APHY 164 - Respiratory System Control of Breathing

ventilation-perfusion coupling

matching of alveolar ventilation with pulmonary blood perfusion, ability of bronchioles to regulate airflow and arterioles to regulate blood flow

medullary respiratory centers

located in the medulla oblongata, ventral respiratory group, and dorsal respiratory group

ventral respiratory group (VRG)

functions in forced breathing, stimulates the accessory muscles needed for forced inspiration and expiration

dorsal respiratory group (DRG)

where the primary respiratory pacemaker is found, stimulates the diaphragm and external intercostal muscles to contract resulting in inspiration, when activity in the DRG decreases the muscles relax resulting in expiration

pontine respiratory centers

located in the pons, include apneustic and pneumotaxic centers

apneustic center of pons

stimulates the DRG, controls the depth of breathing, prolongs inspiration, breathe slower and deeper

pneumotaxic center

inhibits inspiration (DRG), controls the respiratory rate, controls the DRG and VRG to create a smooth transition between inspiration and expiration

carbon dioxide levels

responsible for stimulating the respiratory centers to inhale and exhale

central chemoreceptors

receptors in the brain and medulla oblongata, monitor the pH of cerebrospinal fluid (CSF) to help regulate ventilation rate.

peripheral chemoreceptors

receptors in the carotid arteries and the aorta that monitor blood pH (pCO2 and O2) to help regulate ventilation rate

respiratory proprioceptors

monitor respiratory muscle stretch/position to alter depth of breathing

baroreceptor reflex

receptors located in aortic & carotid bodies, maintains normal BP, if BP increases reflex causes decrease in respiratory rate

Hering-Breuer reflex

also called the inflation reflex, protects the lungs from damage due to overinflation.

high altitude effects

a decrease in atmospheric pressure at high altitude leads to a decrease in the partial pressure of oxygen, hemoglobin saturation is lower at high altitudes resulting in lower blood oxygen levels

acute mountain sickness (AMS)

condition that occurs as result of acute exposure to high altitude due to a low partial pressure of oxygen - headache, dyspnea, nausea, vomiting, anorexia, insomnia

acclimatization to high altitude

decline in blood O2 stimulates the kidneys to produce more erythropoietin (EPO) -> increased RBC production -> more Hgb -> increased oxygen carrying capacity