Heart Anatomy Flashcards
Where is the heart positioned?
- L lateral view - between ribs 3-6 at an angle with its base lying cranial and dorsal to the apex
- Dorso-ventral view - lies to the L of midline
- Lies within the pericardium in the mediastinum
What is the pericardium?
- a serous membranous sac surrounding the heart filled with serous fluid
- consists of parietal and visceral layers
- reflects over the great vessels at the base of the heart to form the sternopericardial ligament ventrally, anchors the apex to the sternum
What is the structure of the heart wall?
- Epicardium - superficial layer made of deep fibroelastic CT
- Myocardium - cardiac muscle, contains endomysium (CT that runs between individual cardiac fibres)
- Endocardium - endothelium and CT, simple squamous epithelium (continuous with blood vessels), contains purkinje fibres
Label the R side of the heart:
- coronary groove
- aorta
- R azygous vein
- L and R ventricles
- R atrium
- cranial and caudal vena cava
- pulmonary vessels
Label the L lateral/auricular surface of the heart:
- R and L auricles
- aorta
- pulmonary trunk
- L interventricular groove (paraconal)
- L atrium
- coronary groove
Where does the blood entering the R atrium come from?
- Venous return from systemic circulation enters via cranial and caudal vena cava (separated by intervenous tubercle) and azygos vein
- Venous return from cardiac tissue - coronary veins via coronary sinus
What is the intervenous tuberlce?
A fibrous triangular structure which reduces turbulence in the atria and directs blood flow to the ventricles
Label the structures of the interior of the R atrium
Draw the structure of the tricuspid valve
What are the main features of the R ventricle?
- Wall - endocardium, epicardium, myocardium
- Trabecular septomarginalis - moderator band, short cut for impulses to the papillary muscles
- Trabeculae carnea - dampens turbulence?
- R V extends arounf cranial margin of the heart
- Pulmonary trunk exits the R V on the L lateral side of the heart
How do the semilunar valves work?
Pockets fill with blood and close to prevent backflow. Responsible for 2nd heart sound ‘Dub’
What is the ligamentum arteriosum?
Foetal remnant of the ductus arteriosus which joins the aorta to the pulmonary trunk.
What are the main features of the interior of the L ventricle?
- Oxy blood enters via pulmonary veins
- Mitral/biscuspid valve
- L ventricle forms apex of heart
- Aortic semilunar valve at entrance to aorta
- Aorta exits in the middle of the base
