Anatomy Of The Heart And Coronary Vessels

Question 1

What are the 3 layers of the pericardium and what are their functions?

Answer 1

• Fibrous pericardium attaches to great vessels and diaphragm to anchor heart in place and provide a protective layer
• Serous pericardium parietal (attached to epicardium) and visceral layer (attached to fibrous pericardium) create a space
• Gap filled with serous fluid allows the heart to move

Question 2

What are the functions of the pericardium?

Answer 2

• Prevents excessive movement of heart (cases of acute volume overload)
• Lubrication
• protection from infection from other organs
• fixes heart in mediastinum to limit movement

Question 3

What happens in pericardial effusion?

Answer 3

Fluid gathers between parietal and visceral pericardium so the heart has nowhere to go

Question 4

What is cardiac tamponade and what does it cause?

Answer 4

• accumulation of fluid under high pressure
• compresses cardiac chambers
• impairs diastolic filling of ventricles

Question 5

What are the 3 layers of the heart wall and their functions?

Answer 5

• myocardium (cardiac muscle fibres arranged in bundles) squeezes blood out of heart
• endocardium lines chambers and valves
• Epicardium visceral layer of serous pericardium

Question 6

What makes up the right border and surface of the heart?

Answer 6

Right atrium and ventricle

Question 7

What vessels enter the right atrium

Answer 7

Superior vena cava, inferior vena cava and coronary sinus

Question 8

What valves does the right heart contain?

Answer 8

• tricuspid between atrium and ventricle

- pulmonary semilunar valve between ventricle and pulmonary trunk

Question 9

What makes up the posterior aspect and base of heart?

Answer 9

Left atrium and ventricle

Question 10

What vessels enter the left atrium?

Answer 10

4 pulmonary veins

Question 11

What valves does the left heart contain?

Answer 11

• mitral valve between atrium and ventricle

- aortic semilunar valve between ventricle and ascending aorta

Question 12

What is the path of the right coronary artery?

Answer 12

• gives rise to the post interventricular artery

- anastomoses with circumflex branch of left coronary artery

Question 13

What is the path of the left anterior descending artery?

Answer 13

• loops around apex

- anastomoses with post interventricular artery

Question 14

How is dominance determined?

Answer 14

• determined by the arteries that supply the posterior and inferior wall of the left ventricle

Question 15

What is the path of venous drainage of the cardiac muscle?

Answer 15

• cardiac veins drain into coronary sinus on posterior surface of heart
• coronary sinus empties into right atrium

Question 16

What is the fibrous skeleton of the heart?

Answer 16

• dense connective tissue surrounding AV and outflow vessel valves
• fuses together and merges with intraventricular septum

Question 17

What is the function of the fibrous skeleton of the heart?

Answer 17

• supports the valves
• prevents overstretching of valves
• insertion point of cardiac muscle bundles
• electrical insulator between atria and ventricles

Question 18

What is the function of the semilunar valves?

Answer 18

• prevent backflow from aorta into ventricles

- prevent backkflow from pulmonary trunk into ventricles

Question 19

What is the Semilunar valves function in diastole?

Answer 19

• backflow fills cusps and closes valves

- increases the blood pressure

Question 20

What is the function of semilunar valves in systole?

Answer 20

• valves open to allow filling

Question 21

What happens in diastole?

Answer 21

AV valves open and allow blood to flow from atria into ventricles when ventricle pressure is lower atrial pressure.

Question 22

What happens in systole?

Answer 22

AV valves close preventing backflow of blood into atria when ventricles contract pushing valve cusps closed.

Question 23

What makes up the heart conducting system?

Answer 23

• cardiac muscle fibres form 2 networks via gap junctions at intercalated discs
• atrial network
• ventricular network
• separated by fibrous skeleton

Question 24

What nerves provide innervation to the heart?

Answer 24

• heart is supplied by the cardiac plexus
• parasympathetic form vagus nerve
• sympathetic from sympathetic trunk
• visceral sensory afferents

Question 25

What does sympathetic innervation control in the heart?

Answer 25

• increases heart rate

- increases force of contraction

Question 26

Where are the sympathetic neurones?

Answer 26

• cardio respiratory centre in medullary reticular formation
• preganglionic sympathetic neurones in thoracic spinal cord
• postganglionic sympathetic neurones to SA & AV node end in coronary V&M

Question 27

What does parasympathetic innervation control in the heart?

Answer 27

Slows heart rate

Question 28

What is the pathway of the parasympathetic innervation?

Answer 28

• reticular formation in medulla (cardioinhibitory centre)
• vagus nerve
• to SA & AV nodes

Question 29

Where is the pain from damage to cardiac muscle felt?

Answer 29

• damage to cardiac muscle stimulates visceral sensory nerve endings in myocardium
• visceral afferent nerve fibres ascend to CNS through cardiac beaches of sympathetic trunk
• organ and skin pain fibres travel to spinal cord together
• pain in felt in skin supplied by T1-5 on left side of chest, neck and face and left arm