host defence in the lungs : innate immunity

Question 1

define innate immunity

Answer 1

Immunity that is present at birth and lasts a person’s entire life. Innate immunity is the first response of the body’s immune system to a harmful foreign substance

Question 2

3 features of innate immunity in the lungs

Answer 2

quick
non-specific
no memory - can respond to new pathogens

Question 3

3 features of adaptive immunity in the lungs

Answer 3

takes longer
antigen specific
uses memory

Question 4

key cells involved in innate immunity (5)

Answer 4

• neutrophils
• macrophages
• mast cells
• dendritic cells
• NK cells

Question 5

key cells involved in adaptive immunity

Answer 5

• B cells (memory/plasma> antibodies)
• T cells (helper/cytotoxic)

Question 6

what usually causes inflammation in the lungs

Answer 6

pathogens or by exposure to toxins, pollutants, irritants, and allergens

Question 7

which diseases cause acute inflammation

Answer 7

pneumonia

acute respiratory distress syndrome (ARDS)

Question 8

which diseases cause chronic inflammation

Answer 8

asthma and chronic obstructive pulmonary disease (COPD)

Question 9

what is the first site of contact with inhaled agents in the lungs

Answer 9

the airway epithelium

Question 10

what are the physical innate mechanisms to protect the lungs

Answer 10

respiratory epithelium

production of antimicrobial molecules

coughing

sneezing

surfactant

Question 11

how does coughing protect the lungs

Answer 11

natural reflex

clears airways by getting rid of air from respiratory tract

1. inspiration causes epiglottis to close
2. thoracic pressure increases
3. air is forced out down pressure gradient

Question 12

how does the respiratory epithelium protect the lungs

Answer 12

1. produces antimicrobial proteins
2. mucus layer
3. cilia
4. mucociliary clearance/escalator
5. tight junctions between cells

Question 13

which antimicrobial proteins are produced by respiratory epithelium protect the lungs (5)

Answer 13

1. lysozyme
2. mucins
3. defensins
4. lactoferrin
5. nitric oxide

these all kill bacteria

Question 14

how does mucus protect the lungs

Answer 14

forms a protective physical barrier that

prevents attachment of bacteria to the epithelium

prevents microorganism and noxious substances from reaching the surface of the epithelium

sticky substance - helps with trapping and removing foreign particles

Question 15

what is the mucociliary escalator

Answer 15

is inside of the conducting airways

uses mucus to trap dirt, air pollution particles and pathogens

then cilia, small hairs that undulate in the moving mucus, sweep the unwanted matter towards our throat where it is coughed or swallowed

Question 16

how do tight junctions between cells in respiratory epithelium protect lungs

Answer 16

prevent pathogen entry

Question 17

how does surfactant protect lungs

Answer 17

reduces surface tension at the air–water interface in the alveoli

preventing collapse of these structures at end-expiration

Question 18

what are non physical innate immune responses

Answer 18

alveolar macrophages

Question 19

what are alveolar macrophages

Answer 19

a type of white blood cell on the surface of alveoli

Question 20

why are alveoli not protected by mucus and cilia

Answer 20

because of the requirements of gas exchange

mucus is too thick and would slow movement of oxygen and carbon dioxide.

Question 21

how do alveolar macrophages work

Answer 21

they seek out foregin particles, bind to them, ingest them, kill any that are living, and digest them.

when the lungs are exposed to serious threats, additional white blood cells in the circulation, especially neutrophils, can be recruited to help ingest and kill pathogens

Question 22

why is inflammation a double-edged sword

Answer 22

it used as our defence against infection and a hostile environment

but

inflammatory processes can cause diseases that lead to death