Physiology Chp 17

What is the primary function of the respiratory system?

Exchange of gases between the atmosphere and the blood.

What gas is exchanged from the atmosphere to the blood?

Oxygen (O2).

What gas is exchanged from the blood to the atmosphere?

Carbon dioxide (CO2).

How does the respiratory system help regulate body pH?

By managing the concentration of CO2 in the extracellular fluid (ECF).

What role does the respiratory system play in protection?

It protects from inhaled pathogens and irritating substances.

What is vocalization in the context of the respiratory system?

The use of airflow to vibrate vocal organs.

What is a major challenge of mammalian respiration?

The enormous surface area required for gas exchange.

Why must the vascular surface of the respiratory system be kept moist?

To facilitate gas exchange and prevent tissue damage.

What is the principle of bulk flow in respiratory air exchange?

Flow occurs from regions of high pressure to lower pressure.

What creates pressure gradients in the respiratory system?

A muscular pump.

What are the four basic steps to functional gas exchange?

1) Gas exchange between atmosphere and lung, 2) Gas exchange between lung and circulation, 3) Gas transport in blood, 4) Gas exchange between blood and tissues.

What distinguishes external respiration from cellular respiration?

External respiration involves pulmonary ventilation and gas exchange with the atmosphere, while cellular respiration refers to cellular metabolism.

What is the structure of lung tissue?

Soft, spongy, and organized into several major lobes.

What is the function of the pleural sacs?

They encase the lungs in a fluid-filled sac, providing mechanical buffering and allowing lateral movement.

What does the upper respiratory system include?

The nasal and oral cavities as well as the larynx.

What components make up the lower respiratory system?

The trachea, bronchi, and smaller branching airways leading to the alveoli.

What is the site of gas exchange in the lungs?

The alveoli.

How many times do the airways branch from the trachea to the alveoli?

More than 20 times.

What is the significance of the branching of airways?

It massively increases the total surface area for gas exchange.

What is the primary function of the upper airways?

To condition inspired air before it reaches the lower respiratory system.

How does the body condition incoming air?

By warming it to body temperature, adding water vapor, and filtering out foreign material.

What type of epithelium is found in the trachea and bronchi?

Ciliated epithelium.

What role do cilia play in the respiratory system?

They sweep mucus, which traps foreign particles, to the larynx where it is swallowed.

What are alveoli?

Clusters of microscopic, rounded air chambers surrounded by capillaries.

What are the two main types of cells found in alveoli?

Type I cells (perform gas exchange) and Type II cells (secrete surfactant).

What is the function of surfactant in the alveoli?

To reduce water surface tension and prevent alveoli collapse.

What is the pathway of blood in pulmonary circulation?

Right ventricle → pulmonary trunk → lungs → pulmonary veins → left atrium.

What is the role of gas diffusion in the lungs?

Gases diffuse between blood plasma and the air within the lungs according to physical gas laws.

What do gas laws describe?

The physics of gases, including their movement, pressure:volume relationships, and properties in mixtures.

What happens to gases in areas of different pressures?

Gases move from areas of high pressure to areas of low pressure.

What is the relationship between pressure and volume in gases?

Pressure and volume change inversely; if volume increases, pressure decreases, and vice versa.

What is atmospheric pressure at sea level?

760 mm Hg.

What is partial pressure?

The pressure that a specific gas alone exerts in a mixture of gases.

How is the partial pressure of a gas calculated?

Pgas = Patm × % of gas in atmosphere.

What is respirometry used for?

To measure subject ventilation and make volumetric measurements such as tidal volume (TV), residual volume (RV), vital capacity (VC), inspiratory reserve volume (IRV), and expiratory reserve volume (ERV).

What is the process of negative pressure inhalation?

It involves increasing thoracic cavity volume, decreasing thoracic cavity pressure, resulting in atmospheric pressure being greater than lung pressure, causing air influx.

What is the relationship between flow, pressure difference, and resistance in ventilation?

Flow is directly proportional to the pressure difference and inversely proportional to resistance.

What muscles are primarily used for inhalation?

Inspiratory muscles, including the diaphragm and intercostal muscles.

How does the diaphragm contribute to inhalation?

Its contraction lowers its position, increasing thoracic cavity volume and decreasing pressure, allowing air to flow into the lungs.

What happens during passive exhalation?

The diaphragm and intercostal muscles relax, causing the rib cage to move downward and inward, decreasing thoracic cavity volume.

What is compliance in the context of lung function?

Compliance refers to the ability of lung tissue to stretch under force.

What is elastance in lung tissue?

Elastance is the ability of lung tissue to return to its resting position after being stretched.

What effect does low compliance have on ventilation?

Low compliance requires more ventilatory force to fill the lungs.

What can cause decreased lung compliance?

Restrictive lung diseases, such as fibrotic lung diseases, and inadequate surfactant production.

What is airway resistance and its significance?

Airway resistance is a primary determinant of airflow; it is influenced by the diameter of airways.

What is total pulmonary ventilation?

Total pulmonary ventilation is calculated as ventilation rate multiplied by tidal volume.

What is dead space in the respiratory system?

Dead space is the volume of the conducting zone where inspired air does not participate in gas exchange.

How is alveolar ventilation calculated?

Alveolar ventilation is calculated as ventilation rate multiplied by (tidal volume - dead space volume).

What happens to alveolar gas levels with increased alveolar ventilation?

Alveolar PO2 increases and PCO2 decreases.

What is ventilation-perfusion matching?

It is the process of ensuring that ventilation and perfusion levels are properly matched for effective gas exchange.

How do blood gases affect local control of circulatory and pulmonary vessels?

Changes in local gas levels can cause dilation or constriction of both circulatory and pulmonary vessels.

What are some clinical aspects of ventilation?

Auscultation is used to detect airway resistance, pneumothorax, and pleura inflammation; apneas indicate respiratory rhythm issues.

What is chronic obstructive pulmonary disorder (COPD)?

COPD is a group of obstructive lung diseases that significantly reduce airflow, including asthma, emphysema, and chronic bronchitis.

What occurs when a lung is punctured?

A punctured lung releases the adhesion between the chest wall and lungs, causing the lungs to contract away from the chest wall.