Anatomy & Physiology Flashcards
Made up of 4 chambers:
- left and right atria
- left and right ventricles
left and right sides r separated by the septa
- right side pumps blood 2 the lungs
- left side pumps 2 the body
Heart
Made up of 3 layers:
- endocardium
- myocardium
- pericardium
Heart wall
A layer of the heart wall
Promotes blood flow through the heart
Endocardium
A layer of the heart wall
Propels blood forward
Myocardium
A layer of the heart wall
Consists of connective tissue which forms the sac around the heart
Provides protection and lubrication
Pericardium
Made up of 4:
- tricuspid
- bicuspid
- pulmonary semilunar
- aortic
Controls the direction of blood flow through the heart and when synchronized, ir prevents blood from flowing backward
Made up of leaflets or flaps that r strong but floppy
Contains chordae tendineae
Heart valves
Located w/in the heart valve
Supports valve leaflets which prevents regurgitation of blood
Anchored 2 papillary muscles inside the ventricle walls
Chordae tendineae
2 names for 1 of 4 heart valves
separates right atrium from the right ventricle
Tricuspid valve
Right atrial ventricular
3 names for 1 of the 4 heart valves
Separates the left atrium from the left ventricle
Bicuspid valve
Mitral valve
Left atrial ventricular
1 of 4 heart valves
Located between the right ventricle and pulmonary arteries
Pulmonary semilunar valve
1 of 4 heart valves
Located between the ventricle and the aorta
Aortic valve
1 of 4 heart chambers
Receives deoxygenated blood from the systemic circulation by way of the superior and inferior vena cava
Coronary circulation returns blood from the coronary sinus in2 this heart chamber
Pumps blood through the tricuspid valve in2 the right ventricle
Depolarization occurs here first
Houses the SA node aka pacemaker of the heart
Right Atrium
1 of 4 chambers of the heart
pumps blood through the pulmonary semilunar valve 2 the pulmonary arteries
Right ventricle
Directs blood 2 the lungs 4 oxygenation
Pulmonary arteries
1 of 4 chambers of the heart
Receives oxygenated blood from capillary beds w/in the lungs via pulmonary veins
Pumps blood through the mitral valve in2 the left ventricle
Depolarization occurs after the other side depolarizes
Left atrium
1 of 4 valves of the heart
Pumps blood through the aortic semilunar valve in2 the aorta
Receives blood from the left atrium through the mitral valve
Left ventricle
Right atrium > tricuspid valve > right ventricle > pulmonary semilunar valve > pulmonary arteries > lungs
Blood flow through the right side of the heart
Lungs > left atrium > mitral valve > left ventricle > aortic semilunar valve
Blood flow through the left side of the heart
Passive, low pressure system
These 2 arteries arise from the root of the aorta
Occurs during ventricular diastole and systole
Coronary circulation
Part of coronary circulation
Semilunar flaps of aortic valve occlude the orifices causing pressure 2 rises inside the ventricles causing high pressure on the epicardium and compresses the coronary vessels
As the ventricular myocardium contracts, the surface length becomes shorter than during diastole which causes coronary vessels on the epicardium 2 become tortuous
Attempting 2 profuse these vessels would b inefficient
Ventricular systole
1 of 2 main arteries that carry oxygenated blood 2 the myocardium
Supplies oxygenated blood 2 the right ventricle and the inferior wall of the left ventricle
Perfuses the SA node in 50% of the population
Some people r said 2 b right side dominance when the posterior descending artery arises from it’s distal location
Right coronary
RCA
Supplies the SA node
Occlusion of this artery can manifest as extreme sinus bradycardia on the EKG
Sinoatrial artery
SA
Perfuses the AV node from the RCA in more than 90% of the population
Occlusion of this artery results in high degree heart block on the EKG
Only connection between the atria 2 the ventricles
Below lies the junction if the SA node fails
Holds the electrical signal received from the SA node 4 a short period of time 2 allow the ventricles 2 completely fill w/blood
Conducts impulses to the bundle of His
Atrioventricular node artery
AV node
1 of 2 main arteries that carry oxygenated blood 2 the myocardium
Is short and branches out in2 the LCx(left circumflex artery) and the left anterior descending artery
Left main coronary artery
LMCA
Supplies oxygenated blood 2 the posterolateral aspect of the left ventricle
Left circumflex artery
LCx
Supplies oxygenated blood 2 the anterior wall of the left ventricle
Occlusion can lead 2 arrhythmias and death witch is y it is referred 2 as the Widow Maker”
Left anterior descending artery
LAD
R not interconnected but if perfusion decreases, small arteries may lengthen and connect forming collateral vessels which compensate for reduced oxygen supply and delay the symptoms of heart disease
Large coronary arteries
Controls the synchronic rhythmic contraction of the heart
Electrical impulses r initiated in the SA node and r conducted through both atria and r directed 2 the AV node
then
AV node delays transmission signal 2 the ventricles allowing them 2 fill w/blood
then
Depolarization continues towards the apex of the heart through the bundle of His and the left and right bundle branches which terminate in the Purkinje fibers
As the electrical impulses reach the myocardium, the muscle cells depolarize and contract
Normal conduction system
Occurs when the heart muscle initiates it’s own impulses
These impulses r called ectopic beats
Automaticity
Occurs when the tissue becomes irritated, initiating impulses from outside normal pathways
Seen on the EKG as premature atrial, junctional or ventricular complexes
Ectopic beats
Known as the pacemaker of the heart and fires 60 - 100 times a minute
Conducts the electrical impulse 2 the AV node via the internodal pathways located in the walls of the atria
3 pathways connect it to the AV node:
- anterior
- medial
- posterior
SA node
Connects the right and left atria
Bachmann’s bundle
Creates the P wave on a EKG
Atrial depolarization
Lies below the AV node and acts as a backup pacemaker should the SA node fail to function
Fires 40 - 60 times per minute
Junction
The time needed 4 an impulse 2 travel from the SA node through the AV node 2 the ventricles
An increase of time may indicate that the AV node isn’t conducting impulses normally
Absence of signal conduction indicates a complete heart block
PR interval
When the AV node is unable 2 conduct impulses from the SA node 2 the ventricles effecting the PR interval
Complete heart block
Located in the interventricular septum
Transmits impulses 2 the right and left bundle branches
Bundle of His
Interventricular bundle
Located in the interventricular septum
Carries impulses from the AV node 2 the Purkinje fibers of the right ventricle causing depolarization
Receives oxygenated blood from the LAD
Right bundle branch
RBB
Houses the RBB (right bundle branch) and the LAD (left anterior descending artery supplies it
Interventricular septum
Located in the interventricular septum
Carries impulses from the AV node 2 the Purkinje fibers of the left ventricle causing depolarization
Receives oxygenated blood from the LAD
Is short and divided in2 2 sections:
- left anterior fascicle
- left posterior fascicle
Left bundle branch
LBB
1 part of the LBB
Runs along the anterior surface of the heart
Left anterior fascicle
1 part of the LBB
Runs the length of the septum
Conducts impulses 2 the Purkinje fibers on the posterior surface of the left ventricle
In addition 2 the blood from the LAD, it also receives blood from the RCA causing it 2 b more resistant 2 ischemia (inadequate blood supply 2 the heart)
Left posterior fascicle
A network of conduction pathways that traverse the surface of the ventricles and depolarize them initiating myocardial contraction
Absense of SA and AV node stimulation causes it 2 fire at 20 - 40 times per minute
Purkinje fibers
