Excess post exercise consumption

Question 5

What happens during EPOC?

Answer 5

the muscles are quickly restoring their glycogen levels, needing O2, as well as their phosphocreatine and ATP stores

Question 6

Why is increasing O2 consumption by sucking O2 into the air not proven to be beneficial?

Answer 6

Because all the O2 that we need is in the atmosphere and there is only so much O2 that can cross the alveoli barriers.
Atmospheric O2 is around 150mmHg but only 105mmHg enters the sacs and then only 100 mmHg end go into the arteries. This means that increasing the atmospheric pressure by sucking O2 out of the can does not mean that is it going to boost O2 levels down to the muscle tissues

Question 7

The extent of O2 debt that you are going to enter is related to the what?

Answer 7

the workload/intensity of the exercise

Question 8

The more intense the exercise, will put you in more/less O2 debt

Answer 8

more

Question 9

The _____ O2 debt that you incur at the beginning of exercise, the ________ you are going to need for recovery to replenish the stocks of _______, _________ and _______

Answer 9

more
longer
creatine-phosphate
glycogen
ATP

Question 10

What is the main role of cardiovascular system when it comes to exercise?

Answer 10

to increase blood flow to the active skeletal muscles

Question 11

What is a major cardiovascular response to exercise?

Answer 11

there is a huge increase n cardiac output

Question 12

What is the resting value for cardiac output?

How does this change in response to exercise?

Answer 12

5L/min

this changes to about 20L/min for an untrained person and 40L/min for a trained person

Question 13

What is the increase in cardiac output due to?

Answer 13

This is due to both an increase in heart rate and stroke volume

Question 14

Heart rate increases in a _______ fashion ie. as we increase intensity, heart rate _______

Answer 14

linear
increases
(there is a slight dip in the linear line at 100% maximal intensity)

Question 15

Stroke volume increases in a _________ fashion but only up until ________% of maximal exercise intensity. Then there is a _______ of stroke volume

Answer 15

linear
40-60%
plateau

Question 16

What is regulating the increase in heart rate and SV?

The ________ command activates the __________ neurons which release _________ that slow down the ________ node which regulates the ________ rate (bpm). When we are at _______, a signal is sent along the ___________ neurons releasing ACh that inhibits the SA node. When we start to exercise, a signal parasympathetic neurons that stops releasing __________ that inhibits the _________ node so the SA node activity ____________.
When we are exercising, the ___________ drive takes over and there is stimulation of ___________ cardiac nerve which release ____________ (adrenaline) that accelerate the SA node to get a faster _________ in the HR.
They also extend to the ___________ to increase myocardial __________ so the heart pumps harder with each beat so SV ___________.

Answer 16

The central command activates the parasympathetic neurons which release ACh that slow down the SA node which regulates the heart rate (bpm). When we are at rest, a signal is sent along the parasympathetic neurons releasing ACh that inhibits the SA node. When we start to exercise, a signal parasympathetic neurons that stops releasing ACh that inhibits the SA node so the SA node activity increases.
When we are exercising, the sympathetic drive takes over and there is stimulation of sympathetic cardiac nerve which release catecholamines (adrenaline) that accelerate the SA node to get a faster increase in the HR.
They also extend to the myocardium to increase myocardial contractility so the heart pumps harder with each beat so SV increases.

Question 17

Describe how the heart rate differs at rest, in anticipation for exercise and during exercise

Answer 17

There is an increase in the heart rate in preparation for exercise and then an even greater increase in heart rate during exercise. This is because the parasympathetic drive is shutting off the inhibitory function on the SA node and so the SA node becomes more active in anticipation for exercise

Question 18

Our parasympathetic and sympathetic systems are responsible for regulating our heart rate during exercise is evidence from a hypnosis test. Describe this

Answer 18

There were two groups, one that has high hypnotisability and one have low hypnotisability. As they did exercise for three minutes, their heart rate increased in linear fashion by the same amount.
Then they were asked to imagine the exercise the exercise they just did and those that have a high hypnotisability, their heart rate increased too

Question 19

Define stroke volume

Answer 19

this is the volume of blood ejected from the ventricles with each contraction

Question 20

Stroke volume increases _______ as exercise intensity ______ but only up to _____% of maximal intensity. After this point, the SV values reach a _____-

Answer 20

linearly
increases
40-60%
plateau

Question 21

Why do we see a drop off in our stroke volume?

