Module 6 Chapter 17 Flashcards
1
Q
Provide examples of physical barriers and mechanical defences of the human immune system and describe how they function to protect us
A
2
Q
Explain how microbes can provide defense against infection and disease
A
3
Q
What are the different physical defenses?
A
- Physical barriers
- Mechanical defenses
- Microbiome
4
Q
What do physical barriers do?
A
- Prevent microbes from reaching tissues that are susceptible to infection
-Cell junctions
5
Q
The skin barrier
A
- Physical barrier
- Three layers of closely packed cells
- Thin upper layer is epidermis
- Second thick layer is the dermis (contains hair follicles, sweat glands, nerves, and blood vessels)
- Layer of fatty tissue called hypodermis lies beneath the dermis
- Keratin on skin makes the skin’s surface mechanically tough and resistant to degradation by bacterial enzymes
- Fatty acids on the skin’s surface create a dry, salty, and acidic environment that inhibits the growth of some microbes and is highly resistant to breakdown by bacterial enzymes.
- Skin sheds, so do microbes with it
- Breaks in skin cause infections
6
Q
Mucous membranes
A
- Line the nose, mouth, lungs, and urinary and digestive tracts
- Provide another nonspecific barrier against potential pathogens
- Consist of a layer of epithelial cells bound by tight junctions.
- Epithelial cells secrete a moist, sticky substance called mucus, which covers and protects the more fragile cell layers beneath it and traps debris and particulate matter, including microbes
- Mucus secretions also contain antimicrobial peptides
- Movement of mucus is always away from area of infection in the body
- Expelled mucus is then swallowed and destroyed in the stomach or coughed up, or sneezed out: This system of removal is often called the mucociliary escalator
7
Q
Endothelia
A
- Epithelial cells lining the urogenital tract, blood vessels, lymphatic vessels, and certain other tissues
- Tightly packed cells provide a particularly effective frontline barrier against invaders.
8
Q
Mechanical Defenses
A
- Physically remove pathogens from body
- Shedding of skin
- Expulsion of mucus
- Urine
- Tears
- Eyelashes
- Eyelids
- Blinking
9
Q
Microbiome
A
- Resident microbiota serve as an important first-line defense against invading pathogens
10
Q
What are some examples of cellular barrier?
A
- Skin
- Mucous membranes
- Endothelial cells
11
Q
What is the function of cellular barrier?
A
Deny entry to pathogens
12
Q
What are some examples of Mechanical defenses?
A
- Shedding of skin cells,
- Mucociliary sweeping
- Peristalsis
- Flushing action of urine and tears
13
Q
What is the function of mechanical defenses?
A
Remove pathogens from potential sites of infection
14
Q
What are some examples of microbiome?
A
- Resident bacteria of the skin
- Upper respiratory tract
- Gastrointestinal tract
- Genitourinary tract
15
Q
What is the function of microbiome?
A
- Compete with pathogens for cellular binding sites and nutrients
