Chapter 16: Host-Microbe Interactions: Invasion Continued

Question 1

Name the 3 portals of entry for invasion

Answer 1

1. Mucous membranes
2. Skin
3. Parenteral Route

Question 2

Name the 4 portals of entry as per mucous membranes

Answer 2

1. respiratory tract
2. GI tract
3. Genitourinary Tract
4. Conjunctiva

Question 3

How is the respiratory tract a portal of entry? (2)

Answer 3

• most common portal of entry
• microbes inhaled into nose or mouth
  ex. colds, influenze

Question 4

How is the GI tract a portal of entry? (3)

Answer 4

• germs enter in food or water
• most are destroyed by acid (stomach) or by bile (intestine)
• some can survive, Ex. Vibrio Cholera

Question 5

How is the Genitourinary Tract a portal of entry? (2)

Answer 5

• STIs
• most pathogens require a broken mucous membrane
  ex. a cut or a microabrasion

Question 6

How is the conjunctiva a portal of entry?

Answer 6

• membrane covering the eye

Question 7

How is the skin a classification of a portal of entry? (3)

Answer 7

• unbroken skin is impenetrable by most microbes
• some microbes can cause infections of hair follicles (acne)
• most require a wound for entry

Question 8

How is the parenteral route a classification of a portal of entry?

Answer 8

• microbes deposited directly into tissues when skin or membranes are broken
  note that parenteral means outside of the digestive tract (not mouth or alimentary canal)

Question 9

Give 2 examples of how the parenteral route is a portal of entry

Answer 9

1. Tick bite can introduce bacteria into host, causes lyme disease
2. Intravenous injections with contaminated syringe can cause HIV