Control of ventilation (control of respiration) refers to the physiological mechanisms involved in the control of physiologic ventilation. Gas exchange primarily controls the rate of respiration. This article or section does not cite any references or sources. ... In respiratory physiology, ventilation is the rate at which gas enters or leaves the lung. ...

The most important function of breathing is gas exchange (of oxygen and carbon dioxide). Thus the control of respiration is centered primarily on how well this is achieved by the lungs. Breathing transports oxygen into the body and carbon dioxide out of the body. ... This article is about the chemical element and its most stable form, or dioxygen. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ...

Control Unit

The control unit of ventilation consists of a processor (the breathing centre in the brain) which integrates inputs (emotional, chemical and physical stimuli) and controls an effector (the lungs) via motor nerves arising from the spinal cord. In humans, quiet breathing occurs by the cyclical contraction of the inspiratory muscles, particularly the diaphragm. Inhalation is normally an active process, and exhalation is passive. However, when ventilation is increased (over 40 litres per minute), such as during heavy exercise, muscle activity becomes involved in exhalation. Under these circumstances, the work of breathing over time can exceed the metabolic rate of the rest of the body. For other uses, see Brain (disambiguation). ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ... Motor nerves enable the brain to stimulate muscle contraction. ... The Spinal cord nested in the vertebral column. ... In the anatomy of mammals, the diaphragm is a shelf of muscle extending across the bottom of the ribcage. ... Exhalation (or expiration) is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing. ... The term Exercise can refer to: Physical exercise such as running or strength training Exercise (options), the financial term for enacting and terminating a contract Category: ...

Ventilatory Pattern

Ventilation is normally autonomic, with only limited voluntary override, but an exception to this is Ondine's curse, where autonomic control is lost. Ondines Curse, also called congenital central hypoventilation syndrome (CCHS) or primary alveolar hypoventilation, is a respiratory disorder that is fatal if untreated. ...

The pattern neuronal firing when breathing can be divided into inspiratory and expiratory phases. Inspiration shows a sudden ramp increase in motor discharge to the inspiratory muscles (including pharyngeal dilator muscles). Before the end of inspiration, there is a decline in motor discharge. Exhalation is usually silent, except at high minute ventilation rates. Respiratory minute volume (or minute ventilation, or flow of gas) is the volume of air which can be inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a persons lungs in one minute. ...

The mechanism of generation of the ventilatory pattern is not completely understood, but involves the integration of neural signals by respiratory control centres in the medulla and pons. The nuclei known to be involved are divided into regions known as the following: Medulla in general means the inner part, and derives from the Latin word for marrow. In medicine it is contrasted to the cortex. ... For other uses, see Pons (disambiguation). ...

• medulla (reticular formation)
  • ventral respiratory group (nucleus retroambigualis, nucleus ambiguus, nucleus parambigualis and the pre-Botzinger complex). The ventral respiratory group controls voluntary forced exhalation and acts to increase the force of inspiration.
  • dorsal respiratory group (nucleus tractus solitarius). The dorsal respiratory group controls mostly inspiratory movements and their timing.
• pons
  • pneumotaxic centre. The pneumotaxic centre is involved in fine tuning of respiration rate.
  • apneustic centre

There is further integration in the anterior horn cells of the spinal cord. The reticular formation is a part of the brain which is involved in stereotypical actions, such as walking, sleeping, and lying down. ... The ventral respiratory group is a group of neurons in the medulla which initiates inhalation. ... The nucleus ambiguus (literally ambiguous nucleus) is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. ... The dorsal repiratory group is found in many types of fish and marine mammals. ... The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI). ... The anterior horn is the anterior division of the lateral ventricle of the brain. ... The Spinal cord nested in the vertebral column. ...

Determinants of Ventilatory Rate

Ventilatory rate (minute volume) is tightly controlled and determined primarily by blood levels of carbon dioxide as determined by metabolic rate. Blood levels of oxygen become important in hypoxia. These levels are sensed by chemoreceptors in the medulla oblongata for pH, and the carotid and aortic bodies for oxygen and carbon dioxide. Afferent neurons from the carotid bodies and aortic bodies are via the glossopharyngeal nerve (CN IX) and the vagus nerve (CN X), respectively. Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Santorio Santorio (1561-1636) in his steelyard balance, from Ars de statica medecina, first published 1614 Metabolism (from μεταβολισμος(metavallo), the Greek word for change), in the most general sense, is the ingestion and breakdown of complex compounds, coupled with the liberation of energy, and the consequent generation of waste... This article is about the chemical element and its most stable form, or dioxygen. ... Hypoxia is a pathological condition in which the body as a whole (generalised hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. ... A Chemosensor, also known as chemoreceptor, is a cell or group of cells that transduce a chemical signal into an action potential. ... The medulla oblongata is the lower portion of the brainstem. ... The carotid body is a small cluster of chemoreceptors and supporting cells located near the bifurcation of the carotid artery. ... The aortic body is one of several small cluster of chemoreceptors, baroreceptors, and supporting cells located along the aortic arch. ... The glossopharyngeal nerve is the ninth of twelve cranial nerves. ... The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the abdomen. ...

Levels of CO₂ rise in the blood when the metabolic use of O₂ is increased beyond the capacity of the lungs to expel CO₂. CO₂ is stored largly in the blood as bicarbonate (HCO₃^-) ions, by conversion first to carbonic acid (H₂CO₃), by the enzyme carbonic anhydrase, and then by disassociation of this acid to H⁺ and HCO₃^-. Build-up of CO₂ therefore causes an equivalent build-up of the disassociated hydrogen ion, which, by definition, decreases the pH of the blood.

