(A) Heart Attack, also known as myocardial infarction, occurs when the blood flow to the heart is blocked or reduced, causing damage to the heart muscle. The common causes of heart attack include:
- Coronary artery disease: This is the most common cause of heart attack. It occurs when the arteries that supply blood to the heart become narrow or blocked due to the buildup of plaque (a fatty substance). This reduces the blood flow to the heart and increases the risk of a heart attack.
- High blood pressure: High blood pressure puts a strain on the heart and increases the risk of heart attack.
- High cholesterol: High levels of cholesterol can lead to the buildup of plaque in the arteries, increasing the risk of a heart attack.
- Diabetes: People with diabetes have an increased risk of developing heart disease and heart attack.
- Obesity: Being overweight or obese can put a strain on the heart and increase the risk of heart attack.
- Smoking: Smoking damages the blood vessels and increases the risk of heart attack.
- Family history: If there is a history of heart disease or heart attack in the family, the risk of developing a heart attack is higher.
- Age and gender: Men are at a higher risk of developing heart disease and heart attack than women. The risk of heart attack also increases with age.
(B) Drug addiction and drug abuse are often used interchangeably, but they have different meanings. Drug abuse refers to the use of illegal drugs or the excessive use of legal drugs, while drug addiction refers to the physical and psychological dependence on a drug.
Drug abuse can lead to drug addiction, but not everyone who abuses drugs becomes addicted. Addiction is characterized by compulsive drug use, even in the face of negative consequences.
(C) The human ear is divided into three main parts: the outer ear, middle ear, and inner ear.
The outer ear consists of the pinna and the ear canal. The pinna collects sound waves and directs them into the ear canal. The ear canal is a narrow, curved tube lined with hair and wax-producing glands. The wax helps to protect the ear canal and keep it clean.
The middle ear contains three tiny bones called the ossicles: the malleus, incus, and stapes. These bones amplify and transmit the sound waves from the eardrum to the inner ear.
The inner ear contains the cochlea and the semicircular canals. The cochlea is responsible for converting sound waves into electrical signals that are sent to the brain. The semicircular canals are responsible for detecting the movement and orientation of the head.
The ear also contains the eustachian tube, which connects the middle ear to the back of the throat. This tube helps to equalize the pressure in the middle ear and prevent fluid buildup.
(D) Vitamins are organic compounds that are essential for the normal functioning of the body. They play a crucial role in maintaining good health and preventing disease.
There are two types of vitamins: water-soluble vitamins (such as vitamin C and the B vitamins) and fat-soluble vitamins (such as vitamins A, D, E, and K). Fat-soluble vitamins are absorbed and stored in the body’s fat tissue, while water-soluble vitamins are not stored and are excreted in the urine.
Fat-soluble vitamins have a variety of functions in the body. Vitamin A is important for vision, immune function, and skin health. Vitamin D is important for bone health and immune function. Vitamin E is an antioxidant that helps protect cells from damage. Vitamin K is important for blood clotting.
Sources of fat-soluble vitamins include animal products (such as liver, fish, and dairy products) and plant oils (such as vegetable oil.