Lecture 7 - Anatomy of the heart Flashcards
Where is the heart located?
Behind the sternum
Between ribs 2-5 and protected by rib cage
Slightly left of mid line
Apex is in the 5th intercostal space in the midclavicular line
What are the types of pericardium?
Fibrous Serious Parietal and Visceral
What is the fibrous pericardium?
An inelastic sac of dense connective tissue
Fuses inferiorly with diaphragm and superiorly with the great vessels
Prevents over filling of the heart
Anchors the heart in position
What is the serious pericardium?
A double layered serous membrane
Deep to the fibrous pericardium
What is the parietal pericardium?
It lines the inner surface of the fibrous pericardium
What is the visceral pericardium?
Adheres tightly to the hearts surface
What is the pericardial cavity?
Potential space between parietal and visceral layers that contains tissue fluid
What is the heart wall composed of?
Endocardium, myocardium and epicardium
What is the endocardium?
Inner layer of the heart wall
Made of epithelium
What is the myocardium?
Middle layer of the heart wall
Made of cardiac muscle
What is the epicardium?
Outer layer of the heart wall
Made up of the visceral pericardium
What is the fibrous skeleton?
Bands of fibrous connective tissue between the atria and the ventricles
What are the atrioventricular valves and what do they do?
Tri and bicuspid
Opened by blood flow from atria to ventricles
Anchored by chordae tendinae to papillary muscles
Controls the contraction of papillary muscles
What are the semilunar valves?
Pulmonary and aortic valves
Guard entrance to aorta and pulmonary trunk
Opened by the force of blood when ventricles contract
What is coronary circulation?
Circulation of blood in vessels that supply the myocardium
Blood is delivered to myocardium during ventricular relaxation
Cardiac veins drain into coronary sinus which empties into right atrium
Anterior cardiac veins drain into the right atrium
What is the conducting system?
Coordinates heart contraction
Consists of non contractile cells that initiate electrical impulses
Why is foetal circulation different to adult?
Oxygen and nutrients are received from the placenta by the umbilical cord
Need to bypass non functional lungs
What are the 3 circulatory shortcuts in foetuses?
Ductus venosus connects the umbilical cord to the inferior vena cava
Foramen ovale connects the left and right atria
Ductus arteriosus connects the pulmonary trunk to the arch of the aorta
What changes occur at birth in regards to circulation?
Lungs expand, blood rushes into pulmonary circulation, oxygen levels rise and ductus arteriosus is constricted
Left atrial pressure increases, causes the foramen ovale to close and become fossa ovalis
Umbilical cord tied, closes the umbilical vessels and the ductus venosus fibroses
What is the left coronary artery?
Anterior interventricular
Circumflex
What is the right coronary artery?
Marginal artery
Posterior interventricular
