Bacteria Chapter 6: Host Cell Defense Mechanisms

Question 1

How do sebaceous glands inhibit growth of microorganisms?

Answer 1

secrete fatty acids and lactic acids, which decrease pH of skin

Question 2

How do sweat glands inhibit growth of microorganisms?

Answer 2

express genes encoding antimicrobial peptides, which are secreted into sweat and transported to epidermal surface

Question 3

How does the upper respiratory tract barricade microbial infection? (3)

Answer 3

mucociliary system (mucous membranes that contain mucous-secreting cells and ciliated cells) 
- mucus traps bacteria, and cilia sweep them out

antimicrobial peptides in body secretions – in tongue and throat

microbiota – may include opportunistic pathogens

Question 4

What are the 3 host defense mechanisms of the lower respiratory tract?

Answer 4

mucociliary system – moves particles up towards throat

lungs – alveoli lack ciliated membrane, and are protected by alveolar macrophages and antibodies

antimicrobial proteins and peptides

Question 5

What are the host defence mechanisms of the GI tract?

Answer 5

• stomach acidity
• peristalsis
• microbial antagonism from microbiota