Control of Breathing PDF
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This document describes the control of breathing, focusing on the role of the medulla oblongata and sensory neurons, particularly chemoreceptors and baroreceptors. It explains how these mechanisms respond to changes in blood pH and oxygen levels to regulate breathing rate.
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Control of Breathing → the following is involved 1. Medulla Oblongata (hindbrain) 2. Sensory neurons a. Special types of neurons that terminates in a synapse that is triggered by certain environmental changes Diagram Synapse → this region is triggered by certain env...
Control of Breathing → the following is involved 1. Medulla Oblongata (hindbrain) 2. Sensory neurons a. Special types of neurons that terminates in a synapse that is triggered by certain environmental changes Diagram Synapse → this region is triggered by certain environmental stimuli → it sends an action potential (signal)--> spinal column → medulla 2 types of sensory neurons A. Chemoreceptors a. They initiate a signal or action potential when the blood pH drops below 7 (acidosis) Normal situation Blood pH → stable at 7-7.1 → the metabolic output of CO2 does not allow it to build up Carbonic-buffer system in CO2 transport → cells our co2 carbonic → co2 + h20 ------------> h2co3 (aq) Plasma Anhydrate The normal amount of h2co3 is counteracted by the break down rate in the alveoli H2co3 ------------------> hco3 → co2 (at the cellular level) |--> h20 }alveoli As long at the rate of formation is approx same as the rate of breakdown → blood pH is stable If the rate of formation exceed that of breakdown the h2co3 levels increase and the chemoreceptors initiates its action potential (its trigger) ← drop in blood pH B. Baroreceptors a. Specialized sensory neurons that initiates an action potential upon 2 triggers 1. Drop in the arterial blood oxygen levels, it does so by the hemoglobin (Hb) saturation point Set point → arterial blood HB saturation of o2 is typically 80-90% Trigger conditions → trigger point is when the Hb saturation drops to 50-60% 2. Blood pressure → the force of arterial blood on the walls of the arteries → the more blood pressure, the more the arteries expand → either over or under expansion (drop in blood pressure) will be the trigger event - Low BP = hypotension 3. diaphragm → } 3 and 4 allows for rapid changes in the chest vol. → 4. Rib cage muscles → increase in the breathing rate (BR) and allows the body to tap into the IRV and ERV to maximize the gas exchange 5. The neural connection from the medulla to the sinoatrial nude (SA nude) of the heart → the circulatory system keeps pace with the metabolic changes in the respiratory system
