The Immune System Flashcards
Role of lymph nodes
Filter fluids in collecting vessels
4 lymphoid organs
- Spleen
- Lymph nodes
- Tonsils
- Thymus
What occurs at the arterial end of the capillaries- state the direction of fluid
Filtration - fluid moves out
What occurs at the venous end of the capillaries - state the direction of fluid
Reabsorption - fluid moves in
How much excess fluid is drained OUT of the blood into the lymphatic system?
3L
Why does fluid move out of the capillaries at the arterial end?
The hydrostatic pressure is greater than osmotic pressure
Why does fluid move into the capillaries at the venous end?
The osmotic pressure is greater than the hydrostatic pressure
What type of cells are lymph capillaries made from?
Endothelial cells
2 unique structural modifications in the capillaries
- Cells overlap to create valves
2. Gaps in the wall to prevent leakage
3 tunics of lymph collecting vessels
- Interna
- Media
- Externa
What do lymphatic vessels in the skin travel with?
Superficial veins
What do vessels in the deep lymphatic system travel with?
Deep arteries
Which parts of the body drain into the right lymphatic duct?
- right arm
- right side of brain
- right side of thorax
where does most of LHS of body drain into ?
Thoracic duct
What veins does the lymph enter? (2)
- Subclavian vein
2. Internal jugular vein
Does the lymph system have a pump?
No
What type CT is there in lymphoid tissue?
Reticular
Where in the lymphatic system are B cells stored?
Nodules
2 distinct regions of the lymph node
- Inner medulla
2. Outer cortex
Where does lymph enter the lymph nodes?
Afferent lymphatic vessels
Where does lymph leave the lymph nodes?
efferent lymphatic vessels at the hilus
4 types of tonsils
- Palatine
- lingual
- Pharyngeal
- Tubal
Where does interstitial fluid collect?
Intercellular spaces
Why is lymph slow moving and has a low pressure?
The lymphatic system does not have a pump
Which places is lymphoid tissue stored?
- Most organs
2. Nodules
What is lymphoid tissue?
Immune tissue
Where are lymph nodules found?
Within lymph nodes
Function of lymph sinuses
allow macrophages to enter
Which area of the spleen contains the venous sinus, red cells and splenic cord?
Red pulp
What does the white pulp of the spleen contain?
Lymphocytes on reticular fibres
What hormones does the thymus secrete to make T cells immunocompetent?
- thymosin
2. thymopentin
2 areas of the thymus
- Dark staining cortex
2. Light staining medulla
Which area of the thymus contains densely packed lymphocytes?
Dark staining cortex
Role of Thymic corpuscle?
converts self-reactive T cells into immunosupressive T cells
Role of tonsils
gather inhaled/ingested pathogens
Which tonsil surrounds the auditory tube?
Tubul
Which tonsil is at the back of the nasopharynx?
Pharyngeal
Which tonsil is under the tongue?
Ligual
Where are the palatine tonsils?
Either side of the posterior oral cavity
What do viruses need to replicate?
A host
Do viruses contain any organelles?
No
How to viruses bind to the host cells?
Surface proteins that host cells recognise
Name a virus and disease which the virus dormant time can be decades
Chicken pox - shingles
What structure can bacteria form to act together?
Biofilms
Which type of bacteria have purple staining?
Gram +ve
describe the cell wall in gram -ve bacteria
Thin peptidoglycan wall
Extra cell membrane - lipopolysaccharide
What is cellulitis an infection of?
The skin
Are fungi eukaryotes or prokaryotes?
Eukaryotes
Why are fungal infections hard to treat?
Because they have the same organelles as human
3 types of fungi
- Yeast
- Mould (pores)
- Dimorphic
What is dimorphic fungi?
Fungi that can switch between types
Thrush, athletes foot and ringworm are all types of what infection?
Mild fungal infection
Parasite that lives outside of the body
Ectoparasite
Parasite that lives inside of the body
Endoparasite
Parasite that lives inside of another parasite
epiparasite
2 classes of human parasites
- Protazoa
2. Helminths
What is the name of the protazoa that causes diarrhoea?
Giardia
Which human cell does malaria enter?
RBC
3 types of helminths
- Trematodes
- Nematodes
- Cestodes
Name of helminth tapeworms
Cestodes
What diseases can cestodes cause:
- Malnutrition
2. Malabsorption
How does a fluke enter a human body
By the skin
What is the smallest infective agent?
