Lecture 15: Anatomy of the Great Vessels Flashcards
Parts of the mediastinum
Superior
Inferior (middle, posterior, anterior)
Borders of the mediastinum
Top: Neck, arm
Left: left lung
Right: right lung
Bottom: Abdomen
Heart orientation and surfaces
Ressembles a pyramid that has fallen over
Base (posterior)
Anterior surface
Left pulmonary surface
Diaphragmatic surface (inferior)
Right pulmonary surface
See figure
What is most visible on the anterior side of the heart? Posterior?
Anterior: right ventricle
Posterior base: left atrium, part of right atrium
Inferior: left ventricle and part of right ventricle
See figure
What are the great vessels?
Aorta: aortic arch, ascending aorta, descending aorta
Pulmonary trunk: right pulmonary artery, left pulmonary artery
Pulmonary veins: two veins from each lung
Vena cavae: Superior vena cava (SVC) and inferior vena cava (IVC)
See figures
What is the ligamentum arteriosum?
Shunts blood from pulmonary artery to aortic arch
See figure
Where does the heart connect to the lungs?
At the hilum of each lung
1 pulmonary artery enters each lung
2 pulmonary veins leave the lung
See figure
Layers of the pericardium
Superficial fibrous pericardium
Two layer serous pericardium
Two layers of the serous pericardium
Parietal layer: attached to fibrous pericardium
Visceral layer (epicardium): lines the surface of the heart
What do the serous pericardium layers form? What fluid do they contain?
the pericardial cavity
Contains a thin fluid film (serous fluid)
Role of serous fluid
Allows heart to move inside pericardium without friction
What is the pericardial sac attached to inferiorly?
The diaphragm
Moves with respiration
How are the pericardial sinuses formed?
Lines of reflection between the visceral and parietal pericardium
Where is the transverse pericardial sinus?
Lies anterior to the superior vena cava and posterior to the ascending aorta and pulmonary trunk
Where is the oblique pericardial sinus?
Lies posterior to the heart in the pericardial sac
What are the four chambers of the heart?
Right atrium
Right ventricle
Left atrium
Left ventricle
See figures
What is the sinus venarum?
In the right atrium of the heart
The smooth, thin-walled posterior part of the atrium on which the SVC, the IVC and the coronary sinus open
Allows blood flow
What are the pectinate muscles?
A rough muscular wall of the right atrium
Present in the auricles and part of the atrial wall
What is the role of the right auricle?
Small muscular pouch that projects from the right atrium
Increases capacity of right atrium
What is the interatrial septum? What does it contain?
Separates the two atria
Has an oval depression called the oval fossa, which is a remnant of the oval foramen and its valve in the fetus
What is the conus arteriosus?
The superior tapered portion of the right ventricle
What are the trabeculae carnae?
Right ventricle
Irregular muscle elevations
What is the supra ventricular crest?
A thick muscular ridge
Separates the ridged muscular wall of the inflow part of the chamber from the smooth wall of the conus arteriosus (outflow part)
What are the different parts of the papillary muscles in the right atrium?
Anterior
Posterior
Septal
Where do the chordae tendinae attach?
Papillary muscles
What is the role of the papillary muscles and the chordae tendinae?
The papillary muscles begin to contract before the contraction of the ventricles, which tightens the cords and draws the cusps together
This prevents the cusps from collapsing as blood is pumped into the semilunar valves
What is the septomarginal trabeculae? Function?
Aka Moderator band
Right ventricle
Curved muscular band that runs from the inferior IV septum to the base of the anterior papillary muscle
Carries part of the right bundle branches of the AV bundle of the conducting system to the anterior papillary muscle
Facilitates conduction time and allows coordinated contraction
What valves are in the right ventricle?
Tricuspid valve
Pulmonary valve
How many cusps does the tricuspid valve have?
Three.
Anterior, posterior and septal
How many cusps does the pulmonary valve have?
Three
Anterior, right and left
Where is the bicuspid valve? How many cusps?
aka mitral
Between the left atrium and the left ventricle
2 cusps
How many pulmonary veins enter the left atrium?
Four
Thickness of left ventricle vs right ventricle
Left ventricle is much thicker
How many papillary muscles are in the left ventricle?
Two: anterior and posterior
Trabeculae carnae of the left ventricle vs right ventricle
The left side are finer and more numerous than those in the right ventricle
General function of the atria
Receiving chambers of the heart
Where does blood enter the right atrium?
Deoxygenated blood enters from the superior and inferior vena cava and the coronary sinus
Where does blood enter the left atrium?
Oxygenated blood enters the left atrium from the pulmonary veins
General function of the ventricles
Discharge chambers
What marks the ventricular walls?
Papillary muscles and trabeculae carnae
What blood is pumped by the ventricles? Where is it pumped?
Right ventricle pumps deoxygenated blood into the pulmonary trunk
Left ventricle pumps oxygenated blood into the aorta
What separates the ventricular volume from the atrial volume?
Atrioventricular valves (mitral and tricuspid)
What separates ventricular volume from the great vessels of the outflow tract?
Semilunar valves (aortic and pulmonary)
What do the valves of the heart ensure?
That blood flow in one direction
What are valves of the heart composed of?
Connective tissue and endocardium (inner layer of heart)
Where are the atrioventricular valves? What are their names?
