Heart and Coronary circulation Flashcards
What forms the base of the heart?
Formed mainly by the left atrium, into which open the 4 pulmonary veins
What separates the base of the heart from the descending aorta and oesphagus?
Oblique sinus of pericardium
What is the base of the heart inferiorly bounded by?
Posterior part of the coronary sulcus
What forms the diaphragmatic surface?
Formed by the 2 ventricles- mainly the left ventricles (2/3)
What separates the diaphragmatic surface from the base of the heart?
Part of the coronary sulcus called the post
What separates the two ventricles?
Separated by the posterior interventricular groove
What is the pericardium?
It is a fibro-serous sac which surrounds the heart and great vessels.
What is the pericardium differentiated into?
Outer fibrous layer - fibrous Pericardium and inner serous sac- serous pericardium
Where does the pericardium lie
Lies posterior to body of the sternum & 2-6 costal cartilages
Lies anterior to 5-8 thoracic vertebrae
What is the role of the fibrous pericardium?
Protects the heart against sudden overfilling
What is the fibrous pericardium attached to?
Fused with the central tendon of the diaphragm
Attached to the posterior surface of the sternum b y sternopericardial ligaments
Fused with the tunica adventitia of the great vessles
What pierces the central tendon of the diaphragm and pericardium on where?
Inferior vena cava
What is serous pericardium?
It is a closed sac which is formed of 1-parietal layer
What is the serous pericardium required for?
Lines the inner surface of the pericardium and reflected around the roots of great vessels to become continuous with the visceral layer
What two layers make up the serous pericardium?
Visceral layer and parietal layer
What does the visceral layer do/
Closely covers heart
What does the pericardial cavity contain contain and what is its function?
Contains pericardial fluid and acts as a lubricant
What are the main branches of the pericardium and where do they come from?
Pericardiacophrenic and musclophrenic arteries - they are branches of the internal thoracic arteries
Where does the pericardium receive pericardial branches from?
Bronchial, oesphageal, and superior phrenic arteries
What supplies the epicardium?
Coronary arteries
What are the two types of pericardial sinuses?
Transverse sinuses and oblique sinus
What is a transverse sinus?
A recess of serous pericardium between aorta & pulmonary T, and upper parts of 2 atria & S.V.C
Where does the transverse sinus run?
Runs transversely between the great arteries and great veins
What is an oblique sinus?
A recess of serous pericardium behind the base of heart
Where does the oblique sinus occur?
On the posterior surface of the heart, surrounded by the large veins (a blind pocket)
What is the nerve supply of the fibrous and parietal layer of the serous pericardium?
Phrenic nerve
What is the nerve supply of the visceral layer of the serous pericardium?
Branches of the sympathetic trunk and vagus nerves
What is functional circulation?
Coronary circulation is the functional blood supply to the heart muscle
What is the role of collateral routes?
Ensure blood delivery to heart even if major vessels are occluded
What do the branches of the left coronary artery supply?
Left atrium Most of left ventricle Most of interventricular septum AV bundles and branches SA node in 40% people
What do the branches of the right coronary artery supply?
Right atrium Most of right ventricle Part of left ventricle SA node in 60% AV node in 80% Part of the left atrium Part of interventricular septum
How does the blood drain from the heart?
Most of the blood drains into the drain into right atrium through Coronary Sinus
What are the tributaries of the coronary sinus?
Small and middle cardiac veins
Where is the remainder of the blood returned to?
The right atrium directly by anterior cardiac vein and by small veins open directly into heart chambers
What type of innervation does the heart receive?
Heart receives visceral motor innervation
What is sympathetic motor innervation?
heart speeds up
What is parasympathetic innervation?
Heart slows down
How does fetal circulation differ to adults?
the presence of 3 major vascular shunts
What are the three major vascular shunts in the fetus?
Ductous venosus
Foramen ovale
Ductus arteriosus
Where is the ductus venosus?
Between the umbilical vein and inferior vena cava
Where is the foramen ovale?
Between the right and left atrium
Where is the ductus arteriosus?
Between the pulmonary artery and arch of aorta
What is the foramen ovale?
A hole between the right and left atria, allowing blood pass from the right side to the left and not ever get pumped to the lungs
What is the role of the ductus arteriosus?
Allows blood to skip past the lungs and join up with the partially oxygenated blood that is being pumped out of the left ventricle
What is the adult remnant of the foramen ovale?
Fossa ovale
What is the adult remnant of the ductus arteriosus?
ligamentum artiosum
What is the adult remnant of the umbilival artery (within fetus)
Medial umbilical ligaments
What is the adult remnant of the umbilcal vein?
Round ligament of liver
What is the adult remnant of the ductus venosus?
Ligamentum venosum
What are the two main coronary arteries?
The left coronary artery- which subdivides into the left anterior descending and circumflex branches
The right coronary artery
What are the two main coronary arteries?
The left coronary artery- which subdivides into the left anterior descending and circumflex branches
The right coronary artery
What is a myocardial ischaemia?
Occurs when the blood flow demands of the heart exceed the blood supplied by the coronary arteries
What is the leading cause of myocardial ischaemia?
Atherosclerosis
Blockage of coronary arteries due to the accumulation of lipid plaques/ thrombus
What is meant by ischaemia?
Inadequate blood flow to a tissue or part of the body
What is angina pectoris?
It is the major symptom of myocardial ischaemia
How does angina pectoris present?
Commonly presented as- pain
pressure or a burning sensation in the area of the sternum
What is an myocardial infarction?
Irreversible injury and eventual death of myocardial tissue that results from ischaemia and hypoxia
What are most MIs the direct result of?
Occlusion of a coronary blood vessel by lipid deposit
