L21

Question 1

When you go all out, you will feel out of breath and you will need to take some deep breaths

What are you doing during this period of time

Answer 1

replenishing the O2 debt that you have paid during the onset of excerise

Question 2

what makes the O2 deficit/O2 debt at the stat of exercise

Answer 2

At the start of excerise the O2 requirement is higher then the O2 supply this is what makes the O2 deficit/O2 debt

Question 3

when do you enter steady state of O2 consumption

Answer 3

As you continue to excersize then the O2 consumption is ballanced by O2 required which means that you have entered the steady state of O2 consumption

Question 4

what is EPOC

Answer 4

When you end your excersize you still have a high O2 consumption which will slowly drop down back to resting O2 consumption. This time for recovery is called the excess post-excersize O2 consumption or EPOC

Question 5

what is happening during excess post-excersize O2 consumption (EPOC)

Answer 5

During EPOC the muscles are quickly restoring their glycogen and phosphocreatine which requires energy

Question 6

after excersizing is it beneficial to breathe in pure O2

Answer 6

no there is as much O2 as you need in the air

this is because there is only a set amount of air that can cross the BBB

Atm O2 levels 159mmHg, only 105 enter the alveolar sacs and 100 ends up in the blood which is all that you need

Question 7

The harder the excersize will put you in more O2 debt

what happens when you do really intense excersize right at the start of a workout

Answer 7

The more O2 dect that you incer at the start of your excerise then the longer you are going to need to replenish your glycogen and ATP and creatine phosphate

Question 8

what is the main role of the CVS during excersize

Answer 8

to increase blood flow to the skeletal muscles

Question 9

what is the resting CO and what can it increase to during excersize

Answer 9

Resting value of Q is 5L/min

During excersize

• 20L/min when excersizing your an untrained athleat
• 40L/min for trained athleats

Question 10

how do HR and SV increase with excersize

Answer 10

HR increases in a linear fassion with the intensity of excersize (will increase linearly all the way to VO2 max)

SV is linear at the start and then once it gets to 40-60% of maximal excersize then you start to see a plato

Question 11

What is causing the increase in CO

Answer 11

When we first start to excersize the central command stimulates the parasympathetic NS which activates the PSN neurons to releases Ach which retards the SA node

At rest the PSN nerves inhibit the SA node. When we start to excersize ACH stops the blockade in the SA node (that usually causes by the PSN) and the HR increases

The SNS starts to take over and there is stimulation of the sympathetic cardio accelerator neurons which releases catecholamines such as norepinephrine and or epeneffron

These neuron hormones accelerate the SA node so that we get an even faster increase in HR

They also extend to the myocardium to increase contractility doubling the force

Heart is beating faster and stronger increases SV and HR therefore increasing CO

Question 12

what is SV

Answer 12

the volume of blood ejected from the ventricles with each contraction

Question 13

when is maximal SV reached

Answer 13

during submaximal excersize

Question 14

why does SV not increase linearly like HR

Answer 14

The reason for this is that as we are excersizing at high intensities which means that the heart is beating very fast. As the HR increases there is less time for filling so the LV has less blood in it

Question 15

what causes the shape of the SV curve with excerise intensity

Answer 15

Increase in SV at the stat is because as we are excersizing we are increasing venous return because of respiratory and mussel pumps. This increase only happens until the HR starts going to fast for sufficient filling

Question 16

describe BP with excersize

Answer 16

As BP increases with excersize (mostly the systolic BP)

Diastolic increases but to a lesser extent to the systolic pressure

Question 17

how does the Body control BP

Answer 17

through the baroreceptor reflex (BRR)

Question 18

during resting conditions describe the baroreceptor reflex

Answer 18

The BRR involve BR that stimulate various sensitive cells in the solitary tract.

These cells send signals send signals to the baro sensitive cells then signals to the cordial ventrolateral medullar –> rostal ventrolateral medulla which inhibit the sympathetic NS

This leads to vasodilation decreasing BP

Therefore activation of the BR leads to a decrease in BP

Question 19

how does exercise modify the baroreceptor reflex

Answer 19

exercise modifies the normal BRR through central command

When stretch receptors are active in active skeletal muscles these are inputs to the central command, the CC then sends a signal to the inhibitory cells in the NTS, these then send a signal to the barro sensitive cells which block the input from the baroreceptors which shuts down the whole pathway

The central command then sends a signal straight to the rostal ventrolateral medulla (RVLM) which activates the SNS. This causes an increase in BP

Question 20

compeer and contrast the baroreceptor reflex at rest and when excersizing

Answer 20

at rest BR inputs acts on barasensitive cells in the nucleus of the solitary tract (NTS) –> then caudal ventrolateral medulla (CVLM) –> rostral ventrolateral medulla (RVLM)

excercise
stretch receptors in muscle activate central command which sends inhibitory signals to the barrosensitve cells of the NTS which means that they can never be activated by the baroreceptor input. the CC directly prevents the RVLM from decreasing sympathetic activity

Question 21

describe blood flow distribution during excerise

Answer 21

Increased cardiac output ->
Increased available blood flow

Must redirect increased blood flow to areas with greatest metabolic need (contracting skeletal muscle)

Sympathetic nerve activation leads to vasoconstriction & shunts blood away from less-active regions

Question 22

describe CO to the brain during excerise

Answer 22

Less CO goes to the brain during excersize (in terms of %) but the CO in terms of VOLUME doesn’t change

Question 23

Local vasodilation permits additional blood flow in exercising muscle

what is this causes by

Answer 23

metabolic, endothelial products

Sympathetic vasoconstriction in muscle offset by sympatholysis

Local vasodilation > neural
vasoconstriction

Question 24

during exercise how does blood flow to the skin increase

Answer 24

As temperature rises, skin vasodilation also occurs- thermal stress overrides
sympathetic vasoconstrictions
• Permits heat loss through skin temperature regulation

Question 25

what is sympatholysis

Answer 25

when Sympathetic vasoconstriction being sent via central command is being overridden by the local metabolic factors of the endothelial cells.

Question 26

does sympatholysis happen in the skin

Answer 26

no

Vasodilation happens in the skin happens because of thermal stress.

Question 27

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

Answer 27

C

As you are excersizing the ventilation goes up until you get to your anaerobic and lactate threshold and then ventilation takes off really quickly