During moderate exercise, ventilation increases in proportion to metabolic production of carbon dioxide. During strenuous exercise, ventilation increases more than needed to compensate for carbon dioxide production. Lactic acid produced during anaerobic metabolism lowers pH and thus increases breathing. In aerobic metabolism, one molecule of acid (CO₂) is produced in order to produce 6 molecules of the energy carrier ATP, whereas in anaerobic metabolism, 6 molecules of lactic acid are produced to provide the same amount of energy. The term Exercise can refer to: Physical exercise such as running or strength training Exercise (options), the financial term for enacting and terminating a contract Category: ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... For the production of milk by mammals, see Lactation. ... Glycolysis is the initial metabolic pathway of carbohydrate catabolism. ... For other uses, see PH (disambiguation). ... This article or section should include material from aerobic respiration. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ...

Mechanical stimulation of the lungs can trigger certain reflexes as discovered in animal studies. In humans, these seem to be more important in neonates and ventilated patients, but of little relevance in health. The tone of respiratory muscle is believed to be modulated by muscle spindles via a reflex arc involving the spinal cord. A muscle spindle is a specialized muscle structure innervated by both sensory and motor neuron axons. ...

Drugs can greatly influence the control of respiration. Opioids and anaesthetic drugs tend to depress ventilation, especially with regards to Carbon Dioxide response. Stimulants such as Amphetamines can cause hyperventilation. An opioid is any agent that binds to opioid receptors found principally in the central nervous system and gastrointestinal tract. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Amphetamine is a synthetic drug originally developed (and still used) as an appetite suppressant. ... In medicine, hyperventilation (or hyperpnea) is the state of breathing faster or deeper (hyper) than necessary, and thereby reducing the carbon dioxide concentration of the blood below normal. ...

Pregnancy tends to increase ventilation (lowering plasma carbon dioxide tension below normal values). This is due to increased progesterone levels and results in enhanced gas exchange in the placenta. Ventilation is temporarily modified by voluntary acts and complex reflexes such as sneezing, coughing and vomiting. This article is about human pregnancy in biological females. ... Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ... The placenta (Latin for cake, referencing its appearance in humans) is an ephemeral organ present in placental vertebrates, such as eutherial mammals and sharks during gestation (pregnancy). ...

Feedback control

Receptors play important roles in the regulation of respiration; central and peripheral chemoreceptors, and mechanoreceptors. In a sensory system, a sensory receptor is a structure that recognizes a stimulus in the internal or external environment of an organism. ... A Chemosensor, also known as chemoreceptor, is a cell or group of cells that transduce a chemical signal into an action potential. ... A mechanoreceptor is a sensory receptor that responds to mechanical pressure or distortion. ...

• Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface, are sensitive to the pH of their environment.

• Peripheral chemoreceptors act most importantly to detect variation of the oxygen in the arterial blood, in addition to detecting arterial carbon dioxide and pH.

• Mechanoreceptors are located in the airways and parenchyma, and are responsible for a variety of reflex responses. These include:
  • The Hering-Breuer reflex that terminates inspiration to prevent over inflation of the lungs, and the reflex responses of coughing, airway constriction, and hyperventilation.
  • The upper airway receptors are responsible for reflex responses such as, sneezing, bradycardia, coughing, closure of glottis, and hiccups.
  • The spinal cord reflex responses include the activation of additional respiratory muscles as compensation, gasping response, hypoventilation, and an increase in breathing frequency and volume.

In addition to involuntary control of respiration by the respiratory center, respiration can be affected by conditions such as emotional state, via input from the limbic system, or temperature, via the hypothalamus. Voluntary control of respiration is provided via the cerebral cortex, although chemoreceptor reflex is capable of overriding conscious control. Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface, are sensitive to the pH of their environment. ... For other uses, see PH (disambiguation). ... Peripheral chemoreceptors act most importantly to detect variation of the oxygen in the arterial blood, in addition to detecting arterial carbon dioxide and pH. These nodes, called the aortic body and carotid body, are located on the arch of the aorta and on the common carotid artery, respectively. ... This article is about the chemical element and its most stable form, or dioxygen. ... Look up mechanoreceptor in Wiktionary, the free dictionary. ... The airways are those parts of the respiratory system through which air flows, to get from the external environment to the alveoli. ... Parenchyma is a term used to describe a bulk of a substance. ... The Hering-Breuer reflex is a reflex triggered to prevent overinflation of the lungs. ... Cough is also the name of a band, see Cough (band) A cough is a sudden, often repetitive, spasmodic contraction of the thoracic cavity, resulting in violent release of air from the lungs, and usually accompanied by a distinctive sound. ... In medicine, hyperventilation (or hyperpnea) is the state of breathing faster or deeper (hyper) than necessary, and thereby reducing the carbon dioxide concentration of the blood below normal. ... A sneeze is the semi-autonomous, convulsive expulsion of air from the nose. ... Bradycardia, as applied to adult medicine, is defined as a resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. ... The space between the vocal cords is called the glottis. ... A hiccup is an involuntary spasm of the diaphragm. ... The Spinal cord nested in the vertebral column. ... The limbic system is a historically defined set of brain structures that support a variety of functions including emotion and memory. ... For other uses, see Temperature (disambiguation). ... The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). ... For other uses, see Cortex. ...

External links

• Paul, Anthony D., et al., Neuronal Connections of a Ventral Brainstem Respiratory Chemosensitive Area: “Ventral Brainstem Mechanisms and Control of Respiration and Blood Pressure” [1]
• Rabbany, Sina Y., “Breathing Coordination”, Hofstra University [2]
• Webber, Charles L., Jr., Ph.D, Pulmonary Curriculum Function:“Neural Control of Breathing”, Stritch School of Medicine, Loyola University-Chicago [3]