Respiratory Therapy Anatomy & Physicology

What are the two main parts of the respiratory system?

The upper respiratory tract (nose, nasal cavity, pharynx, larynx) and the lower respiratory tract (trachea, bronchi, bronchioles, lungs, alveoli)

What is the main function of the respiratory system?

To exchange gases—oxygen (O₂) and carbon dioxide (CO₂)—between the body and the environment

What structure connects the pharynx to the trachea?

The larynx (voice box)

What is the trachea lined with to help trap and move particles out of the airway?

Cilia and mucus-producing cells

How many lobes does each lung have?

Right lung = 3 lobes; Left lung = 2 lobes

What are alveoli?

Tiny air sacs in the lungs where gas exchange occurs.

What is the function of surfactant?

It reduces surface tension in the alveoli, preventing them from collapsing

What are bronchioles?

Small airways that branch from bronchi and lead to the alveoli

Where does external respiration occur?

In the alveoli—exchange of gases between air and blood

Where does internal respiration occur?

Between the blood and body tissues—oxygen moves into cells and CO₂ moves out

How does oxygen travel in the blood?

Mostly bound to hemoglobin in red blood cells

What gas drives the urge to breathe?

Carbon dioxide (CO₂), detected by chemoreceptors

What muscle is primarily responsible for breathing?

The diaphragm

What happens during inhalation?

The diaphragm contracts and moves down, the chest cavity expands, and air flows into the lungs

What happens during exhalation?

The diaphragm relaxes and moves up, the chest cavity decreases, and air is pushed out

What is tidal volume (TV)?

The amount of air inhaled or exhaled during a normal breath

What is vital capacity (VC)?

The maximum amount of air exhaled after a maximum inhalation (TV + IRV + ERV)

What is residual volume (RV)?

The air remaining in the lungs after a full exhalation

What is total lung capacity (TLC)?

The total volume of air the lungs can hold (VC + RV)

Which part of the brain controls breathing?

The medulla oblongata and pons in the brainstem

What is the main chemical factor that controls breathing rate?

The level of CO₂ in the blood (pH changes due to carbonic acid formation)

What receptors detect changes in CO₂ and O₂ levels?

Chemoreceptors in the medulla, carotid arteries, and aortic bodies

What is the cough reflex?

A protective mechanism to clear irritants or mucus from the airways

What is the sneeze reflex?

A response to irritation in the nasal cavity that expels air to clear particles

How does mucus help protect the respiratory system?

It traps dust, microbes, and debris before they reach the lungs