Respiratory System Flashcards
Inspiratory muscles
Respiratory diaphragm - inc the volume of the cavity and creates and negative pressure to bring air in External intercostal muscles Sternomastoids Serratus anterior muscles Scalene muscles
Expiratory muscle
Passive at rest
Forceful: abdominal muscles, internal intercostals
What is lung capacity?
The maximum volume of gas the lungs can hold
A capacity is made up of two or more volumes
Total lung capacity is made of distinct, non-overlapping sub-compartments: lung volumes
What is the tidal volume?
500 ml
Volume of air that is inspired or expired with each breath at rest
Inspiratory reserve volume
3000 ml
Volume that can be inspired in addition to tidal volume with forceful inspiration
Expiratory reserve volume
1100 ml
The additional volume f air that can be expired at end of tidal volume by forceful expiration
Residual volume
1200 ml
Volume of air remaining in lungs after forceful expiration
What’s the difference between vital capacity and total lung capacity?
Vital capacity is 4600 ml
The sum of all the volumes that can be inspired or exhaled
Total lung capacity is 5800 ml. The sum of all the volumes = vital capacity plus residual volume
Minute ventilation
Total volume of gases moved into or out of the lungs per minute
(Breaths per minute) x (tidal volume) = minute ventilation
Alveolar ventilation
Total volume of gases that enter spaces participating in gas exchange per minute
(Breaths per minute) X (tidal volume - dead space) = alveolar ventihilation
0.35 L x breathing rate
Dead space
150 ml
Portions of the anatomy that don’t participate I n gas exchange: trachea, bronchi, bronchioles
Anatomic dead space + ventilated alveoli with poor or absent blood supply
What is transpulmonary pressure?
Difference between the alveolar pressure and the pleural pressure
Pleural pressure: pressure of the fluid between the parietal pleura and the visceral pleural
Alveolar pressure: pressure of the air inside the alveoli
What is lung compliance?
The extent to which lungs will expand for each unit increase in the transpulmonary pressure
In liters, normal: 200 ml/water cm
Measure of the expansibility of the lungs and trachea
Increase in vol/increase in pressure
Distensibility x volume
What is lung elastance?
Compliance is the reciprocal of elastance,
Elastance is the measure of the tendency of a hollow viscous to recoil towards it’s original dimension upon removal of the ditending or collapsing force.
What center’s of the brain are used for normal respiration?
Medullary respiration group:
dorsal respiratory group
the ventral respiratory group
Pontine repiratory centers: located in the pons.
What respiratory center establishes the ramp signal? What is the ramp signal?
Dorsal respiratory group
Nervous signals to inspiratory muscles
- weak
- then intense for 2 secs
- stops for 3 allows expirations
Allows lung elasticity ^^
What’s the main purpose of the PRG in regards to the ramp signal?
To control the switch-off point for the inspiratory ramp. PRG causes the ramp signals to stop abruptly
Strong PRG causes more breathing than normal
Weak PRG causes less breathing than normal
What is apneusis? What center is it associated with?
Apneusis is the failiure to turn off inspiration
Pontine group: apneusis center. -> Gasping
Inferior pons
Ventral respiratory group
Ventrolateral portion of the medulla
Usually inactive during normal respiration. Not part of oscillation that control normal breathing
Increased pulmonary ventihalition causes signals to spilllover from the DRG to the VRG with increases repiratory drive.
Contains expiratory neurons: botzinger complex
Hering-Breuer Inflation Reflex
Relies is a protective mech to prevent excess inflation of the lungs
Shuts off the inspiratory ramp
-stretch receptors in the walls of the bronchi and bronchioles
Chemoreceptors
increase their activity when hypoxia or hypercapnia occur
Hypercapnia - increased carbon dioxide
Central - sensitive to pH of blood
peripheral chemoreceptors
Central chemoreceptors
Sensitive to pH of blood, carbon dioxide levels.
Or [H+]
-essentially the same thing because carbon dioxide dissociated into H+ and HCO3-
Peripheral chemoreceptors
Sensitive to change in O2 levels.
In bifurcation of the common carotid in the carotid arteris and aortic arch.
Type I: glomus cells - chemosensors potassium channels that are oxygen dependent. ^ in O2, K+ release and hyperpolarization. O2 dec _> depolarization, Ca++ releases and NT release.
Type II - support cells, like glial cells
Mechanoreceptors
Located in the airways of lungs
Sensitive to the stretch of airways
Causes: termination of inspiration and prolonged expiration
Important for controlling respiration in infants and adults during exercise
J receptors
sensory ends in alveolar wall next to pulmonary capillaries
Sensitive to pulmonary edema
Travel Vargas nerve
Causes: cough, tachypnea
Override normal respiratory control centers
What is cheyne-stokes breathing?
Abnormal pattern of breathing characterized by a repeating pattern
Increasingly deeper and rapid breathing - hyperpnea
Followed by a gradual decrease
Then a temporary stop - apnea
Pattern repeats: cycle about 30 sec to 2 minutes.
How is periodic breathing or central sleep apnea syndrome different from Cheyenne-stokes breathing?
Essentially the same. In Periodic breathing instead of apnea you see hypopnea
If the above happens during sleep is central sleep apnea syndrome.
-damage to central repiratory centers
-abnormalities of the respirator neuromuscular apparatus
What conditions override the damping factors that would stop Cheyne-stokes breathing from occuring?
A long delay in the transport of blood from the lungs to the brain like seen in cardiac failure
Increased negative feedback like seen in brain damage.
-pCO2 and pO2 feedback get out of sync
