Respiratory Physiology Flashcards
What does the upper respiratory tract contain?
Nose Nasal cavity Mouth Pharynx Larynx
What does the lower respiratory tract contain?
Trachea Lungs -Bronchi -Bronchioles -Alveolar duct -Alveolar sacs -Alveolus
What does the conduction zone contain?
Trachea
Lungs
-Bronchi
-Bronchioles
What does the respiratory zone contain?
- Alveolar duct
- Alveolar sacs
- Alveolus
What are the two types of alveoli cells?
Type I
Type II
Describe Type I alveolar cells
Form the lining
Primary site of gas exchange
Describe Type II alveolar cells
Tiny microvilli
Collecting debris
Pulmonary secretions (reduce alveolar surface tension)
What are the respiratory control centres?
Groups of neurons that control how we breath (depth and frequency)
What are the areas of the pons?
Apneustic area
Pneumotaxic area
What is within the medulla oblongata?
Rhymiticity area
-Ventral and dorsal respiratory group (VRG and DRG)
What does the phrenic nerve signal and via which root
Diaphragm via C3-C5
What does the intercostal nerve signal and via which root
Intercostal muscles via T1-T11 root
What are the types of receptors?
Chemoreceptors
Mechanoreceptors
-Stretch receptors (pressure and distortion)
Irritant receptors
Peripheral Proprioceptors (within muscles and joints)
Where are chemoreceptors?
Carotid body
Aortic body
What are the main muscles involved in respiration?
Diaphragm
Intercostal muscles
What are the accessory muscles involved in respiration?
Abdominal muscles (rectus abdominus, transverse abdominus, internal/external obliques) Sternocleidomastoid, scalenes, pectoralis minor, serratus anterior
What is Boyle’s Law?
“Pressure of a gas in a closed container is inversely proportional to volume of container at a constant temperature”
Describe inhalation (rest)
Diaphragm contracts to become flatter and pushes organs down
External intercostal muscles contract to push ribs up and out
Volume in the chest cavity increases
Pressure drops lower that atmospheric pressure
Air is drawn into the lungs
Describe expiration (rest)
Diaphragm relaxes and is pushed up by organs underneath
External intercostal muscles relax and ribs fall
Volume in the chest cavity decreases
Pressure in the lungs increases above atmospheric pressure
Air is moved out of the lungs
Describe inspiration (exercise)
Diaphragm contracts with more force
External intercostal muscles contract to push ribs up and out with more force
Additional muscles are used:
• Scalenes
• Pectoralis Major
• Sternocleidomastoid
Volume in the chest cavity increases further
Pressure drops lower that atmospheric pressure
More air is drawn into the lungs
Describe expiration (exercise)
Diaphragm relaxes and is pushed up with more force
External intercostal muscles relax and ribs fall
Additional muscles are used:
• Internal intercostal muscles
• Rectus abdominis
• External obliques
Volume in the chest cavity decreases further
Pressure in the lungs increases above atmospheric pressure
More air is moved out of the lungs
What is the function of the dorsal respiratory group
a. Sends impulses to the diaphragm, external intercostals and VRG
b. Controls basic rhythm
What is the function of the ventral respiratory group
a. Receives impulses from DRG cranial nerve X and IX
What is the function of the pneumotaxic area
- Inhibitory impulse to inspiratory neurons
* Limits duration of breath
What is the function of the apneustic area
- Controls prolonged & slow breathing
- Stimulates inspiratory neurons in the DRG and VRG
- Over-ridden by the PNS
- Apneustic breathing- normal breath in, little breath out
Glomus cells are an example of what type of receptor
peripheral chemoreceptor
What do glomus cells respond to
- Increase CO2
- Decrease O2 (<60mmHg)
- Decrease pH
Describe the glomus cells hypoxic response
low o2 –> K channels shut –> Ca2+ moves into the cell –> dopamine is released and binds to nerve cells to increase resp rate
What is the hering-breuer reflex
Limits the degree of inspiration, preventing the over inflation of the lungs.
Describe irritant receptors
These are found in the nose and bronchioles.
If an irritant is detected, a signal is sent via the vagus nerve to cough/sneeze.
Describe juxtacapillary receptors
They are stimulated by an increase in size of the pulmonary capillaries and cause rapid shallow breathing.
If volume increases, pressure —-?
decreases
What is resistance
- Reduction of airflow during inspiration & expiration
- Shortness of breath
- Difficulty exhaling all the air in the lungs
Example of a restrictive disease
- Increased resistance is an example of an obstructive disease
- Asthma
- COPD- emphysema and bronchitis
What is compliance
- Reduction in lung volume
- Cannot fill lungs fully
- Measure of the lungs ability to stretch and expand (distensability of elastic tissue)
Example of decreased compliance disease
- Decreased compliance is an example of a restrictive disease
- Sarcoidosis
- Idiopathic pulmonary fibrosis
Describe healthy FVC curve
sharp increase, plateau
FVC curve in obstructive disease
slower increase to reach healthy plateau
FVC curve in restrictive disease
Sharp increase, lower plateau than healthy
Define FEV
forced expiratory volume (FEV), which measures how much air can be forced out of the lung over a specific period, usually one second
Define TLC
Total lung capacity (TLC).
o This is the total amount of air your lungs can hold.
Define RV
Residual volume (RV)
o This is the amount of air that remains in your lungs after you exhale as much as you can.
Define ERV
Expiratory reserve volume (ERV)
o The difference between the amount of air in your lungs after a normal exhale (FRC) and the amount after you exhale with force (RV).
Define tidal volume
Tidal volume
o The amount of air breathed in or out during normal respiration
Define IRV
Inspiratory reserve volume (IRV)
o The additional amount of air that can be inhaled after a normal inhalation.
Define IC
The inspiratory capacity (IC)
o The amount of air that can be inhaled after the end of a normal expiration.
Define FRC
The functional residual capacity (FRC)
o The amount of additional air that can be exhaled after a normal exhalation.
Minute Ventillation (Ve) Equation?
resp rate x Tv = Ve
Describe the Ventilatory threshold
is the point when respiration increases significantly due to the accumulation and exhalation of metabolic by-products.
What is the respiratory compensation point
where the second ventilatory threshold occurs.
What is the metaboreflex
This is the fatiguing contraction of the diaphragm due to: • Increased metabolites • Decreased effort perceptions • Decreased blood flow • Increased vasoconstriction
