2: Cardiovascular System Flashcards
Where is blood pressure highest?
Aorta (also very high in arteries supplying the heart)
What is an anastomosis?
intercommunication between 2 arteries ensuring blood flow to an are even if one artery is blocked
What is systole?
Contraction phase (blood is pumped out of the chamber)
What is diastole?
Relaxation phase (blood fills the chamber)
What are the factors of intrinsic control of the heart?
- Autorhythmaticity
- SA node
- AV node
- Purkinje fibers
What is autorhymaticity?
the ability to initiate impulse for contraction at regular intervals
What does the SA Node do?
it is the pacemaker of cardiac contraction
What does the AV node do?
delays impulses by 1/10 of a second, allowing the atria to contract before the ventricles
What do the Purkinje fibers do?
rapidly spread the impulse to contract throughout ventricles
What are the factors of extrinsic control of the heart?
- Parasympathetic nerve fibers
- Sympathetic nerve fibers
- Endocrine glands
- Bradycardia
What do parasympathetic nerve fibers do?
decrease the heart rate
What do sympathetic nerve fibers do?
increase the heart rate
What are some features of cardiac muscle (myocardium)?
- Capable of contraction and force generation (like skeletal muscle)
- Autorhythmaticity
- Intercalated discs that spread impulses to contract
- Synctial conraction
What is Syncytial contraction?
fibers contract simultaneously
What are the features of the fibers of the myocardium?
- Have high mitochondrial density
- Have extensive capillary network
- Use aerobic energy for contraction
What is the correlation between cardiac wall thickness and force generation?
The thicker the wall of the cardiac chamber, the greater the force
Which wall is the thickest?
Left ventricle (supplies the whole body)
What does regular physical training do to wall thickness?
Thickens the L ventricle wall and increases L ventricular mass
What does chronic hypertension do to wall thickness?
Thickens the L ventricle wall and increases L ventricular mass
How does training affect the wall thickness in the atria and right ventricle?
no increase
Which portion of the electrocardiogram correlates with the P wave?
atrial depolarization
Which portion of the electrocardiogram correlates with the QRS interval?
ventricular depolarization
Which portion of the electrocradiogram correlates with the ST segment and T wave?
ventricular repolarization
What is cardiac output?
amount of blood pumped per minute