CV Gross Anatomy

Question 1

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

Answer 1

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

Question 2

Capillary and Lymphatic Pressures with Associated Complications

Answer 2

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

Lymphatic obstruction: filariasis

Question 3

Content of Anterior and Posterior Mediastinum

Answer 3

Anterior Mediastinum
Contains: Thymus

Posterior Mediastinum
Contains: Descending aorta and Esophagus

Question 4

Middle Mediastinum Contents

Answer 4

Middle Mediastinum

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

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

Question 5

Superior Mediastinum

Answer 5

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

Contains:

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

Question 6

Sternal Angle

Answer 6

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

Question 7

Folding of the Heart Tube

Answer 7

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

Question 8

Serous Pericardial Layers

Answer 8

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

Question 9

Cardiac Temponade

Answer 9

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

Question 10

Transverse Pericardial Sinus

Answer 10

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

Question 11

Valves with Cusps

Answer 11

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

Question 12

Tricuspid Valve Cusps with Papillary Muscles

Answer 12

Anterior papillary muscle: connected to anterior and posterior cusps

Posterior papillary muscle: connected to posterior and septal cusps

Question 13

Heart Sounds

Answer 13

Beginning of systole “lub” sound = AV valves closing

During end of systole “dub” sound = semilunar valves

Question 14

Cardiac Myocytes

Answer 14

Striated
Branching
Connected by gap junctions/desmosomes

Intercalated discs carry depolarization cell to cell

Purkinje fibers are modified myocytes, not nerves

Question 15

Cardiac Skeleton

Answer 15

Structurally supports valves

Electrically insulates atria from ventricles

Question 16

Sympathetic Innervation of the Heart

Answer 16

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)

Innervate

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

Question 17

Parasympathetic Innervation of the Heart

Answer 17

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)

Question 18

SA and AV Nodal Autonomic Innervation

Answer 18

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

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

Question 19

Coronary Circulation: Main Branches

Answer 19

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

Question 20

Dominance of Heart

Answer 20

> 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