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BPK 142 Chapter Notes - Chapter 9.1.1: Arteriole, Ejection Fraction, Diastole

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crimsondeer101
22 Aug 2018
School
Simon Fraser University
Department
Biomedical Physio & Kines
Course
BPK 142
Professor
All

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1
I.
CARDIAC OUTPUT DURING EXERCISE
A.
Cardiac Output and Oxygen Transport
Cardiac output ("Q") - the amount of blood pumped by either the left or right ventricle of
the heart per minute.
Both the left and right ventricles must have the same cardiac output so that blood flow
through the pulmonary and systemic circuits is maintained equally.
Stroke volume - the amount of blood pumped by either the left or right ventricle
per beat.
Cardiac output = heart rate X stroke volume
Since the blood transports oxygen, when cardiac output increases in exercise more
oxygen will be transported to the working muscles. This relationship can be expressed by
the Fick equation:
VO2 = HR X SV X (a-vO2) diff
where: VO2 = oxygen uptake or utilization by the tissues in the body (a-vO2) diff
= arterial-mixed venous oxygen difference
Therefore, in order to increase oxygen uptake, you must increase cardiac output
and/or extract more oxygen from the arterial blood.
In general, the higher the maximal stroke volume --> higher maximal cardiac
output --> higher maximum oxygen uptake (VO2max.)
B.
Exercise Heart Rate
For any given subject, heart usually increases linearly with increasing workload
until the subject's maximum heart rate is reached.
The heart rate at a given oxygen uptake is higher when the exercise is performed
with the arms than with the legs.
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Document Summary

1: cardiac output during exercise, cardiac output and oxygen transport. Cardiac output (q) - the amount of blood pumped by either the left or right ventricle of the heart per minute. Both the left and right ventricles must have the same cardiac output so that blood flow through the pulmonary and systemic circuits is maintained equally. Stroke volume - the amount of blood pumped by either the left or right ventricle per beat. Cardiac output = heart rate x stroke volume. Since the blood transports oxygen, when cardiac output increases in exercise more oxygen will be transported to the working muscles. This relationship can be expressed by the fick equation: Vo2 = hr x sv x (a-vo2) diff where: vo2 = oxygen uptake or utilization by the tissues in the body (a-vo2) diff. Therefore, in order to increase oxygen uptake, you must increase cardiac output and/or extract more oxygen from the arterial blood.

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Related Questions

Rest activity

min volume 19700ml air/min 43400 ml air /min

breathing rate 13breat/min 21

heartrate 72beats/min 112 beats/min

blood pressure 118/70 158/88

% O2 inhaled air 20.94% (.)2094ml O2/ml air) same

% O2 exhaled air 18.94% (.1894 ml O2/ml air) same

a) claculate Tidal volume [ml air/breath]
b) calculate Oxygen consumption (VO2) [ ml O2 consumed/min] -
c) calculate Oxygen content of arterial blood (CO2a) [ml O2/mlblood] -
d) calculate Oxygen content of venous blood (CO2v) [ml O2/ml blood]-
You need to know that there is 13.3 g hemoglobin/100 ml blood, and1.3
ml O2 binds to each gram of hemoglobin. Assume arterial blood is100%
saturated with oxygen, whereas mixed venous blood is 60%saturated
when the subject is resting.
e) caluclate Cardiac Output (CO) [ ml blood/min ] -
f) caulculate Stroke Volume (SV) [ ml blood/beat] -

g) Tidal volume [ml air/breath]
h) Oxygen consumption (VO2) [ ml O2 consumed/min]
i) Stroke Volume (SV) [ ml blood/beat]
Assume change in stroke volume is the same as the change inpulse
pressure when going from rest to exercise - s
j) Cardiac Output (CO) [ ml blood/min ] -
k) Oxygen content of arterial blood (CO2a) [ml O2/ml blood] = sameas when resting
l) Oxygen content of venous blood (CO2v) [ml O2/ml blood] -

Now answer these questions:

1. By what multiplication factor (e.g. 2 times, 3 times, etc.)did oxygen consumption
increase over resting when the person exercised?
2. a. Did minute volume increase by the same factor that oxygenconsumption
increased? If not, what made up the difference?
b. Did cardiac output increase by the same factor that oxygenconsumption
increased? If not, what made up the difference?
3. What was most responsible for the change in minute volume? i.e.compare the
factorial change in breathing rate with that of tidal volume.
4. What was most responsible for the change in cardiac output? i.e.compare the
factorial change in heart rate with that of stroke volume.
5. Calculate total peripheral resistance during rest and exercise(see pg 21). What
physiological changes led to the change in peripheral resistance?In what part of the
body did they occur, and why is this adaptive?

