The Respiratory System Laboratory Activity

Introduction

The respiratory system is a biological system consisting of specific organs and structures used for gas exchange. Gas exchange in the lungs occurs in millions of small air sacs; in mammals called alveoli. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.

In humans the respiratory tract is divided into an upper and a lower respiratory tract. The upper tract includes the nose, nasal cavities, sinuses, pharynx and the part of the larynx above the vocal folds. The lower tract includes the lower part of the larynx, the trachea, bronchi, bronchioles and the alveoli.

The branching airways of the lower tract are often described as the respiratory tree or tracheobronchial tree. The first bronchi to branch from the trachea are the right and left main bronchi. Second, only in diameter to the trachea (1.8 cm), these bronchi (1 -1.4 cm in diameter) enter the lungs at each hilum, where they branch into narrower secondary bronchi known as lobar bronchi, and these branch into narrower tertiary bronchi known as segmental bronchi. Further divisions of the segmental bronchi (1 to 6 mm in diameter)[7] are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi

Complete Lab Activities for the Respiratory System:

Exercise 1: Respiratory System Anatomy

• Practice – 3D Model Activity – Use Anatomical models of the Respiratory System – available in the lab to identify the following structures:
• Anatomical models available in the lab include: Torsos, Tracheobronchial tree, Giant nose.
• To supplement the lab view the respiratory system anatomical model explained:

Exercise 2: Histology of the Respiratory Tract

University of Michigan – Full Slide List or scan QR code below.

Directions:

1. Click to link shown above to use the microscope simulation – Microscope slide of Trachea (Trachea H&E, 40X) and lung
   1. Trachea – slide #127 (it also contains the esophagus, locate the area where you see hyaline cartilage and pseudostratified columnar ciliated epitheliumn)
   2. Lung – slide # 130 (zoom in and locate the alveoli of the lung and bronchioles (there is cartilage around it)

Instructions to use the simulation:

1. Click to zoom-in and double-click to zoom-out
2. Use the “+” or “-+ to Zoom in or out
3. Click-drag to pan.
4. Alt-click to zoom-in 100% and alt-double-click to zoom-out completely.
5. To return to a prior view simply Alt-click the Reset button on the Toolbar. (On Mac, Option-click rather than Alt-click.)

Note: There are more images you can use in the lab folder for the respiratory system.

Exercise 3: Lung inflation model – Watch the following videos/simulations

Inflation model videos: