Flashcards in Lecture 7 & 8 Deck (22):
What does Ventilatory Control do?
Keeps levels of O2 and CO2 in the blood the same despite uptake and production changing with activity
How does Ventilatory Control work?
1. Sensors (Chemoreceptors of the lung) give input to the Central Control
2. Central Control (Inspiratory and Expiratory neurons of the brain) send an output signal to the Effectors
3. Effectors (Respiratory Muscles) provide Ventilatory Control
Brain Stem control of breathing is...
INVOLUNTARY, aside from Cortical Breathing which is VOLUNTARY
Where are the Central Chemoreceptors and what do they measure?
1. Located in the Medulla
2. Sense changes in pH of Cerebral Spinal Fluid caused by change in paCO2
What happens when paCO2 increases?
1. pH of CSF DECREASES
2. Alveolar Ventilation INCREASES
What effects do Narcotics have on Ventilaton?
1. Suppresses Respiration
2. Reduces slope of response to change in paCO2
Where are the Peripheral Chemoreceptors and what do they measure?
1. Located in Carotid and Aortic Bodies
2. Sense DECREASES in paCO2 and paO2
3. Stimulated by low O2 levels
Name the Peripheral Receptors located in the Lungs (not as important ones):
1. Pulmonary Stretch Receptors- slow adapting to slow respiration frequency
2. Irritant Receptors- rapid adapting to tighten chest
3. J Receptors- cause hyperventilation
4. Bronchial C Fibers- Bronchoconstriction
As paO2 goes down, the Ventilatory Response is...
1. An increase in Ventilation
2. Shape of the Curve depends on paCO2 present.
-So high paCO2 means less drastic slope
Increase in Ventilation increases at a lower paO2 when...
paCO2 is low too
(More sensitive to Hypoxemia when you already have Hypercarbia)
What is Cheyne Stokes Breathing?
Apnea for 10-20 seconds separated by equal periods of hyperventilation with waxing and waning tidal volumes
What is your Respiratory Response to Exercise?
1. Increased O2 Consumption
2. Increased Ventilation
3. Increased CO2 production and Ventilation
4. NO change in paO2 and paCO2
5. CO and Pulmonary blood flow INCREASE
6. Hb Dissociation Curve shifts right
What are some Characteristics of Fetal Circulation and Newborns?
1. In Utero Placental circulation is parallel with peripheral tissue
2. paO2 is 30 mmHg (LOW)
3. Ductus Arteriosus shunts blood from PA to Aorta
4. Newborn babies have dramatic fall in Pulmonary Vascular Resistance due to Lung Expansion
How does the Respiratory System respond to High Altitude?
1. Atmospheric Pressure drops causing the paO2 to drop as well
2. Pulmonary Vasoconstriction due to Hypoxemia
3. Hyperventilation in response to Hypoxemia may lead to Respiratory Alkalosis
4. Polycythemia (increased RBCs) due to EPO stimulation
5. Increased 2,3-DPG shifts Hb Dissociation curve to the right (enhanced release)
What does the Pulmonary Function Test measure?
It measures Forced Expiratory Volume. FEV (AKA FEV1) is the Volume of gas that is exhaled by a forced expiration in 1 second after a max inspiration is taken.
In a normal person, what should the ratio of Forced Expiratory Volume to Vital Capacity (FEV/FVC) be?
In that 1 second measured of forced expiration after a max inspiration, a normal person's FEV should be 80% of their FVC
What effect would an OBSTRUCTIVE Disease have on the FEV/FVC ratio?
Obstructive Disease INCREASES Airway Resistance which:
1. Decreases FEV
2. Decreases FVC
3. REDUCES the ratio to 40%
What effect would a RESTRICTIVE Disease have on the FEV/FVC ratio?
Restrictive Disease increases lung recoil which:
1. Decreases FEV
2. Decreases FVC
3. INCREASES Ratio to 90%
What are some examples of Obstructive Disease in the Lungs?
Obstructs the airways causing DIFFICULTY with breathing OUT:
2. Chronic Bronchitis
What are some examples of Restrictive Disease in Lungs?
Make lungs stiff:
1. Interstitial Fibrosis
What are some characteristics of Chronic Bronchitis (COPD)?
1. Severe Hypoxemia
2. Decreased drive to breathe
3. Elevated paCO2
5. Inflammation and excess mucous in the vessels
6. Cor Pulmonale (enlarged right side of the heart)