Respiratory System

The respiratory system consists of the nose, nasopharynx, trachea, and lungs. It brings oxygen from the air and excretes carbon dioxide and water back into the air. First, air is pulled through the trachea into the lungs by the diaphragm pushing down, which creates a vacuum. Air is briefly stored inside small sacs known as alveoli (sing.: alveolus) before being expelled from the lungs when the diaphragm contracts …

Nervous System

The nervous system consists of the body’s neurons, which together form the nerves and ganglia which in turn form the brain and related structures. The brain is the organ of thought, emotion, memory, and sensory processing, it serves many aspects of communication and controls various systems and functions. The special senses consist of vision, hearing, taste and smell. The eyes, ears, tongue, and nose gather information about the body’s environment. From a …

Musculoskeletal System

The musculoskeletal system consists of the human skeleton (which includes bones, ligaments, tendons, and cartilage) and attached muscles. It gives the body basic structure and the ability for movement. In addition to their structural role, the larger bones in the body contain bone marrow, the site of production of blood cells. Also, all bones are major storage sites for calcium and phosphate. This system can …

Immune System

The immune system consists of the white blood cells, the thymus, lymph nodes, and lymph channels, which are also part of the lymphatic system. The immune system provides a mechanism for the body to distinguish its own cells and tissues from outside cells and substances and to neutralize or destroy the latter by using specialized proteins such as antibodies, cytokines, and toll-like receptors, among …

Endocrine System

The endocrine system consists of the principal endocrine glands: the pituritary, thyroid, adrenals, pancreas, parathyroids, and gonads, but nearly all organs and tissues produce specific endocrine hormones as well. The endocrine hormones serve as signals from one body system to another regarding an enormous array of conditions, and resulting in variety of changes of function. Please follow and …

Circulatory System

The cirlulatory system consists of the heart and  blood vessels (arteries, veins and capillaries). The heart propels the circulation of the blood, which serves as a “transportation system” to transfer oxygen, fuel, nutrients, waste products, immune cells and signalling molecules (i.e.  hormones) from one part of the body to another. Paths of blood circulation within the human body can …