Dry Room 1 Flashcards
What does the thoracic wall enclose?
The thoracic walls enclose the 2 pleural cavities and the centrally-situated mediastinum. The mediastinum contains the contents of the thorax other than the lungs and their covering pleurae. The heart lying within the pericardium is a major component of the mediastinum
What is the mediatinum subdivided into?
A superior and inferior mediastinum.
The inferior mediastinum is then further subdivided into the anterior, middle and posterior mediastinum
Which bone forms the anterior border of the superior mediastinum?
Manubrium of the sternum
2.Which vertebrae form the posterior border of the superior mediastinum?
First four thoracic vertebral bodies
3.What plane separates the superior from the inferior mediastinum?
Thoracic plane
The inferior mediastinum is further divided into three parts – identify these on a skeleton, model and a wet specimen and label on the diagram below:
What is the thymus?
Anterior superior mediastinum
What is in the middle mediastinum?
Heart, pericardium and great vessels
What is in the posterior mediastinum?
Posterior mediastinum
Thoracic duct
Sympathetic chain
What is int he superior mediastinim?
Oesophagus
Azygous vein
What does the pericardium cover?
Covering the heart, the pleura covering the lungs and the peritoneum covering the abdominal viscera all consist of similar outer parietal and inner visceral (serous) layers composed of simple epithelium of similar developmental origin.
The essential difference to this plan is that the heart has, in addition to these two serous membranes, an outermost, thick, fibrous connective tissue layer – the fibrous pericardium.
What are the 3 layers of the pericardium?
Superficial: Fibrous pericardium
Intermediate: Parietal pericardium
Deep: Visceral pericardium
What is the pericardial cavity lie between?
Parietal and visceral pericardium
The pericardial cavity lies between which 2 of the above layers?
Parietal and visceral pericardium
The heart wall is composed of:
An inner Endo cardium composed of a single layer of Simple squamous epithelium
A middle Myo cardium composed of many layers of cardiac muscle
An outer Epi-cardium composed of a single layer of Simple squamous epithelium
1.Which layer belongs simultaneously to the heart wall and the serous pericardium?
Epicardium
2.Which layer of the serous pericardium is inseparably attached to the inner aspect of the fibrous pericardium?
Parietal pericardium
What protective role is fulfilled by the fibrous pericardium?
Dense and loose connective tissue protect the heart by anchoring it to the surrounding walls and preventing it from overfilling with blood
When does cardiac tamponade occur?
Occurs when excess fluid accumulates within the pericardial cavity as a result of a wide variety of pathophysiological factors. The increased pressure exerted by the excess fluid on the heart wall impedes the normal filling of the heart, and, at its most severe, can lead to cardiac failure.
What is the innervation of the pericardium?
The visceral pericardium receives autonomic innervation from T1 –T4 nerves and vagus via the cardiac plexus (same as the heart wall itself).
The parietal and fibrous layers are innervated mainly by the phrenic nerve.
Which layer/s of the pericardium are innervated by pain fibres?
Fibrous part and parietal part
Can you see the left atrium in the in-situ wet specimen? Where is it situated?
Superior part of the heart. Just inside the second costal space on the left hand side
What role do the auricles have in the adult?
Become part of the atrium and help pump blood
Identify the left atrium on the isolated heart and the model provided. Anterior to what tubular organ does it lie? – Confirm this on a wet specimen of the thorax:
Oesophagus
What shape is the heart?
Pyramidal shape
5.Which chamber/s form a) the apex and b) the base of the heart?
a) Left ventricle
b) Right ventricle
Right atrium
Fossa ovalis is a remnant of the foramen ovale in the foetus. What function did the latter perform?
Allows blood to cross atriums and bypass pulmonary circulation
What is an atrial septal defect?
Is one of the more commonly recognized congenital cardiac anomalies presenting in adulthood. Atrial septal defect is characterized by a defect in the interatrial septum allowing pulmonary venous return from the left atrium to pass directly to the right atrium.
What is the function of the moderator band?
Convey the right branch of the atrioventricular bundle of the conducting system
Compare the thickness of the right ventricular wall with that of the left: Which is thickest? By how many times? Why?
Left ventricle is six times as thick
3.How many cusps make up the tricuspid valve? How many papillary muscles are found in the right ventricle?
3 cusps and there is also 3 papillary muscles
What is the LA?
A small, smooth-walled chamber situated posterosuperiorly and forming the base of the heart. Immediately posterior to it lies the oesophagus.
Which valve guards the entry from the left atrium to the left ventricle?
MV
How many cusps are present in this valve?
2
How many papillary muscles are found in the left ventricle?
2
What is the function of the papillary muscles?
Muscles attached to AV valves to prevent inversion
What is the function of the chordae tendineae?
Tough tendinous strands in the heart
What is a VSD?
The interventricular septum separates the left and right ventricles of the heart.
If there is a hole in the wall between the two ventricles, it is called a ventricular septal defect (VSD).
Its aetiology (cause) is as yet indeterminate. Genes and environment may be a factor.
A VSD is common in children with other genetic problems, such as Down’s syndrome.
