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Flashcards in lecture 1 Deck (28):
1

What happens when immune system Goes wronge

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2

How deos the skin act as a physical barrier againts organisms 

  1. Physical barrier - Tightly packed keratinised cells which can constantly replace themselves 
  2. Physiological barrier - Low PH and low oxygen tension 
  3. Sebacous glands - Secretes 
  • Hydrophobic oils
  • Lysozyme
  • Ammonia
  • Antimicrobia peptides 

 

3

How does mucous act as a barrier to prevent infection

  1. Physical barrier - traps invadors 
  2. Secretion of IgA - Prevent attachment and penetration of cells by organisms
  3. Lysozymes, definsins, antimicrobial peptides - directly kill invading pathogens 
  4. Latoferin - starves invading bacteria or Iron 
  5. Cillia - Traps pathogen and leads to clearance of mucous assisted by sneezing and coughing 

4

How does commensal bacterial act as a defence againts other pathogens

  • Production of bactericidins - influence other bacteria
  • Synthesis of vitamins - Vitamin K and B12 
  • Anti-microbial short-chain fatty acids 
  • Compition for nutrients 
  • Reduction of PH in bowel 

5

What can happen if we use broad-spectrum antibiotics 

Eradication of normal bowel flora and leading to opportunistic infections

  • Oral, vaginal candidiasis - after oral antibiotics
  • C. diff after IV antibiotics 

6

How can these barriers be breached by iatrogenic causes 

  • Insertion of hardwire - IV lines, catheters and nasogastritubes
  • Antibiotics 
  • Anti-acid medication 
  • Antimicrobial wipes
  • Nasal decongestants 

7

What are all cells of the immune system 

  1. Phygocytes: neutrophils, macrophages, monocytes and dendritic cells
  2. Lymphocytes: B, T cells and natural killer cells  
  3. Mast cells, eosinophils and basophils 

8

What are all the soluble factors/proteins of the immune system 

  • Antibodies
  • Acute phase proteins 
  • Cytokines 
  • Complement system proteins 

9

What are cytokines 

Diverse collection of proteins and peptides which are activated in responce to infection, inflammation or tissue damagw 

10

What are the key features of cytokines 

  • Multiple functions 
  • Short half-life
  • can act locally or systemically 

11

What are the types of cytokines and whats there function

  • Interferons -                              Anti-viral activity 
  • Tumour necrosis factor           Pro-inflammatory cytokines 
  • Chemokines                             Cell migration 
  • Interleukines                            Various functions 

12

What are the 3 different types of signalling that can be carried out by Cytokines 

  1. Paracrine signaling - Acting on local cells causes a quick reponse and lasting for a short period
  2. Endocrine signalling - Acting on distant cells causing a slower but longer lasting responce 
  3. Autocrine signalling - Acting on the same cells that produced them- signaling and target cell can be the same or similar 

13

Where do B and T cells constantly circulate 

Blood lymph and secondary lymphoid tissue 

14

What are the 2 types of T-cells and whats their function

  1. Helper T cells - regulate immune system
  2. Cytotoxic T cells - kill virally infected Body cells 

15

What are Natural killer cells and whats their function 

  • Large granular lymphocytes - release lytic granules that kill some virally infected cells 
  • Detecting and killing tumour cells and virally infected cells
  • Can also kills antibody bound pathogens 

 

16

What are mast cells 

Live in tissues and protect mucosal surfaces 

17

What are basophils and eosinophils 

Circulate in the blood in small amounts - Recruited to the site of infection by inflammatory signals 

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18

Whats the function of basophils, eosinophils and Mast cells 

  • Granular cells 
  • Release heparin, histamine and pro-inflammatory cytokines 
  • Important defense againts pathogens which are too big - Parasitic worms 
  • Key role in mediating allergic responce 

19

What is the complement system 

  • Family of 30 proteins produced in the liver
  • Circulate as inactive precursor proteins - upon entering infected/inflammed tissue become activated 
  • cleave each-other downstream in a biological cascade 
  • Promote inflammation and defending againts bacterial species 

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20

What are macrophages, monocytes and neutrophils 

Phagocytes

21

What are the functions of phagocytes 

  • Ingesting and killing bacteria + fungi 
  • Clearing debris - dead/dying cells and immune complexes 
  • Production of cytokines 

22

Desctribe the role of monocytes 

Circulates in blood - migrate into peripheral tissue and become macrophages

23

Describe Macrophages 

long-lived tissue resident phagocytes

 

24

what are the different types of macrophages 

  • Kupffer cells
  • Alveolar macrophages - lungs 
  • Mesangial cells - kideny
  • Microglial cells - nervous system

25

What are functions of macrophages 

  • phagocytosis
  • Limit inflammation 
  • Tissue repair and wound healing 
  • Antigen presentation 

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26

Describe neutrophils/ Polynuclear cells 

  • Phagocytic cells that ciruclate the blood 
  • Short-lived
  • rapidly recruited to inflammed, damage and infected cells 

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27

Describe dendritic cells 

  • In peripheral tissue as immature
  • Phagocytose antigens
  • Become mature and migrate into secondary lymphoid tissue where they have a role in antigen presentation 

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28

Compare neutrophils, denritic cells and macrophages 

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