L13-14;C6 Flashcards
What happens to demand of O2 when we increase metabolic activity?
The demand of O2 will increase with it
What are the three major circulatory elements?
- A pump
- Channels or tubes
- A fluid medium
Blood flow must meet ______ demands
Metabolic
Explain the following:
Myocardium
Desmosomes
Gap junction
Myocardium—> Cardiac muscle fibres connected by intercalated disks special to cardiac muscles
Desmosomes—> holds the cell together, acts as a single unit
Gap Junctions—> rapidly conducts action potential, occurs with unified contraction within ventricles
Explain the calcium reduced calcium released method
Stimulation releases Ca, but this isnt sufficient to cause a contraction. But it is sufficient enough to cause stimulation of RYR receptors to release more Ca which eventually causes a contraction
What is the main difference in cardiac and skeletal contractions?
The second burst of calcium in cardiac muscles only happen in their tissues
With respect to myocardial substrate use,
At rest, heart oxidizes ____ to provide majority of its energy for work
At moderate, there is an equal distribution of _____, ______, and ______
At high, mainly _____ is being used
Fat,
Carbs, fats, lactate
Lactate
Training has an effect that there is higher reliance on ______ than _____ in terms of oxidizing. Why?
Fats, carbs
Since ATP synthesis for fats is slower and for lactate it is higher
What happens when atrium and ventricle are contracting at the same time? What happens when they are not?
When they are contracting at the same time, it is insufficient to pump blood.
Having a delay allows for ventricles to fill which is good.
What innervation is an external factor to allowing control of the heart? What does it do?
Vegas innervation and PNS act through the Vegas nerve. This releases Ach to decrease HR and force of cardiac contraction
Strong vagal innervation _____ HR, sympathetic system ______ Hr and contraction
Decreases, increases
SNS increases impulse and contraction of heart, causing chronotropic and ionotropic results. What do these mean?
Chronotropic—> referees to rate of heart
Iontropic—> refers to force of contraction of heart
What kind of people have higher vagal modulations? Wha does this due to their HR?
Active people, this decreases HR during rest
What does less vagal stimulation do?
Increases HR, and increase SNS activity
With respect to a cardiograph, explain the following:
P=
QRS=
ST=
T=
P= Atrial depolarization QRS= ventricular depolarization ST= ventricular repolarization T= ventricular repolarizatrion
Ventricle systole is ____ to ___ wave
QRS, T
Ventricle systole is how much of the hearts cycle? What do the end of contractions mean?
1/3rd the cycle, the contractions mean end diastolic volume
Ventricular diastole is from ___ wave to _____
T, QRS
Ventricle diastole is how much of the cycle? How much fills passively and actively?
It is 2/3 cardiac cycle, fills 70% passively and 30% actively
Blood pressure is mainly driven and drained _______
Passively
What happens to a patient when they have a heart transplant with respect to their CO and SV?
They have a depressed CO and increases SV
After the translation of a heart, recovery rate is ______ and why?
Decreased, due to no para or sympathetic activity. The nerves were severed. This means there is no vagal activity.
Heart rate is _____ before transplant, why?
Lower, since there is no vagal tone to keep HR down. Since HR before will be lower and knows a resting level.
What still influences the heart after transplant?
Hormones, more sympathetic stimulation means a greater hormonal release.
Why do arterioles veins arteries and venules all have smooth muscle?
For vast constriction and dilation that allows blood to flow
Recall, the heart spends ______ in systole, ____ in diastole
1/3, 2/3
