Respiratory System Topic for Lecture Exam 4

What are the major functions accomplished by the respiratory system?

Gas exchange, Regulation of blood pH, Voice production, Olfaction (smell), and Protection

Function of Gas exchange

Supplying oxygen to the blood and removing carbon dioxide.

Function of Regulation of blood pH

By controlling the levels of CO₂, which affects acid-base balance.

Function of Voice production

Through the movement of air over the vocal cords in the larynx.

Function of Olfaction (smell)

Via receptors in the nasal cavity.

Function of Protection

Filtering, warming, and humidifying air to protect respiratory surfaces.

Trace the path of air beginning at the nose and ending at the lungs.

Air enters through the nose → passes through the nasal cavity → pharynx → larynx → trachea → bronchi (right and left primary bronchi) → secondary (lobar) bronchi → tertiary (segmental) bronchi → bronchioles → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs → alveoli (where gas exchange occurs).

Which structures make up the upper respiratory tract?

• Nose, nasal cavity, pharynx, and larynx

Function of the upper respiratory tract?

Filter, warm, and moisten air; detect odors; conduct air to the lower tract; initiate sound production.

Which structures make up the lower respiratory tract?

Trachea, bronchi, bronchioles, alveolar ducts, alveoli, and lungs

Function of the lower respiratory tract?

Conduct air to the lungs (trachea and bronchi), regulate airflow (bronchioles), and perform gas exchange (alveoli).

What is the name of the structure in the lungs where gas exchange occurs?

The alveoli are the structures in the lungs where gas exchange occurs between the air and the blood in surrounding capillaries.

What is the name of the serous membrane that surrounds the lungs?

The serous membrane that surrounds the lungs is called the pleura.

What are the layers that make up this membrane?

• Parietal pleura: Lines the inside of the thoracic cavity.

• Visceral pleura: Covers the surface of the lungs.
  Between the two layers is the pleural cavity, which contains a small amount of pleural fluid to reduce friction during breathing.

How does the central nervous system control breathing?

The central nervous system controls breathing primarily through the respiratory centers in the medulla oblongata and pons of the brainstem. These centers generate rhythmic impulses that stimulate the diaphragm and intercostal muscles to contract.

What factors control the rate and depth of breathing?

• Chemical factors: Levels of CO₂, O₂, and pH detected by chemoreceptors in the medulla and peripheral arteries.

• Neural input: From higher brain centers (e.g., during speaking or emotional changes).

• Stretch receptors: In the lungs that prevent overinflation.

• Irritant receptors: That respond to smoke, dust, etc., by altering breathing patterns.