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Flashcards in CV Gross Anatomy Deck (20)

R vs. L Ventricles: Pressure, SV, and Filling Volume

The left ventricle has more muscle than the right and powers the systemic blood flow at relative high pressures

The right ventricle powers pulmonary blood flow at a much lower pressure, otherwise pulmonary edema occurs

Both the R and L ventricle have the same stroke volume (eject the same amount of blood), but L has slightly higher filling volume


Capillary and Lymphatic Pressures with Associated Complications

Increased hydrostatic pressure: CHF
Reduced Plasma Oncotic Pressure: Nephrotic syndrome

Lymphatic obstruction: filariasis


Content of Anterior and Posterior Mediastinum

Anterior Mediastinum
Contains: Thymus

Posterior Mediastinum
Contains: Descending aorta and Esophagus


Middle Mediastinum Contents

Middle Mediastinum

Pericardium (and its contents): Heart, Roots of vessels, Phrenic nerve, and Pericardiacophrenic vessels

Roots of the following vessels:
Ascending aorta
Pulmonary trunk
Pulmonary veins


Superior Mediastinum

From the superior thoracic inlet to the horizontal plane passing through the sternal angle and the IV disc between T4 and 5

- Thymus
- Great vessels:
- Brachiocephalic veins
- Arch of aorta
- Brachiocephalic trunk
- Left subclavian
- Left common carotid
- Vagus and Phrenic nerves
- Cardiac plexus of nerves
- Left recurrent laryngeal nerve
- Trachea
- Esophagus


Sternal Angle

Plane of sternal angle:
Plane from manubriosternal joint (symphysis) to IV disc T4/T5 marks:
Articulation of 2nd ribs with sternum
Boundary between superior and inferior mediastinum = superior limit of pericardium

Things in plane of sternal angle:
Bifurcation of the trachea
Beginning and ending of aortic arch
Entrance of SVC into pericardium
Superior limit of pulmonary trunk


Folding of the Heart Tube

Occurs in the 4th week

Folding of the heart tube shifts the developing ventricle and conus truncus ventrally and to the right
Subsequent growth of the ventricles appears to twist the heart so that the ventricles comes to lie ventrally (right ventricle) and to the left (left ventricle)

The atrium and sinus venosus come to lie dorsally

Arteries come out in front and veins come out in back


Serous Pericardial Layers

Pericardium — a closed fibroserous sac around heart and proximal great vessels

Fibrous pericardium

Serous pericardium with a parietal layer separated by pericardial cavity from the visceral layer (epicardium)

Lubrication between layers comes from mesothelial cells


Cardiac Temponade

Causes: kidney malfunction, trauma to thorax, inflammation of pericardium

Consequences: less blood pumped to body, ventricles fill with less blood, blood pressure increases

Cures: drugs and pericardiocentesis


Transverse Pericardial Sinus

Transverse Pericardial Sinus: aorta and pulmonary trunk are anterior and SVC is posterior


Valves with Cusps

Pulmonic Valve: anterior, right and left cusps

Aortic Valve: right, left, and posterior cusps

Mitral Valve: anterior (innermost) and posterior cusp (outermost)

Tricuspid Valve: anterior (foremost), medial/septal (innermost), and posterior cusps

Atrioventricular (AV) valves: Tricuspid and Mitral valves Leaflets the chordae tendinae then papillary muscles: prevent eversion during systole


Tricuspid Valve Cusps with Papillary Muscles

Anterior papillary muscle: connected to anterior and posterior cusps

Posterior papillary muscle: connected to posterior and septal cusps


Heart Sounds

Beginning of systole “lub” sound = AV valves closing
During end of systole “dub” sound = semilunar valves


Cardiac Myocytes

Connected by gap junctions/desmosomes

Intercalated discs carry depolarization cell to cell

Purkinje fibers are modified myocytes, not nerves


Cardiac Skeleton

Structurally supports valves
Electrically insulates atria from ventricles


Sympathetic Innervation of the Heart

1st Neuron
- Somata in lateral horn T1-T4
- Axons via ventral rami
- Synapse sympathetic trunk

2nd Neuron
Somata in sympathetic ganglia
Axons in cardiac nerves
Pass through cardiac plexus (do not synapse here)

- Pacemaker cells
- Cardiac myocytes
- Smooth muscle of coronary arteries


Parasympathetic Innervation of the Heart

Vagus – Cranial Nerve X

1st Neuron
- Somata in dorsal vagal nucleus and nucleus ambiguous of brain stem
- Axons in cardiac branches of vagus n.
- travel via cardiac plexus (some synapsing here)

2nd Neuron
- Somata in cardiac plexus or closer to target cells
- Innervate
- Pacemaker cells
- Cardiac myocytes (primarily atrial)


SA and AV Nodal Autonomic Innervation

Noradrenaline on b1– adrenergic receptors
increases Na+ and Ca++ conductance
Increased rate of depolarization

Acetylcholine on muscarinic M2 receptors
Increasing K+ conductance (hyperpolarizing) decreasing rate of depolarization.


Coronary Circulation: Main Branches

Anterior interventricular artery travels with great cardiac vein

Posterior interventricular artery travels with middle cardiac vein

Marginal artery travels with small cardiac vein

Branch to SA node: comes from R coronary artery

Branch to AV node: comes from the posterior interventricular artery


Dominance of Heart

>50% of population is right dominant
Posterior interventricular a. arises from R coronary a.

20% is left dominant
Posterior interventricular a. arises from L coronary a.

30% is balanced