Lecture 1 Flashcards
Circulation and cardiac energetics
What is the difference in pressure and oxygen levels in pulmonary circulation and systemic circulation?
In the pulmonary circulation there is low pressure and high oxygen. Which is the other way around for the systemic circulation
What are the two pumps of the heart?
The left and right side of the heart
What does the heart look like in turtles, lizards and snakes (amount of chambers, aorta etc)?
They have 3 chambers, 2 aorta’s and have no septum between the left and right ventricle
What does the heart of an alligator look like (chambers, aorta etc)?
It has 3 or 4 chambers, a septum and 2 aorta’s.
How does the alligator heart function under water?
It does not use the RV, and has a low bpm of around 10. It can also function at high acidity
How do you get more oxygen through the body?
By a higher frequency of pumping or a bigger tidal volume
What does a sarcomere need to relax?
ATP
How does the mechanism of a muscle contraction work?
Calcium binds to troponin and tropomyosin moves out of the way so that myosin can attach to actin to create the contraction
What is the function of a circa channel?
It takes up calcium, but that does cost lots of ATP
How much of the heart is dedicated to ATP production?
30-40 % of the heart consists of mitochondria, which produce the ATP
What stays the same when there is diastolic heart failure?
The stroke volume
What is the atrial kick?
A high force that occurs during a contraction, late in systole.
What is the cycle of the heart after the atrial kick?
An isovolumetric contraction, which leads to ejection and then there is isovolumetric relaxation and passive filling
What is the Frank-Starling mechanism?
When there is more blood, it means that more blood has to be expelled
What happens when the muscles are more stretched?
This means that more will contract and with more force. Also there is a higher affinity of toponin C to calcium
What is internal work?
The work per heart beat. Which is measured by the stroke volume times the mean pressure
What is the internal work in healthy people?
1.15 J/beat
What is the total internal work in healthy people?
1.34 W
What is the definition of metabolic work?
The oxygen uptake by cardiac muscle
What is the MVO2 of healthy people?
8 ml oxygen/min/100 g
What is the metabolic work in healthy people?
5.3 W
How do you calculate the myocardial efficiency?
The internal work divided by the metabolic work
What is the myocardial efficiency in healthy people?
It is about 25 % for oxygen. The rest goes to heat
What is the myocardial efficiency in people with heart fialure?
It will drop even lower than it is in healthy people
