Anatomy - Cardiovascular System Flashcards
What is the mediastinum?
the area that lies between the lungs.
There are two parts to the mediastinum, what are they?
The inferior and superior mediastinum.
The inferior mediastinum is further divided into 3 sections, what are they?
Anterior, middle and posterior
Where is the heart located within the mediastinum?
The middle mediastinum
What are the details of the middle mediastinum?
It is the sac surrounding the heart called the pericardial sac. There are two layers; the fibrous pericardium and the serous pericardium
What is the fibrous pericardium and its properties?
The outer layer of the pericardial sac, it is very thick and tough. It prevents overfilling of the heart as the layer only stretches enough to accommodate normal filling
Which is continuous? The fibrous pericardium or the serous pericardium?
the serous pericardium, it folded back on itself e.g. fist in balloon
What is the serous pericardium and its properties?
Inner, membranous layer and secretes serous fluid.
Which side of the serous pericardium touches the heart? The parietal or visceral? and what does the other touch?
The visceral, the parietal touches the fibrous pericardium.
“myo” means what?
Muscle
“Auricle” means what?
Ear
What are the three layers of the heart? In order.
Epicardium, Myocardium and Endocardium.
What does the epicardium consist of?
Epicardium is the visceral serous pericardium.
What does the myocardium consist of?
Thick wall of muscle and is the middle layer
What does the endocardium consist of?
It is the internal layer and has a continuous lining of endothelium from the blood vessels.
The posterior surface of the heart is called?
The base
Where does the inferior surface of the heart lie?
The diaphragm
What does the right border consist of?
The right atrium
What does the left border consist of?
The left ventricle
What does the interventricular septum divide?
The right and left ventricles
What does the atrioventricular septum divide?
The atriums from the ventricles.
What a cardiac valves for?
To ensure uni-directional blood flow
What are the four valves?
Tricuspid, Pulmonary, Bicuspid(mitral) and Aortic Valve
What is a normal route for electrical conduction in the heart?
Electrical impulse starts spontaneously at the SA node, it then travels to the AV node at the atrioventricular septum. It travels down the right and left bundles in the atrioventricular septum and spreads out to myocardium through conducting fibres.
What is the crux?
The fibrous cardiac skeleton and a junction where the 4 chambers meet at a cross.
What does the crux do?
It controls where the electrical activity goes as it s an electrical insulator.
What is fibrillation?
The uncoordinated contraction of the cardiac muscle.
Why does normal contraction must be regular and rhythmical?
So that atrial contraction is completed therefore the ventricles are filled completely before ventricular contraction.
What is atrial fibrillation?
When the atrium twitches irregularly.
Which is worse? Atrial or ventricle fibrillation?
Ventricle fibrillation. During ventricle fibrillation, the ventricle cannot create enough power to pump all the blood out of it to get around the body.
What is defibrillation?
Controlled shocks to stop cardiac movements which allow restoration of normal co-ordinated contractions.
What are the external factors that affect the heart through HR and force of contraction?
Nerves - sympathetic and parasympathetic
Circulating hormones - adrenaline.
