Block 4 Flashcards
What activates the alternate pathway?
Polysaccharides such as gram negative bacteria
What determines the function of the antibody?
Heavy chain
What is the role of IgD?
Activation of B cells.
What is type 4 hypersensitivity?
Cell mediated by T helper cells and CD8+ T cells that occurs days after.
How does class switchcing of antibodies occur?
Changes to the constant region of the heavy chain
Which part of the natibody is responsible for antigen affinity?
Variable region
Difference between heavy and light chain
Heavy chain has four segments and light chain has 2 segments
How is the heavy chains linked togehter?
Disulphide bond
How is the heavy chain linked to light chain?
Disulphide bond
Where does antigen bind to antibody?
Fab of either heavy or light chain
Which antibody destroys parasite and worms?
IgE
What is the first antibody to be secreted?
IgM
Which immunogoblin is found in the lungs and skin?
IgE- this mediates allergic and hypersensitivity reactions
Intrinsic pathway
PTT
Which cells kill viruses?
Cytotoxic T cells
MHC 1 X8= 8
MHC2 X 4=8
Which immunogoblin crosss the placenta and cause neonatal probelms?
IgG
Which immunogolbin is found in breast milk?
IgA- protection of mucous membranes so it is found in saliva, tears, mucous and breast milk. It travels by transcytosis.
How does glucose enter the blood?
Facillitated diffusion using GLUT transporter
When do the intrisnic and extrinsic pathways meet?
Factor 10
Which cells control type 4 hypersensitivity?
Th1 lymphocytes
Which cells activate humoural process?
Th2 lymphcytes that activate B cells
What is hyperacute organ rejection?
Occurs a few mins after transplant controlled by B cells. It is a type 2 hypersensitivity.
What is the role of TH1 cells?
Activate CD8+ T cells
What is acute organ rejection?
Days to months after transplant- controlled by Th2 cells and CD8+ T cells in a type 4 hypersensitivty
What causes chronic organ rejection?
Th2 cells and CD8+ T cells in a type 4 hypersensitivity
What is the role of IgM?
Involved in type 2 and 3 hypersensitivity. It is the first to be released following infection and has the highest complement activation capacity.
What determinnes class effect of antibodies?
Fc region
What is the antigen epitope?
The region where the antigen binds to antibody.
How is HIV measured?
CD4 cells
Which cells are most commonly associated with IgE?
Mast cells
Which cells are part of the inate immune response?
NK cells
What causes the oxygen dissoication curve to shift to the right?
CADET- CO2, Acidosis, DPG (2,3), Exercise, temperature.
What is mannose?
An antigen that is a Pathogen-associatied molecular pattern for indicating microbial activity that binds to carbohydrate lecitn
What is a granuloma?
Cluster of WBC produced in type 4 hypersensitivity.
Which antibody is most commonly produced?
IgA- its dimeric structure means its mostly found in secretions. It is present on mucosal membranes and deficiency causes increased infection of respiratory and GI tract
What causes the oxygen dissoication curve to shift to the left?
Alkalosis, reduced temperature
Which cells are important for class switching?
Th2
What is C-reactive protein?
Produced by the liver which is elevated during inflammation
Which antibody is responsible for blood agglutination?
IgM
Which antibody is highest in the blood serum?
IgG
Which T cell is effective against extracellular bacteria and fungi?
TH17
Interferons
Cytokines released during viral infections
Interferon gamma
Produced by NK cells and Th cells for chronic granulomatous disease.
When are lymhpocytes raised?
Acute viral infection or chornic inflammation
Where does the antibody bind to antigen?
Fab region of the epitope.
Extrinsic pathway
PT
Assessing fibrinogen -> fibrin
Thrombin time- prolonged by heparin or fibrin/fibrinogen deficiency
Bradykinin
Causes vasodilation and hypotension and angioedema (swelling of skin.)
What is the smallest antibody?
IgG
What cell surface marker is found on all T cells?
CD3 for total T cell count
What triggers the lectin pathway?
Pathogen surface carbohydrates like lectin
Anaphylactixis
Hypotension, tacycardia, dysoniea, swelling
Which cells are found in caute inflammation?
Neutrophils
What helps to protect or fight infection?
Antigen presentation
What is important for foetal immunity?
IgG
What is important for neonatal immunity?
IgA
Dendritic cells
both myeloid and lymphid lineage. Theyu are responsible for being antigen presenting cells.
What is ferritin?
Iron storage protein
What is transferrin?