Tricuspid and bicuspid (mitral)
Located between the atria and ventricles
Very tight when closed, don’t let blood through
Where are the semilunar valves? What are their names?
Semilunar valves are between the ventricles and their corresponding artery
Regulate blood flow leaving the heart
Allow some regurgitation during ventricular contraction
What supports the AV valves?
The chordae tendinae (fibrous cords)
Chordae tendinae are attached to papillary muscles (inferior surface of ventricles)
Prevents prolapse of the valve leaflets into the atria
See figure
Parts of the semilunar valves
Sinus: formed by the attachment of the sides of each valve leaflet to the wall of the outflow vessel
Lunule: Thickening of the free superior edge of each leaflet
Nodule: thickest part of valve leaflet
See figure
Blood flow in the heart
Blood with low oxygen enters the right atrium from the superior and inferior vena cava
It then flows into the right ventricle, where it is pumped through the pulmonary trunk to the lungs.
Blood becomes oxygenated in the lungs and then flows into the left atrium.
It then flows into the left ventricles and is pumped into the aorta
What is the cardiac cycle?
Period of time that begins with contraction of atria and ends with ventricular relaxation
What is systole? What is diastole
Period of contraction of the heart
Period of relaxation when chambers fill with heart
Which parts of the heart undergo diastole and systole?
Both atria and ventricles
5 phases of cardiac cycle
See table and figure
Where does the heart get its own blood supply from?
The coronary arteries and veins
*there is a substantial variation in the branching and the distribution of the coronary arteries
See figures
What is the first branch of the ascending aorta?
Coronary arteries
Anterior coronary arteries
Right and left coronary arteries (RCA and LCA; in atrioventricular groove)
Marginal artery (MA)
Circumflex artery (CA)
Anterior inter ventricular (AIA; left anterior descending/LAD)
Anterior coronary veins
Small cardiac (SCV)
Anterior cardiac (ACV)
Great cardiac (GCV)
Posterior coronary arteries
Right coronary artery (RCA)
Posterior inter ventricular artery (PIA; found in inter ventricular groove)
Posterior coronary veins
Great cardiac vein (GVC)
Posterior cardiac vein (PCV)
Coronary sinus (CS)
Middle cardiac vein (MCV)
What collects the majority of the venous blood?
Coronary sinus
Opens into the right atrium
What do the coronary arteries connect to?
They are terminated, so they do not connect to other arteries, only connected to one another
What does the right coronary artery supply?
Right atrium
Most of right ventricle
Diaphragmatic surface of left ventricle
Posterior 1/3 of IVS
AV bundle
SA node (in 60% of cases)
AV node (in 80% of cases)
What does the left coronary artery supply?
Left atrium
Most of the left ventricle
Part of the right ventricle
Anterior 2/3 of IVS
AV bundle
SA node (in 40% of cases)
What are the pacemakers of the heart?
SA node (60 bpm)
AV node (40 bpm)
His bundle (20 bpm)
Where is the His bundle located?
IV septum
Components of the conduction system of the heart
SA node
Intraatrial bundles
AV node
AV bundle (bundle of His)
Right and left bundle branches
Septomarginal trabecular (moderator band)
Purkinje fibers
What are the purkinje fibres?
Special conduction system to carry impulses to heart muscle
Synchronize contractions
What are the components of the autonomic regulation of the heart?
Parasympathetics
Sympathetics
Where do the parasympathetic innervations of the heart derive from? What do they travel with? Where of they enter?
Derive from brain stem
Travel with vagus nerve
Enter cardiac plexus
Where do the sympathetic innervations of the heart derive from? Where do they synapse? How do they reach the heart?
Originate from T2-T4 of spinal cord
Synapse in cervical sympathetic ganglia
Reach heart via cardiac plexus
What parts of the heart does sympathetic stimulation act on?
SA node
AV node
Ventricular myocardium
Effect of SNS on heart?
Increase HR
Increase electrical conduction
Increase excitability and contractility of ventricular myocardium
How do sympathetics act on the heart?
Neuronal control
Hormonal: epinephrin and norepinephrine
What part of heart does PSNS act on?
SA node
AV node
No influence on ventricles
Effect of PSNS on heart?
Decreases HR
Decreases electrical conduction and excitability
How to count the ribs?
Find the jugular notch
Move down the sternum until ridge is felt (sternal angle between manubrium and body of sternum)
Costal cartilage of rib II articulates here
Identify rib II
Continue counting the ribs, moving in a downward and lateral direction
See figure
Where does the upper limit of the heart reach?
As high as the third costal cartilage on the right side of the sternum
Second intercostal space on the left side of the sternum
Location of left margin of heart
Descends laterally from the second intercostal space to the apex located hear the midclavicular line in the 5th ICS
Location of the lower margin of the heart
Extends from the sternal end of the right 6th cartilage to the apex in the 5th ICS near the MCL
Where is the aortic valve area?
2nd right ICS, right sternal border
See figure
Where is the mitral valve area?
5th ICS, left MCL
Where is the pulmonic valve area?
2nd left ICS, left sternal border
Where is the tricuspid valve area?
4th left ICS, left MCL
Where is the mitral valve area?
Apex of heart, 5th ICS, left MCL
Which valves are involved in high pressure systems? Low pressure?
High pressure: aortic, mitral
Low pressure: pulmonary, tricuspid
