2.16 Cardiovascular Diseases (CVDs) | Blood Circulatory System Of Man | Biology 12

A group of diseases affecting the heart and blood vessels. The text specifically discusses:

Angina pectoris
Heart attack (Myocardial Infarction)
Heart failure (Congestive Heart Failure)
Congenital heart problems

2.16.1 Angina Pectoris

Cause: Primarily due to atherosclerosis, which narrows coronary arteries, reducing blood flow to the heart muscle. This is often linked to the formation of fatty streaks and atheromas.

Symptoms: Occasional chest pain, especially when the heart is working hard due to physical or emotional stress.

Significance: It is a signal that a part of the heart is not receiving sufficient oxygen, indicating a risk of future heart attack.

2.16.2 Heart Attack (Myocardial Infarction)

Causes:

A blood clot completely blocking a coronary artery.
Atherosclerosis reaching a critical level, leading to massive damage to the heart muscle.
Plaque Rupture: When the fibrous cap of an atheroma breaks, triggering rapid clot formation.

Symptoms:

Sudden, heavy squeezing ache or discomfort in the center of the chest.
Pain may radiate to the shoulder, arm, neck, or jaw.
Other symptoms include sweating, nausea, shortness of breath, dizziness, or fainting.

Process: The entire process is called myocardial (heart muscle) infarction (death due to lack of oxygen).

Consequences:

Dead heart muscle cells are not replaced because cardiac muscles do not divide.
Scar tissue (connective tissue) grows into the damaged areas.
Scar tissue cannot contract like cardiac muscle, permanently weakening the heart.

2.16.3 Heart Failure (Congestive Heart Failure)

Definition: The inability of the heart to pump all the blood coming to it.

Mechanism: The cardiac output (blood pumped out) is unable to keep pace with the venous return (blood returning to the heart). For more on heart cycles, see Phases of Heartbeat→.

Consequence: Leads to a backlog of blood in the venous system and inadequate blood supply to the body. This is often a progression from chronic Cardiovascular Disorders→.

2.16.4 Congenital Heart Problem

Cause: Result from abnormalities in embryonic development of the heart.

Example: Malfunctioning of cardiac valves, such as valvular stenosis (narrowing of a heart valve).

2.16.1 Angina Pectoris

Cause: Primarily due to atherosclerosis, which narrows coronary arteries, reducing blood flow to the heart muscle. This is often linked to the formation of fatty streaks and atheromas.

Symptoms: Occasional chest pain, especially when the heart is working hard due to physical or emotional stress.

Significance: It is a signal that a part of the heart is not receiving sufficient oxygen, indicating a risk of future heart attack.

2.16.2 Heart Attack (Myocardial Infarction)

Causes:

A blood clot completely blocking a coronary artery.

Atherosclerosis reaching a critical level, leading to massive damage to the heart muscle.

Plaque Rupture: When the fibrous cap of an atheroma breaks, triggering rapid clot formation.

Symptoms:

Sudden, heavy squeezing ache or discomfort in the center of the chest.

Pain may radiate to the shoulder, arm, neck, or jaw.

Other symptoms include sweating, nausea, shortness of breath, dizziness, or fainting.

Process: The entire process is called myocardial (heart muscle) infarction (death due to lack of oxygen).

Consequences:

Dead heart muscle cells are not replaced because cardiac muscles do not divide.

Scar tissue (connective tissue) grows into the damaged areas.

Scar tissue cannot contract like cardiac muscle, permanently weakening the heart.

2.16.3 Heart Failure (Congestive Heart Failure)

Definition: The inability of the heart to pump all the blood coming to it.

Mechanism: The cardiac output (blood pumped out) is unable to keep pace with the venous return (blood returning to the heart). For more on heart cycles, see Phases of Heartbeat→.

Consequence: Leads to a backlog of blood in the venous system and inadequate blood supply to the body. This is often a progression from chronic Cardiovascular Disorders→.