Mediastinum
Region of thoracic cavity that contains all thoracic viscera besdies lungs and surrounding pleura
How is mediastinum divided?
Superior and inferior by plane passing from sternal angle to inferior border of 4th thoracic vertebrae
Inferior mediastinum divided into
Anterior, middle, and posterior regions
Superior mediastinum contains
Aortic arch and all branches
Brachiocephalic veins and 1/2 of sup vena cava
Vagus, phrenic, left recurrent laryngeal nerves
Esophagus
Trachea
THoracic duct
Thymus
Anterior mediastinum contains
Basically nothing
Some lymph nodes and fat…thymus in children
Middle mediastinum contains
Heart Pericardial sac Ascending aorta INferior 1/2 of sup vena cava Termination of azygos vein Pulmonary trunk and branches Pulmonary veins Phyrenic nerves
Posterior mediastinum contains
Bifurcation of trachea Descending aorta Esophagus Azygos and hemiazygos veins THoracic duct Vagus and splanchnic nerves Sympathetic chain
How is heart attached to diaphragm?
central tendons attached to fibrous pericardium
Apex of heart is where what two parts come together?
Ventricles
Fibrous pericardium and nerve on surface
Inelastic fibrous sac surrounding heart
Phrenic nerves
Parietal pericadium
Just deep to fibrous pericardium
Serous layer
Visceral pericardium…what is it continuous with and other name for it
Serous layer on surface of the heart
Continuous with parietal at roots of great vessels
Epicardium
Pericardial cavity
Space between visceral and parietal layers
Only contains a few drops of fluid
Adhesions of pericardial cavity
Restrict heart movement and compromise cardiac function
Pericarditis
INflammation of pericardium
Can have effusion into pericardial cavity and compression of the heart
Cardiac tamponade
Extensive fluid in pericardial cavity…compresses heart
Pericardiocentesis
Draining of fluid from pericardial cavity
Transverse pericardial sinus separates
Venous and arterial ends of the heart
Oblique pericardial sinus
Pocket-like recess in the pericardial cavity posterior to base of the heart
Transverse pericardial sinus can be used to isolate
Ascending aorta and pulmonary trunk
Base of heart on which surfaces?
Posterior and superior
Apex of heart projects which way and which intercostal space
Anterioly and inferior
5th intercostal space
Coronary sulcus
Atrioventricular sulcus
Anterior and posterior interventricular sulcus
Marks position of interventricular septum on anterior or diaphragmatic surface surface
Surfaces of heart
Anterior/sternocostal
Posterior (base)
Inferior or diaphragmatic
Auricles fucntion and derivation
Increases capacity of atria
Ear like pouches
Derived from primitive atria
Right and left atrium
Crista terminalis derivation and mistaken for
Muscular right in right atrium seprating smooth from rought portion of internal wall of right atrium
Intracardiac mass
Right atrium only
Rough and smooth portion of atria derivations
Rough - primitive atrium
Smooth - sinus vensosus
Pectinate muscles
Ridges on rough portion of internal wall of both right and left atria
Right and left atrium
Fossa ovalis and what is it a remnant of?
Depression of interatrial septum
Forament ovale
Right only
Trabeculae carnae
Right and left ventricles
Muscular ridges on walls
Papillary muscles
Right and left ventricles
Conical muscular porjections with bases attached to walls
Chordae tendineae
Right and left ventricles
Run from papillary muscles to free edge of AV valve cusps
How to AV valves stay closed during systole?
Papillary muscles contract and pull chordae tendineae tight
Septomarginal trabecula and function
Right ventricle only
Runs from inferior part of interventricular spetum to papillary
Facilitats coordination of electrical impulse to papillary muscles for coordinated contraction of papillary with ventricle
Left vs. right ventricle
Left has bicuspid valve
Thicker wall
Higher pressure
What enters left atrium vs right atrium
Left - pulmonary veins
Right - vena cava
Ventricular relaxation - aortic valve and mitral valve
Mitral valve open and aortic closed
Coronary sulcus
Groove on external surface of heart
Separates atria from ventricles
Anterior and posterior interventricular sulci
Grooves on external of heart separating right and left ventricles
Right coronary artery - what does it supply and what are its branches
Right atrium, right ventricle, and part of left ventricle
Marginal artery
Posterior interventricular artery
Marginal artery runs
Along right margin of the heart
Posterior interventricular artery runs
In posterior interventricular sulcus
Left coronary artery supplies and what are brnahces
Left atrium, left ventricle, and parts of right ventricle
Anterior interventricular artery and circumflex artery
Anterior interventricular artery runs
In anterior interventricular sulcus
Circumflex artery runs
Through coronary sulcus
What does it mean when we say most coronary arteries are end arteries?
Little to no anastomoses with other branches
If slow, onset of clot, anastamoses may form
Coronary sinus - where does it empty, what does it receive drainage from, and where is it located?
Empties into the right atrium between inferior vena cava and right atrioventricular valve
In coronary sulcus
Most veins in heart drain into ti
Great cardiac vein assoicated with
Anterior interventricular artery
Posterior vein of the left ventricle drains and what is it associated with?
Left ventricle
Circumflex artery
Middle cardiac vein associated with
Posterior interventricular artery
Small cardiac vein follows
Marginal and right coronary artery
Anterior cardiac veins and cardiac veins empty into
The heart chambers…NOT the coronary sinus
Most into the RA
SA node location and blood supply
Pacemaker of the heart
In myocardium near anterior margin of opining of SVC in right atrium
Supply from SA nodal artery from right coronary
AV node location and blood supply
Interatrial septum…superior and medial to opening of coranry sinus in right atrium
AV nodal artery from right coronary
AV bundle and division
Begins at AV node and passes through fibrous skeleton…runs along membranous part of IV septum
Divides into the left and right bundle branches at the IV septum
Pukinje fibers
Termination of BUndle of His in the ventricles
Fibrous skeleton of the heart composition and function
Anchoring point of cusps and valves
Keeps orifices patent
Forms electrical insulator
Fibrous connective tissue that surround orifices and valves
Innervation of the heart and nerve fibers
Cardiac plexus
Postgang sym (paravertebral)
Pre gang sym (vagus nerve)
Visceral affarent
Sympathetic and parasympathetic cardiac stimulation
Sympathetic - increase heart rate, impulse conduction, force of contraction…dilation of coronary arteries
Para - decrease HR, impulse conduction, force of contraction…constriction of coronary arteries
Affarent innveration of heart…waht is it sensitive to and what is it not?
Not to touch, cutting, heat, and cold
Ischemia and metabolic product accumulation stimulate pain endings in myocardium
Affarent pain fiber path
In cardiac nerves to sympathetic trunk
Axons of affarent cardiav fibers
Enter spinal cord at T1 through T4-T5
Cardiac pain regions
T1-T5…left pectoral region, shoulder, medial arm, and forearm
Visceral sensory fibers innervate ______ receptors in the heart and travel with _______ back to brainstem
Baro and chemo
Vagus nerve
Base of heart is where?
3rd costal cartilage
Apex of heart is where?
5th intercostal space
Aortic semilunar valve location and where to listen
3rd intercostal space (post to sternum)
Right 2nd intercostal space
Pulmoanry semilunar valve and where to listen
L 3rd costosternal junction
L 2nd intercostal space
Tricuspid valve and where to listen
R 5th costosternal junction posterior to sternum
Left lower sternal border
Bicupsid valve (mitral) and where to listen
4th costosternal junction
L 5th intercostal space