Anatomy of the Heart 1 Flashcards
What are the three layers of blood vessels?
- Tunica intima (endothelium)
- Tunica media (smooth muscle)
- Tunica externa (connective tissue)
What does a capillary sphincter do?
Controls the flow of blood into capillary bed
Why are big arteries elastic?
Maintain blood pressure within them
What are sentinel lymph nodes?
The first few lymph nodes to which a tumor drains etc
Describe the wall of the right atrium.
Anterior wall - roughened, crista terminalis
Posterior wall - smooth, sinus venarum
What is the fossa ovalis?
Embryological remnant
‘window’ into LA
What is the shape of the Right Ventricle?
Crescent shaped
Describe the features of the right ventricle.
Trabeculae carneae (‘meaty ridges’), infundibulum (smooth wall), membranous portion of interventricular septum, chordae tendinae and papillary muscles
Describe the wall of the left atrium
Smooth except at auricle
How many pulmonary veins are there entering the left atrium?
4 - 2 from the left, 2 from the right
How does the LV infundibulum differ to the RV?
It is less pronounced
What are the two types of common heart valve defects?
- Stenotic valve
- Mitral valve prolapse
Both cause regurgitation of blood back into the atria
Which valve is most susceptible to defects and why?
Mitral valve
Due to higher pressure in left heart
How does foetal circulation differ to adult circulation?
- Foramen ovale
- Ductus arteriosus
If they fail to close –> patency
What is the coronary sinus?
Rudimentary/ non functioning valve
Major vein that drains the heart itself
Which muscle fibres arise from the crista terminalis?
Musculi pectinati
What is the most common ‘hole in the heart’?
Ventricular septal defect
Where are the pectinate muscles of the heart found?
Atria
Where are the trabeculae carneae found?
Ventricles
Describe the wall of the left atrium
Smooth walled except the auricle which has a roughened wall
What is the function of the chordae tendinae?
Connect the papillary muscles to the valves (mitral or tricuspid)
What is the function of the papillary muscles?
Prevent inversion/prolapse of the IV valves during systole
How many pulmonary veins are there?
4 - 2 from R, 2 from L
Going into left atrium
Describe the infundibulum of the left atrium.
Less pronounced
Which valve is more likely to suffer a defect?
Mitral valve - under higher pressure
Why is there no requirement for a pulmonary circulation in the fetus?
The fetus is getting oxygen from the mother via the placenta
What causes the foramen ovale to close at birth?
Changes in pressure (left becomes higher pressure)
