Flashcards in CVS and the Mediastium Deck (21):
What factors effect diffusion resistance?
Diffusion resistance includes pore size and number, molecule type and size and pathway length.
What is the total blood flow of a 70kg man at rest and during maximal exercise?
At rest has a total blood flow of 5 l/min and during exercise this can rise to 25l/min
What is the total volume of blood in the body of a 70kg man and how is it distributed?
He has 6l of blood inside him. At any one time (not during exercise) 67% of blood is in the veins 17% in the heart and lungs, 11% in arteries and 5% in capillaries.
Which two organs require a constant uninterrupted blood flow?
The brain and kidneys maintain a constant blood flow and this is because they both require a constant unchanging flow of blood. The brain is very intolerant to flow interruption.
Describe the maximum and minimum blood flows to the: brain, Heart, Kidney, Gut, Skeletal Muscle and Skin
Describe the Mediastium
Central position separating the two pleura cavities. Split into the superior mediastinum (separated at vertebrae T4 and T5) which contains the great vessels and the inferior mediastinum which is further subdivided into the anterior mediastinum in front of the heart, the middle mediastinum which contains the heart and the posterior mediastinum which contains the descending aorta and oesophagus.
Which part of the heart makes up the apex.
Apex of the heart is at the bottom of the right ventricle and points down towards the left foot.
What are the 3 layers of the pericardium?
Heart is surrounded by pericardium which constitutes of 3 layers: an outer fibrous formed of tough connective tissue, then 2 serous layers: the parietal layer lines the inner surface of the fibrous pericardium and the visceral layer adheres to the heart.
What is the pericardial cavity and what is inside it?
A cavity created by the two serous layers of the pericardium and contains a small amount of fluid for the relatively uninhibited contraction of the heart.
Describe how the fibrous pericardium holds the heart in relative situ?
The fibrous pericardium is continuous with the adventitia of the great vessels and is attached to the central tendon of the diaphragm. It is also attached to the sternum by sternopericardial ligaments, this holds the heart in the correct place.
Which nerves innervate the fibrous pericardium?
Phrenic nerves which originate from C3 to C5 pass around the lateral sides of the heart and pass down do innervate the diaphragm but also innervate the fibrous pericardium. This is also true of the pericardiacophrenic vessels.
What is the oblique pericardial sinus?
A small cavity where the two serous layers become continuous at the posterior of the heart near the great veins. The oblique sinus can be found by putting your finger posterior to the apex of the heart and moving superiorly.
What is the transverse pericardial sinus?
A cavity formed for the same reason behind the aorta and pulmonary artery due to the separation of the vena cava from the aorta.
What is pericardial effusion?
Pericardial effusion is a build-up of fluid that puts pressure against the heart preventing it from expanding and contracting properly – cardiac tamponade. This can be treated by inserting a needle between the two layers and relieving the pressure.
What is pericarditis?
Pericarditis is due to an inflammation of the pericardium resulting in symptoms much like myocardial infarction however it is treated very differently to myocardial infarction and can be distinguished using an ECG.
What is constrictive pericarditis?
Constrictive pericarditis is a similar condition resulting from abnormal thickening of the pericardium.
Where are the aortic sinuses located?
These are located inside the cusps of the tricuspid aortic valve.
Where do the coronary arteries originate from?
The coronary arteries come from the aortic sinuses.
Describe the origin and pathway of the right coronary artery.
The right sinus gives the right coronary artery which feeds the right ventricle and atria, SAN, AVN and Interatrial septum. It curves down parallel to the right atria then curves around the posterior of the heart anterior to the inferior vena cava and branches into the posterior interventricular ular branch.
Describe the origin and pathway of the left coronary artery.
The left sinus gives the left coronary artery which feeds the left atrium and ventricle and the interventricular septum. It branches into the circumflex branch which curves around the posterior of the heart underneath the coronary sinus and into the left anterior interventricular branches which heads down towards the apex of the heart and the anterior descending branch at the front of the heart.