Acute<unk>  Acute<unk>  (AR) The first stage of the<unk>  consists of the initial reaction to a<unk>  environment leading up to the peak known as short-term potentiation (STP). The process is induced by a decrease in oxygen partial pressure in blood. Type I glomus cells of carotid bodies detect the change in oxygen levels and release neurotransmitters towards the carotid sinus nerve, which in turn stimulates the brain, ultimately resulting in increased ventilation. The period of increased ventilation varies among different individuals but typically lasts under ten minutes. Short-term potentiation (STP) STP is the increase in ventilation after the acute<unk><unk>  and the eventual return of ventilation to its equilibrium after carotid sinus nerve stimulation, which causes a slowing in heart rate. This mechanism usually lasts between one and two minutes. STP is most apparent in tidal volume or the amplitude of phrenic neural output. Short-term depression (STD) STD is a temporary jump in respiratory frequency at the beginning of carotid chemo afferent stimulation or a temporary drop in respiratory frequency at the end of chemo afferent stimulation. This mechanism lasts from a span of several seconds to a few minutes. STP has only been found in the respiratory frequency of phrenic nerve stimulation, which produces contraction of the diaphragm.<unk><unk>  to sustained<unk>  A continued presence in a<unk>  environment of more than 24 hours leads to a steady flow of ventilation. This contingency in the environment causes hypocapnia which decreases ventilation. Chronic<unk>  Chronic<unk>  results in further physiological changes due to the transcription factor<unk> -inducible factor (HIF). HIF is a dimer composed of the HIF-1α and HIF-1β subunit. HIF-1α is normally unable to bind with HIF-1β. However, lower oxygen partial pressure induces post-transcriptional modification of HIF-1α, allowing HIF-1α to dimerize with HIF-1β to form HIF-1. HIF-1 induces many physiological changes that help the body adapt to the lower availability of oxygen including angiogenesis, increased erythropoietin production, and promoting anaerobic metabolism. Neurology The nervous system plays a key role in the<unk> . The process is triggered by the peripheral nervous system's detection of a low blood oxygen level. In particular, the neurotransmitter glutamate has been shown to have a direct correlation to a rise in ventilation. A study conducted in dogs investigated how their cardiovascular systems respond to various levels of oxygen before and after being given MK-801, which is a glutamate antagonist. With the MK-801, there was a noticeable decrease in both heart rate and breaths per minute under<unk> . According to the study, the fact that the<unk>  was lessened when glutamate was inhibited demonstrates that glutamate is essential to the<unk> .
Hypoxic ventilatory response
Expiratory apnea
Positional asphyxia
Central neurogenic hyperventilation
Hypoventilation
Permissive hypercapnia
Permissive hypotension
Parasympathetic rebound