Persistent increase in blood pressure above 140 mm of Hg (systolic) and 90 mm of Hg (diastolic) is termed as hypertension
It is a major health problem having no as symptoms
It is caused by nervous tension and emotional stress leading to contraction of arteries
It may lead to heart failure, kidney diseases and stroke

Hypotension

Hypotension is the term used for denoting decrease in the arterial blood pressure
This occurs when the systolic pressure gets below 110 mm of Hg and diastolic pressure drops below 70 mm of Hg
It is caused by vasodilation of arterioles, loss of blood, lower pumping action of heart, nervous disorders anaemia etc

Arteriosclerosis

It is the hardening of arteries and arterioles due to the thickening of the fibrous tissue and consequent loss of elasticity of their walls
It can further cause hypertension.
Typically, it occurs in elders
There are two types of arteriosclerosis. In one type calcium gets deposited in the tunica media of arteries while in another the lumen of arterioles become narrow due to deposition of cholesterol

Atherosclerosis

It refers to irregular thickening of arterial walls and narrowing of their lumen
Atherosclerosis occurs due to the deposition of yellow plaques or atheromas in their tunica interna and some parts of tunica media
Atheromas consist of cholesterol and other lipid materials
They are formed of low density lipoproteins
These LDL can pass through the endothelium and get precipitated inside the artery
Atherosclerosis mostly develops in the aorta, coronary arteries and cerebral arteries
Atherosclerosis in cerebral arteries restricts the blood flow to the brain leading to cerebrovascular accident or stroke
Obstruction in blood flow due to atherosclerosis can also cause heart and kidney failure

Fibrillation

It is a condition in which the heart muscles contract very rapidly but in uncoordinated fashion
There can be atrial and ventricular fibrillation

Cardiovascular diseases

There are several cardiovascular diseases which occur due to the malfunctioning of the heart and its conducting vessels.
The two most common diseases related to circulatory system are
Coronary artery disease
It is caused by atherosclerosis of blood vessels that supply blood to the heart
The factors responsible for coronary artery disease are high cholesterol, smoking, hypertension, hyperglycemia, lack of exercise, stress, obesity etc.
Symptoms of coronary artery disease are chest pain, nausea, perspiration, and abnormal ECG.
Preventive measures of coronary artery disease include reducing cholesterol levels in food, avoiding sedentary lifestyle and smoking
Coronary artery disease can be treated by bypass grafting or angioplasty (breaking of arterial blockage by balloon catheter) and coronary stent-implantation.
Coronary artery disease can cause heart attacks (myocardial infarction) and angina

Myocardial infarction

Myocardial infarction is also known as heart attack
It results from the death of a part of heart muscle following cessation of blood supply to it
It is characterised by severe pain in the heart or nearby organ, breathlessness, restlessness, nausea, vomiting etc.

Angina pectoris

Congestive heart failure

It occurs when the heart is unable to pump blood sufficiently in order to meet the body’s needs
It mostly occurs due to dysfunctioning of left ventricle
The failure of adequate output by the left ventricle is marked by lungs congestion and edema
The failure of adequate output by the right ventricle is marked by venous enlargement, hepatic enlargement and edema
Heart failure can be caused by coronary artery disease, high blood pressure, diabetes, obesity etc.