Respiratory System Overview

Respiratory System

• Breath represents life, the first breath of a baby and the last gasp of a dying person are highly dramatic moments
• Breathing is necessary for metabolism, since most ATP synthesis requires oxygen and produces carbon dioxide.
• The respiratory system's primary function is gas exchange, bringing oxygen to the blood and removing carbon dioxide.
• The system consists mainly of tubes that deliver air to the lungs where oxygen diffuses into the blood, and CO2 is released.

Main Function

• The respiratory system is an organ system providing oxygen to the blood and removing carbon dioxide.
• It has diverse functions like gas exchange, communication, smell, sound production, olfaction, acid-base balance, blood pressure regulation, and the expulsion of abdominal contents.

Divisions of the Respiratory System

• Upper Respiratory Tract: Nose, pharynx, larynx and trachea
  • Nose: Warms, cleanses, and humidifies inhaled air, detects odors in the airstream, resonates the voice
  • Pharynx: Passageway for air, food, and liquids.
  • Larynx: Voice box, produces sound, prevents food and drink from entering the airway.
  • Trachea: Windpipe, main airway to the lungs.
• Lower Respiratory Tract: Bronchi, bronchioles, alveoli and the lungs
  • Bronchi: Branches of the trachea leading to the lungs
  • Bronchioles: Small branches of the bronchi, the pathway for air during inhalation
  • Alveoli: Tiny air sacs that allow for gas exchange to occur between air and the bloodstream

Larynx

• The larynx, or voice box, is a cartilaginous chamber about 4 cm long
• Its primary function is to keep food and liquid out of airways, it also produces sound.

Trachea and Bronchi

• The trachea is a tube about 12 cm long and 2.5 cm in diameter, positioned anterior to the esophagus.
• The trachea has 16 to 20 C-shaped rings of hyaline cartilage.
• The trachea branches into the right and left bronchi at the level of the sternal angle and vertebra 15.

Bronchial Tree

• The branching of the bronchi follows a pattern, starting with primary bronchi, leading to secondary and tertiary bronchi, then to bronchioles, and ending with the smallest, terminal bronchioles.

Lungs

• Lungs consist of three faces (diaphragmatic, costal, mediastinal)
• The lung's root (hilum) is an entrance/exit point for structures like bronchi, vessels, and nerves.
• Lungs have lobes (usually 3 on the right, 2 on the left).

Pleura

• Pleura is a two-layered serous membrane that surrounds the lungs, with layers called the visceral pleura(next to the lungs) and parietal pleura (lining the thoracic cavity).
• These layers form a space surrounding the lungs called the pleural cavity, containing serous fluid that prevents friction during breathing.