Potentially useful information: one mL = one cm3 = 10-6 m3, one mmHg = 133.3 Pa (N/m2). SV = EDV – ESV. CO = HR X SV. Ejection Fraction = SV/EDV


Hints: calculate heart rate for each condition. Remember to calculate work for the entire volume of blood that is pressurized i.e., end diastolic volume (EDV). Therefore you will need to use the data provided to calculate the EDV to answer this question.

The work done by the heart is Pressure-Volume work. While both ventricles are doing work, in this problem you will just calculate the work done by the left (high pressure) ventricle. In lecture you saw that if both pressure and volume are expressed in SI units, their product is N·m (work!) In this assignment you will calculate the work done by the left ventricle of the heart each minute to support a cardiac output of 5L/min.

1.)In a healthy person make the following assumptions: Stroke volume is 70mL and the Ejection Fraction is 58% (these are normal values). If systolic pressure is 120 mmHg, what is the work that the heart must perform each minute to produce a cardiac output of 5 L/min?

2.) Individuals with hypertension (high blood pressure) have a much greater resistance in their blood vessels and thus their heart not only has to produce greater pressure, it will have a much greater volume left following contractions (end systolic volume, ESV) Calculate the work the heart (for the identical cardiac output of 5L/min) in an individual with stage one hypertension for which these values apply: systolic blood pressure of 150 mmHg, an ejection fraction of 40% and a stroke volume of 60mL.

3.) 150mmHg is 25% greater than 120 mmHg. In this individual, how much greater is their cardiac work?

True of False: Freshwater environments have a higher concentration of oxygen than saltwater environments.

QUESTION 2 If the difference in partial pressure of gas on either side of the barrier to diffusion is 0, which of these events will occur?

The area for gas exchange will increase to accommodate this similarity.

The constant for diffusion will decrease.

The rate of diffusion will be 0.

The distance thickness of the barrier to diffusion will also be 0.

QUESTION 3 On the x-axis of the oxygen–hemoglobin equilibrium curve is the partial pressure of oxygen in tissues. Which type of blood is most likely to be represented by the right-hand side of the axis? (Hint: the oxygen-hemoglobin equilibrium curve is figure 45.14 in your book on pg 913)

blood found in the left ventricle

blood found in the right atrium

blood found in the superior vena cava

blood found in the inferior vena cava

QUESTION 4 Which of these is an example of pulmonary circulation?

Blood is pumped from the right ventricle to the lungs.

Blood is pumped from the left ventricle to the aorta.

Blood is pumped from the aorta to the cardiac vein.

Blood is pumped from the inferior vena cava to the right atrium.

QUESTION 5 O2 will diffuse from blood to tissue faster in response to which of the following conditions?

an increase in the PO2 of the tissue

a decrease in the PO2 of the tissue

an increase in the thickness of the capillary wall

a decrease in the surface area of the capillary

QUESTION 6 Which of the following promotes oxygen release from hemoglobin?

a decrease in temperature

a decrease in carbon dioxide levels

a decrease in pH

a decrease in carbonic anhydrase

QUESTION 7 How does the medulla oblongata sense the amount of carbon dioxide in the blood?

A. Carbonic anhydrase produced by cells performing cellular respiration is exported and travels though the blood, and binds to a receptor on the medullary respiratory center, which causes a signal amplification resulting in a change in gene expression which results in the production of proteins that will cause the diaphragm to contract

B. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which increases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

C. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which decreases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

D. A and B

E. A and C

QUESTION 8 Which of the following parts of the lung are considered "dead space"? A. The alveoli B. The trachea C. The bronchi D. B and C E. All of the above

QUESTION 9 Which of the following blood vessels have the thinnest walls?

arteries

arterioles

capillaries

venules

veins

QUESTION 10 How does the interstitial fluid return to the bloodstream?

A. Interstitial fluid flows into the capillary where the osmotic pressure driving fluid into the bloodstream is greater than the blood pressure driving fluid out of the blood

B. Interstitial fluid flows into the capillary where the blood pressure driving fluid into the bloodstream is greater than the osmotic pressure driving fluid out of the blood

C. Interstitial fluid leaves the tissue via lymphatic ducts and travels through the lymphatic system, which returns the fluid to the veins. D. A and C

E. B and C

QUESTION 11 True or False: When an electrocardiogram (EKG or ECG) shows a flat line (aka asystole), medical personnel will restart the heart using a defibrillator.