This lesson will describe the function and basic anatomy of your trachea, which is an important structure within your respiratory system. A post-lesson quiz will test what you have learned.
Getting Oxygen to Your Tissues
Your trachea is essentially an air-conducting tube (commonly known as your windpipe) that connects your larynx to the rest of your respiratory system. Though the cylindrical tube is only about three-quarters of an inch in diameter and 4 to 5 inches long, you wouldn’t be able to survive without it.
Every cell in your body needs oxygen to produce energy. Without a constant supply of oxygen, your tissues and organs would falter and eventually cease functioning. Some highly active organs, such as your brain and heart, can be irreversibly damaged if their oxygen supply is interrupted for only a few minutes.Most of your cells, tissues, and organs lie far beneath the surface of your body and don’t have access to the oxygen in the atmosphere. Therefore, they must have oxygen delivered to them from some distance away. Fortunately, nature has devised a way to address this problem.
Your body relies on two closely intertwined organ systems to provide the oxygen your cells require. Your respiratory system is responsible for drawing oxygen into your body, while your circulatory system is charged with delivering the oxygen to your tissues.These two systems overlap in your lungs, where oxygen from inhaled air is absorbed into your bloodstream.
At the same time, carbon dioxide, a waste product of cellular metabolism, is removed from your bloodstream and transferred to the air you exhale with every outward breath.
The Respiratory Tree
Much of your respiratory system is composed of simple conduits, or pipes, that conduct gases between the atmosphere and your lungs. As you inhale, air is drawn through your nose and mouth, funneled into your throat, and routed through your larynx, or voice box.
Your Adam’s apple, which is formed by a broad, tough ring of cartilage surrounding your larynx, is a surface landmark showing the location of your larynx.As inhaled air passes through your larynx, it enters your trachea (from the Greek word for rough). Your trachea extends downward into the center of your chest, where it divides into two separate tubes called bronchi.
(Bronchi is the plural form of bronchus.) Your bronchi then divide into progressively smaller tubes that deliver air to each segment of your lungs.The overall structure of your major airways resembles an upside-down tree. (In fact, doctors often refer to this system of tubes as the respiratory tree.) If you imagine your larynx as the root of the up-ended tree, you can see how your trachea would represent the tree’s trunk, and the bronchi and smaller airways would represent the progressively smaller branches of the tree.
External Anatomy of the Trachea
Many of the tubes in your body – your arteries, veins, and intestine, for example – are at least partially collapsible. Your trachea and bronchi are specifically designed to resist squashing, making them unlike these other structures. If the trachea wasn’t a rigid tube, every time you tried to exhale the pressure in your chest would collapse the trachea’s walls – much like pinching the end of an inflated balloon – and trap the air within your lungs.Your trachea maintains its rigidity by virtue of a series of cartilaginous rings arranged along its length, called C-shaped cartilage rings. The open part of each ‘C’ is found at the back of your trachea, which rests directly against your esophagus. The esophagus is the collapsible tube leading from the back of your throat to your stomach. If the cartilage rings in your trachea completely encircled it, they would press against your esophagus and you would have difficulty swallowing your food.
The gaps between the trachea’s cartilage rings are bridged by strong elastic membranes. Thus, while your trachea is very resistant to compression, it does have the ability to stretch slightly along its length, like a long, tubular accordion. This permits it to lengthen and shorten somewhat during breathing.
Internal Anatomy of the Trachea
Your trachea is a living structure. Its inner wall is lined by a layer of cells that produce large volumes of mucus. This mucus coat moistens and warms the air you inhale, making it less irritating to your lungs.The cells that line the inner surface of your trachea are covered with tiny, hair-like projections called cilia, which beat in a coordinated fashion to move mucus, trapped dust, cellular debris, and bacteria upward and out of your airways.
You unconsciously swallow several cups of mucus from your lungs every day.This mucociliary ladder serves an important ‘street-sweeping’ function: it protects you from infections and inhaled substances that could be harmful to your lungs. Cigarette smoke paralyzes the cilia in your airways, which partially accounts for the higher incidence of respiratory infections in smokers.
The trachea is an important structure within your respiratory system, which is the organ system that delivers oxygen to your bloodstream. The trachea is a rigid tube that conducts air from your larynx to your bronchi. The trachea’s rigidity is maintained by a series of cartilaginous rings arranged along its length called C-shaped cartilage rings. These cartilage rings are C-shaped to provide room for your esophagus, which lies along the backside of your trachea. The gaps between the cartilage rings are bridged by a tough elastic membrane.The trachea is very resistant to compression, but it is capable of stretching lengthwise.
These physical characteristics prevent your trachea from collapsing during respiration while simultaneously allowing it to compensate for the chest motions associated with breathing.The inner surface of your trachea is lined by a mucus membrane, which is itself covered with cilia. The mucociliary ladder continually sweeps debris and infectious organisms out of your airways and toward your mouth, where they can be swallowed.
- trachea: an air-conducting tube (commonly known as your windpipe) that connects your larynx to the rest of your respiratory system
- respiratory system: organ system responsible for drawing oxygen into your body
- circulatory system: organ system responsible for delivering oxygen to your tissues
- carbon dioxide: a waste product of cellular metabolism
- larynx: commonly known as the voice box
- bronchi: two separate tubes from the trachea that divide progressively into smaller tubes that deliver air to each segment of the lungs
- C-shaped cartilage rings: a series of cartilaginous rings arranged along its length in the trachea
- cilia: tiny, hair-like projections that line the inner surface of the trachea
When the lesson ends, it will be time to take on these challenges:
- Define the trachea
- Identify the parts of the trachea
- Describe the significant role of the trachea in the respiratory system