Lung volumes and sounds

Question 1

Arterial Chemoreceptors

Answer 1

AC’s monitor and respond to changes in the partial pressure of oxygen and carbon dioxide in the arterial blood, making sure it stays in the correct range (of pH too). Arterial chemoreceptors located in the aortic and carotid bodies respond to hypoxemia (low O2) and hypercapnia. (high CO2).

Question 2

Pneumotaxic centre

Answer 2

1 of 2 of the Resp. Centres in the Pons. Helps to fine tune breathing, smoothing out the transition from inspiration to expiration and vice versa. PC inhibits DRG (affecting volume and rate).

Question 3

Functional residual capacity (FRC)

Answer 3

The volume of air present in the lungs at the end of passive expiration. At FRC, the opposing elastic recoil forces of the lungs and chest wall are in equilibrium and there is no exertion by the diaphragm or other respiratory muscles.

Question 4

Residual volume

Answer 4

The volume of air that remains in a person’s lungs after fully exhaling. It is often affected after surgery and physios improve it by positioning patients to standing.

Question 5

Tidal volume

Answer 5

The volume of air moved into and out of the lungs during each ventilation cycle. Improving the tidal volume of patients can benefit them hugely, it allows sputum to be loosened in air turbulence as well as allowing more O2 to reach target muscles etc. making it achievable for the patient’s RR to decrease.

Question 6

Minute volume

Answer 6

The volume of gas inhaled from a person’s lungs per minute. This can be calculated by measuring the patients tidal volume and multiplying it by their RR.

Question 7

Functional Vital Capacity (FVC)

Answer 7

The max. volume of air a person can expel from the lungs after a max. inhalation. It is equal to the sum of inspiratory reserve volume + tidal volume + expiratory reserve volume. A person’s vital capacity can be measured by a spirometer.

Question 8

Normal breath sounds

Answer 8

Normal findings on auscultation include:
Loud, high-pitched bronchial breath sounds over the trachea.
Medium pitched bronchovesicular sounds over the mainstream bronchi, between the scapulae, and below the clavicles.
Soft, breezy, low-pitched vesicular breath sounds over most of the peripheral lung fields.

Question 9

Bronchial breathing

Answer 9

Bronchial breath sounds are tubular, hollow sounds which are heard when auscultating over the large airways (e.g. second and third intercostal spaces). They will be louder and higher-pitched than vesicular breath sounds.

Question 10

Crackles

Answer 10

Crackles are the clicking, rattling, or crackling noises that may be made by one or both lungs of a human with a respiratory disease during inhalation heard on auscultation. Sound caused by the “popping open” of small airways and alveoli collapsed by fluid, exudate, or lack of aeration during expiration.

Question 11

Wheeze

Answer 11

Wheezing is a high-pitched whistling sound made while breathing. The most common causes of recurrent wheezing are asthma and (COPD). Both cause narrowing and spasms (bronchospasms) in the small airways of your lungs.