Anatomy of thorax - case 2 Flashcards
What are the superior and inferior mediastinum separated by?
The superior and inferior mediastinum are separated by the transverse thoracic plane which extends from the sternal angle anteriorly and the junction of T4 and T5 posteriorly
What is the crista terminalis?
It is a ridge on the inside between the atrium and right auricle.
Where does the crista terminalis extend from?
From the superior vena cava (SVC) to the inferior vena cava (IVC).
posterior to the crista terminalis, what texture is the wall?
Posterior to the crista terminalis the wall is
smooth
Tell me about musculi pectinati?
Musculi pectinati are anterior to the cristae terminalis.
the walls of musculi pectinati are roughened by bundles of muscle fibres
what is Fossa ovale?
Marks location of embryonic foramen ovale, which allows blood to bypass the lungs in fetal circulation
Tell me about the atrioventricular orifice?
It directly communicates with ventricle. and atrioventricular orifice is closed by tricuspid valve
what is the right auricle?
It’s an Ear-like, conical, muscular pouch
overlapping the aorta
List the 5 steps of cardiac conduction
1) SA node fires
2) Excitation spreads through atrial myocardium
3) AV node fires
4) Excitation spreads down AV bundle
5) Purkinje fibres distribute excitation through ventricular myocardium
What is the SA node and where is it located?
SA (sinoatrial) node is the pacemaker of the heart, and SA node is located in right atrium.
pacemaker - stimulates the heart muscle and regulates its contractions
What forms most of the base of the heart?
The left atrium forms most of the base of the heart.
How does blood enter the left atrium?
Blood enters the left atrium through the four pulmonary veins.
What is the texture of the left atrium’s wall?
All of the left atrium’s wall is smooth.
What is the relationship between the anterior half of the left atrium and the left auricle?
The anterior half of the left atrium is continuous with the left auricle.
What is the outflow tract that leads to the pulmonary trunk called?
The outflow tract that leads to the pulmonary trunk is called the infundibulum or conus arteriosus.
What happens when the ventricle contracts?
When the ventricle
contracts, papillary muscles contract. This prevents the cusps from turning inside out into the atrium as intra-ventricular pressure rises.
What are chordae tendinae?
Chordae tendinae are tendon-like fibrous cords.
What do chordae tendinae connect?
They connect the free edges of the cusps of the valve to the papillary muscles.
What are trabeculae carnae?
trabeculae carnae are muscular, irregular structures
A few trabeculae carnae are known
as papillary muscles
Tell me about the Left Ventricle
- Blood flows into the aortic vestibule
- aortic vestibule is guarded by the aortic valve
- As blood recoils after ventricular
contraction, and fills the aortic sinuses
formed by the cusps, it is forced into
coronary arteries
what does the coronary sulcus separate?
separates the atria from the ventricles
what does the anterior interventricular sulcus?
marks the boundary between ventricles anteriorly
what does the posterior interventricular sulcus?
marks the boundary between ventricles posteriorly
what do the sulci/grooves on the surface of the heart contain?
blood vessels and fat
