Respiratory physiology Flashcards
Ventilation vs respiration
- Ventilation: the physical act of moving air in and out of the lungs
- Respiration: The exchange of oxygen and carbon dioxide.
Define: Inspiration, expiration, oxygenation
Inspiration: “Inhaling” moving air in (active process)
Expiration: “exhaling: moving air out (passive process)
Oxygenations: the process of delivering O2 from the alveoli to the tissues in order to maintain cellular activity
atmospheric pressure vs intrathroacic pressure
Atomospheric pressure: pressure of the air outside of the body
**Intrathoracic pressure ** is the pressure within the thoracic cavity
Increasing the size of the thoracic cavity decreases intrathoracic pressure
How does ventilation occure
- Phrenic never sends impulses to the diaphragm and the intercostal nevers send impulses to the intercostal muscles
- the diaphragm contracts (moves down) and the intercostal muscles contract (moving up and out) which increases thoracic cavity space which decreases the the intrathoracic pressure
- the pressure in the lungs is lower than the pressure from out side (atmospheric pressure) which causes air to rush from the high pressure to low pressure
- When the pressure in the lungs is = to the pressure outside, inspiration stops
- the diaphragm relaxes (recoils) due to its natural elasticity which causes air to be exhaled passively
Define tidal volume (Vt) and what is a normal tidal volume in an adult male and infants
volume of air that is inhaled and exhaled during a normal respiratory cycle
male: roughly 500ml or 5-6 ml/kg
child: 6-7 ml/kg
Internal respiration vs external respiration
Interal respiration: exchange of gas between the blood and tissues/cells (cellular respiration)
external respiration: the exchange of gas between the alevoli and pulmonary capillaries (pulmonary respiration)
what is negative pressure ventilation and positive pressure ventilation
negative pressure ventilation: the exchange of air between a high pressure and a low pressure area
Postive pressure ventilation: forcing air into the lung (using a BVM)
what is inspiratory reserve volume (IRV)
the amount of air that can be inhaled in addition to Vt
What is dead space and dead space volume (Vd)
Dead space: any portion of the airway where lung lingers but doesnt participate in the gas exchange
Dead space volume: air that stays in the upper airway passage
anatomical dead space vs physiological dead space
Anatomical dead space: any structures where air lingers after inspiration (trachea and bronchi)
Physiological dead space: is dead space that is created due to intrapulmonary obstruction or atelectasis
What is minute volume and how is it calculated
the amount of air move in and out per minute
Vt x RR = Vm
What is alveolar volume
is the amount of air that doesnt reach the alveoli and there for doesnt participate in the exchange of gas
what is minute alveolar volume (Va) and how is it calculated
The amount of air that reachs the aveoli and participates in the gas exchange per min
(Vt - Vd) x RR = Va
What is functional residual capacity
Amount of air forced from the lungs during 1 exhalation
what is expiratory reserve volume and residual volume
Expiratory reserve volume: the amount of air that can be exhaled after 1 normal exhalation
residual volume: is the air that remains in the lungs following exhalation
What are central chemoreceptors
- Monitor Ph of the CSF
- located adjacent to the respiratory centers in the medulla
- a decreased pH in the CSF triggers the receptors to increases rate and depth of respiration
What are peripheral chemoreceptors
- Monitor CO2 in the arterial blood and are located in the carotid bodies and aortic arch
- Sense minute changes in the Paco2 and send signals via the glosspharyngeal and Vagus nerve
What do the stretch receptors do in the respiratory system
- They pick up stretch within the chest wall and bronchioles
- They send signals to the apneustic center causing inhalation to stop and exhalation to start
- this process is called the Hering-breuer relfex this stops the lungs from over expanding
What are the 3 breathing centers
- Respiratory thythmicity centre
- apneustic centre
- pneumotaxic centre
What respiratory centres are located in the pons and what do they do
- Apneustic centre: Controls respiratory rate by increasing # of respirations per min
- Pneumotaxic centre: inhibits inspiration
What respiratory centre is located in the medulla and what does it do
The respiratory rythmicity centre: controls breathing by setting the resting respiratory rate
Define oxygen saturation
is how many oxygen-saturated hemoglobin there are relative to total hemoglobin in the blood
What does oxyhemoglobin mean and what is the oxyhemoglobin dissocation curve
Oxyhemoglobin: hemoglobin that has O2 attached to it
Oxyhemoglobin dissociation curve: is the relationship between oxygen saturation and oxygen dissolved in the blood
