Basic Human Biology

Respiratory System

The way in which air moves through our body is in this order

  • Nostrils
  • Nasal cavity
  • Pharynx
  • Larynx
  • Trachea
  • Thoracic cavity
  • Bronchi
  • Alveoli


The respiratory system has two zones, which include:

  • Upper respiratory tract
  • Lower respiratory tract
We inhale and exhale the air we breathe.

During inhalation, we normally take in 10 to 18 breaths per minute during resting. When doing exercise or strenuous activities the breath rate can be as much as 35 breaths in one minute.

The muscles that aid in inhalation are:

  • Sternocleidomastoid
  • Platysma
  • Strap muscles of the neck


Exhalation is when be breath out. This process is accomplished with the help from:

  • Abdominal muscles
  • Internal intercostal muclses