Respiratory System

What is respiration?

The process of exchanging gases between the atmosphere and body cells.

Is ventilation the same as respiration?

No, ventilation is just moving air in and out of the lungs, one part of respiration.

What are the steps of respiration?

Ventilation, external respiration, gas transport, internal respiration, and cellular respiration.

What is external respiration?

Gas exchange between lungs and blood.

What is internal respiration?

Gas exchange between blood and body cells.

What is cellular respiration?

The use of oxygen by cells to produce ATP and release carbon dioxide.

What divides the upper and lower respiratory tract?

The larynx.

What structures make up the upper respiratory tract?

Nose, nasal cavity, sinuses, and pharynx.

What structures make up the lower respiratory tract?

Larynx, trachea, bronchi, lungs.

Why is nose breathing better than mouth breathing?

Nose filters, warms, and humidifies air; mouth does not.

What are nasal conchae?

Curved structures that increase surface area in the nasal cavity for filtering, warming, and moistening air.

What are sinuses and their purpose?

Air

What is the larynx and its function?

Voice box; prevents foreign objects from entering trachea and houses vocal cords.

What are the vocal cords?

Muscular folds inside the larynx that vibrate to produce sound.

What is the glottis?

The triangular slit between the vocal cords that opens for breathing and closes during swallowing.

What is the epiglottis?

A flap that covers the glottis during swallowing to prevent food from entering the trachea.

What is the trachea?

Windpipe that carries air to the bronchi; lined with ciliated mucous membrane.

How is the trachea supported?

By 20 C

What is tracheal deviation?

A shift in the position of the trachea, usually due to chest trauma or pressure.

What is the bronchial tree?

A branching system of airways from trachea to alveoli, including primary, secondary, and tertiary bronchi.

Where does gas exchange occur?

In the alveoli of the lungs.

What are alveoli?

Tiny air sacs in the lungs where gas exchange occurs with capillaries.

What keeps alveoli from collapsing?

Surfactant, a substance that reduces surface tension.

What causes pneumothorax?

Air in the pleural cavity disrupts pressure and may collapse the lung.

What causes hemothorax?

Blood in the pleural cavity, often from trauma.

What is tidal volume?

The amount of air that moves in and out of the lungs during normal breathing (~500 mL).

What is inspiratory reserve volume?

The extra air that can be inhaled beyond normal breath.

What is expiratory reserve volume?

The extra air that can be exhaled beyond normal breath.

What is residual volume?

The air left in the lungs after maximal exhalation (~1200 mL).

What is vital capacity?

Total of tidal volume + inspiratory reserve + expiratory reserve (~4600 mL).

What is total lung capacity?

Vital capacity plus residual volume (~5800 mL).

What is anatomical dead space?

Air in the bronchi/trachea that doesn’t participate in gas exchange.

Where is the respiratory center located?

In the medulla oblongata and pons of the brainstem.

What is the role of the ventral respiratory group?

Sets the basic rhythm of breathing.

What is the role of the dorsal respiratory group?

Modifies rhythm during changes like exercise.

What do chemoreceptors detect?

Changes in CO₂, H⁺, and O₂ levels in the blood.

What causes increased breathing rate?

High CO₂ or H⁺ concentrations; low pH.

What happens during hyperventilation?

Too much CO₂ is lost, causing alkalosis (high pH).

What is the inflation reflex?

Prevents over

What is alveolar gas exchange driven by?

Differences in partial pressures (diffusion).

What is partial pressure?

The pressure a single gas contributes to a mixture of gases.

How is oxygen transported in blood?

Mostly bound to hemoglobin (98%); small amount in plasma.

What is hypoxia?

Deficiency in oxygen reaching the tissues.

What does carbon monoxide do?

Binds hemoglobin irreversibly, preventing oxygen transport.

How is CO₂ transported in blood?

As bicarbonate (70%), bound to hemoglobin (23%), dissolved in plasma (7%).

What enzyme forms carbonic acid?

Carbonic anhydrase.

What is the chloride shift?

Exchange of bicarbonate out of and chloride into red blood cells to maintain charge balance.

What is spirometry?

Test measuring air volumes and capacities to assess lung function.

What is negative pressure breathing?

Breathing method where thoracic volume increases, causing pressure to drop and air to enter.