Immune System and Diseases: Surface Barriers

Question 1

The first line of defence

Answer 1

Surface barriers

Question 2

Types of surface barries

Answer 2

Skin and mucous membranes

Question 3

How is skin a surface barrier?

Answer 3

-Protects external structures (outer body parts)

-Secretes lactic acid and fatty acids to lower the pH

-Has biochemical defense agents

Question 4

The biochemical defense agents on the skin

Answer 4

Sebaceous glands secrete chemicals and enzymes which inhibit microbial growth on the skin

Question 5

How is mucous membranes a surface barrier

Answer 5

-Protects internal structures (externally accessible cavities and tube such as esophagus, urethrae, and trachea)

-Consists of thin region of living surface cells

-Biochemical defense agents

-May be ciliated to aid in the removal of pathogens

Question 6

Function of cells in mucous membranes

Answer 6

Release fluids to wash away pathogens

Question 7

Fluids used to wash away pathogens

Answer 7

Mucus, saliva, tears

Question 8

Secreted biochemical defense agents in mucous membranes

Answer 8

Lysozyme destroys cell walls and cause cell lysis

Question 9

Overview of Physical and Chemical Surface Barriers

Answer 9

-Lysozyme in tears and other secretions

-Removal of particles by cilia in nasopharynx (nostril)

-Mucus lining trachea

-Rapid pH change in gut

-Vaginal acids (in females)

-Flushing of urinary tract)