Respritory System

Respiratory System Basic Functions

Gas exchange (O2 in, CO2 out) and maintenance of pH (homeostasis)

Respiratory System Main Structures

Respiratory tract and lungs

Nasal Cavity Function

Warms and humidifies incoming air

Pharynx (Throat)

Passageway for air before entering the esophagus

Larynx (Voice Box)

Contains vocal cords, produces sound, directs food away from airway

Trachea

Main airway tube located in front of the esophagus; supported by C-shaped cartilage rings

Bronchial Tree

Branching tubes that lead to both lungs

Alveoli

Tiny air sacs where gas exchange occurs; surrounded by capillaries

Surfactant

Lipoprotein coating that reduces surface tension and prevents alveolar collapse

Inspiration Definition

Inhalation; air moves into lungs

Expiration Definition

Exhalation; air moves out of lungs

Ventilation

The cycle of inspiration and expiration

Inspiration Step 1

Diaphragm contracts and moves downward

Inspiration Step 2

External intercostal muscles move rib cage up and out

Inspiration Step 3

Thoracic pressure becomes less than atmospheric pressure

Expiration Step 1

Diaphragm relaxes and moves upward

Expiration Step 2

Internal intercostal muscles move rib cage down and in

Expiration Step 3

Thoracic pressure becomes greater than atmospheric pressure

Tidal Volume

Amount of air moved during normal breathing

Vital Capacity

Amount of air moved during forced breathing

Respiratory Control Centers

Regulate rate and depth of breathing

Upper Respiratory Control Centers

Control breathing rate

Lower Respiratory Control Centers

Control breathing depth

Chemoreceptors Location

Aortic arch and carotid arteries

Chemoreceptors Function

Detect CO2, O2, and pH levels and send signals to adjust breathing

Most Monitored Factor in Breathing

Carbon dioxide (CO2)

Smoking Effects

Increases cancer risk and causes lungs to blacken

Pneumonia

Fluid buildup in alveoli

Bronchitis

Infection that reduces airway diameter

Pulmonary Fibrosis

Scar tissue buildup in lungs

Tuberculosis

Bacterial infection forming nodules in alveoli

Emphysema

Destruction of alveoli leading to reduced surface area

Asthma

Inflammation and smooth muscle spasms that narrow airways