Cardiovascular L1.2 Flashcards
Diagram showing circulatory system
Mediastinum - Refer to Resp L1.1
State 3 structures present in the superior mediastinum
- Great vessels
- Nerves (vagus, phrenic)
- Thymus
Diagram showing subdivisions of the mediastinum
State 2 structures present in the anterior mediastinum
Thymus (in children)
Lymph nodes
State the role of the thymus
Primary lymphatic organ
Production of T lymphocytes (cell mediated immuniry)
1) Why is the thymus large in children?
2) What is a “Thymic Sail Sign” on a Chest X-Ray?
Actively producing + maturing T cells
Therefore, Occupies significant space in anterior mediastinum
2) In children, size of thymys produces visible outline on chest X-Ray. Shadow of thymus
State 3 structures found in the middle mediastinum
- Heart
- Pericardium
- Origins of great vessels
State structures in the posterior mediastinum
- Thoracic aorta
- Oesophagus
- Thoracic duct
1) Where are vagus nerves located in the cardiovascular system?
2) What is the fucntion of recurrent laryngeal nerves?
3) How do the positions of the recurrent laryngeal nerves differ between left and right side of heart?
4) What happens when the recurrent laryngeal nerves are damaged?
1) Anterior to subclavian vessels on both sides of eart and pass through mediastinum
2) Recurrent laryngeal nerves branch off the vagus nerve. Motor control of intrinsic muscles of larynx
3) Right recurrent laryngeal nerve:
-Loops under right subclavian artery
Left recurrent laryngeal nerve
-Loops under aortic arch
4) Hoarseness, voice loss, vocal cord paralysis
How can the mediastinum regions be viewed on CXRs?
Costodiaphragmatic recess
Pleural effusion collects
Anterior mediastinum - contains part of thymus gland
On a CXR, what should you look for to detect abnormalities within the mediastinum?
Describe mediastinitis
- Widening (too broad)
- Shift (mediastinym displaced from normal position)
Mediastinitis:
Inflammation + infection of mediastinal tissues, due to bacteria. Can be caused due to infection, oesophageal rupture, post surgical.
Why is the heart mostly on the left side of the chest in adults?
- During early development, heart located in middle of chest
- As heart grows, rotates to left side of body
- Rotation causes tip (apex) of heart to point towards left
RIGHT SIDED STRCUTRES SIT ANTERIORLY
LEFT SIDED STRUCTURES SIT POSTERIOTLY
(The rotation cuases right side of heart (RA, RV) to move to front of chest, while left side (LA, LV) moves more to back) - Left shift allows heart to fit properly in chest
Describe the 5 surfaces of the heart
1) Anterior
2) Posterior
3) Inferior
4) Right pulmonary surface
5) Left pulmonary surface
Anterior (sternocostal surface): Front of heart, mostly right ventricle
Posterior (base of pyramid) - Left atrium
Inferior (diaphragmatic) - Left, right ventricles (rests on diaphragm)
Right pulmonary surface: RHS of heart, right atrium faces right lung
Left pulmonary surface: LHS of heart, left ventricle faces left lung
Describe the four borders of the heart
1) Right border
2) Left border
3) Inferior
4) Superior
1) Right atrium
2) Left ventricle + partially left atrium
3) Left + right ventricke
4) Right + left atrium + great vessels
Describe the structure of the pericardium
(What are the two layers?)
What is the nerve supply to the pericardium?
Fibroserous sac - surrounds heart + great vessels
2 components
Fibrous pericardium
(tough connective tissue outer layer of heart, defines boundaries of middle mediastinum)
Serous pericardium
PHRENIC NERVE
Where is the transverse pericardial sinus found?
What is the function of the transverse pericardial sinus?
Describe its location
1) Pericardium
2) Coronary Artery Bypass Grafting (CABG). By passing finger / instrument through this space, they can easily identify + temporarily tie off major arteries (aorta, pulmonary trunk) to control blood flow during the proceadure.
3) Posterior to ascending aorta + pulmonary trunk
Anterior to superior vena cava
Superior to left atrium
What is the function of heart valves?
What is the function of AV valves?
What are the two AV valves?
What is the function of semilunar valves?
What are the two semilunar valves?
1) Unidirectional blood flow
2) Between atria + corresponding ventricle
3) Tricuspid - RA - RV
4) Bicuspid - LA - LV
5) Ventricles + corresponding artery
Regulate blood flow leaving heart
6) Pulmonary valve - RV - Pulmonary trunk
7) Aortic valve - LV - Ascending aorta
State the role of papillary muscles in AV valves
What happens when these muscles are damaged?
