Flashcards in Control of Respiration Deck (29)
What are the involuntary adjustments in rate and depth of breath controlled by?
They are controlled by neurons in the pons and receptor feedback from lungs and airways.
How can you differentiate between the dorsal respiratory group and the ventral respiratory group?
The dorsal respiratory group is at the back
The ventral respiratory group is at the front.
When is expiration passive?
While at rest.
Describe the centralchemoreceptors involved in the chemical control of respiration.
Detect changes in pH in the cerebrospinal fluid caused by changes In arterial PCO2 (CO2 freely diffusible across blood-brain barrier)
Why is it that changes in alveolar ventilation affect dissolved CO2 more than O2?
Because CO2 is more soluble.
What is the first step in the neural control of respiration?
Nerve impulses from medullary respiratory centres are sent via motor neurons to the diaphragm (phrenic nerve) and intercostal muscles (intercostal nerves)
What do Nerve impulses from medullary respiratory centres sent via motor neurons to the diaphragm (phrenic nerve) and intercostal muscles (intercostal nerves) do?
Stimulate contraction and thus inhalation.
Describe the Negative Feedback of the chemoreceptor response.
Start at homeostasis: Normal arterial PCO2
Homeostasis is disturbed (PCO2 Increases)
Stimulation of arterial chemorecptors and increased PCO2 and decreased pH in CSF
Stimulation of respiratory muscles and stimulation of CSF chemoreceptors at medulle oblongata
Increased respiration rate with increased elimination of CO2 at alveoli
CO2 is blown off at lungs and homeostasis is restored.
What is the involuntary establishment of basic breathing rhythm determined by?
The rhythm centre
What is neural control?
Involuntary establishment of basic breathing rhythm
Involuntary adjustment of rate and depth
What are the two types of chemoreceptors that detect PCO2, pH (i.e. H+) and PO2?
Describe the ventral respiratory group.
Inspiratory and expiratory centre
Functions only in forced breathing
What are the chemoreceptors that aid in the control of respiration?
Sensors that detect PCO2, pH (i.e. H+) and PO2
Under a basic breathing rhythm, how many inhalations per minute are there?
How do chemoreceptors affect respiration?
They exert secondary control over breathing.
What are the two groups of neurons in the medullary centre?
Dorsal Respiratory Group (DRG)
Ventral Respiratory Group (VRG)
How often does the average person expire?
Once every 3 seconds
What is the role of chemical control in respiratory control?
Regulate O2 consumption and CO2 production
Detection of arterial PO2 and H+
Describe the peripheral chemoreceptors involved in the chemical control of respiration.
In the aorta and carotid arteries
Strongly detect changes in plasma pH (caused by changes in CO2)
Weaker response directly to PCO2
Weak response to PO2 – ONLY when very low (<60 mmHg; <90% saturation)
What are the three levels of control of respiration?
Which is quicker; inspiration or expiration, and why?
Inspiration is always quicker because it's an active process.
What occurs to alveolar PO2 and PCO2 as alveolar ventilation increases?
As alveolar ventilation increases, alveolar PO2 increases and PCO2
decreases. The opposite occurs as alveolar ventilation decreases.
Which is more soluble, CO2 or O2?
How often does the average person inspire?
Once every 2 seconds
What part of the body is involved with voluntary control of respiration?
The cerebral cortex.
What can be said about PCO2 detection via chemical control?
PCO2 detection is indirect via pH (i.e. H+) in cerebrospinal fluid
What occurs to respiration when impulse ceases?
Expiration occurs (passive process)
Describe the dorsal respiratory group.
Functions in quiet and forced breathing