Heart And Cardiac System Flashcards
Superficial palpations
- 3rd costal cartilage
- 2nd intercostal space
- 5th intercostal space
- 6th costal cartilage
- Midclavicular line
Arterial system
A. High pressure
B. Fast flow
C. Smooth muscle provided patency and shock absorption
Venous system
- Low pressure
2. Slow flow - like canal and reservoir
Mediastinum
Space between pulmonary cavities 1. Borders: A. Lateral: mediastinal pleura B. Anterior: sternum C. Posterior: bodies of thoracic vertebrae D. Superior: superior thoracic aperture E. Inferior: diaphragm 2. Subdivisions: sup and inf divided by line thru T4-T5 space and sternal angle A. Superior contains: 1. Superior vena cava 2. Ascending aorta and arch 3. Thoracic duct 4. Trachea 5. Esophagus 6. Thymus 7. Vagus nerve 8. Left recurrent laryngeal nerve 9. Phrenic nerves B. Inferior contains: 1. Anterior A. Remnants of thymus B. Lymph nodes C. Fat and CT 2. Middle A. Pericardium B. Heart C. Roots of great vessels D. Arch of azygos vein E. Main stem bronchi 3. Posterior A. Esophagus B. Thoracic aorta C. Azygos and hemiazygos veins D. Thoracic duct E. Vagus nerve F. Sympathetic trunks G. Splanchnic nerve
Fibrous pericardium
Part of mediastinum
- Tough outer layer
- Constrains heart
- Protects heart from overfilling
- Inferior blends w/ central tendon of diaphragm
Cardiac tamponade
Fluid build-up in pericardium (fibrous)
- Damage
- Infection
Pericardial cavity
Part of mediastinum
1. Serous pericardium
A. Parietal: covers internal aspect of fibrous pericardium
B. Visceral (epicardium)
C. Serous fluid between parietal and visceral
Mediastinum sinuses
- Transverse pericardial: passes transversely between where aorta and pulmonary trunk exit and SVC
A. Can be used to tie off aorta and pulmonary arteries - Oblique pericardial: blind recess posterior heart wraps behind vena cava and pulmonary veins
Mediastinum innervation
- Fibrous and partietal pericardium: somatic afferent of phrenic nerve (C3-C5)
- Visceral pericardium and heart: autonomically
A. Vagus (parasympathetic)
B. T1-5 sympathetic trunks
Heart layers
- Epicardium: visceral fascia
- Myocardium: muscle
- Endocardium: internal fascia
Atria
Collecting chambers
1. Muscle bundles attach to upper surface of fibrous rings that form AV openings
2. Right
A. Sinus venarum: most of RA w/ smooth muscle walls
*remnant of embryonic venous sinus
B. Right auricle: conical muscular pouch
*remnant of primordial atrium
C. Coronary sinus: larger vein/sinus
1. Collects coronary venous drainage from sm, middle, and large coronary veins
D. Fossa ovalis: remnant of foramen ovals, along interatrial septum
E. Crista terminalis: thick muscular crest, separated primordial atrium and sinus venarum
F. Pectinate muscles: rough striated muscular wall of RA
- Left
A. Slightly thicker wall than RA
B. Left auricle: similar to right auricle- Remnant of primordial atrium
- Contains pectinate muscles
C. Smooth walled portion: remnant of resorted embryological pulm veins
Ventricles
Right
1. Tricuspid valve: separates right atrium and ventricle
A. Cordae tendineae attach papillary muscles (anterior, posterior, septal)
2. Moderator band: from interventricular septum thru anterior papillary muscle
A. Shortcut for perkinje conductiion for simultaneous contraction of all 3 papillary muscles
3. Tribiculae Carneae: roughened textured striated muscle forms external wall
4. Conus arteriosus: thinner, smooth walled part - leads to pulmonary valve
Left
- Wall 2-3x thicker than RV
- Bicuspid (mitral) valve: chordae tendineae arise off 2 cusps
- Tribelulae carneae: finer and more numerous than RV
- Papillary muscles bigger
- Aortic vestibule: smooth non-muscular outflow tract
Outflow valves
Aortic and pulmonary (semilunar)
1. Prevent backflow
2. Don’t have external support, thicker at margins
3. 3 cusps
A. Pulmonary: right, left, anterior
B. Aortic: right, left, posterior
4. Openings to right and left coronary arteries during ventricle diastole
Coronary supply and return
Right and left coronaries supply heart tissue 1. Many variants 2. Right: supplies RA, SA node, post interventricular septum, and some left ventricle A. Branches 1. Nodal 2. Right marginal 3. Posterior interventricular 3. Left: supplies LA, most LV, anterior interventricular septum, and some RV A. Branches 1. Anterior interventricular (LAD) 2. Circumflex 3. Left marginal 4. Posterior interventricular
Cardiac venous return
Thru cardiac veins
1. Left: primary great cardiac vein
A. Begins at end LAD -> circumflex -> coronary sinus -> RA
B. Picks up left marginal and posterior ventricle veins
2. Right: 2 routes
A. Small and middle cardiac veins
B. RA via anterior cardiac veins
Cardiac autonomic control
Meet body demand
1. Sympathetic: inc. HR and force of contraction
A. 1st vasoconstriction then dilate
B. From symp chain T1-T5
1. Post-synaptic from paravertebral ganglia -> cardiac plexus -> SA node, AV node, and coronary artery muscle
- Parasympathetic: dec. HR and force of contraction
A. Vasoconstricts
B. Vagus n.
Referred pain
- visceral afferents carry signal to dorsal root ganglia
A. Brain thinks it came from dermatomes of T1-T5 (usually left shoulder)
Synchronization of heart contractions
- Cardiac muscle allows spontaneous and rhythmic contraction
A. Direct fiber -> fiber spread - Separation between atria and ventricle releases from synchronization
- SA node: starts atrial contraction
- AV node: slows signal and bundle rapidly transfers signal
- Purkinje fibers: continuation of AV node and bundles into ventricle
Pericarditis
Inflammation/infection of serous membrane of pericardium
1. Dx: auscultation - “rustle of silk”
Pericardial tamonade (effusion)
Fluid in pericardial cavity
1. Restricts contraction
Thrombi
Blood clot in wall of LA (usually)
1. Dislodge and block arteries
Valvular heart disease
Ossification or plaque build-up of valves -> backflow
1. Aortic stenosis (common) -> LV atrophy
Aortic aneurism
Aortic wall integrity dec. -> enlargement -> possible hemorrhage (fatal)
1. Change in voice if impinges recurrent laryngeal nerve
Coronary heart disease
Plaque build-up -> dec. O2 to cardiac tissues +> work harder, less efficient
Artheriosclerosis
Lipid deposits narrow coronary arteries
Myocardial infarction
Coronary artery plugged -> necrosis supplied tissue
- Anterior IV 40-50%
- RCA 30-40%
- Circumflex 15-20%
Atrial/ventricular fibrillation
Rapid, irregular contraction
1. Defibrillation resets
Bypass
Vessels grafted to supply tissue if coronary arty not working
1. Usually internal thoracic arteries or great saphenous vein in leg used
Angioplasty
Artery stretched w/ balloon, can place stent
Pacemaker/defibrillator
Inserted into one or both nodes to help if arrest or arrhythmia occur