Anatomy ✅ Flashcards
What does the morphological approach to considering the heart enable?
Easier description of congenital cardiac malformations
Why does morphological description of the heart enable easier description of cardiac malformations?
In congenitally malformed hearts, where the chambers do not occupy their usual positions, the positional distinction between left and right becomes confusion
What segments is the heart built from?
- Atria
- Ventricular masses
- Arterial trunks
What joins the segments of the heart?
- Atrioventricular junction
- Ventriculoarterial junction
What is a normal heart described as?
Situs solitus, concordant atrio-ventricular connection and concordant ventriculo-arterial connection
How does the right atria compare to the left?
The right atrium is slightly larger, but its walls are thinner
What is the internal wall of the right atrium composed of?
- A smooth, posterior portion
- Ridge like, muscular anterior portion
What drains into the posterior portion of the internal wall of the right atrium?
Vena cava and coronary sinus
What is characteristic of the anterior portion of the internal wall of the right atrium?
Pectinate muscles distributed down into the vestibule of the tricuspid valve
What drains into the left atrium?
The 4 pulmonary veins
Where do the pulmonary veins drain into the left atrium>
It’s smooth walled posterior surface
What common wall do the atria share?
The atrial septum
What does the atrial septum contain?
A flap valve of the fossa ovalis
How is shunting across the atrial septum prevented?
The fossa ovalis overlaps the atrial walls, so even if not fused, there will be no shunting
When might shunting across the atrial septum occur?
If left atrial pressure exceeds that of right
What does the vestibule of the left atrium support?
The leaflets of the mitral valve (two cusps)
Is the vestibule of the left atrium smooth or rough?
Smooth
What components do the ventricles consist of?
- Inlet
- Apical trabecular
- Outlet
What is the shape of the normal right ventricle dependant on?
The inlet being inferior and to the right of the outlet
What is the relationship between the inlet component of the right ventricle and the tricuspid valve?
The inlet component of the right ventricle surrounds and supports the leaflets and tension apparatus of the tricuspid valve
What is characteristic of the right ventricle?
Coarser trabeculations than those on the left
How many cusps does the pulmonary semilunar valve have?
3
What is the pulmonary semilunar valve supported by?
A muscular infundibulum
What is the relationship between the inlet component of the left ventricle and the mitral valve?
The inlet component of the left ventricle contains and surrounds the mitral valve
What is characteristic of the mitral valve?
It has no cordal attachments to the ventricular septum
Describe the apical part of the left ventricle?
It has fine criss-crossing trabeculations and a smooth septal surface
How many leaflets does the atrial valve have?
3
How are the 3 leaflets of the aortic valve attached?
In a semilunar fashion, but (unlike the pulmonary valve) the hinge lines attach in part to fibrous structures, and in part to the muscular walls of the ventricle
Where does the aorta arise from?
The middle of the base of the heart
What happens to the aorta after its origin?
It curves upwards to the aortic arch
What does the aortic arch give rise to?
- Brachiocephalic artery
- Left common carotid artery
- Left subclavian artery
What supports the leaflets of the aortic valve?
The three sinuses of Valsalva
What do the sinuses of Valsalva give rise to?
2 of the sinuses give rise to the right and left coronary arteries
Where does the pulmonary trunk arise from?
The pulmonary infundibulum
What supports the pulmonary valve?
The sinuses of the pulmonary trunk
What happens to the pulmonary trunk after its origin in the pulmonary infundibulum?
It bifurcates into the left and right pulmonary arteries
Where does the ductus arteriosus extend in fetal circulation?
From the pulmonary trunk into the descending aorta
What does the ductus arteriosus demarcate in fetal circulation?
The isthmus of the aorta
What layers are the vessels of the peripheral circulation made up of?
- Tunica intima
- Tunica media
- Tunica adventitia
What is the tunica intima?
A single layer of flattened epithelial cells
What is the purpose of the tunica intima?
It provides a smooth lining
What is the tunica media?
Elastic fibre and smooth muscle arranged in a circular fashion
How does the tunica media in arteries compare to that in veins?
It is thicker in arteries than in veins
What does the tunica media in arteries allow for?
Vasoconstriction/vasodilation
What is the contractile activity of the tunica media affected by?
- Autonomic nerves supplying it
- Vasoconstrictor substances in the blood, in particular angiotensin
What is the tunica adventitia?
The outermost, fibrous layer composed of connective tissue
What is encased in the pericardial sac?
The heart and roots of the great vessels
What does the pericardial sac consist of?
Fibrous and serous parts
What does the outer fibrous part of the pericardial sac fuse with?
- The central tendon of the diaphragm
- The ends of the great vessels as they enter or leave
Where does the fibrous part of the pericardial sac fuse with the central tendon of the diaphragm?
Underneath the heart
What is the purpose of the fusion of the fibrous part of the pericardial sac with surrounding structures?
It helps to anchor the heart in its central position
What are the layers of the inner, serous pericardium?
- Parietal layer
- Visceral layer (or epicardium)
What does the parietal layer of the serous pericardial sac do?
Adheres to the inner surface of the fibrous pericardium
How does the parietal layer of the serous pericardial sac become the visceral layer?
It becomes reflected onto the outer surface of the heart as the visceral layer
How are the adjacent surfaces to the serous pericardium kept lubricated?
By pericardial fluid
What does the pericardial fluid allow?
The surfaces to glide over one another as the heart beats
