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A complete, schematic view of the human respiratory system.
A complete, schematic view of the human respiratory system.

In humans and other mammals, the respiratory system consists of the airways, the lungs, and the respiratory muscles that mediate the movement of air into and out of the body. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Within the alveolar system of the lungs, molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous environment and the blood. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products Thus, the respiratory system facilitates oxygenation of the blood with a concomitant removal of carbon dioxide and other gaseous metabolic wastes from the circulation. Oxygenation refers to the amount of Oxygen in a medium In Blood it may be taken to be synonymous with Saturation, which describes the degree to which Metabolic wastes or excretes are Substances left over from respiratory processes which cannot be used by the Organism (they are surplus or have This is an article about the rock music band "Circulatory System" [1] The system also helps to maintain the acid-base balance of the body through the efficient removal of carbon dioxide from the blood. In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and

Contents

Anatomy

In humans and other animals, the respiratory system can be conveniently subdivided into an upper respiratory tract and lower respiratory tract, trachea and lungs, or into the conducting zone (for gas transport, anywhere from atmosphere to alveoli) and the respiratory zone (the alveolated region where gas exchange occurs). The Upper respiratory tract refers to the following parts of the Respiratory system: Nose and Oral cavity Throat The Lower respiratory tract refers to the portions of the Respiratory system from the Trachea to the Lungs Lower respiratory tract infection lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive The respiratory zone also contains the transitional zone.

Air moves through the body in the following order

Upper respiratory tract/conducting zone

The conducting zone begins with the nares (nostrils) of the nose, which open into the nasopharynx (nasal cavity). In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species The nasal cavity (or nasal fossa) is a large air-filled space above and behind the nose in the middle of the face The pharynx (plural pharynges) is the part of the Neck and Throat situated immediately Posterior to (behind the Mouth and Nasal The larynx (plural larynges) colloquially known as the voicebox, is an organ in the Neck of Mammals involved in protection of the The traceartes, or windpipe, is a tube that has an inner diameter of about 20-25 mm and a length of about 10-16 cm in humans The thorax is a division of an Animal 's body that lies between the head and the Abdomen. A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the Respiratory tract that conducts air into the Lungs No Gas An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity Anatomically a nose is a protuberance in Vertebrates that houses the Nostrils or nares which admit and expel air for respiration in conjunction with the The nasopharynx ( nasal part of the pharynx) is the part of the Pharynx that lies behind the Nose and above the level of the Soft palate; it differs The primary functions of the nasal passages are to: 1) filter, 2) warm, 3) moisten, and 4) provide resonance in speech. Speech refers to the processes associated with the production and perception of Sounds used in Spoken language. The nasopharynx opens into the oropharynx (behind the oral cavity). The Oropharynx ( oral part of the Pharynx) reaches from the Soft palate to the level of the Hyoid bone. The oropharynx leads to the laryngopharynx, and empties into the larynx (voicebox), which contains the vocal cords, passing through the glottis, connecting to the trachea (wind pipe). In human anatomy the hypopharynx (or laryngopharynx) is the bottom part of the Pharynx, and is the part of the Throat that connects to the Esophagus The larynx (plural larynges) colloquially known as the voicebox, is an organ in the Neck of Mammals involved in protection of the The vocal folds, also known commonly as vocal cords, are composed of twin infoldings of Mucous membrane stretched horizontally across the Larynx. The glottis is defined as the combination of the Vocal folds and the space in between the folds (the Rima glottidis) The traceartes, or windpipe, is a tube that has an inner diameter of about 20-25 mm and a length of about 10-16 cm in humans

Ventilation

Ventilation of the lungs is carried out by the muscles of respiration. In Respiratory physiology, ventilation (or ventilation rate) is the rate at which gas enters or leaves the Lung.

Control

Ventilation occurs under the control of the autonomic nervous system from parts of the brain stem, the medulla oblongata and the pons. The nervous system is a Network of specialized cells that communicate information about an animal's surroundings and itself The brain stem (or brainstem) is the lower part of the Brain, adjoining and structurally continuous with the Spinal cord. The medulla oblongata is the lower portion of the Brainstem. It deals with autonomic functions such as breathing and blood pressure The pons (sometimes pons Varolii after Costanzo Varolio) is a structure located on the Brain stem. This area of the brain forms the respiration regulatory center, a series of interconnected brain cells within the lower and middle brain stem which coordinate respiratory movements. Brain Cell is a Mail art project begun by Ryosuke Cohen in June 1985 The sections are the pneumotaxic center, the apneustic center, and the dorsal and ventral respiratory groups. The pneumotaxic center, also known as the pontine respiratory group ( PRG) is a network of neurons in the Rostral Dorsal Lateral This section is especially sensitive during infancy, and the neurons can be destroyed if the infant is dropped and/or shaken violently. The result can be death due to "shaken baby syndrome. Shaken baby syndrome ( SBS) is a form of Child abuse that occurs when an abuser violently shakes an infant or small child creating a whiplash -type "[2]

