Chapter 16, Problem 1R

Identify at least one physical and one chemical factor that prevent microbes from entering the body through each of the following:

1. a. urinary tract
2. b. reproductive tract

Summary Introduction

To review:

The physical and chemical factors of the urinary tract and reproductive tract which prevent the entry of microbes.

Introduction:

Innate immunity refers to non-specific defense mechanisms, which acts immediately after the exposure of antigens or foreign substances on the body. On the other hand, adaptive immunity refers to antigen-specific immunity that adapts the immune system by the formation of immune cells or memory cells for a specific antigen.

The physical and chemical barriers act as a protective coat or first line of defense for skin and mucus membrane against the environmental pathogens. The physical barrier protects the surface of the body, whereas the chemical factors protect the entry of pathogens through the mucous membrane.

Explanation of Solution

1. a. Urinary tract:

Physical factor - It involves the cleaning mechanism of the urethra by the excretion of urine.

Chemical factor - The urinary tract contains the lysozyme enzyme in acidic state, which helps to inhibit the entry of microbes.

1. b. Reproductive tract: 

Physical factor – It helps to move out the microbes from the female reproductive system.

Chemical factor - In the female reproductive system, the chemical factor is involved in two ways; one is to remove the microbes by creating an acidic environment. The creation of acidic conditions mainly arises due to the breakdown of glycogen in vaginal epithelial cells by lactic acid bacteria. Another one is by cervical mucus, which has antimicrobial ability.

Conclusion

The physical and chemical factors that play a major role in nonspecific defense against foreign substances or microbes is a primary immune response of all vertebrates