Lab 6 - Heart Size

Question 1

What is a echocardiography?

Answer 1

An ultrasound test that checks the structure and function of your heart.

= you can use it to work out heart size

Question 2

Why is the LV of more interest?

Answer 2

Because the LV is what ejects blood out of the heart via the aorta during systole

LV is what creates a flow wave

*whereas blood from the RV just goes to the lungs via the pulmonary artery

Question 3

What is peripheral brachial blood pressure?

Answer 3

The combination of the forward pressure wave and the reflected pressure wave

Question 4

What is the conduit artery?

Answer 4

The aorta

Question 5

What does the destensibility of the conduit artery allow for?

Answer 5

Storage of a substantial fraction of the SV of the heatt during systole and then recoil during diastole = creates continous blood flow through capillaries.

Question 6

When the aorta becomes stiffer how is flow through cpaillaries changed during diastole and systole respectively?

Answer 6

increased flow during systole and decreased flow during diastole = pulsatile = limits the exchagne of oxygen and nutrients.

Question 7

What is a reflected wave created by?

Answer 7

Reflection of the forward pressure wave (aortic blood pressure) at bifurcations.

Question 8

What does timing and amplitude of reflected wave depend on?

Answer 8

arterial stiffness and length of arterial system (body size)

Question 9

Is there a pressure wave during diastole?

Answer 9

No

*therefore diastole BP between aortic and brachial same

Question 10

How do you calculate BMI?

Answer 10

weight / height squared

Question 11

How do you calculate BSA?

Answer 11

square root of weight x height divided by 3600

Question 12

How do you calculate TFM?

Answer 12

weight x fat percentage divided by 100

Question 13

How do you calculate FFM?

Answer 13

weight x (1- (fat percentage /100))

Question 14

What is anthropometry?

Answer 14

Quantitive measurements of the body e.g., height, weight, WC, fat%

Question 15

Why is it important that the aorta turns pulsatile flow laminal?

Answer 15

It ensures consistent blood flow for exchange of oxygen and nutrients in the tissue

Question 16

What causes there to be less blood flow reserved in the heart?

Answer 16

Stiffness

Question 17

What does shear stress release?

Answer 17

NO (nitric oxcide)

Question 18

Explain the difference between blood pressure values with a small and large cuff:

Answer 18

A cuff that is too small will not cover at least 80% of the upper arm - this means that it will have to be pumped up to a much higher pressure to completely obstruct blood flwo trhough the brachial artery - this means that the Korotkoff sounds (marking systolic pressure) start earlier during release of pressure from the cuff giving a higher measurement.

A cuff that is too large will cover more than 80% of your upper arm - this means that it will obstruct blood flow through the brachial artery for longer to a lower pressure - so the Korotkoff sounds start later during the release of pressure from the cuff giving a lower measurement.

Question 19

What is the brachial artery?

Answer 19

The brachial artery is the major blood vessel supplying blood to your upper arm, elbow, forearm and hand

Question 20

Will BP be higher in a small or large cuff?

Answer 20

Small

Question 21

How much of our upper arm do we want a BP cuff to cover?

Answer 21

80%

Question 22

Is a manual or augumented BP measurement more acccurate?

Answer 22

Depends who is doing it - a doctor (who is good at doing it) will tend to do manuallu.

*important this for accuracy of BP is not trustly a single measurement.

Question 23

What is correlation?

Answer 23

A measure of an assocuation between 2 varibales and the correlation coefficient (r) indicates the strength of the relationship

Question 24

If r is 1 what is the strength of the relationship?

Answer 24

Very strong

*a r of 0 suggests no correlation

Question 25

What is the correlation between LV volume and height?

Answer 25

Strong correlation

Taller people have larger hearts with larger LV volume with is required to perfuse more body tissue

Question 26

LV volume is also called what?

Answer 26

EDV

Question 27

What is the strength of the correlation between LV volume and FFM, BSA and body weight (body size measurements)?

Answer 27

Moderate correlations

Question 28

Why do females tend to have smaller hearts than males?

Answer 28

because female hormone estrogen is involved in a braod arrray of LV hypertropic signalling and protects the heart from hypertrophy (growth)

Question 29

Is there a correlation between LV volume and adiposity (BMI or total fat mass)?

Answer 29

No

Question 30

Is there a relationship between LV volume and SBP, HR and EF?

Answer 30

No

Question 31

Is LV volume correlated to VO2 max?

Answer 31

Yes strong correlation

Question 32

What explains the strong correlation between LV volume and VO2 max?

Answer 32

Exercise results in physiological remodelling of the heart - increase LV from LV dilation is to accomodate the increased CO required by the body during exercise.

= your heart grows and becomes stronger when trained just like any other muscle in the body

Question 33

What is important to remeber about correlations?

Answer 33

THEY ARE ASSUMPTIONS NOT PROVE OF CAUSALITY