Prions
How do prions affect proteins
causes them to change their folding shape - becomes non-functional
What is microflora?
Microorganisms on the surface of the skin - preventing other bacteria from entering
Name 4 ways to recognise antibody binding
- Enzyme
- Collodial gold
- Radioactive element
- Fluorescent dye
Why is the indirect method using fluorescent dyes for immunohistochemistry not persistant?
The antibodies do not stay attached for long
What colour stain is produced with the indirect method of IHC using an enzyme?
brown
What antibody is biotinylated in IHC?
Secondary antibody
What is used to preserve a antibody staining?
Chemical fixatives
Why are chemical fixatives sometimes a problem?
Identification of the antibody binding is lost
Why is an isotyte antibody used during Immunohistochemistry?
To test for a false positive
During ELISA, why are the plates washed?
to remove unbound antibodies
Advantage of competitive ELISA
more specific
Do bacterial cells have a nuclear membrane?
No
What are the 70s bacterial ribosomes split into?
30s and 50s
What are the 80s mammalian ribosomes split into?
40s and 60s
What is an aerobic organism?
requires oxygen to grow
What is an anaerobic organism?
Doesnt require oxygen for growth
What is the name of an organism which can use oxygen for growth but also has anaerobic methods of energy production
Facultative
What are atypical bacteria?
Do not stain either gram +ve or -ve
Name 3 types of atypical bacteria
- Mycoplasmas
- Chylamadiae
- Rickettsiae
How is DNA carried in bacteria?
Plasmids in the cytoplasm
Term that describes: medicine that inhibits the growth/destroys microorganism
Antibiotic
Term that describes: destructive/inhibiting growth of bacteria
Antibacterial
Term that describes: destructive/inhibiting growth of microorganisms
Antimicrobial
Term that describes: chemical liquid that destroys bacteria
Disinfectant
Term that describes: drug/substance which kills bacteria
Bactericidal
Term that describes: Capable of inhibiting the growth of bacteria
Bacteriostatic
Name of 2 types of antibiotics acting on the cell wall
- beta lactams
2. Glycopeptides
Function of beta lactam
break cross links in peptidoglycan cell wall
Mechanism of action of penicillin
work on penicillin-binding-proteins on bacterial cell wall to weaken it and affect cell division
How do glcopeptides function?
inhibit peptidoglycan formation - prevention of joining dimers
Why cant glycopeptides work against gram -ve bacteria?
It is too large to penetrate through the lipopolysaccharide wall
Name a type of glycopeptide
Vancomycin
Where do lipopeptide antibiotic work?
Cell membrane
How do lipopeptide antibiotics work?
Depolarise the cell membrane
Which antibiotic acts on the 23s subunit of 50s ribosome?
Linezoid
Mechanism of chlorophenicol, macrolides and lincosamides (antibiotics)
Attach to 50s ribosomal unit - prevents AA chain forming
Which antibiotic prevents the attachment of mRNA to the ribosome?
Aminoglycosides
Role of tetracyclin antibiotics
Attach to 30s ribosomes - tRNA cannot bind to mRNA
3 Antibiotics acting on nucleic acid synthesis
- Ramfipicin
- Quinolones
- Metranidazole
Role of ramfipicin
inhibits RNA polymerase
Role of Quinolones
Inhibits DNA gyrase - strands cannot reseal
Role of metranidazole
Attaches to DNA strand - causing breakage in strands
How does the antibiotic trimethoprim work?
Interferes with a metabolic pathway
What does trimethoprim inhibit?
dihydrofolate reductase - formation of folic acid
What is antibiotic prophylaxis
using antibiotics before surgery & chemotherapy to prevent infection
What is instrinsic resistance?
The entire species is resistant before the antibiotic has been introduced
3 types of gene transmission in bacteria
- conjugation
- transduction
- transformation
Define a nosocomial disease
An infection not present or incubating prior to admittance to hospital - usually occuring 48 hours after admittance
What pathogen causes Hospital Acquired Pneumonia?
Bacteria
What is CAUTI
Cathetar associated urinary tract infections
What type of bacteria is E Coli?
Gram negative
What does sepsis cause?
Injury to own tissues & organs
What type of bacteria is MRSA?
Gram +ve
What 2 classes of antibiotics are MRSA resistant to?
Penicillin and cephalosporin
How does methicillin kill a bacterial cell, what organelle specifically?
It attaches to penicillin binding sites- weakening the cell wall.
How is MRSA resistant to all penicillins?