What is the name of the tendon?
1) A valves formed by flap-like cusps anchored to ventricular walls by tendons
Papillary muscles prebent valve cusps being blown into atrium during ventricular contraction (DO NOT CONTRACT TO OPEN VALVES)
2) Papillary muscle damage - Valve incompetence + cardiac murmur
3) Chordae tendinae
What is the function of the fibrous skeleton of the heart?
Strong tissue. Sits between atria + ventricles
1) Anchoring valves: AV valves attached to fibrous tissue
2) Electrical insulation: Barrier, prevents electrical signals from passing directly from atria to ventricles. ATRIA + VENTRICLES do not contract at same time
Describe the structure of aortic + pulmonary valves
Semi-lunar (3 cusps)
State the function of the right coronary artery
Which structures are supplied by RCA?
For the majory of individuals, which artery does the SA node artery originate from?
What does the marginal artery supply?
What does PIVA (posterior ventricular artery) supply?
1) Dominant 60% of people because it gives off Posterior Interventricular Artery (PIVA), supplies heart’s posterior side
2) RA, RV
SA Node
AV node
Posterior interventricular septum
3) RCA - SA node artery supplies SA node. Also supplies RA, LA
4) Reaches APEX
5) Posterior 1/3 of septum, AV node in majority
What is the role of the left coronary artery?
What does it supply?
What are its branches?
1) Dominant in 40%. Gives off PIVA
2) Supplies
LA+ LV
Anterior IV Septum (majority)
AV bundle (right + left bundles)
3) Circumflex artery (supplies LA., LV, in 40% ppl it continues as PIVA, making LCA dominant, in 20%, gives off AV nodal branch, supplies AV node.) left anterior descending artery (Anterior interventricular artery, supplies LV, RV, 2/3 of interventricular septum, AV bundle, right/left bundle branches, 20% ppl supplies AV node), marginal artery (reaches apex)
Where do cardiac veins drain into?
Where does the coronary sinus empty?
1) Coronary sinus
2) Right atrium
What is the importance of understanding the surface anaotmy of the heart?
- Clinical examination
- Injury
- Guiding surgical approach
- X-ray, ultrasound
More heat surface anatomy (ask Hifza!)
State two internal features of the right atrium
- AV Node
- SAA node
State two left atrium internal features
State three right ventricle internal features
Complete the following sentences:
1) Right ventricular wall is ……… than left
2) Cross section is …… shaped
3) RV is useful for ……. identification
- Right ventricular wall thinner than left
- Cross section is crescent shaped
- Useful for CT/MRI idenfification
State three left ventricular features
Complete the following sentences
1) Left ventricular wall is ….. than right
2) Cross section is
3) Useful for …… identification
1) 3x thicker
2) Relatively rounded
3) CT/MRI identification
Diagram showing great vessels of the heart
Conduction system (Ask Hifza! If this is not repeated in later lectures, make sure to come back to it)
1) How do electrical impulses spread thoughout RA, LA
2) How do electrical impulses spread thoughout RV, LV
3) State two factors that can impact conduction
*fibrous skeleton - prevents free electrical conduction
Electrical impulse spread from sinus Node throught LA, RA
Electrical impulses spead from bundle branches thoughout LV, RV
Venitricular septal defetcs + infarctions affect conduction
1) State the role of the cardiac plexus
2) What is the role of the parasympathetic supply? Which nerve provides parasympathetic supply?
Where is the cardiac plexus located? Which type of fibres are needed to reduce heart rate?
What is the role of the sympathetic supply? Where do these nerves arise?Which fibres are needed to reduce heart rate?
During a heart attack, why is pain felt in the left arm and chest?
1) Regulation of heart rate, contractility. Receives input from both parasympathetic + sympathetic nervouse system
2) Reduce heart rate. Vagus nerve. Cardiac branches of vagus nerve arise from thorax, travel to cardiac plexus (LOCATED BETWEEN AORTA + TRACHEA). POST GANGLIONIC FIBRES
3) Increase heart rate + contractility
Nerves arise from T1-T4 segments of sympathetic chain
Visceral sensory fibres from the heart travel back to CNS alongside sympathetic nerves
Reffered cardiac pain occurs because visceral sensory fibres share pathways with nerves supplying medial upper limb, this is why heart pain during a heat attack is felt in left arm or chest
