Lecture 3 Flashcards
Pericardial sac
Function/parts
Function:
-Holds heart/roots of great vessels
Parts:
1) Fibrous Pericardium
- Defines boundaries of middle mediastinum
- Continuous w the adventitia of great vessels
2) Serous pericardium
- Has parietal layer that lines Fibrous pericardium
- Visceral layer covers the heart
(Between two layers of serous pericardium = pericardial cavity)
Pericardium:
Neurovasculature
Arteries, veins, nerves
Arteries:
1) Internal thoracic
2) Musculophrenic branches
3) Inferior phrenic
4) Thoracic aorta
Veins:
1) Azygos
2) Internal Thoracic
3) Superiorphrenic
Nerves:
1) Visceral layer of serous paricardium
- Vagus nerve/sympathetic trunk (motor innervation)
- Visceral afferents for pain (sensory)
- Fibrous pericardium (somatic sensory) by phrenic nerve
Pericarditis
What is it
Causes
Procedure
– Inflammation of pericardium
– Causes • Infectious • Renal failure • Post myocardial infarction • Post-surgical etc.
– Pericardial friction rub: Sound due to roughness of the parietal lining from inflammatory process.
Pericardial effusion
– The accumulation of excess fluid within the pericardial space may occur slowly or rapidly
– Causes:
• Pericarditis
• Connective tissue diseases
• Hypothyroidism
-Can lead to cardiac tamponade
Cardiac tamponade
-Rapid Large fluid (usually blood) accumulation
in the pericardial space leading to compression
which prevents adequate filling of the chambers
Clinical signs = *Beck’s Triad:
• Hypotension→ decreased cardiac output
• Distant heart sounds→ fluid in pericardial cavity
• Distended neck veins→ decreased diastole
filling
Treatment:
• Paraxiphoid approach – tip of the xiphoid, or
between xiphoid and left costal margin, angled
towards left shoulder.
• Apical approach - left 5th or 6th intercostal
space
Pericardium reflections (Foldings) Sinus’s
-Foldings of pericardium around vessels
1) Transverse sinus: This space would be entered to place a clamp around the proximal aorta and pulmonary trunk
(Can be clamped in surgery)
2) 2. Oblique sinus: This is a cul-de-sac formed where the serous pericardium reflects onto the pulmonary veins
Heart surface anatomy
Margins
Right pulmonary surface:
-right pulmonary surface faces the right lung and consists of the right atrium
The left pulmonary surface:
Faces the left lung and consists of the left ventricle and part of the left atrium
inferior margin (acute): The sharp edge between the anterior and diaphragmatic surfaces of the heart
Obtuse margin:
Separates the anterior and left pulmonary surfaces it is round and extends from the left auricle to the cardiac apex
(Margins outline surfaces)
How are the anterior/stenocostal surface and inferior or diaphragmatic surface formed
The sternocostal surface:
-RIGHT ventricle
The diaphragmatic:
-left ventricle
Where is the Atrioventricular or Coronary sulcus (groove) and Interventricular sulcus (groove)
Between the atria and ventricles
Where does the Interventricular sulcus (groove) lie
Between the ventricles
What are Auricles and what are structure of the heart are they associated with?
- Appendages of the atria
- Associated with aorta and pulmonary trunk anteriorly
Where are they located?
Superior and inferior vena cava
-located posterior to right atrium
Where is the apex located?
Left ventricle Located
at 5th intercostal space
What is located at the base of the heart?
1) Left atrium
2) Proximal parts of
pulmonary veins
3) Part of right atrium
4) proximal parts of SVC and IVC
What would an anterior penetrating wound most likely penetrate?
Right ventricle
If a pt swallowed an object such as a nail what structure would most likely be at risk?
Left artrium (most posterior structure of heart)
What can happen if the left atrium is enlarged?
Dysphagia (Left atrium could compress the esophagus)
-Can do a Transesophageal ultrasound to investigate this
What’s the normal width of the heart at inferior margin?
