Cardiac Anatomy Flashcards
location of heart
- on diaphragm near midline of thoracic cavity
- lies in mediastinum
- 2/3 of heart’s mass lies left of midline
apex
-rest on the diaphragm and formed by the tip of the left ventricle
base
- formed by atria
- beneth 2nd rib
definition of pericardial sac
keeps heart in place with mediastinum
-contains heart and roots of great vessels
what are the two parts of the pericardial sac
- fibrous
2. serous
what is the fibrous part of the pericardial sac
- most outside layer
- attached to diaphragm, posterior to sternum
- anchors heart in mediastinum
- prevents over stretching of heart and serves as protection
what is the serous part of the pericardial sac
-thinner, delicate membrane that forms double layer around heart
what are the layers of the serous part of the pericardial sac
- parietal layer
- pericardial cavity
- visceral
what is the parietal layer of the pericardial sac
fused to fiberous membrane
what is important about the pericardial cavity and where is it located
located between the parietal and visceral part of the pericardium
-contains pericardial fluid, which is thin film of lubricating fluid secreted by pericardial cells that reduce friction as heart moves
what is the visceral layer of the pericardial sac
- epicardium
- one of the layers of heart wall and adheres to surface of the heart
what are the layers of the heart
- epicardium (external)
- myocardium (middle)
- endocardium (internal)
what is important to know about the myocardium
- middle layer of the heart
- pumping action of the heart
- cardiac muscle tissued
- 95% of wall is striated like skeletal muscle
- involuntary like smooth muscle
what is important to know about the endocardium
- lines all of the heart chambers and heart valves
- continuous with the endothelium of blood vessels
what are the four chambers of the heart
- 2 atria
- 2 ventricles
what does the 2 atrias of the heart do
-superior receiving chambers that receive blood from veins returning from the rest of the body
what do the 2 ventricles of the heart do
-inferior receiving chambers that eject blood from the heart into the arteries
where does the right atrium receive blood from
- inferior vena cava
- superior vena cava
- coronary sinus
- and right anterior veins?
what is the interarterial septum
thin wall between the right and left atrium
what does the tricuspid valve do
- helps blood flow from right atrium to right ventricle
- 3 cusps
- also known as right atrioventricular valve
what does the right ventricle do
- forms most of the anterior surface of the heart
- contracts and pumps blood that came through tricuspid valve through the pulmonary semilunar valve to go to the lungs
what does the chordae tendena and papillary muslces help to do
- chordae tendena is a tendon like chord that connects to the cusps of atrioventricular valves and papillary muscles
- the papillary muscles contract and pull on the chordae tendena to help prevent prolapse on inversion of the atrioventricular valves
what is interventricular spetum
-separates the right and left ventricles
what is the role of the left atrium
- forms most of the base of the heart
- receives blood from the pulmonary veins
what is the role of the bicuspid valve
- valve where the blood flows from the left atrium to the left ventricle
- 2 cusps
- also known as the left atrioventricular valve
what is the left ventricle
- thickest chamber
- forms apex of heart
- contracts and pushes blood from the left atrium up the aortic valve and into the systemic circulation
what is the aortic valve
- also known as aortic semilunar valve
- blood flows from LV to ascending aorta
details about the fibrous skeleton of the heart
- part of the heart wall, made of dense connective tissue
- composed of 4 annuli that surround the valves of the heart and come together with one another a merge with the interventricular septum
- important because it forms the structural foundation of heart valves
- helps prevent over stretching, helps electrical insulation b/w atria and ventricles
what do the heart valves do
- open and close based on pressure changes as heart contracts and relaxes
- ensures unidirectional flow of blood through heart
- close passively when ventricles contract (sistole), pressure drives cusps upward until they meet
- chordae tendenae are tightened by papillary muscles to prevent cusps going into atria
atrial ventricular valves
- open passively wen pressure is higher in atria than in ventricles
- ends of cusps project into ventricle
semilunar valves
-aortic and pulmonary valve
-each have 3 cusps
allow ejection of blood from the heart into the arteries and prevent backflow into venticles
-open when pressure in ventricles is greater than pressure in arteries
-allows ejection of blood from ventricles into pulmonary trunk and aorta
-when ventricles relax, back flow of blood fills the valve cusps and cause them to close
what does the left side of the heart do
- pump for systemic circulation
- receives oxygen rich blood from lungs
what does the right side of the heart do
- pump for pulmonary circulation
- receives oxygen poor blood from systemic circulation
what does the coronary circulation consist of
-made up of arteries, arterioles, capillaries, venules, and veins
what are the coronary arteries
-left and right coronary arteries branch from the ascending aorta, above the aortic valve in the sinus of Valsalva
what is the opening of the coronary arteries known as
coronary ostia
how do the coronary arteries get blood
when the ventricle relaxes and the backflow of blood closes the aortic semilunar valve, this causes the filling of coronary arteries
Branches of the right coronary artery (RCA)
- SA Nodal branch
- acute marginal branch: supplies right ventricular wall and gives off collaterals to the terminal branches of LAD
- posterior descending branch: supplies 1/3 of interventricular septum
- posterior septal branch: supplies AV node
- atrioventricular branch
Right coronary artery
- supplies small branches to the right atrium
- travels forward and down the right AV sulcus
- travels toward apex and continues on posterior
Branches of left coronary artery
- Left anterior descending (LAD)
- circumflex branches
- Ramus Medianus (RX)
Left coronary artery
- passes inferior to the left auricle and divides in the LAD and circumflex branch
- there is a ramus medianus branch but not all patients have that
Left anterior descending branch
- also known as the “widow maker”
- located in the anterior sulcus
- supplies oxygenated blood to walls of ventricles
- supples anterior 2/3 interventricular septum
- branches into the septal and diagonal branch
circumflex branch
- curves around the left side of the heart
- supplies oxygenated blood to walls of left ventricle and left atrium
- further branches into the obtuse marginal branches
what is the third coronary artery
the conus artery
- majority of cases has independent ostium, may share ostium with right coronary artery
- supplies anterior wall of RV when present
what are the three coronary arteries
- left coronary artery
- right coronary artery
- conus artery
explain coronary circulation
-blood passes through coronary arteries, flows into capillaries, where delivers oxygen and nutrients to muscles and collects CO2 and waste then travels to coronary veins
details of coronary venous system
- twice as many veins as there are arteries supplying the heart
- two parts: coronary sinus system and anterior cardiac venous system
what does the coronary sinus system do
- left cardiac venous system
- collecting system for most of the superficial veins of the heart
what does the anterior cardiac venous sytem do
- right cardiac venous system
- made up of veins which open directly into right atrium
coronary sinus details
- collection of veins that join together to form a large vessel that collects blood from the heart muscle (myocardium)
- empties directly into right atrium
- primary collector of cardiac venous blood with largest cardiac vein in terms of diameter
- retrograde cardioplegia given
what are the veins in the coronary sinus system?
- great cardiac vein: largest vein
- left marginal vein: aka lateral vein
- left posterior vein aka inferior veins of left ventricle
- middle vein aka posterior interventricular vein
anterior cardiac venous system details
-drain veins that originate on the anteriolateral surface of the RV and enter directly into the RA
what veins are in the anterior cardiac venous system?
- right marginal vein
- small cardiac vein
- sinus node vein
