Trachea The trachea, colloquially called windpipe, is a tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in all air-breathing animals with lungs. Only in the lungfish, where the lung is connected to the pharynx and the trachea, is it absent. ??? Bronchus A bronchus (plural bronchi, adjective bronchial), also known as a main or primary bronchus, is a passage of airway in the respiratory tract that conducts air into the lungs. The bronchus branches into smaller tubes, which in turn become bronchioles.[1] No gas exchange takes place in the bronchi. ??? Pulmonary alveolus An alveolus (plural: alveoli, from Latin alveolus, little cavity) is an anatomical structure that has the form of a hollow cavity.[1] Found in the lung parenchyma, the pulmonary alveoli are the terminal ends of the respiratory tree, which outcrop from either alveolar sacs or alveolar ducts, which are both sites of gas exchange with the blood as well.[2] Alveoli are particular to mammalian lungs. Different structures are involved in gas exchange in other vertebrates.[3] The alveolar membrane is the gas-exchange surface. Carbon dioxide rich blood is pumped from the rest of the body into the alveolar blood vessels where, through diffusion, it releases its carbon dioxide and absorbs oxygen.[4] ??? Thoracic diaphragm In human anatomy, the thoracic diaphragm, or simply the diaphragm (Ancient Greek: διάφραγμα diáphragma “partition”), is a sheet of internal skeletal muscle[2] that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs. The term diaphragm in anatomy can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but the diaphragm generally refers to the thoracic diaphragm. Other mammals have diaphragms, and other vertebrates such as amphibians and reptiles have diaphragm-like structures, but important details of the anatomy vary, such as the position of lungs in the abdominal cavity. ??? Nostril From Wikipedia, the free encyclopedia Nares redirects here. For information about the nostrils of a bird, see Beak#Nares. For other uses, see Nares (disambiguation). Raccoon nostrils A nostril (or naris /ˈnɛərɨs/, plural nares /ˈnɛəriːz/) is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation. Fish do not breathe through their noses, but they do have two small holes used for smelling which may, indeed, be called nostrils. ??? Lung From Wikipedia, the free encyclopedia Page semi-protected For other uses, see Lung (disambiguation). This article is about lungs in general. For human lungs, see Human lung. Lunged redirects here. For other uses, see Lunge. Sketch of the human lungs. The human lungs flank the heart and great vessels in the chest cavity[1] Air enters and leaves the lungs via a conduit of cartilaginous passageways—the bronchi and bronchioles. In this image, lung tissue has been dissected away to reveal the bronchioles[1] The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart. Their principal function is to transport oxygen from the atmosphere into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere. A large surface area is needed for this exchange of gases which is accomplished by the mosaic of specialized cells that form millions of tiny, exceptionally thin-walled air sacs called alveoli. To understand the anatomy of the lungs, the passage of air through the nose and mouth to the alveoli must be studied. The progression of air through either the mouth or the nose, travels through the nasopharynx, oropharynx, larynx, and the trachea (windpipe). The air passes down the trachea, which divides into two main bronchi; these branch to the left and right lungs where they progressively subdivide into a system of bronchi and bronchioles until the alveoli are reached. These many alveoli are where the gas exchange of carbon dioxide and oxygen takes place.[2] Breathing is driven by muscular action; in early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, which is still found in amphibians. Reptiles, birds and mammals use their musculoskeletal system to support and foster breathing. Medical terms related to the lung often begin with pulmo-, such as in the (adjectival form: pulmonary) or from the Latin pulmonarius (of the lungs), or with pneumo- (from Greek πνεύμων lung).
Posted on: Thu, 10 Jul 2014 07:04:55 +0000
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