Innate Immune System-2

Innate Immune - Innate Immune System Innate Immune System Our world is covered in microbes and for the most part they play an important and

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Innate Immune System
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Our world is covered in microbes and for the most part, they play an important and essential role. However, our bodies represent a fantastic source of nutrients and shelter and without an extremely active defense system, we would quickly succumb to their constant attack. We have evolved very effective defenses against this onslaught and in this e-module, we will focus on the branch of the immune system called the innate immune system and examine how this system protects us from disease. The innate immune system is also called constitutive immunity, because this system is always active. The innate immune system will respond to any invading microbe and does not require prior exposure. This defense system is often the initial line of defense against a pathogen. If your body is like a castle, the defense strategies employed are somewhat akin to forming walls and moats (physical barriers to prevent entry) and roaming patrols (soldiers to kill invaders). In addition, there is an arsenal of chemicals and proteins that can assist in these tasks . These defenses are considered non- specific because they will target any microbe. The innate immune system is evolutionarily very old and can be found in various forms in nearly all forms of life including plants, fungi, and insects. Innate Immune System Figure 1 Castle Neuschwanstein
Background image of page 2
Figure 2 Mechanical removal of Microbes Preventing entry of a microbe into the body is the first line of defense for the innate immune system. Anything exposed to the outside environment needs an extra level of defense, and common ports of entry include the surface of our skin, the respiratory tract and the digestive tract. There are three methods of defense: physical barriers, inhibitory chemicals or proteins and mechanical removal (see figure 2). Skin is the largest organ in vertebrates, in an adult human 15% of the total weight is skin, and it is an absolutely essential organ. Besides keeping water in, skin also keeps microbes out. This is very important when you consider the fact that one square inch of skin contains around 50 million bacteria that no amount of cleaning can completely remove. Skin keeps these microbes on the surface by providing a nearly impenetrable physical barrier that is supplemented with chemical weapons. For example, oil and sweat glands within the skin lower the pH to a level that inhibits microbial growth. Sweat produces a chemical weapon called lysozyme that digests the cells walls of many bacteria. Skin cells also produce proteins called anti- microbial proteins that are known as “natural antibiotics” because of their ability to kill a wide-array of microbes. Lastly, dead skin is constantly sloughing off taking the adherent microbes along with it. Maintaining a basic level of hygiene also goes a long way in assisting
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/21/2008 for the course BIOL 100 taught by Professor Lee during the Winter '07 term at San Diego State.

Page1 / 11

Innate Immune - Innate Immune System Innate Immune System Our world is covered in microbes and for the most part they play an important and

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online