CP LEC 1 Flashcards
Where is the right portion of the heart located in relation to the ribs?
3rd costal cartilage to 6th intercostal space
Where is the left portion of the heart located in relation to the ribs?
From the 2nd to the 5th intercostal cartilage
The viseral pericardium is also known as the….
Epicardium
4 Layers of the heart
which one makes the pericardial fluid?
Parietal Pericardium
Visceral Pericardium (epicardium - pericardial fluid)
Myocardium
Endocardium
Which layer of the heart contains the coronary blood vessels?
visceral pericardium (epicardium)
What are the 2 parts of an intercalated disc and their functions?
Desmosomes- attach cells together
Connexins- spread electrical impulse
The right coronary artery supplies
most of right ventricle, SA node, AV node in 55%
(and right posterior descending and right marginal branches)
The left coronary artery supplies
left ventricle muscles, left atrium, ventricular septum, left anterior descending (widow maker), left circumflex artery, SA in 45% of people
Why is it a problem if you have a blockage in your left anterior descending artery? (widow maker)
left ventricle wont get blood/oxygen, and wont be able to contract and pump oxygenated blood to the body!
What are the consequences of having a history of MI in the right atrium?
Previous MI may have resulted in scarring of the myocardium, which doesn’t conduct like normal myocardial cells. the SA node/pacemaker is in this atria, so we need conduction to set good HR!
Primary cause of coronary artery disease (CAD)
atherosclerosis
due to high BP, high cholesterol, diabetes, smoking
The SA node automatically paces the heart to beat ___bpm
100
The parasympathetic NS (via the vagus nerve) slows it down to 60-90
The SA node must set a pace of depolarization that is _____ than any other cell
Faster
The AV node can spontaneous discharge at a rate of…
40-60bpm
Why is the SA node suspectible to disease?
Proximity to epicardium (Pericarditis)
Coronary artery occulsion
What does the PR interval represent on an EKG
The conduction time between the atria and the ventricles
time it takes for electrical signal to go from SA node to AV node and into ventricles
INCLUDES DELAY AT AV NODE before ventricular depolarization
What does the QT interval represent
The time between the onset of ventricular depolarization and the end of ventricular repolarization
What is a bundle block and what is the consequence?
electrical signal delay or blocked at the L or R bundle branch, causing delay in ventricular contraction = decreased CO
SA - AV - bundle of his - R and L bundles - pujunkee fibers
What does the red portion of the chart represent?
Rapid influx of ___ ions during depolarization
Calcium (Ca2+)
The green part of the chart represents what ion?
K+ Ions
Normal K+ levels are __ to __
hypokalemia would cause
hyperkalemia would cause
3.5-5.0
hypokalemia - *arrhythmias, cramps (increased with diuretic)
hyperkalemia - nausea, vomiting
normal levels of Ca are __ to ___
hypocalcemia would cause
hypercalcemia would cause
9-11
hypo - decreased myocardial contractility
hyper - erratic cardiac contraction
Ca, think contractility
what are 3 main properties of the myocardium
automaticity - conduct without external stimuli (different than skeletal mm)
rhythmicity
conductivity - nerve impulses transmitted from one myocardial cell to another because intercalated discs
Normal stroke volume is ____L and may increase ____ times during exercise
5-6L of blood
x4-7 or 40-60%