Penicillins all contain the beta lactam ring. Resistant strands modify the PBP so penicillins cannot attach.
What type of bacteria is C.diff?
Gram +ve
How is C.diff transmitted?
- Orally
2. Through faeces
what does C.diff form?
Spores
Which enzyme identifies C.diff?
Glutamate dehydrogenase
2 types of toxin tests
1) ELISA
2) PCR
How can antibiotics be a risk factor for C.diff?
They alter gut flora - allowing C.diff to flourish & produce toxins
What is conservative treatment?
Avoiding invasive treatments - watchful waiting etc.
What antibiotics is glycopeptide resistant enterococci resistant to?
1) Vancomycin
2) teicoplanin
What type of bacteria does daptomycin work against?
Gram +ve
Define Vmax
Maximum velocity (rate) of reaction - at saturating [S]
Define Km
[S] at which rate if half of Vmax (maximum rate)
What Km will an enzyme have with low affinity for substrate?
high Km
Define necrosis
Tissue degeneration by lysosomal enzymes due to disease.
What does tissue repair inhibit?
Mast cell activation
Define dysplasia
Loss of normal architecture of cells
Define metaplasia
When tissues adapt to environmental stimuli by change in cell differentiation
What do cells differentiate to and from in the cervix?
columnar to squamous
What is well differentiated malignancy?
cells that closely resemble tissue of origin
What is atheroscleorosis?
Thickening and inelasticity of artery walls
Where are B and T cells produced, developed and matured?
Red bone marrow and thymus gland
3 secondary lymphatic organs
- Spleen
- Lymph nodes
- Lymph nodules
Role of physical barriers in the body
prevent pathogen reaching epithelia
Define haematopoiesis
Formation of blood components
What are interferons produced by?
Lymphocytes, macrophages and fibroblasts which have been infected by a virus
3 types of interferons
- Alpha
- Beta
- Gamma
Which pathogens do interferons work against?
Viruses
Which antimicrobial protein works by puncturing holes in the cell membrane?
Complement cascade
What 3 pathogens do M1 (classically activated macrophages) defend against?
- Viruses
- Bacteria
- Protazoa
What is macrophage plasticity?
Macrophages behave differently depending on what protein they express.
What does PAMPS stand for?
Pathogen associated molecular patterns
What is an epitope?
The small component of an antigen which only initiates an immune response.
What are the 5 types of immunoglobins?
GAMED
How many polypeptide chains does an antibody have?
4
What 3 processes occur when the antigen binds at the variable region?
1) Neutralisation
2) Agglutination
3) Precipitation
In monoclonal antibody technique, what cells are taken from the mice?
Spleen
Which proteins are involved in complement?
C1-C9
which 3 factors are involved in complement?
- Factor B
- Facor D
- Factor P (Properdin)
In terms of complement, which binding protein is involved in the lectin pathway?
Mannose binding protein
3 pathways of complement
- Innate - lectin
- Innate - alternative
- Classical
What enzyme produces alpha gal residues?
alpha-1,3- galactose transferase
What is the name of the type of tolerance which is non-reactivity to an antigen that should cause an immune response?
Acquired tolerence
Where do Pre T cells develop self-recognition?
In the thymus
Which antibody isotype encourages mast cell degranulation?
IgE
Which immune cells are responsible for allergic contact eczema - type 4 hypersensitiivty?
T cells
Which antibody type induces type 1 hypersensitivity?
IgE
Biological effect of a chemokine in type 1 hypersensitivity
Attracts macrophages, neutraphils and monocytes
Which hormone relaxes bronchiole smooth muscle
Epinephrine/adrenaline
Which immune cells phagocyte when the parasite is too large to be engulfed by a phagocyte?
Eosinophil
2 methods of diagnosis for allergies?
- Pinprick test
2. ELIZA - blood sample; IgE titre is taken
What cells undergo apoptosis in atopic dermatitis?
Keratinocytes - skin
Which antibody isotype cause type 2 hypersensitivity?
IgG
2 type 2 hypersensitivity diseases
- Anaemia
2. Thrombocytopenia
In type 2 hypersensitivity, what do IgG antibodies attack?
RBC/platelets
What antibodies cause type 3 hypersensitivity?
IgG
In type 3 hypersensitivity why can only phagocytosis act?
The antigens are soluble
What response does type 3 hypersensitivity bring about?
Inflammatory
What is destroyed in coeliac disease?
Villi in intestine
