Control Breathing Flashcards
The area from which nerve impulses are sent to the respiratory muscles to control respiratory rate. Located in both the Pons and Medulla Oblongata.
Respiratory Center:
Medullary Respiratory Center. Located in the Medulla Oblongata fx
controls the basic rhythm of respiration.
Dorsal Respiratory Group (DRG) (formally known as Inspiratory area):
-Generates nerve impulses establishing basic rhythm of quiet normal breathing.
-Innervate the diaphragm via the phrenic nerve and external
intercostal muscles via the intercostal nerves causing contraction.
-Nerve impulses last for approx. 2 seconds, after (pauses)which the inspiratory area becomes inactive for (approx. 3 seconds) causing the diaphragm and external intercostal muscles to relax.
Ventral Respiratory Group (VRG) (formally known as Expiratory Area):
-Neurons of this area supply nerve impulses for forceful breathing (inhalation and exhalation) and remain inactive during quiet breathing.
-Impulses constrict the internal intercostal muscles and abdominal muscles causing decrease in size of the thorax producing forceful expiration.
Pontine Respiratory Group (PRG) (formally known as the Preirrhotaxic Area):
Active during inhalation and exhalation. Transmit nerve impulses to the DRG in the medulla. Plays a role in both inhalation and exhalation by modifying the rhythm of breathing generated by the VRG as when exercising, speaking, or
sleeping.
Moderator
The cerebral cortex has connections with the inspiratory center. Allows us to hold our breath voluntarily. (Prevent harmful gases or water from being inhaled).
Results in a buildup of CO2 and hydrogen ions (H+). When blood concentrations become too elevated, the inspiratory area becomes stimulated and breathing resumes.
Impossible to kill one’s self by holding breath. Even if person faints breathing will resume.
Cortical Influences on Respiration
What system emotional stimuli is used to alter respirations, i.e. laughing or crying.
Hypothalamus and limbic system
CO2 easily diffuses into the cells via the plasma membrane. Combines with water to become
Carbonic acid (H2CO3).
Then is quickly breaks down into H+ and HCO3.
Located in the medulla, respond to changes in H+ and CO2 levels in the cerebrospinal fluid (CSF).
Central Chemoreceptors:
Located within the the arch of the aorta and common carotids are sensitive to levels of O2, H+, and CO2 in the blood.
Peripheral Chemoreceptors:
Chemoreceptors participate in a ____________ that regulates the
levels of CO2, O2 and H+ in the blood.
negative feedback system
Rate and depth of respiration increase. Hyperventilation (rapid breathing) allows for exhalation of CO2 until PCO2 and H+ levels are normalized.
Fact
Described as an increase in the arterial PCO2, even slightly above the normal 40mmhg. This causes the central chemoreceptors to respond vigorously due to the resulting increase H+ caused by the elevated CO2.
Hypercapnia:
Described as deficiency in O2, caused by the elevated CO2 mmHg) to about 50 mmHg, the peripheral chemoreceptors are strongly stimulated.
Hyopoxia:
Increase in rate and depth of
respiration due to input from proprioceptors as a result of joint and muscle movement. These stimulate the inspiratory area of the medulla.
Respiration increases even before changes in PCO2, PO2 or H+
occur.
Proprioceptor stimulation of respiration:
