Control of Breathing Flashcards
What are the three main controls of breathing?
Rhythmic discharge from pons, Chemical control, Nonchemical influences
Where is the automatic system for breathing?
Pons and Medulla. Sends impulses to respiratory motor neurons
Where is the voluntary system for breathing?
Cerebral Cortex. Sends impulses to respiratory motor neurons in the spinal cord
What is the relationship between expiratory muscles and inspiratory muscles?
The motor neurons to the expiratory muscles are inhibited when the insiratory muscles are active, and vice versa
Where is there a feedback mechanism in the control of breathing?
The chest wall/diaphragm/conducting airways can send signals to the spinal cord to help regulate the respiratory muscles.
What are the main stimuli for breathing control
Increased PCO2 –main one of the three
Decreased PO2
Decreased pH
What are the two things that an increase in PCO2 can stimulate?
The Peripheral Chemo receptors and
Central Chemo receptors
What has a stronger effect, Increase in PCO2 or decrease in pH?
increase in PCO2
What is the range when peripheral chemoreceptors are particularly sensitive to changes in PO2?
60 to 30 mmHg
This is the range when the Hb dissociation curve drops dramatically
What does a low PO2 do to alveolar ventilation?
Increases it INDEPENDENT of PCO2
What gives rise to most of the H found in blood?
Rise in CO2
Does H easily cross the BBB?
NO
What has a greater effect on stimulating chemosensitive neurons, H or CO2?
CO2, even though stimulating these neurons happens by CO2 changing the local H concentration
Where are the peripheral chemoreceptors located?
Aortic bodies and the Carotid bodies
Do the Aortic bodies and carotid bodies respond more to changes in blood O2, CO2, or H more?
O2, and to a lesser extent CO2 and H
Are the central chemoreceptors more sensitive to O2, CO2, or H?
CO2 and H.
What is the tractus solitarius?
The termination site for the vagal and glossopharyngeal nerves which transmit signals from the
Peripheral chemoreceptors,
Baroreceptors,
Other receptors in the lungs
Where do the vagal and glossopharyngeal nerves receive their sensory input from in respiration?
Peripheral chemoreceptors
Baroreceptors
Other receptors in the lungs
What is the pre-Botzinger complex?
A part of the brain between the Nucleus ambiguus and the Lateral Reticular nucleus that contains PACEMAKER cells to control the rhythmic respiration. medulla
What does the Dorsal Respiratory Group signal?
It sends out repetitive bursts of INSPIRATORY APs
What is the Pneumotaxic center?
an area in the upper pons that transmits signals to the inspiraratory area and controls the switch off point in inspiration signals.
Functions to LIMIT INSPIRATION
What is the Ventral Respiratory Group?
When respiratory drive for increase pulmonary ventilation increases a lot, the signal spills over into the VRG.
VRG neurons contribute to both inspiration and exhalation
Normally inactive during quiet breathing
How does the brain contribute to increased breathing during exercise?
When sending impulses to the muscles for contraction during exercise, the brain also sends COLLATERAL IMPULSES to the respiratory center
What do irritant receptors do?
Cause coughing/sneezing. may also cause bronchial constriction.
Located in the trachea, bronchi, bronchioles
What are J receptors and where are they?
Located in alveolar walls, they give a feeling of dyspnea when the pulmonary arteries become engorged or in cases of pulmonary edema
Patients with CHF will feel dyspnea when they lay down due to stimulation of these
How can brain edema affect the respirator center?
It can compress it.
Hypertonic solutions can be administered to relieve this
Where are stretch receptors located and what do they do?
They are located in the muscular portions of the bronchi and bronchioles. When stretched, they send signals to teh DRG via vagal nerves to switch off the inspiratory ramp. They increase the rate of respiration
What is the Hering-Breuer inflation reflex?
It is the stretch receptors response. It isnt activated until it is stretched 3x normal. protective
What is Kussmaul’s breathing?
Relentless, rapid, deep breathing found in metabolic acidosis
What is Cheyne-Stoke’s BreathingL?
Ventilatory oscillations with long cycle times
Found in stroke, encephalopathies, HF
What is Biot’s Breathing?
Group of quick shallow inspirations followed by regular or irrregular periods of apnea
Found in medullary trauma, stroke
