Lab 6 - Heart Size Flashcards
What is a echocardiography?
An ultrasound test that checks the structure and function of your heart.
= you can use it to work out heart size
Why is the LV of more interest?
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
What is peripheral brachial blood pressure?
The combination of the forward pressure wave and the reflected pressure wave
What is the conduit artery?
The aorta
What does the destensibility of the conduit artery allow for?
Storage of a substantial fraction of the SV of the heatt during systole and then recoil during diastole = creates continous blood flow through capillaries.
When the aorta becomes stiffer how is flow through cpaillaries changed during diastole and systole respectively?
increased flow during systole and decreased flow during diastole = pulsatile = limits the exchagne of oxygen and nutrients.
What is a reflected wave created by?
Reflection of the forward pressure wave (aortic blood pressure) at bifurcations.
What does timing and amplitude of reflected wave depend on?
arterial stiffness and length of arterial system (body size)
Is there a pressure wave during diastole?
No
*therefore diastole BP between aortic and brachial same
How do you calculate BMI?
weight / height squared
How do you calculate BSA?
square root of weight x height divided by 3600
How do you calculate TFM?
weight x fat percentage divided by 100
How do you calculate FFM?
weight x (1- (fat percentage /100))
What is anthropometry?
Quantitive measurements of the body e.g., height, weight, WC, fat%
Why is it important that the aorta turns pulsatile flow laminal?
It ensures consistent blood flow for exchange of oxygen and nutrients in the tissue
What causes there to be less blood flow reserved in the heart?
Stiffness
What does shear stress release?
NO (nitric oxcide)
Explain the difference between blood pressure values with a small and large cuff:
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.
What is the brachial artery?
The brachial artery is the major blood vessel supplying blood to your upper arm, elbow, forearm and hand
Will BP be higher in a small or large cuff?
Small
How much of our upper arm do we want a BP cuff to cover?
80%
Is a manual or augumented BP measurement more acccurate?
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.
What is correlation?
A measure of an assocuation between 2 varibales and the correlation coefficient (r) indicates the strength of the relationship
If r is 1 what is the strength of the relationship?
Very strong
*a r of 0 suggests no correlation
What is the correlation between LV volume and height?
Strong correlation
Taller people have larger hearts with larger LV volume with is required to perfuse more body tissue
LV volume is also called what?
EDV
What is the strength of the correlation between LV volume and FFM, BSA and body weight (body size measurements)?
Moderate correlations
Why do females tend to have smaller hearts than males?
because female hormone estrogen is involved in a braod arrray of LV hypertropic signalling and protects the heart from hypertrophy (growth)
Is there a correlation between LV volume and adiposity (BMI or total fat mass)?
No
Is there a relationship between LV volume and SBP, HR and EF?
No
Is LV volume correlated to VO2 max?
Yes strong correlation
What explains the strong correlation between LV volume and VO2 max?
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
What is important to remeber about correlations?
THEY ARE ASSUMPTIONS NOT PROVE OF CAUSALITY
