Respiratory Control Flashcards
What does the pre-Botzinger complex control? Where is it located?
The timing (frequency) of the respiratory rhythm. It is a central pattern generator. In the medulla.
What is apneusis?
Failure to turn respiration off (stuck in inspiration)
What happens when the PRG is lesioned?
Apneusis. Lose the ability to turn inspiration off without additional info from the vagus nerve.
What are the four medullary respiratory centers?
- ) DRG
- ) VRG
- ) PRG
- ) Botzinger complex
What two things control the length of inspiration under normal circumstances?
- ) Pre-botzinger complex
2. ) PRG
What is the function of the DRG?
It receives a lot of sensory information which it then relays to the phrenic nerve. The sensory information allows it to generate a pattern appropriate to the circumstances.
It controls depth of breathing
What are the two portions of the VRG? Where are they located?
The dorsal and caudal portions. Each have different functions to control inspiration and expiration. Located in the medulla.
What is the function of the rostral portion of the VRG?
Premotor to phrenic and other inspiratory muscles
What is the function of the caudal portion of the VRG?
Premotor to the upper airway and muscles of expiration
What two things determine the depth of a breath?
- ) DRG
2. ) VRG
What is the function of the PRG? Where is it located?
Modifies inspiratory timing and shuts off inspiration. If it malfunctions it leads to apneusis. It is located in the pons.
What is the appearance of apneusis, what does it result from, and what are the effects?
Appearance: maintained inspiration
Results from: damage to the pons
Effects: Increased CO2, decreased O2, and death if not supported
What is the appearance of apnea, what does it result from, and what are the effects?
Appearance: failure of inspiration (no effort)
Results from: medulla or spinal cord damage
Effects: Increased CO2, decreased O2, and death if not supported.
What is a chemoreceptor?
A neuron that is sensitive to a specific chemical. In the respiratory system, these chemicals are CO2, O2, and hydrogen.
What changes in chemical concentrations will increase the firing rate of a chemoreceptor? (3 things)
- ) Increase CO2
- ) Decrease O2
- ) Increase H+
How do chemoreceptors work?
They notice either a decrease or increase in a chemical concentration in the blood and then activate the respiratory centers.
Function of chemoreceptors during hypoxia or hypercapnia?
They notice and increased amount of CO2, decreased amount of O2, or increased H+. They then active the respiratory centers and increase respiration.
What are the two sets of chemoreceptors? Where are each located?
- ) Central - in the ventral surface of the brainstem (medulla)
- ) Peripheral - in the carotid artery (carotid body) and the aorta (aortic arch)
Each has a different role.
How do central chemoreceptors work?
They are indirectly sensitive to CO2 and directly sensitive to CSF pH. They are not sensitive to O2 or H+ concentration in the blood.
CO2 crosses the BBB, reacts with water in the CSF, goes through bicarb process, and the H+ produced stimulates the chemoreceptors.
What neurotransmitter has an affect on carotid peripheral chemoreceptors?
Dopamine
What are the peripheral chemoreceptors directly sensitive to?
O2, CO2, and H+
What are the influence and effects of central chemoreceptors?
Influence: “respiratory drive” or drive to breath
Effects: Increased respiratory rate and depth in response to hypercapnia.
What are the influence and effects of peripheral chemoreceptors?
Influence: Acute changes in blood gas
Effects: Increased respiratory rate and depth in response to hypercapnia, hypoxia, or acidosis.
Pulmonary stretch receptors are also known as what? (2 types)
slowly adapting pulmonary stretch receptors
or
rapidly adapting pulmonary stretch receptors
Where are slowly adapting pulmonary stretch receptors located? What are they sensitive to? What is their effect?
Location: airways
Sensitive to: Stretch of airways (directly proportional to lung volume)
Effect: inhibition of inspiration and prolongation of expiration
When are slowly adapting pulmonary stretch receptors important? (2 populations of people)
- ) Infants
2. ) Adults during exercise
Where are rapidly adapting pulmonary stretch receptors located? What are they sensitive to? What is their effect?
Location: Airways
Sensitive to: Irritation, foreign bodies in airway
Effect: Cough
Where are J (juxtacapillary) receptors located? What are they sensitive to? What is their effect?
Location: near blood vessels of alveoli
Sensitive to: Pulmonary edema
Effect: Cough, tachypnea
Can the cortex influence breathing?
Yes, it acts as a failsafe. It can override the function of the respiratory centers.