Answer 21

As we are exercising at higher intensities, the heart rate is increasing a lot and so it is going really fast.
As the heart rate increases, there is less time for the filling of the left ventricle and so it can’t fill with as much blood and so the SV decreasing.

Question 22

Why do we get an initial steady increase in SV?

Answer 22

As we are exercising, we are increasing out venous return. On top of this, we have sympathetic drive to pump blood out of ventricles

Question 23

What happens to blood pressure when you exercise?

Answer 23

it increases

both systolic and diastolic in both the upper and lower body

Question 24

When the body is trying to control blood pressure, it does this through the _________ reflex

Answer 24

baroreceptor

Question 25

Describe the baroreceptor reflex

The baroreceptors stimulate __________ cells in the _________ of the __________ tract. These __________ cells send signals to barosensitive cells in the ________ ________ medulla and then they send signals to the __________ which _________ the sympathetic nerve system. There is __________ and so there is a ___________ in blood pressure

Answer 25

The baroreceptors stimulate barosensitive cells in the nucleus of the solitary tract. These barosensitive cells send signals to barosensitive in the caudal ventrolateral medulla and then they send signals to the RVLM which inhibits the sympathetic nerve system. There is vasodilation and so there is a decrease in blood pressure

Question 26

Where are the NTS, CVLM and RVLM located?

Answer 26

in the brainstem

Question 27

How is the baroreflex affected during exercise?

This occurs through _________ command:
When ________ receptors are active in active __________ muscle, these are inputs that act through the central command which send a signal to the ____________ cells which are located in the ___________. These ____________ cells then send a signal to the ____________ cells that block the input from the __________. Because this has been blocked, this pathway is ________ ________
Instead central command sends a signal straight to the ___________ and this activates the _________ nervous system to __________ blood pressure

Answer 27

This occurs through central command:
When stretch receptors are active in active skeletal muscle, these are inputs that act through the central command which send a signal to the inhibitory cells which are located in the NTS. These inhibitory cells then send a signal to the barosensitive cells that block the input from the baroreceptors. Because this has been blocked, this pathway is shut off.
Instead central command sends a signal straight to the RVLM and this activates the sympathetic nervous system to increase blood pressure

Question 28

Why do you feel sick if you do exercise after eating?

Answer 28

The increased blood flow from our increased cardiac output is directed towards our areas of activity like our skeletal muscles whereas blood flow to our digestive regions is decreased. There is sympathetic activation to cause vasoconstriction and shunt blood away from the less-active regions of the body.

Question 29

How does the percentage of cardiac output going to different regions of the body change in response to exercise?

Answer 29

At rest, a lot of blood goes to the kidneys.
As we exercise, the percentage of CO doesn’t change for the heart but it changes for the brain (it decreases, same volume but smaller percentage) and hugely increases going to the skeletal muscles.
Blood also gets diverted to the skin for cooling strategy. There is vasodilation to these areas.

Question 30

How does vasodilation occur?

_________ vasodilation permits additional blood flow in _________ muscle. This occurs through the __________ of blood vessels and their endothelial cells are producing products that cause _______ vasodilation so endothelial cells will make things like ___________. These endothelial cells are triggered by _________ products that are being secreted by the contracting ________ muscle cells. _________ vasoconstriction which is being sent by _______ command is being over ridden by the _________ vasodilation. This process is called ______________ and it occurs in the _______ muscle.
In the skin, as temperature _______, skin _________ also occurs- thermal stress _________ sympathetic ________. This permits heat _______ through skin- temperature regulation

Answer 30

Local vasodilation permits additional blood flow in exercising muscle. This occurs through the endothelium of blood vessels and their endothelial cells are producing products that cause local vasodilation so endothelial cells will make things like NO. These endothelial cells are triggered by metabolic products that are being secreted by the contracting skeletal muscle cells. Sympathetic vasoconstriction which is being sent by central command is being over ridden by the local vasodilation. This process is called sympatholysis and it occurs in the skeletal muscle.
In the skin, As temperature rises, skin vasodilation also occurs- thermal stress overrides sympathetic vasoconstrictions. This permits heat loss through skin- temperature regulation

Question 31

While exercising, ventilation is directly related to exercise:
A. frequency B. Time of day C. intensity
D. duration

Answer 31

intensity