The Role of the Respiratory System in Gas Exchange

What is the primary function of the respiratory system?

To provide the link with the external environment for taking in O2 and eliminating CO2.

What are the two phases of pulmonary ventilation?

Inspiration (air intake) and expiration (air expulsion).

What muscles are involved in inspiration?

The external intercostals and diaphragm.

How does the diaphragm change during inspiration?

It moves from a relaxed dome shape to a flattened position, increasing the vertical dimension of the thoracic cavity.

What happens to the thoracic cavity during inspiration?

It increases in size, which lowers the air pressure inside the lungs and allows air to flow in.

What is the process that occurs during expiration?

The inspiratory muscles relax, causing the elastic lung tissue to recoil, which increases intrapulmonary pressure and forces air out.

What are bronchial sounds?

Sounds produced by air rushing through the large respiratory passageways (the trachea and bronchi).

What are vesicular breathing sounds?

Sounds resulting from air filling the alveolar sacs, resembling the sound of rustling leaves.

What can produce abnormal chest sounds like rales and wheezing?

Diseased respiratory tissue, mucus, or pus.

What is the normal volume of air moved during quiet breathing?

About 500 ml of air per breath.

What is a spirometer used for?

To measure respiratory volumes and capacities.

What are the two major types of spirometers?

Handheld dry spirometers and wet spirometers.

What does FVC stand for and what does it measure?

Forced Vital Capacity; it measures the amount of gas expelled after taking the deepest breath and exhaling forcefully.

What does FEVT stand for and what does it assess?

Forced Expiratory Volume; it assesses the percentage of vital capacity exhaled during specific time intervals of the FVC test.

What is the normal FEV1 percentage for healthy individuals?

75% to 85% of their FVC in the first second.

Where are the neural centers that control respiratory rhythm located?

In the medulla and pons.

What is the Hering-Breuer reflex?

A reflex that modifies the respiratory rate based on input from stretch receptors in the lungs.

What happens when medullary centers are completely suppressed?

Death occurs as respiration ceases.

What physical phenomena can modify the rate and depth of respiration?

Talking, yawning, coughing, and exercise.

What chemical factors influence breathing?

Changes in oxygen or carbon dioxide concentrations in the blood and fluctuations in blood pH.

What triggers a newborn's first breath?

The buildup of carbon dioxide in the blood.

What is the carbonic acid-bicarbonate buffer system's role in blood pH?

It helps stabilize arterial blood pH at 7.4 ± 0.02.

What happens to carbon dioxide in the blood from tissue cells?

Much of it enters red blood cells and combines with water to form carbonic acid.

What is the chloride shift?

The exchange phenomenon where bicarbonate ions diffuse out of red blood cells into plasma, drawing Cl− into the cells.

What is respiratory acidosis?

A condition that can result from hypoventilation, where carbonic acid increases in the blood.

What is respiratory alkalosis?

A condition that can result from hyperventilation, where carbonic acid decreases in the blood.

Why is maintaining normal breathing rate and depth important?

It is crucial for proper control of blood pH.