Inhalation is initiated by the diaphragm and supported by the external intercostal muscles. Inhalation (also known as respiration) is the movement of air from the external environment through the air ways and into the Alveoli. For other types of diaphragm see Diaphragm. In the Anatomy of Mammals the thoracic diaphragm is a sheet of Muscle The Intercostales externi ( External intercostals) are eleven in number on either side Normal resting respirations are 10 to 18 breaths per minute. Its time period is 2 seconds. During vigorous inhalation (at rates exceeding 35 breaths per minute), or in approaching respiratory failure, accessory muscles of respiration are recruited for support. These consist of sternocleidomastoid, platysma, and the strap muscles of the neck. In Human Anatomy, the sternocleidomastoid (pronounced /ˌstɚ Platysma is also a plant taxon synonym with Podochilus, an orchid genus This article refers to muscles of the feline (cat anatomy For "strap muscles" in humans please see "infrahyoid muscles

Inhalation is driven primarily by the diaphragm. When the diaphragm contracts, the ribcage expands and the contents of the abdomen are moved downward. In Vertebrate Anatomy, ribs ( Latin costae) are the long curved Bones which form the ribcage. This results in a larger thoracic volume, which in turn causes a decrease in intrathoracic pressure. The thorax is a division of an Animal 's body that lies between the head and the Abdomen. As the pressure in the chest falls, air moves into the conducting zone. Here, the air is filtered, warmed, and humidified as it flows to the lungs.

During forced inhalation, as when taking a deep breath, the external intercostal muscles and accessory muscles further expand the thoracic cavity. The Intercostales externi ( External intercostals) are eleven in number on either side The thoracic cavity (or chest cavity) is the chamber of the human body (and other animal bodies that is protected by the Thoracic wall ( Thoracic cage

Exhalation

Exhalation is generally a passive process; however, active or forced exhalation is achieved by the abdominal and the internal intercostal muscles. The human abdomen (from the Latin word meaning "belly" is the part of the body between the Pelvis and the thorax. The Intercostales interni ( Internal intercostals) are eleven in number on either side During this process air is forced or exhaled out.

The lungs have a natural elasticity; as they recoil from the stretch of inhalation, air flows back out until the pressures in the chest and the atmosphere reach equilibrium. [3]

During forced exhalation, as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles, generate abdominal and thoracic pressure, which forces air out of the lungs.

Circulation

The right side of the heart pumps blood from the right ventricle through the pulmonary semilunar valve into the pulmonary trunk. The right ventricle is one of four chambers (two atria and two ventricles in the Human Heart. The pulmonary valve, is the semilunar valve of the heart that lies between the Right ventricle and the Pulmonary artery and has three cusps The pulmonary arteries carry Blood from the Heart to the Lungs. The trunk branches into right and left pulmonary arteries to the pulmonary blood vessels. The pulmonary arteries carry Blood from the Heart to the Lungs. The pulmonary blood vessels are those Blood vessels which carry Blood to and from the Lungs The Pulmonary arteries, which carry blood from The vessels generally accompany the airways and also undergo numerous branchings. Once the gas exchange process is complete in the pulmonary capillaries, blood is returned to the left side of the heart through four pulmonary veins, two from each side. Capillaries are the smallest of a body's Blood vessels measuring 5-10 μm in diameter which connect Arterioles and Venules and enable the interchange The four pulmonary veins carry Oxygen -rich Blood from the Lungs to the left atrium of the Heart. The pulmonary circulation has a very low resistance, due to the short distance within the lungs, compared to the systemic circulation, and for this reason, all the pressures within the pulmonary blood vessels are normally low as compared to the pressure of the systemic circulation loop. Pulmonary circulation is the portion of the Cardiovascular system which carries Oxygen -depleted Blood away from the heart to the Lungs, and Systemic circulation is the portion of the Cardiovascular system which carries Oxygenated Blood away from the heart to the Body, and returns

Virtually all the body's blood travels through the lungs every minute. The lungs add and remove many chemical messengers from the blood as it flows through pulmonary capillary bed. The fine capillaries also trap blood clots that have formed in systemic veins. A thrombus, or blood clot, is the final product of the Blood coagulation step in Hemostasis.

