Composition of the human body

Overview of the chemical composition of the human body

The composition of the human body refers to the chemical elements and compounds that make up the human body. The human body is composed of a variety of elements, with the majority being oxygen, carbon, hydrogen, and nitrogen. These elements combine to form the complex molecules that are essential for life.

Major Elements

The human body is primarily composed of four major elements:

• Oxygen (O) - Approximately 65% of the human body's mass is oxygen. It is a key component of water and is essential for cellular respiration.
• Carbon (C) - Making up about 18% of the body, carbon is the backbone of all organic molecules, including proteins, lipids, carbohydrates, and nucleic acids.
• Hydrogen (H) - Comprising about 10% of the body, hydrogen is a component of water and organic molecules.
• Nitrogen (N) - About 3% of the body is nitrogen, which is a critical component of amino acids and nucleic acids.

Minor Elements

In addition to the major elements, the human body contains several minor elements that are vital for various physiological functions:

• Calcium (Ca) - Essential for bone and teeth structure, muscle contraction, and nerve function.
• Phosphorus (P) - Important for the formation of bones and teeth, and is a component of DNA, RNA, and ATP.
• Potassium (K) - Crucial for nerve function and muscle contraction.
• Sulfur (S) - A component of some amino acids and vitamins.
• Sodium (Na) - Vital for maintaining fluid balance and nerve function.
• Chlorine (Cl) - Important for maintaining fluid balance and is a component of stomach acid.
• Magnesium (Mg) - Involved in over 300 biochemical reactions in the body.

Trace Elements

Trace elements are present in smaller amounts but are essential for health:

• Iron (Fe) - A component of hemoglobin, which is necessary for oxygen transport in the blood.
• Zinc (Zn) - Important for immune function and enzyme activity.
• Copper (Cu) - Involved in iron metabolism and the formation of connective tissue.
• Iodine (I) - Essential for the synthesis of thyroid hormones.
• Selenium (Se) - Plays a role in antioxidant defense and thyroid hormone metabolism.
• Manganese (Mn) - Involved in bone formation and metabolism.

Water and Organic Molecules

The human body is composed of approximately 60% water, which is essential for maintaining homeostasis, transporting nutrients, and removing waste. Organic molecules such as proteins, lipids, carbohydrates, and nucleic acids are crucial for structure, function, and regulation of the body's tissues and organs.

Related Pages

• Human anatomy
• Biochemistry
• Metabolism
• Nutrition