Respiratory physiology

Question 1

Ventilation vs respiration

Answer 1

• Ventilation: the physical act of moving air in and out of the lungs
• Respiration: The exchange of oxygen and carbon dioxide.

Question 2

Define: Inspiration, expiration, oxygenation

Answer 2

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

Question 3

atmospheric pressure vs intrathroacic pressure

Answer 3

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

Question 4

How does ventilation occure

Answer 4

1. Phrenic never sends impulses to the diaphragm and the intercostal nevers send impulses to the intercostal muscles
2. 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
3. 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
4. When the pressure in the lungs is = to the pressure outside, inspiration stops
5. the diaphragm relaxes (recoils) due to its natural elasticity which causes air to be exhaled passively

Question 5

Define tidal volume (Vt) and what is a normal tidal volume in an adult male and infants

Answer 5

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

Question 6

Internal respiration vs external respiration

Answer 6

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)

Question 7

what is negative pressure ventilation and positive pressure ventilation

Answer 7

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)

Question 8

what is inspiratory reserve volume (IRV)

Answer 8

the amount of air that can be inhaled in addition to Vt

Question 9

What is dead space and dead space volume (Vd)

Answer 9

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

Question 10

anatomical dead space vs physiological dead space

Answer 10

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

Question 11

What is minute volume and how is it calculated

Answer 11

the amount of air move in and out per minute
Vt x RR = Vm

Question 12

What is alveolar volume

Answer 12

is the amount of air that doesnt reach the alveoli and there for doesnt participate in the exchange of gas

Question 13

what is minute alveolar volume (Va) and how is it calculated

Answer 13

The amount of air that reachs the aveoli and participates in the gas exchange per min
(Vt - Vd) x RR = Va

Question 14

What is functional residual capacity

Answer 14

Amount of air forced from the lungs during 1 exhalation

Question 15

what is expiratory reserve volume and residual volume

Answer 15

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

Question 16

What are central chemoreceptors

Answer 16

• 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

Question 17

What are peripheral chemoreceptors

Answer 17

• 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

Question 18

What do the stretch receptors do in the respiratory system

Answer 18

• 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

Question 19

What are the 3 breathing centers

Answer 19

1. Respiratory thythmicity centre
2. apneustic centre
3. pneumotaxic centre

Question 20

What respiratory centres are located in the pons and what do they do

Answer 20

• Apneustic centre: Controls respiratory rate by increasing # of respirations per min
• Pneumotaxic centre: inhibits inspiration

Question 21

What respiratory centre is located in the medulla and what does it do

Answer 21

The respiratory rythmicity centre: controls breathing by setting the resting respiratory rate

Question 22

Define oxygen saturation

Answer 22

is how many oxygen-saturated hemoglobin there are relative to total hemoglobin in the blood

Question 23

What does oxyhemoglobin mean and what is the oxyhemoglobin dissocation curve

Answer 23

Oxyhemoglobin: hemoglobin that has O2 attached to it
Oxyhemoglobin dissociation curve: is the relationship between oxygen saturation and oxygen dissolved in the blood