221 Human Body Parts Encyclopedia

Hormones are chemicals that are secreted in small amounts in one part of the body (endocrine gland) and then they travel through the bloodstream to control the activity of some other part of the body (target cell). The glands that produce hormones are principally controlled by the brain. Hormones speed up or slow down or […]

The endocrine system is a series of glands that are spread throughout the body. These glands secrete regulatory chemicals called hormones or chemical messengers that control bodily functions. So, in short, the endocrine system is a collection of glands that control the various functions of the human body by secreting hormones. Hormone is the main

Respiration is a process in which oxygen is taken in and carbon dioxide is given out of the body. The cells use oxygen to produce energy and carbon dioxide is generated in the process. The human lung is the main organ in the respiratory system, which performs two important functions: inhalation and exhalation. The whole

Asthma is a disease which makes breathing difficult. Asthma attacks all age-groups but often starts in childhood. The main reason behind asthma is inflammation in air passages that carry air to and fro from the lungs. These inflammations make the airways narrower. Due to the narrow airways, less air can pass through them, which in

An arched muscle separating thoracic cavity (chest region) from the abdominal cavity, located below the lungs, is called the diaphragm. It helps in respiration process. During breathing in the diaphragm flattens while during breathing out the diaphragm relaxes and becomes arched again. The diaphragm also compresses the abdominal cavity when the inhalation of oxygen occurs.

Each lung is surrounded by a double serous membrane, the pleura. The part of the pleura covering each lung is called the visceral pleura. The pleura lining the ribs, is the parietal pleura. With each breath, the lungs expand and contract. The whole inner lining that covers the lungs and the ribs secretes mucus which

The lungs are the principal organs of respiration. A human body has a pair of lung present inside the rib cage above an arched muscle called the diaphragm. The lungs are covered by two thin membranes called pleura. The lungs are cone-shaped organs with spongy texture. This spongy texture helps in the incorporation of inhaled

Bronchi The wind pipe branches into two smaller tubes. These tubes are called the bronchi (in plural), or bronchus (singular). Each bronchus opens into a lung. The main function of the bronchus is to conduct air into the lungs. In lungs, the bronchus divides further into several tributaries called bronchioles, just like a branch of

Pharynx The pharynx is a muscular tube which extends from the base of the skull to the oesophagus. It makes a bridge between the nasal cavity and the larynx and the oesophagus. It is common to both the respiratory tract and the digestive tract. In the respiratory tract it acts as an air passage during

Nasal Cavity The nostrils open into the nasal cavity which is the space inside the nose between the base of the skull and the roof of the mouth. It connects the nostrils to the upper part of the pharynx (throat). The whole cavity is covered with mucous membrane (lining that secretes slimy fluid) and tiny

Respiratory System The respiratory system is a set of organs that help a human being to breathe. Breathing is the process of inhaling oxygen and exhaling carbon dioxide. The respiratory passage consists of the nose, nasal cavity, pharynx, trachea, bronchi, lungs and diaphragm. Human beings can involuntarily control the process of breathing but overall the

The bile is a liquid secreted by the liver. It plays an important role in the digestion of food. The bile is composed of bile pigments, bile salts, cholesterol and phospholipids. The bile helps break down fats and in the activation of enzymes required for the digestion of fat. The human body secretes approximately 1

The liver vessels help in the transport of substances to and from the liver. Four vessels of the liver are as follows: (1) the hepatic artery that arises from the aorta and supplies oxygenated blood to the liver; (2) the portal vein supplies oxygenated blood to the liver; (3) the hepatic vein returns the blood

Liver The liver is the largest gland in the body, divided into two main lobes, the right and the left. It secretes bile into the small intestine. It is the largest chemical factory that carries out most of the intermediate metabolic functions. For example: (1) it breaks down and builds up new biological molecules, stores