CH 9: Cardiovascular Response to Exercise Flashcards
What is the purpose/driving factor of the cardiovascular system?
To create and maintain pressure appropriate to the circumstances (Exercise intensity)
Name and briefly characterize the layers of the heart wall
-Epicardium: Lubricative outer covering
-Myocardium: Provides muscular contractions that eject blood from the heart chambers
-Endocardium: Serves as the protective inner lining of the chambers and valves
What structure in myocardium cells allow them to share a depolarization signal?
Intercalated Disks
How many fiber types are in the heart and how can they be characterized?
The heart has a homogenous fiber type.
Similarly to type I muscle fibers, they are slow-oxidative and resistant to fatigue.
True or False: One of the biggest advantages of myocardium compared to muscle, is the presence satellite cells.
False - Satellite cells are absent from myocardium
How is the absence of satellite cells significant to the heart?
Satellite cells facilitate the repair of damage in muscle cells (mainly following exercise). Since the heart does not contain satellite cells, scar tissue appears when damage occurs in the heart (i.e. after a heart attack).
What is the meaning of “Cardioprotective benefit of aerobic exercise” (aka cardioprotection)?
If an individual suffers from a heart attack, adverse effects are minimal if a moderate aerobic session occurred shortly prior (6~10 days). Training should be frequent
EDV, aka __________ is primarily influenced by _______ ________.
Preload
Venous Return
Name at least 3 factors that influence Venous Return.
1.) Q/Cardiac Output
2.) Blood flow redistribution
- Vasoconstriction
3.) Muscle Pump/ One-way venal valves
4.) Respiratory Pump
5.) Gravity
What 2 factors outside of venous return influence EDV?
1.) Stiffness of the heart
- More likely in older/diseased population
2.) Heart Rate
What issues may be inferred if the venous return is not equivalent to cardiac output in an individual?
If venous return is less than cardiac output, this may point towards some form of blood loss (internally or externally) or a blockage in the system.
True or false? Myocardium cells have a resting membrane potential similarly to muscle cells.
False: Myocardium cells constantly creep towards depolarization as they have an affinity for both sodium and calcium ions to leak.
The SA Node acts as what mechanism in the heart?
Pacemaker
What is the intrinsic rate of the SA Node in a normal healthy person?
Approximately 100 BPM
What is the advantage of the use of Beta-Blockers in heart patients if it lowers heart rate?
Lowering heart rate allows for longer fill time which increases the stretch on the heart making the contraction force stronger (by way of the Frank-Starling mechanism) without excess oxygen demand.
What is the role of the intercalated disks inside the myocardium?
It facilitates the transmission of the depolarization signal from one cell to the next cell.
True or false? Intercalated disks are found in the myocardium of the atrial and ventricular chambers.
True. There are no intercalated disks between the atrial and ventricle chambers but there are intercalated disks inside the myocardium within their chambers.
Fill in the blanks.
A patient who has been battling some serious heart problems and was very susceptible to a myocardial infarction ended up having one today. As we are familiar with the heart’s muscular structure we know that after a heart attack _____ ______ cells will replace the _______ ________. With this adverse event, the lack of _________ _____ cells found in ___________ ___________ which ____________ _____ __________ _____ ___________ in muscle cells would lead to higher caution to prevent instances like this from occurring.
Scar Tissue Cells
Myocardial Cells
Satellite Cells
Skeletal Muscles
Facilitate the repair of damage
What are the two things that influence ESV?
Inotropic Factors and afterload