-Less than one hemithorax (half of the thoracic diameter)
Greater can lead to cardiomegly
Cardiac chambers: Right Atrium
Where receives blood and structures within
-Receives blood from SVC, IVC & coronary sinus.
-cristaterminalis separates the smooth posterior part atrium from the area roughened by
the pectinate muscles.
-The inter-atrial septum has an oval depression (fossa ovalis)
Cardiac chambers: Left Atrium
Where receives blood and structures within
Receives arterialized (oxygenated) blood from FOUR pulmonary veins; 2 left & 2 right
• Inter-atrial surface forms part of the anterior wall and has an impression of the fossa ovalis
Where do the papillary muscles on the right ventricle attach to?
The tricuspid valve
(The muscles also keep the valve closed)–> Lub
Semilunar Valves:
What are the cusps associated with the aortic and pulmonary valve?
Aortic:
- right, left and posterior
- 2 Coronary cusps
- Right and left contain sinus’s that fill ventricular contraction closing valves and coronary arteries
Pulmonary:
-right ,left and anterior (have no associated vessels)
Valves, Location, Auscultation
Aortic
Pulmonary
Tricuspid
Mitral
Aortic
- Posterior to left side sternum at 3rd intercostal space
- Right sternal border at 2nd intercostal space
Pulmonary
- Left 3rd costal cartilage
- Left costal border at 2nd intercostal space
Tricuspid
-Behind sternum at 4th& 5th intercostal space
-Left sternal border at 5
the intercostal space
Mitral
- Behind sternum at 4th costal cartilage
- 5th left intercostal space in midclavicular line
Blood supply:
Right coronary artery
Branches
-Right coronary artery emerges from right aortic sinus –> Coronary sulcus
2) Right Marginal artery (acute marginal):
- supplies most of right ventricle
3) Posterior interventricular (posterior descending) artery:
- Supplies posterior 1/3 of IV septum
-Also supplies blood to the right atrium, SA/AV nodes/ part of left ventricle
Blood supply
Left Coronary Artery
Branches
1) Anterior interventricular branch (Most frequently occluded)
- Septal branches (anterior 2/3 IV septum)
2) Circumflex artery
-Left marginal branch of
circumflex artery
-Posterior left
ventricular branch
of circumflex artery
4) Diagonal branch(es)
of LAD → anterior
wall and anterior
papillary m.)
Supplies Left atrium Left ventricle Anterior 2/3 of interventricular septum AV bundle (of Hiss) and its branches. Circumflex a. may also supply SA and AV nodes (rare).
What can coronary heart disease lead to?
-hypoxia
-ischemia
-infarction of the myocardial tissue supplied by the
obstructed artery
How to tell if someone is left or right dominant
Right dominant:
-Right coronary gives rise to PIV (most people)
Left dominant:
-Left coronary artery gives rise to PIV
Sympathetic motor innervation of heart
- Preganglionic
- Synapse
- Postganglionic
Preganglionic:
Lateral horn –> Cell bodies in intermediolateral cells columns from T1-T4
Synapse:
Preganglionic sibers –> T1-4 chain ganglia or ascend the chain and synapse at cervical ganglia
Postganglionic sympathetic:
Cell bodies are located in cervical and upper thoracic chain ganglia –> Carried to the cardiopulmonary nerves to the cardiac plexus –> Cardio pulmonary nerves terminate at SA and AV nodes
Parasympathetic innervation of the heart
Preganglionic:
- parasympathetic cell bodies in the vagal nuclei
- Branch from vagus nerve –> Vagal cardiopulmonary branches
Postganglionic:
-Cell bodies: Atrial wall and interatrial septum
How do visceral afferents for pain travel
w sympathetics
How do visceral afferents for physiological reflexes travel (Ex: Stretch)
Follow parasympathetic fibers to the vagus nerve
