Heart Anatomy

Protective outer layer of heart

Fibrous pericardium 

1

Apex

2

Right Atria

3

Left Atria 

4

Right ventricle 

5

Left ventricle

6

Superior vena cava

7

Inferior vena cava

8

Right pulmonary vein

9

Left pulmonary veins

10

Right pulmonary artery

11

Left pulmonary artery 

12

Ascending aorta 

13

Aortic arch

14

Pulmonary trunk artery

15

Small cardiac vein 

16

Great cardiac vein 

17

Middle cardiac vein

18

Right coronary artery

19

Left coronary artery

20

Anterior interventricular artery

21

Posterior interventricular artery

22

Coronary sinus

23

Right marginal artery

24

Circumflex artery

1

Brachiocephalic artery

2

Right subclavian artery

3

Left subclavian artery

4

Right common carotid artery 

5

Left common carotid artery 

6

Descending aorta

1

Interventricular septum

2

Interatrial septum

3

Papillary muscles

4

Tricuspid Valva

5

Bicuspid Valve

6

Aortic valve

7

Pulmonary valve

8

Chordae tendinae

Serous pericardium

• Parietal layer on fibrous pericardium

• Visceral layer on the heart muscle

Layers of the heart

Epicardium: visceral serous pericardium

• Loose connective tissue

Myocardium: muscle layer

• Muscle tissue 

Endocardium: epithelium and connective tissue, inner most layer

• Loose connective tissue

Atria, Right and Left chamber of the heart

• Receive blood 

• Thin walled 

• Auricles

Ventricles, Right and Left Chamber of the heart

• Pump blood 

• Thick walled 

• Trabecula carnae

• Papillary muscles

Veins of the heart function

Bring blood to the heart

Arteries of the heart function

Carry blood away from the heart

Brings blood to the right atrium

Superior and inferior vena cava

Brings blood to the left atrium

Right and left pulmonary veins

Carries blood to the lungs

Pulmonary trunk, left and right pulmonary aortas

Carries blood to the body

Ascending aorta, Aortic arch, descending aorta

Pulmonary Semilunar Valve

Prevents blood flow back into the right ventricle

Aortic Semilunar Valve

Prevents blood flow back into left ventricle

Systole

contracting

Diastole

Resting and expanding

Lubb

AV valves closing

Dubb

Semilunar valves closing. This is the loudest sound

Coronary Vessels

Supply myocardium with blood and start at the base of aorta (aortic sinus)

Anterior Right Coronary Arteries

Right Coronary Artery

Marginal artery

Posterior interventricular artery

Anterior Left Coronary Arteries

Left Coronary Artery

Anterior interventricular artery

Circumflex artery

Posterior Coronary Vessels

Anastamoses

Atherosclersosis

Arteriosclerosis

Coronary Veins

Drain deoxygenated blood for the myocardium

Anterior View of Coronary Veins

Great cardiac vein

Small cardiac vein

Posterior view of Coronary Veins

Middle Cardiac Vein

Posterior cardiac Vein

Coronary sinus

Sinoatrial Node

Isolated SA node cells depolarize at 80-100 times per minute.
Parasympathetic nervous system affects. SA node to lower resting Heart Rate (HR)
to 70-80 beats per min.
Bradycardia = slower than normal HR
Tachycardia = higher than normal HR

Impulse Pathway

• SA node fires → atria contract

• Signal reaches AV node → brief pause (allows ventricular filling)

• Impulse travels through:

  • AV bundle (Bundle of His)

  • Bundle branches

  • Purkinje fibers

• Ventricles contract

Electrocardiogram (ECG)

• P wave: atrial depolarization (atrial contraction)

• QRS complex: ventricular depolarization (ventricular contraction)

• T wave: ventricular repolarization

Heart rate and the CNS

Parasympathetic system to slow the heart rate (vagus nerve)
Sympathetic system to increase heart rate

Tunica Interna

• Endothelium

• Elastic fibers

Tunica media

• Smooth muscle

• Controls vasoconstriction & vasodilation

Tunica externa (adventitia)

• Connective tissue

• Contains vasa vasorum (vessels that supply vessels)

Types of Arteries

• Elastic arteries: conducting; act as a “2nd pump” (aneurysms common)

• Muscular arteries: distributing

• Arterioles: regulate blood flow into capillaries

• Capillaries: exchange vessels

Types of Veins

• Venules

• Veins

How does blood return to the heart?

• Skeletal muscle contractions + one-way valves

• Negative pressure in thoracic cavity during inspiration