
To review:
The three ways in which the immune system combats pathogens.
Introduction:
The immune system is said to have three lines of defense – physical, non-specific and specific.

Explanation of Solution
The immune system has levels at which it defends the body against pathogens.
Physical barriers make up the first level of defense, by preventing the pathogens from entering and establishing infection in the body. The skin, hair in the nose and ears, and the mucus membranes are examples of physical barriers. They also secrete some chemicals that stop the growth of pathogens.
Non-specific immunity refers to the immune cells that attack all foreign objects, without specifically attacking one type of pathogen. This type of defense is rapid and is seen in almost all multicellular organisms. This is also called innate immunity since we are born with it.
Specific immunity refers to the cells and molecules that recognize specific pathogens, remember them and attack them strongly when they re-enter the body. This is slow to activate, but offers the best protection once activated. This is also called adaptive immunity.
Physical barriers are the surfaces such as the skin, hair and the mucus membranes, that prevent the entry of pathogens into the body. Non-specific immunity refers to the immune cells that recognize any foreign object and attack it rapidly, without being specific to one pathogen. Specific immunity refers to the immune cells and molecules that recognize and fight off specific pathogens, that the body has been previously exposed to.
Want to see more full solutions like this?
Chapter 27 Solutions
EBK WHAT IS LIFE? A GUIDE TO BIOLOGY
- 22. Which of the following mutant proteins is expected to have a dominant negative effect when over- expressed in normal cells? a. mutant PI3-kinase that lacks the SH2 domain but retains the kinase function b. mutant Grb2 protein that cannot bind to RTK c. mutant RTK that lacks the extracellular domain d. mutant PDK that has the PH domain but lost the kinase function e. all of the abovearrow_forwardWhat is the label ?arrow_forwardCan you described the image? Can you explain the question as well their answer and how to get to an answer to an problem like this?arrow_forward
- Describe the principle of homeostasis.arrow_forwardExplain how the hormones of the glands listed below travel around the body to target organs and tissues : Pituitary gland Hypothalamus Thyroid Parathyroid Adrenal Pineal Pancreas(islets of langerhans) Gonads (testes and ovaries) Placentaarrow_forwardWhat are the functions of the hormones produced in the glands listed below: Pituitary gland Hypothalamus Thyroid Parathyroid Adrenal Pineal Pancreas(islets of langerhans) Gonads (testes and ovaries) Placentaarrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage LearningMedical Terminology for Health Professions, Spira...Health & NutritionISBN:9781305634350Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. SchroederPublisher:Cengage Learning
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage LearningBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning



