lecture 1 Flashcards

(28 cards)

1
Q

What happens when immune system Goes wronge

A
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2
Q

How deos the skin act as a physical barrier againts organisms

A
  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
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3
Q

How does mucous act as a barrier to prevent infection

A
  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
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4
Q

How does commensal bacterial act as a defence againts other pathogens

A
  • 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
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5
Q

What can happen if we use broad-spectrum antibiotics

A

Eradication of normal bowel flora and leading to opportunistic infections

  • Oral, vaginal candidiasis - after oral antibiotics
  • C. diff after IV antibiotics
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6
Q

How can these barriers be breached by iatrogenic causes

A
  • Insertion of hardwire - IV lines, catheters and nasogastritubes
  • Antibiotics
  • Anti-acid medication
  • Antimicrobial wipes
  • Nasal decongestants
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7
Q

What are all cells of the immune system

A
  1. Phygocytes: neutrophils, macrophages, monocytes and dendritic cells
  2. Lymphocytes: B, T cells and natural killer cells
  3. Mast cells, eosinophils and basophils
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8
Q

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

A
  • Antibodies
  • Acute phase proteins
  • Cytokines
  • Complement system proteins
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9
Q

What are cytokines

A

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

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10
Q

What are the key features of cytokines

A
  • Multiple functions
  • Short half-life
  • can act locally or systemically
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11
Q

What are the types of cytokines and whats there function

A
  • Interferons - Anti-viral activity
  • Tumour necrosis factor Pro-inflammatory cytokines
  • Chemokines Cell migration
  • Interleukines Various functions
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12
Q

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

A
  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
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13
Q

Where do B and T cells constantly circulate

A

Blood lymph and secondary lymphoid tissue

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14
Q

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

A
  1. Helper T cells - regulate immune system
  2. Cytotoxic T cells - kill virally infected Body cells
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15
Q

What are Natural killer cells and whats their function

A
  • 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
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16
Q

What are mast cells

A

Live in tissues and protect mucosal surfaces

17
Q

What are basophils and eosinophils

A

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

18
Q

Whats the function of basophils, eosinophils and Mast cells

A
  • 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
Q

What is the complement system

A
  • 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
20
Q

What are macrophages, monocytes and neutrophils

21
Q

What are the functions of phagocytes

A
  • Ingesting and killing bacteria + fungi
  • Clearing debris - dead/dying cells and immune complexes
  • Production of cytokines
22
Q

Desctribe the role of monocytes

A

Circulates in blood - migrate into peripheral tissue and become macrophages

23
Q

Describe Macrophages

A

long-lived tissue resident phagocytes

24
Q

what are the different types of macrophages

A
  • 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**
26
Describe neutrophils/ Polynuclear cells
* Phagocytic cells that ciruclate the blood * Short-lived * **rapidly recruited to inflammed, damage and infected cells**
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**
28
Compare neutrophils, denritic cells and macrophages