Respiratory Organs

The following is a listing of the respiratory organs and their functions.

Nostrils/Nares

• The spaces where air enters the nose.

Nose

• Filters, warms, and moistens the air.
• Contains olfactory (smell) receptors.
• Serves as a resonating chamber for sounds.

Nasal Conchae

• Spaces that have folds of tissue with mucosal linings to help filter, warm, and moisten the air.

Paranasal Sinuses

• 4 of them, located in the following regions: (1) maxilla, (2) ethmoid, (3) sphenoid, (4) frontal.
• Help lighten the skull
• Warm and moisten air.

Pharynx

• Description: A tube formed by skeletal muscle that helps carry air from the nasal cavity to the lungs.
• Location: posterior to the nasal and oral cavities, and just anterior to the cervical vertebrae.
• Consists of three parts: the nasopharynx, which exchanges air with the nasal cavities; the oropharynx, contains two pairs of tonsils; and the laryngopharynx, which connects to the esophagus and larynx..

Larynx

• Description: the "voice box." A short tube of cartilage, lined by a mucus membrane, that connects the pharynx and trachea.
• Location: lies in the midline of the neck, anterior to the 4th, 5th, and 6th cervical vertebrae.
• Consists of four parts: Thyroid cartilage (Adam's apple), forms the anterior wall; the epiglottis, a leaf-shaped piece of elastic cartilage that opens or closes in conjunction with swallowing movements; the cricoid cartilage, a ring of hyaline cartilage attached to the first cartilage ring of the trachea; and the arytenoid cartilage, which is located superior to the cricoid cartilage and attaches to the true vocal cords and pharyngeal muscles to function in voice production.

Trachea

• The tube that carries air to the lungs.
• It braches, and is located anterior to the esophagus.
• Cartilaginous rings help keep it patent (open).

Primary Bronchi

• The first branches off the trachea.
• These have cartilaginous rings in them, same as in the trachea.

Secondary Bronchi

• The next set of branching tubes to carry air to the lungs.
• Secondary bronchi still have cartilaginous rings as well.

Bronchioles

• Smallest form of bronchi carrying air throughout the lungs, to the alveoli.
• Do NOT have cartilaginous rings.

Lungs

• The lungs have two coverings: (1) parietal pleura, which is tight to the thoracic wall; and (2) the visceral pleura, which is tight to the lungs.

Alveoli

• Small, grape-like structures, located within the lobes of the lungs.
• Walls are made of elastic tissue.
• Part of the respiratory zone: where gas exchange actually occurs.

Diaphragm

• Muscle that separate the thoracic cavity from the abdominal cavity.
• It creates negative pressure when contracted, allowing air to flow into the respiratory tract.
• The diaphragm is relaxed during exhalation.