Heart notes
What is the Heart?
The heart is a muscular organ that pumps blood throughout the body.
Located in the thoracic cavity (chest), slightly towards the le .
Size: Approximately fist-sized (~300 grams in adults).
Covered by a double-layered membrane called Pericardium which contains
pericardial fluid to reduce fric on.
Structure of the Heart
The human heart has four chambers:
Upper chambers: Atria (singular: Atrium)
Right atrium: receives deoxygenated blood from the body.
Le atrium: receives oxygenated blood from the lungs.
Lower chambers: Ventricles
Right ventricle: sends deoxygenated blood to the lungs.
Le ventricle: sends oxygenated blood to the rest of the body (most muscular
chamber).
Heart Diagram (Labeled)
Here is a labeled diagram of the human heart:
If image doesn't display, you can ask me to generate or send as a PDF version.
Blood Circula on Pathway
There are two types of circula on in the body:
1. Pulmonary Circula on (Lungs)
Right ventricle → Lungs → Le atrium
Blood gets oxygenated in the lungs.
, 2. Systemic Circula on (Body)
Le ventricle → Body → Right atrium
Blood delivers oxygen to body ssues and becomes deoxygenated.
Flow of Blood in the Heart
1. Deoxygenated blood from body → Right atrium
2. Right atrium → Right ventricle (via tricuspid valve)
3. Right ventricle → Lungs (via pulmonary artery) → blood becomes oxygenated
4. Oxygenated blood from lungs → Le atrium
5. Le atrium → Le ventricle (via bicuspid or mitral valve)
6. Le ventricle → Aorta → whole body
Valves in the Heart
Valve Name Loca on Func on
Tricuspid Right atrium → Right ventricle Prevents backflow
Bicuspid (Mitral) Le atrium → Le ventricle Prevents backflow
Pulmonary Valve Right ventricle → Pulmonary artery Controls flow to lungs
Aor c Valve Le ventricle → Aorta Controls flow to body
Heartbeat and Cardiac Cycle
Normal human heartbeat: 72 mes per minute.
Controlled by:
o SA Node (Sinoatrial Node) – natural pacemaker
o AV Node, Bundle of His, and Purkinje fibers
Cardiac Cycle:
One complete contrac on + relaxa on of the heart = 0.8 seconds
What is the Heart?
The heart is a muscular organ that pumps blood throughout the body.
Located in the thoracic cavity (chest), slightly towards the le .
Size: Approximately fist-sized (~300 grams in adults).
Covered by a double-layered membrane called Pericardium which contains
pericardial fluid to reduce fric on.
Structure of the Heart
The human heart has four chambers:
Upper chambers: Atria (singular: Atrium)
Right atrium: receives deoxygenated blood from the body.
Le atrium: receives oxygenated blood from the lungs.
Lower chambers: Ventricles
Right ventricle: sends deoxygenated blood to the lungs.
Le ventricle: sends oxygenated blood to the rest of the body (most muscular
chamber).
Heart Diagram (Labeled)
Here is a labeled diagram of the human heart:
If image doesn't display, you can ask me to generate or send as a PDF version.
Blood Circula on Pathway
There are two types of circula on in the body:
1. Pulmonary Circula on (Lungs)
Right ventricle → Lungs → Le atrium
Blood gets oxygenated in the lungs.
, 2. Systemic Circula on (Body)
Le ventricle → Body → Right atrium
Blood delivers oxygen to body ssues and becomes deoxygenated.
Flow of Blood in the Heart
1. Deoxygenated blood from body → Right atrium
2. Right atrium → Right ventricle (via tricuspid valve)
3. Right ventricle → Lungs (via pulmonary artery) → blood becomes oxygenated
4. Oxygenated blood from lungs → Le atrium
5. Le atrium → Le ventricle (via bicuspid or mitral valve)
6. Le ventricle → Aorta → whole body
Valves in the Heart
Valve Name Loca on Func on
Tricuspid Right atrium → Right ventricle Prevents backflow
Bicuspid (Mitral) Le atrium → Le ventricle Prevents backflow
Pulmonary Valve Right ventricle → Pulmonary artery Controls flow to lungs
Aor c Valve Le ventricle → Aorta Controls flow to body
Heartbeat and Cardiac Cycle
Normal human heartbeat: 72 mes per minute.
Controlled by:
o SA Node (Sinoatrial Node) – natural pacemaker
o AV Node, Bundle of His, and Purkinje fibers
Cardiac Cycle:
One complete contrac on + relaxa on of the heart = 0.8 seconds
