Lungs

• Trachea


  • Contains rings of cartilage to prevent it from collapsing when we inhale
• Air passage into the lungs

  1. Trachea

  2. Bronchi

  3. Bronchioles

  4. Alveoli
• Alveoli


  • Microscopic air sacs where gas exchange occurs
• Alveoli adaptations for gas exchange


  • Huge surface area
  • Very thin walls (short diffusion path)
  • Good blood supply
• Oxygen diffuses into the bloodstream


  Carbon dioxide diffuses out of the bloodstream
• Breathing


  Brings fresh oxygen into the alveoli and takes away carbon dioxide, increasing the concentration gradients for these gases
• The adaptations of the lungs for gas exchange are very important and you will find plenty of questions on them in the revision workbook
• The pleural membrane lines the thoracic cavity and covers the surface of the lungs, allowing them to move freely during breathing.
• Each lung is divided into lobes, with the right lung having three (upper, middle, lower) and the left lung having two (upper, lower).
• The right lung has three lobes, while the left lung has two due to the heart taking up space on its side.
• Each lobe is divided into smaller segments called bronchopulmonary segments.
• The respiratory system also plays a role in vocalization and the sense of smell.
• The lungs are the organs responsible for gas exchange between the body's internal environment and external air.
• Another crucial function of the respiratory system is to help regulate the body's pH levels by controlling the levels of carbon dioxide in the blood.
• The primary function of the respiratory system is to supply oxygen to the body and remove carbon dioxide.
• On the other hand, if there is not enough carbon dioxide in the bloodstream, alkalosis may occur, leading to symptoms like confusion, muscle spasms, and seizures.
• If there is too much carbon dioxide in the bloodstream, it can lead to acidosis, which can have serious consequences such as coma or death.
• Bronchioles are small branches that lead to alveoli, where gas exchange occurs.
• The trachea divides into primary bronchi that enter the hilum of each lung.
• Carbon dioxide is produced during cellular metabolism and must be removed from the body through exhalation.
• There are about 300 million alveoli in total.
• The trachea connects the pharynx to the main bronchi, which branch off from it.
• Air enters through the nostrils or mouth and passes down the nasal passages, which warm and moisten it.
• Alveolar ducts lead to small groups of alveoli that form an acinus.