Respiratory System Functions & Composition

Plura

The thin double layered membrane around the lungs (visceral pleura) and inner walls of the chest (parietal pleura), with a fluid in between (parietal fluid). Reduces friction between the lungs and chest wall when breathing.

Alveoli

Tiny air sacs in the lungs surrounded by capillaries made of a thin layer of epithelial cells for easy defusion. Where gas exchange occurs, oxygen enters the blood and carbon dioxide exits.

Bronchi

C shaped cartilage rings lined with mucus and cilia, including the primary, secondary, and tertiary bronchi. Connects trachea (windpipe) to direct oxygen into the lungs.

Bronchioles

Made of smooth muscle allowing expansion and contraction. Very small branches of bronchi that direct airflow into the alveoli.

Function: Diaphragm

Main muscle used for breathing, contracts for inhalation and relaxes for exhalation.

Composition: Diaphragm

A large, flat skeletal muscle at the bottom of the chest cavity.

Epiglottis

A flap of cartilage that covers the windpipe while swallowing.

Function: Larynx

Produces sounds when vibrating as air passes through vocal chords, ande ensures food doesn’t enter the trachea.

Composition: Larynx

Made of cartilage, contains mucus membrane vocal cords (voicebox).

Composition: Lungs

Soft spongy tissue divided into lobes, right lung has 3 while left has 2.

Function: Lungs

The central organ of the respiratory system where gas exchange occurs.

Mouth

The opening through which food is taken in and vocalizations emerge.

Composition: Nasal Cavity

Lined with mucous membrane and cilia (tiny hairs that capture dust and debris).

Function: Nasal Cavity

Curved tubes inside the nose that warm, moisten, and filter air.

Composition: Pharynx

Muscular tube lined with mucus.

Function: Pharynx

Passageway for air and food.

Composition: Trachea

C shaped cartilage rings for support, lined with mucus producing epithelium and cilia.

Function: Trachea

Tube that carries air from the larynx to the lungs, trps debris with cilia and mucus.

Ribs

The curved bones that form the protective rib cage.

Esophagus

The muscular tube through which food passes from the throat to the stomach.

Intercostal Muscle

Muscles between the ribs that help expansion and contraction of the chest during breathing.