Lecture 2 - Heart & Great Vessels Flashcards
What is the mediastinum?
The mediastinum is the central compartment in the chest cavity, located between the two lungs. It contains several vital structures, including the heart, great blood vessels (such as the aorta and vena cava), trachea, esophagus, thymus, and lymph nodes.
What is the different parts of mediastinum?
- Superior mediastinum
- Inferior mediastinum (anterior & posterior)
- Middle mediastinum
What are features of the superior mediastinum?
- arch of the aorta and its branches
- brachiocephallic trunk
- superior vena cava (SVC)
- vagus nerve (CNX)
- trachea and the upper oesophagus
What is the inferior mediastinum broken into?
- divided into anterior, middle and posterior and the heart
What is found in the anterior part of the inferior mediastinum?
anterior - between the sternum and the pericardial sac
- Thymus gland in children, remnants in adults
- Loose connective tissue and fat
- Lymphatic vessels and nodes
- Internal thoracic vessels
What is found in the posterior part of the inferior mediastinum?
posterior - behind the heart and anterior to the vertebral bodies
- oseophagus (with vagal trunks)
- descending aorta
- thoracic duct
- azygos, hemizygous and accessory hemizygous veins
- sympathetic trunk
What are parts of the middle mediastinum?
The heart and the pericardial sac
Great vessels:
- ascending aorta
- pulmonary trunk
- pulmonary veins (L/R)
- superior vena cava (SVC)
Trachea, carina and bronchi bifurcation (before hilum)
Phrenic nerves (innervates diaphragm)
What innervates the diaphragm?
phrenic nerves
Describe the surface anatomy of the heart
Apex of heart points down and to the left
(anterior, inferior and to the left)
- Pyramid with apex pointing anterior, inferior and to the left and the BASE facing posterior
What are features of the right border?
- 3rd to 6th costal cartilage, 1cm lateral to right border of sternum
- Mostly right atrium
What are features of the left border?
- 2nd intercostal space, left border of sternum
- 5th intercostal space just medial to mid-clavicular line (apex)
What are different surfaces of the heart?
- Anterior (sternocostal)
- Left pulmonary
- Right pulmonary
- Diaphragmatic surface (inferior)
- Base (posterior - back)
What are the different margins of the heart surface?
Apex - pointy bottom
Obtuse margin - edge runs from apex up from the left pulmonary to left atrium
Inferior (acute) margin - edge runs from apex across the right atrium
What are the internal chambers of the heart?
- left atrium
- left ventricle
- right atrium
- right ventricle
What are the valves of the heart?
- aortic (left ventricle - aorta)
- mitral (left atrium - left ventricle)
- pulmonary (right ventricle - pulmonary artery)
- tricuspid - (right atrium - right ventricle)
What are the 3 arteries that leave from the aorta?
(from right to left - on the heart)
- brachiocephallic artery
- left common carotid artery
- left subclavian artery
What are the different parts of the right atrium?
- Fossa ovalis - (remnant of the foramen ovale)
- Crista terminalis - on the border
- Pectinate muscles - on the inside (on the ‘lid’ when opened)
Describe features of the right atrium
One of the smallest chambers, but receives a high blood flow. The wall is folded.
What are the advantages of the wall of the right atrium being folded?
- increased surface area - greater volume of blood to full the chamber
- efficient contraction - facilitates more efficient contraction
- structural support - provides structural
- distensibility - allows atrium to expand
What are the internal structures of the right and left ventricles?
Trabeculae carnae - muscular ridges
Chordae tendineae - attached to the valves
Papillary muscles - attached to chordae tendineae
Contraction of papillary muscles pull the chordae tendinease to prevent eversion of blood during ventricular systole
Describe the flow of blood flow of oxygen-poor blood
- Deoxygenated blood from the SVC, IVC and coronary sinus –> right atrium
- Right atrium –> right ventricle via the tricuspid valve
- Right ventricle –> pulmonary trunk via the pulmonary valve
- Pulmonary artery –> lungs to be oxygenated
Describe the flow of blood of oxygen-rich blood
- Oxygenated blood –> pulmonary veins
- Pulmonary veins –> left atrium
- left atrium –> left ventricle via Mitral (bicuspid) valve
- left ventricle –> aorta via aortic valve
- aorta –> the rest of the body
What are embryological remnants?
Remnants of foetal development, when nonfunctional lungs are bypassed
Fossa ovalis - depression remnant of the foramen ovale, vessel that allows blood to pass from the right atrium to the left atrium
Ligamentum arteriosum - fibrous remnant of the ductus arteriosus, vessel that connects the pulmonary trunk and the descending aorta
What are the 3 great vessels?
- Arch of the aorta
- Superior vena cava
- Pulmonary trunk
What are the parts of the arch of the aorta?
brachiocephallic artery
(-right common carotid
(-right subclavian)
left common carotid artery
left subclavian artery
What feeds into the superior vena cava?
- right brachiocephallic vein
- left brachiocephallic vein
What does the pulmonary artery bifurcate into?
- right pulmonary artery
- left pulmonary artery
What are the 2 types of coronary arteries?
- left coronary artery
- right coronary artery
What comes off from the left coronary artery?
- left anterior descending artery
- left circumflex artery
- posterior descending artery
What comes off the right coronary artery?
- right marginal artery
- posterior descending artery
What feeds into the posterior descending artery?
Left coronary artery & Right coronary artery
What artery supplies the posterior interventricular artery?
The dominant artery
- right dominant - 70-80%
- left dominant - 5-10%
- co-dominance - 20%
