Free Case Study On Short Answer Questions:

QUESTION 1:

In normal respiration, when the air is inhaled quietly, there is movement of inspiratory muscles which raises the intrapulmonary pressure by contracting and flattening the diaphragm and elevating the rib cage. The increase in volume causes a fall in intrapulmonary pressure of about 1 mmHg as compared to the atmospheric pressure. This pressure difference facilitates the rush of air into the lungs till the pressure equalizes. In the expiratory phase, this sequence is reversed by relaxation of respiratory muscles causing reduction in volume and raising the intrapulmonary pressure to 1 mmHg as compared to atmospheric pressure. Such pressure difference causes expulsion of air out of the lungs.

QUESTION 2:

The greatest resistance to airflow is encountered not in the small lumened parts of bronchial tree but in the large bronchioles and bronchi in the vicinity of the trachea. It so happens because bronchioles are present in thousands as compared to bronchi. These bronchioles are arranged parallel to each other and minute amount of air has to pass through them.

QUESTION 3:

Compliance of the Lungs:
The extent of expandability of the lung tissue for every time a person inhales during respiration is called as lung compliance.

Surface tension:

The water based surfactant present in the alveoli prevents them from collapsing. Surface tension is the force exerted on the walls of the alveoli to compress forcing the air out of them. Such a contractile elastic force of the entire lung tissue is called as surface tension.

Airway resistance:

The airway of the respiratory tract differs in size from trachea till the terminal bronchioles. Therefore, the pressure and resistance is different in the respiratory tree from start till end.

In this case, there is increased airway resistance.

QUESTION 4:
Mike’s intrapulmonary pressure should drop 1-2 mmHg during inspiration for the air to efficiently go inside the lung tissue and during expiration his intrapulmonary pressure should rise further than the atmospheric pressure to facilitate the expulsion of air from the lung cavity.

QUESTION 5:

Mike should be instructed to take medications as directed and wear warm clothes. He should avoid the stimulus of his asthmatic attack. He can use an easily available cheap device called peak-flow meter. It can help him with his respiratory mechanics.

QUESTION 6:

The normal FEV1/FVC ratio is about 75-80% and in this case, it is lower than normal which points towards an obstructive disease. FEV1 is the volume expired in the 1st second of the forceful expiration. The air expired after maximal inspiration and this test measures the rapidness of emptying of fully aerated lungs. FVC is the forced vital capacity and it signifies the amount or air inhaled or exhaled after maximal force. FVC is also measure immediately after forceful maximum inhalation. Therefore, in asthmatic patients, there is a sloping and steady FVC which ultimately results in a smaller FEV1.

QUESTION 7:

Albuterol is a β2 agonist which relieves the symptoms of narrowing of the bronchus. The narrowed bronchus is relieved by relaxing the smooth muscles lining the airway. This aids in facilitating the patient to inhale without resistance and causes the expulsion of the trapped air in the lung cavities. This is useful especially in acute exacerbation during exercise and exertion and helps in maintaining regular respiration even during exertion.