Gas exchange

The major function of the respiratory system is gas exchange. Gas exchange or respiration takes place at a respiratory surface—a boundary between the external environment and the interior of the body As gas exchange occurs, the acid-base balance of the body is maintained as part of homeostasis. Homeostasis (from Greek: ὅμος hómos, "equal" and ιστημι istēmi, "to stand" lit If proper ventilation is not maintained, two opposing conditions could occur: 1) respiratory acidosis, a life threatening condition, and 2) respiratory alkalosis. Respiratory acidosis is Acidosis (abnormally increased acidity of the blood due to decreased ventilation of the pulmonary Alveoli, leading to Respiratory alkalosis results from increased alveolar respiration ( Hyperventilation) leading to decreased plasma Carbon dioxide concentration

Upon inhalation, gas exchange occurs at the alveoli, the tiny sacs which are the basic functional component of the lungs. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity The alveolar walls are extremely thin (approx. 0. 2 micrometres), and are permeable to gases. The alveoli are lined with pulmonary capillaries, the walls of which are also thin enough to permit gas exchange.

Development

The respiratory system lies dormant in the human fetus during pregnancy. A fetus (or foetus or fœtus) is a developing Mammal or other Viviparous Vertebrate, after the Embryonic stage and Pregnancy ( Latin graviditas) is the carrying of one or more offspring known as a Fetus or Embryo, inside the Uterus of a Female At birth, the respiratory system has under-developed lungs. This is due to the incomplete development of the alveoli type II cells in the lungs, necessary for the production of surfactant. Surfactants are wetting agents that lower the Surface tension of a liquid allowing easier spreading and lower the Interfacial tension between two liquids The infant lungs do not function due to collapse of alveoli caused by surface tension of water remaining in the lungs, which in normal cases would be prohibited by the presence of surfactant. This condition may be avoided by giving the mother a series of steroid shots in the final week prior to delivery, which will have weard the development of type II alveolar cells. A steroid is a Terpenoid Lipid characterized by a Carbon skeleton with four fused rings generally arranged in a 6-6-6-5 fashion [4]

Role in communication

The movement of gas through the larynx, pharynx and mouth allows humans to speak, or phonate. Phonation has slightly different meanings depending on the subfield of Phonetics. Because of this, gas movement is extremely vital for communication purposes.

Conditions of the respiratory system

Disorders of the respiratory system can be classified into four general areas:

The respiratory tract is constantly exposed to microbes due to the extensive surface area, which is why the respiratory system includes many mechani to defend itself and prevent pathogens from entering the body. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually A pathogen (from Greek πάθος pathos "suffering passion" and γἰγνομαι (γεν- gignomai (gen- "I give birth to" infectious

Disorders of the respiratory system are usually treated internally by a pulmonologist or respiratory physician. In Medicine, pulmonology (aka pneumology) is the specialty that deals with Diseases of the Lungs and the Respiratory tract.

Gas exchange in plants

Plants use carbon dioxide gas in the process of photosynthesis, and then exhale oxygen gas, a waste product of photosynthesis. Plants are living Organisms belonging to the kingdom Plantae. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the However, plants also sometimes respire as humans do, using oxygen and producing carbon dioxide. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the

Plant respiration is limited by the process of diffusion. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement Plants take in carbon dioxide through holes on the undersides of their leaves known as stomata (sing:stoma). In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. However, most plants require little air. Most plants have relatively few living cells outside of their surface because air (which is required for metabolic content) can penetrate only skin deep. However, most plants are not involved in highly aerobic activities, and thus have no need of these living cells. Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from

See also

References

Notes

  1. ^ Maton, Anthea; Jean, Hopkins Susan, Johnson Charles William, McLaughlin Maryanna Quon Warner David, LaHart Wright, Jill D. (1995). Human Biology and Health. Englewood Cliffs, New Jersey: Prentice Hall, 108-118. ISBN 0-12-981176-1.  
  2. ^ *Fact sheet on Shaken Baby Syndrome
  3. ^ A simple model of how the lungs are inflated can be built from a bell jar
  4. ^ Department of Environmental Biology, University of Adelaide, Adelaide, South Australia

External links

A bell jar is a piece of Laboratory glassware similar in shape to a bell.

Dictionary

respiratory system

-noun

  1. (anatomy) The system of organs serving for respiration.
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