Unit 5- respiratory system

What are the primary functions of the respiratory system?

• Bring oxygen (O₂) into the body

• Remove carbon dioxide (CO₂)

• Help regulate blood pH

• Produce speech

• Provide the sense of smell (olfaction)

What is pulmonary ventilation?

Breathing—the movement of air into and out of the lungs.

What is external respiration?

Gas exchange between the alveoli and the blood.

What is internal respiration?

Gas exchange between the blood and the body tissues.

What is cellular respiration?

Cells use oxygen to make ATP (energy) and produce carbon dioxide as a waste product.

What are the functions of respiratory mucus?

• Traps dust

• Traps bacteria

• Traps other particles

• Moistens inhaled air

• Protects respiratory tissues

What do cilia do?

Move mucus and trapped debris toward the throat to be swallowed or coughed out.

What is the conducting zone?

The portion of the respiratory tract that conducts air but does NOT perform gas exchange.

Which structures make up the conducting zone?

• Nose

• Nasal cavity

• Pharynx

• Larynx

• Trachea

• Bronchi

• Bronchioles

What are the functions of the conducting zone?

• Conduct air

• Warm air

• Humidify air

• Filter air

What are the nasal conchae?

Curved bones that:

• Increase surface area

• Warm air

• Humidify air

• Filter air

What is the function of the uvula?

Closes the nasopharynx during swallowing to prevent food from entering the nose.

What is the function of the epiglottis?

Closes over the larynx during swallowing to prevent food from entering the airway.

What is the glottis?

The opening between the true vocal cords.

What is the larynx?

The voice box that:

• Produces sound

• Protects the airway

• Connects the pharynx to the trachea

What are the true vocal folds?

The vocal cords that produce sound.

What are the false vocal folds?

Do not produce sound.
Help protect the airway and support the true vocal cords.

What are the three tonsils?

• Pharyngeal tonsil (adenoids)

• Palatine tonsils

• Lingual tonsils

What is the function of the tonsils?

Trap pathogens entering through the nose or mouth and help fight infection.

What are adenoids?

Another name for the pharyngeal tonsils.

Why does the trachea have C-shaped cartilage?

• Prevents the trachea from collapsing

• Open side allows the esophagus to expand during swallowing

What is the respiratory zone?

The area where gas exchange occurs.

Which structures make up the respiratory zone?

• Respiratory bronchioles

• Alveolar ducts

• Alveoli

Where does gas exchange occur?

In the alveoli.

Why are alveoli good for gas exchange?

They have:

• Thin walls

• Large surface area

• Rich capillary supply

What is the visceral pleura?

The membrane that covers the lungs.

What is the parietal pleura?

The membrane lining the thoracic cavity.

What is the function of pleural fluid?

Reduces friction and helps keep the lungs attached to the chest wall during breathing.

What do Type II alveolar cells secrete?

Surfactant

What is the function of surfactant?

Reduces surface tension and prevents alveoli from collapsing.

How is oxygen transported in the blood?

Mostly bound to hemoglobin inside red blood cells.

How is carbon dioxide transported in the blood?

Mostly as bicarbonate ions (HCO₃⁻).

Small amounts:

• Bound to hemoglobin

• Dissolved in plasma

What is tidal volume?

The amount of air inhaled or exhaled during normal breathing.

What is inspiratory reserve volume (IRV)?

Extra air that can be inhaled after a normal inspiration.

What is expiratory reserve volume (ERV)?

Extra air that can be exhaled after a normal expiration.

What is residual volume?

The air remaining in the lungs after maximal exhalation.

What is sinusitis?

Inflammation of the sinuses.

What is bronchitis?

Inflammation of the bronchi.

What happens during an asthma attack?

• Bronchioles constrict

• Airways become inflamed

• Excess mucus is produced

• Breathing becomes difficult

What is pneumonia?

Infection in which the alveoli fill with fluid or pus, reducing gas exchange.

What is a pneumothorax?

A collapsed lung caused by air entering the pleural cavity.

How does smoking affect cilia?

Smoking damages or destroys cilia, making it harder to remove mucus and debris.

How does smoking affect mucus production?

It increases mucus production.

Name four harmful effects of smoking.

• Lung cancer

• COPD

• Chronic bronchitis

• Emphysema

Why does smoking increase respiratory infections?

Because damaged cilia cannot effectively remove bacteria and mucus.

Why is surfactant essential for normal breathing?

Without surfactant, alveoli collapse, making breathing extremely difficult.

Which structure prevents food from entering the trachea during swallowing?

Epiglottis

Which respiratory zone performs gas exchange?

Respiratory zone

Which respiratory zone only conducts air?

Conducting zone

A patient has fluid filling the alveoli. Which respiratory disorder does this describe?

Pneumonia