Cardiac Physiology Flashcards
Mean arterial pressure
The difference of systolic maximum pressure exerted on arterial wall during ventricular contraction and diastolic pressure in vasculature in ventricular relaxation.
- Average pressure for circulation
- Indication of tissue perfusion
Stroke volume x HR = ?
Cardiac Output
Which 2 factors determine blood pressure?
Cardiac output and Systemic vascular resistance
Ejection fraction =?
Fraction of blood expelled during contraction
Stroke volume/EDV
What is a normal EF?
60%
Hypocalcemia
Reduced calcium levels
Depresses the heart
Hypercalcemia
Prolongs plateau phase of action potential
Makes heart more irritable
Leads to spastic heart contractions
Hypernatremia
Excessive Na
Inhibits transport of Ca into cells
Blocks heart contraction
Hyperkalemia
Excessive K
Lowers resting potential
May lead to heart block and cardiac arrest
Hypokalemia
Life threatening
Heart beets feebly and arrhythmically
Where is the CV center in the brain?
Medulla
Where is the cardioacceleratory center located?
This is a sympathetic center
Projects from medulla to the T1 to T5 levels of the spinal cord
Innervates SA and AV node
Where does the parasympathetic (cardioinhibitory center) center send signals to?
Dorsal vagus nucleus in the medulla.
This is sent via vagus nerve branches to SA and AV node
SLOWS heart rate
Pressoreceptors
Detect changes in BP
Located in aortic and carotid sinuses
Chemoreceptors
Detect changes in blood O2 content
Located in aortic and carotid bodies
