respiratory-4

pons rhythm controllers

pons: -apneustic center: has an excitatory function -pneumotaxic center: can inhibit inspiration

medulla rhythm controllers

-dorsal respiratory group: associated with inspiration -ventral respiratory group: associated with expiration -pre-botzinger complex: pattern generator (also ventral)

central controller

-respiratory centers of the brain are responsible for generating the rhythmic pattern of inspiration and expiration -the respiratory centers are located in the brainstem (medulla and pons) -input comes from central and peripheral receptors (as well as the cerebral cortex) -major output is via the phrenic and intercostal nerves

response to reduced pH

-sensed by the peripheral chemoreceptors -important in metabolic acidosis -if the reduction is severe, central chemoreceptors may be stimulated

other regions of brain that can affect respiration

1. cortex: can exercise voluntary control 2. limbic system and hypothalamus: emotional states (panic attacks, etc)

secondary muscles of inspiration

Larynx and Pharynx, Tongue, Sternocleidomastoid and trapezium Muscles, Nares. Innervated by Vagus and Glossopharyngeal nerves, Hypoglossal Nerve, Accessory Nerve, and Facial Nerve

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion. -ventral and dorsal aspect control of ventilation

peripheral chemoreceptors are located

carotid and aortic bodies

controller vs effectors vs sensors

controller: cerebrum, brain stem, spinal cord effectors: lungs, muscles sensors: chemoreceptors (peripheral arterial, cns medullary)

primary muscles of inspiratio

diaphragm and external intercostal muscles

Central chemoreceptors located in the medulla provide feedback to increase the rate and depth of breathing when they sense:

elevations in co2 or a decrease in pH of CSF

secondary muscles of expiration

intercostals; abdominal muscles

response to PaO2 by peripheral chemoreceptors

is influenced by PaCO2 and pH

central chemoreceptors

most important receptors involved in the minute-byminute control of ventilation several central chemoreceptor sites have been identified

respiratory control system

receptors: gather information and feed it to the central controller in the brainstem which coordiantes the information and, in turn, sends its impulses to the effecors (respiratory muscles) which cause ventilation

peripheral chemoreceptors

respond rapidly to changes in arterial PO2 and pH, and increases in arterial PCO2

central chemoreceptors respond to changes in

the [H+] of the cerebral spinal fluid (CSF) or more accurately the brain interstitial fluid caused by changes in arterial PCO2

respiratory control center is in

the medulla -respiratory related neurons within the medulla have different firing patterns

PaCO2 is

the most important stimulus to ventilation: very tightly controlled -most of the stimulus comes from central chemoreceptors (p chemoreceptors also contribute a bit and their response is faster)

integrated responses

the nts integrates response to co2 and o2

the sensors

the primary sensors of the respiratory control system are neural receptors that are sensitive to changes in arterial pco2, po2, and pH (chemoreceptors_ and lung distension (stretch receptors) -central chemoreceptors -peripheral chemoreceptors -slowly adapting pulmonary receptors