Heart and Pericardium Flashcards
Describe the divisions, boundaries, and contents of the middle mediastinum.
The middle mediastinum encloses the heart and bases of the great vessels.
The anterior mediastinum is between the pericardium and the sternum. The posterior mediastinum is between the pericardium and the vertebral bodies.
Define the term pericardium.
The pericardium is a sac that contains the heart and bases of the great vessels. It contains 2 sacs:
- outer fibrous pericardium
- inner serous pericardium
Define the term fibrous pericardium.
Fibrous cone-shaped sleeve that blends with CT surrounding the great vessels (superiorly) and fuses with the central tendon of the diaphragm (inferiorly) via the PERICARDIACOPHRENIC LIGAMENT.
Anteriorly CT attaches it to the sternum
Posteriorly it blends with CT of the posterior mediastinum.
Define the term serous pericardium.
membranous sac made of mesothelium with two layers:
- outer parietal layer: derived from somatic mesoderm, adheres to the inner surface of the fibrous pericardium
- inner visceral layer: derived from splanchnic mesoderm, adheres to external heart surface
Define the term transverse pericardial sinus.
horizontal space posterior to aorta & pulmonary trunk and anterior to SVC
Define the term oblique pericardial sinus.
between IVC and pulmonary veins
Describe the grooves of the heart.
3 external grooves:
- atria & ventricles are separated by a circumferential coronary or AV groove
- anterior boundary between right and left ventricles is the anterior interventricular groove
- posterior boundary between right and left ventricles is the posterior interventricular groove
Describe the fibrous skeleton of the heart.
- -components
- -purpose
CT skeleton supports the heart and includes:
–4 fibrous rings - one surrounding each heart valve
–2 fibrous trigones connecting the rings
–the membranous part of the interventricular septum
Purpose:
–anchor cardiac muscle
–maintain valve orifices
–attach to valve leaflets
–insulate electrical impulses
Describe the specific features of the right atrium.
- auricle
- sinus venarum
- pectinate muscle
- crista terminalis
- fossa ovalis
- small stationary valves that guard the IVC and coronary sinus openings
- right AV orifice
Describe the specific features of the right ventricle.
- trabeculae carnae
- tricuspid valve
- anterior, septal, and posterior cusps of tricuspid valve
- anterior, septal, and posterior septal muscles
- chordae tendinae
- moderator band
- right AV bundle branch (not visible)
- pulmonary trunk with semilunar valve
Describe the specific features of the left atrium.
- auricle
- orifices for 2 superior and 2 inferior pulmonary veins
- the other side of the remnant of the foramen ovale, in the interatrial septum
- left AV orifice
Describe the specific features of the left ventricle.
- trabeculae carnae
- aortic vestibule
- mitral/bicuspid valve
- anterior and posterior cusps of mitral valve
- anterior and posterior papillary muscles
- chordae tendinae
Name and describe the semilunar valves.
Pulmonary valve: has anterior, right, and left cusps
Aortic valve: has posterior, right, and left cusps
Name the component parts of the conducting system and their area of distribution.
Pacemaker of heart = SA node: in wall of right atrium at intersection of SVC and crista terminalis
AV node in right interatrial septum near the orifice of the coronary sinus
AV bundle of His: in the membranous interventricular septum
2 bundle branches, right and left
Describe the pathways of the sympathetic innervation to the heart.
Preganglionic sympathetic fibers from T1 - T5 ->
cervical & thoracic ganglia of sympathetic chain where they synapse ->
postganglionic fibers along cardiopulmonary splanchnic nerves ->
cardiac plexus ->
SA node, AV node, ventricles, etc
