Regulation of respiration

\( \newcommand\) • • • • • Chemoreceptors detect the levels of carbon dioxide in the blood by monitoring the concentrations of hydrogen ions in the blood. Key Points • An increase in carbon dioxide concentration leads to a decrease in the pH of blood due to the production of H + ions from carbonic acid. • In response to a decrease in blood pH, the respiratory center (in the medulla ) sends nervous impulses to the external intercostal muscles and the diaphragm, to increase the breathing rate and the volume of the lungs during inhalation. • Hyperventilation causes alakalosis, which causes a feedback response of decreased ventilation (to increase carbon dioxide), while hypoventilation causes acidosis, which causes a feedback response of increased ventilation (to remove carbon dioxide). • Any situation with hypoxia (too low oxygen levels) will cause a feedback response that increases ventilation to increase oxygen intake. • Vomiting causes alkalosis and diarrhea causes acidosis, which will cause an appropriate respiratory feedback response. Key Terms • hypoxia: A system-wide deficiency in the levels of oxygen that reach the tissues. • central chemoreceptors: Located within the medulla, they are sensitive to the pH of their environment. • peripheral chemoreceptors: The aoritic and carotid bodies, which act principally to detect variation of the oxygen concentration in the arterial blood, also monitor arterial carbon dioxide and pH. Chemoreceptor regulation of breathing is a for...

\( \newcommand\) • • • • • • The medulla and the pons are involved in the regulation of the ventilatory pattern of respiration. Learning Objectives • Describe the neural mechanism of the respiratory center in respiration control Involuntary respiration is any form of respiratory control that is not under direct, conscious control. Breathing is required to sustain life, so involuntary respiration allows it to happen when voluntary respiration is not possible, such as during sleep. Involuntary respiration also has metabolic functions that work even when a person is conscious. The Respiratory Centers Involuntary respiration is controlled by the respiratory centers of the upper brainstem (sometimes termed the lower brain, along with the cerebellum). This region of the brain controls many involuntary and metabolic functions besides the respiratory system, including certain aspects of cardiovascular function and involuntary muscle movements (in the cerebellum). Anatomy of the brainstem: The brainstem, which includes the pons and medulla. The respiratory centers contain chemoreceptors that detect pH levels in the blood and send signals to the respiratory centers of the brain to adjust the ventilation rate to change acidity by increasing or decreasing the removal of carbon dioxide (since carbon dioxide is linked to higher levels of hydrogen ions in blood). There are also peripheral chemoreceptors in other blood vessels that perform this function as well, which include the aortic a...

AMA Citation Regulation of Respiration. In: Barrett KE, Barman SM, Boitano S, Brooks HL. Barrett K.E., & Barman S.M., & Boitano S, & Brooks H.L.(Eds.), Eds. Kim E. Barrett, et al.eds. Ganong’s Review of Medical Physiology, 25e. McGraw Hill; 2018. Accessed June 15, 2023. https://accessmedicine.mhmedical.com/content.aspx?bookid=1587§ionid=97166494 APA Citation Regulation of respiration. Barrett KE, Barman SM, Boitano S, Brooks HL. Barrett K.E., & Barman S.M., & Boitano S, & Brooks H.L.(Eds.), Eds. Kim E. Barrett, et al. (2018). Ganong’s Review of Medical Physiology, 25e. McGraw Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=1587§ionid=97166494 MLA Citation "Regulation of Respiration." Ganong’s Review of Medical Physiology, 25e Barrett KE, Barman SM, Boitano S, Brooks HL. Barrett K.E., & Barman S.M., & Boitano S, & Brooks H.L.(Eds.), Eds. Kim E. Barrett, et al. McGraw Hill, 2018, https://accessmedicine.mhmedical.com/content.aspx?bookid=1587§ionid=97166494. • Locate the pre-Bötzinger complex and describe its role in producing spontaneous respiration. • Identify the location and probable functions of the dorsal and ventral groups of respiratory neurons, the pneumotaxic center, and the apneustic center in the brainstem. • List the specific respiratory functions of the vagus nerves and the respiratory receptors in the carotid body, the aortic body, and the ventral surface of the medulla oblongata. • Describe and explain the ventilatory responses to inc...

\( \newcommand\) • • • • • The Hering–Breuer inflation reflex prevents overinflation of the lungs. Key Points • Pulmonary stretch receptors present in the smooth muscle of the airways and the pleura respond to excessive stretching of the lung during large inspirations. • The Hering–Breuer inflation reflex is initiated by stimulation of stretch receptors. The deflation reflex is initiated by stimulation of the compression receptors (called proprioceptors) or deactivation of stretch receptors when the lungs deflate. • Activation of the pulmonary stretch receptors (via the vagus nerve ) results in inhibition of the inspiratory stimlus in the medulla, and thus inhibition of inspiration and initiation of expiration. • An increase in pulmonary stretch receptor activity leads to an elevation of heart rate ( tachycardia ). • A cyclical, elevated heart rate from inspiration is called sinus arrhythmia and is a normal response in youth. Inhibition of inspiration is important to allow expiration to occur. Key Terms • sinus arryhthmia: A normal cyclical heart rate change in which an increase in heart rate occurs during inspiration, but returns to normal during expiration. • pulmonary stretch receptors: A sensory receptor that sends an action potential when it detects pressure, tension, stretch, or distortion. The lungs are a highly elastic organ capable of expanding to a much larger volume during inflation. While the volume of the lungs is proportional to the pressure of the pleural ca...

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Respiratory Center Consists of: • Brain stem (Pons & Medulla) ; Main Centre • Cortex — Voluntary control centre. – Voluntary Hyper ventilation. – Breath holding • Other parts of Brain – Hypothalamus – Limbic system (Rage & Fear) • Pre- Botzinger complex located on either side of medulla • DRGN & VRGN in medulla project to the pre- Botzinger pacemaker neurons. • Pre-Botzinger neurons discharge rhythmically and produce rhythmical discharges in Phrenic nerves (respiration). Respiratory Center in Brain Stem: Commonly called “ Respiratory Center ”. Composed of: • Medullary respiratory center – Dorsal respiratory group (DRG) of neurons – Ventral respiratory group (VRG) of neurons 2.Apneustic center 3.Pneumotaxic center Dorsal Respiratory Center : Site: Dorsal region of Medulla Nucleus Tractus solitarius Role: Inspiration Mechanism: – Intrinsic periodic firing – Insp. ramp signals (Inhibited by Pneumotaxic Center ) Ventral Resp. Group: Site: 5 mm Ant & Lat. to Dorsal respiratory group of neurons. in Nucleus ambiguus & Retro ambiguus Role: – Quiescent during quiet breathing – Expiration during exercise Apneustic Center : in lower pons – Excitation of inspiratory area. – Prolong Insp. ramp. Pneumotaxic Center : Inhibits Inspiration by “Switching off” Insp. ramp. Chemical Control of Respiration Objective: To maintain proper concentration of O2, CO2 & H+ in the tissues. Chemoreceptors: • • Central chemoreceptors (chemo sensitive area) – Direct chemical control of Resp. center activit...