Anatomy of heart and cardiovascular system (lecture) Flashcards
Describe some surface markers of the heart
- midsteranl line
- second rib
- sternum
- diaphragm
- left border of heart stretches from 2nd to 5th intercostal space, and from 1 cm off the sternal border to the midclavicular line (tricuspid valve can be heard along here, at 5th intercostal space, pulmonary at 2nd intercostal space)
- right border stretches from 3rd to 6th costal cartilages, 1 cm from sternal border (listen at 2nd intercostal space for aortic valve)
- apex of heart is located in 5th intercostal space (i.e. between ribs 5 and 6), along the midclavicular line (can hear mitral valve here, slide closer to sternum for tricuspid valve)
note apex points left
What causes the heart sounds?
The closing of valves:
S1 - atrioventricular valves (“lub”)
S2 semilunar valves (“dub”)
Describe the major sulci of the heart
-Sulci or grooves contain: fat and coronary vessels
- coronary sulcus/AV groove: contains right coronary artery, left circumflex artery, small cardiac vein and coronary sinus
- anterior IV sulcus: on anterior surface of heart, separates left and right ventricles – contains LAD(i.e. anterior IV artery) and great cardiac vein
- posterior IV sulcus: on posterior surface of heart, separates left and right ventricles– contains posterior IV artery and middle cardiac vein
The pericardial sinuses are not the same as ‘anatomical sinuses’ (such as the paranasal sinuses). They are passageways formed the unique way in which the pericardium folds around the great vessels.
The oblique pericardial sinus is a blind ending passageway located on the posterior surface of the heart.
The transverse pericardial sinus is found superiorly on the heart. It can be used in coronary artery bypass grafting (identify and ligate arteries of heart during grafting) – KENhub
Describe the coronary arteries
- There are two main coronary arteries: the right and the left coronary artery
- The right coronary artery supplies most of the heart i.e. RA, RV, IVS, SA and AV nodes
- The left coronary artery supplies the LV, LA and IVS
- The right coronary artery branches off into two: R. marginal branch and Post. IV (or Post. descending)
- The left coronary artery branches into circumflex, marginal and LAD(or Ant IV)
n.b. can be left or right dominant, depending on origin of PDA- RCA/LCiA
Think LCA supplies left chambers and IVS
IVS supplied by both arteries
RCA- everything else
small percentage of populaiton: co-dominant, PDA supplied by both
Describe the coronary veins
The coronary veins parallel the arteries
- three mains: small, great and middle
- branch off coronary sinus, which sits in coronary sulcus
- there are also ant and post. veins, and ant. IV veins
Describe some of the structures that can be observed on the anterior sternocostal surface
- RA, V most prominent
- LA, V more posterolateral – note V is more on the base, can only really see ventricle wall
- SVC
- IVC
- pulmonary trunk
- cardiac vessels
- apex
- ascending, arch, and beginning of descending aorta
nb ligamentum arteriosum –> was an artery in development, bypassing lungs
nb2: LEFT ventricle is more Lateral
Describe some of the structures that can be observed on the inferior diaphragmatic surface
- LA and V more prominent
- R atrium mostly anterior
- R ventricle only lateral side
- SVC and IVC
- CORONARY SINUS AND SULCUS
- pulmonary veins
List the layers of the heart wall
From superficial to deep:
- fibrous pericardium
- parietal layer of serous pericardium
- pericardial cavity
- epicardium/visceral layer of serous pericardium: outermost, made of mesothelium and thin connective tissue^
- myocardium or cardiac muscle: thickest layer, muscular, forms bulk of heart, responsible for pumping action
- endocardium: innermost layer, comprising endothelum and thin connective tissue (similar to epi)– provides smooth lining for chambers and vessels
note: accumulation of blood or other fluids in pericardial cavity–>restrict cardiac filling–> restrict cardiac output (i.e. impacts SV)
-cardiac tamponade: 200-300ml is enough to reduce effective pumping; removing only 20ml can provide relief
Provide an overview of the position of the chambers, therir features and functions
- Four chambers, two types: atria and ventricles
- Atria (right and left): lie posterior and superior, and are ‘receiving chambers
- divided by inter-atrial septum
- have ear like appendage, called **auricles, that protrude towards the corresponding great vessel ** e.g. pulmonary trunk, veins
-Ventricles (right and left) are larger, ‘pumping’ chambers
- Divided by interventricular septum
Describe the features of the right atrium
- RA receives blood from SVC, IVC, and coronary sinus
- The RA is divides into anterior and posterior compartments by the crista terminalis
- the anterior portion is termed the atrium proper, and contains pectinate muscles and the right auricle
- posterior portion is known as sinus venarum and contains openings for SVC, IVC and coronary sinus
- The RA opens to right ventricle through right AV orifice, and tricuspid valve (which surrounds the orifice)
nb fossa ovalis in interatrial septum
Describe features of left atrium
- Receives blood from 4 pulmonary veins vs IVC, SVC, coronary sinus in RA
- Most of the interior wall is smooth and thin: pectinate muscles only in left auricle–difference between RA, LA
- opens to left ventricle through left atrioventricular orifice and mitral valve (orifice covered by valve)
- valve is **bicuspid ** - difference between RA, LA
- major difference between RA and LA: only pectinates
Compare and contrast the ventricles
- RV has three papillary muscle groups, LV has two groups
- wall of LV is a lot thikcer: ejecting blodo to systemic vs pulmonary circulation
True or false: LAD and anterior descending artery often anastomose
True
Describe the right ventricle
- One of the “pumping” chambers
- interventricular septum
- receives blood from right atrium
Several key structures:- trabeculae carnae = “fleshy beams” – raise bundles, form a mesh
- three groups of papillary muscles (septal, anterior and posterior), which attach to extensions of valves called chordae tendineae (heart strings)
- conus arteriosus/outflow track – smooth
Describe the left ventricle
- receives blood from left atrium and sends to body via systemic circulation
- overall similar structure to right ventricle
- two groups of papillary muscles
- trabeculae carneae —raised bundles of cardiac muscles
- chordae tendinae
- mitral (bicuspid valve)
- the muscular wall is a lot thicker compared to right ventricle, as it must be able to pump blood out to the rest of the body
