Focus on cardiovascular system due to its impact on mortality rates.
Significance of understanding blood vessels and blood pressure.
Structure: Heart is divided into chambers.
Atria: Top chambers of the heart.
Left atrium (labeled).
Right atrium (located on the opposite side).
Ventricles: Bottom chambers of the heart.
Left ventricle.
Right ventricle.
Heart dissection: Front of the heart removed for internal view, essential for lab work.
Representation in diagrams: Yellow elements show the electrical conducting system.
Sinoatrial (SA) Node:
The pacemaker of the heart where electrical excitation begins.
Generates action potentials independently without external nervous system input.
Atrioventricular (AV) Node:
Located between atria, situated at the bottom of the right atrium.
Receives signals from the SA node; embedded within the atrial wall.
AV Bundle (Bundle of His):
Takes signals from the AV node.
Thin structure that runs down the septum between the ventricles.
Bundle Branches:
Two branches (left and right) extending down each side of the septum.
Purkinje Fibers:
Spread electrical signals throughout the ventricles, facilitating contraction.
The contraction begins at the apex of the heart and moves upward toward the atria.
Directional Flow of Blood:
Ventricles push blood upwards (to aorta and pulmonary trunk), atria push it downwards.
This process resembles squeezing a tube of toothpaste.
The contraction sequence is crucial for effective blood circulation.
Used to study heart's electrical activity.
Origin of terms:
EKG comes from "Kardiogramm" in German; ECG is the English equivalent.
Key Components of ECG:
P Wave: Atrial electrical excitation (smallest wave).
QRS Complex: Signifies ventricular excitation and is the most significant part of the ECG.
T Wave: Indicates ventricular repolarization.
Importance of recording good quality waveform for practical understanding in lab sessions.
Cycle Overview:
Sequence of electrical excitation and subsequent contraction.
P wave (atrial excitation) leads to contraction.
QRS complex (beginning of ventricular excitation) observed next.
T wave indicates return to resting state after ventricular contraction.
The entire process repeats continuously in the cardiac cycle.
Systematic Flow:
Blood flows from the body into the right atrium via the vena cava.
Moves through the right atrium, passes through the tricuspid valve (right AV valve) into the right ventricle.
Exit to lungs through the pulmonary valve into the pulmonary trunk.
Oxygenation Process:
Blood becomes oxygenated in lungs, returns to the left atrium via pulmonary veins.
Passes to the left ventricle via the mitral valve (left AV valve) and exits through the aortic valve into the aorta.
Supplies blood to the heart tissue itself.
Coronary Arteries:
First branches off the aorta, responsible for heart muscle perfusion.
Importance of coronary circulation in overall heart health.