Transportation of iron to the liver and bone marrow
How is serum CO2 levels controlled?
Negative feedback
Which immunogolbiins are secreted as monomers?
All immunogoblins
Which immunogoblins are pentamers?
IgM
Which WBC are the first to be recruited?
Neutrophils which is multilobed
What is the feature of eosinohpils?
Bilobed nucleus
Macrophage and mast cells
Single ncuelus
How does HIV enter cells?
CD4
What activates macrophages?
Interferon-gamma produced by Th1 cells
How is the clotting cascade controlled?
Positive feedback
Which antibody crosses the placenta?
Only IgG
What receptor is involved in platelet adhesion?
GP1B
How do platelets bind in adhesion?
vWF is present when the subendothelial layer is exposed. Platelets bind to vWF on the subendothelial layer via GP1b receptor. It then releases ADP to activate more platelets. ADP acts via metabatropic P2Y1 or P2Y12 on platelet receptors and causes a confromational change for activation of GP2b3a. Activation of Gp2b3a causes platelet aggregation to form a clot.
How does P2Y12 receptor work?
Responds to ADP binding. It is a Gi receptor that reduces cAMP for increase of Ca2+ activation of GP2B3A receptor for platelet aggregation
What is the role of integrin?
It is a receptor which spans the length of the membrane aka GP2b3a receptor. It binds to vWF and fibrinogen for platelet adhesion and aggregation. Formed via calcium dependent association via ADP acting on PY receptors.
What is Glanzmann’s thrombasthenia
Defiiency in integrin/GP2b3a that reduces platelet adhesion and aggrefgtion and causes bleeding
What is the cause of immune thromboocytopenia purpura?
Type 2 hypersensitivity that targets integrin/GP2b3a
What is ritixumab?
Monoclonal antibody derived from the Fab that causes the depletion of B cells to treat lymphoproliferative disorders. It inhibits integrin and causes excess bleeding
What is C3 convertase?
C3B
What is C5 convertase?
C4bC2aC3b
What activates alternative pathway?
Spontaneuous hydrolysis
Where is lectin produced?
What is the MBL pathway?
Mannose binding lectin associated protease (MASP) forms which -> MBL protease. This causes lysis of C4 and C2 to form C4AC2B.
What begins the extrinsic pathway?
What begins intrisnic pathway?
FXIIa which activates FXI, FIX and FVIII to activate FX-> FXA
What activates fibrinogen?
Thromobin
What activates throbmin?
FVa and Factor Xa to cause prothrombin -> thrombin
What is the role of vWF?
Carries FVIII and responsible for platelet adhesion and aggregation when exposed in subendothelial layer
Structure of platelets
Glycoprotein coat of GP1B and GP2B3A receptor. Made up of arachidionic acid. It has a Ca2+ surface canalicular system
What do platelets contain?
Conrtains PDGF to repair vessels after clot and alpha and dense granules/
What are alpha granules?
Protein granule which contain factor 13, PDGF, vwF and a store of fibrinogen.
What are dense granules?
Non protein and contain ADP and Ca2+
What is the role of Ca2+
For contraction and activation of GP2B3A and binding agent for vitamin K dependent factors.
What are vitamin K dependent factors?
Factor 2, 7, 9, 10
Where are platelets found?
Peripheral blood and 1/3 in the spleen
Difference between acute and chronic myeloid leukemia
Acute has decrease in neutrophils; chronic has increase in neutrophils
What is the heavy chain?
What is the light chain?
What activates mast cells and basophils?
Nerves using substance P, C3a and C5a and IgE
What is the cause of haematuria?
Breakdown of RBC present in urine due to Classical complement antigen-antibody
What is the Fc region?
Heavy chain only
Where is the variable domain of heavy chain?
Fab region
What is the effect of splenomegaly?
Reduced platelet and RBC count
Order of absorption
Iron in Duodenum, Folate in jejunum, B12 in ileum
How is coblamain metabolised and absorbed?
Transcoblamain I allows B12 to be transported from salivary gland in mouth to stomach to protect it from acid. It is taken up and absorbed in jejunum by instrinisc facotr produced by parietal cells. Transcobalamin transports B12 in blood to tissue
How is folate absorbed?
In jejunum by conjugase enzyme in form of tetrahydrofolate. Transfers methyl group to B12. Both are essential for RBC DNA defiency
Folate defiency
Occurs in alcoholics, when there is malabsorption, in pregancy, haemlytic anaemia, breast feeding.
What is HbS?
Hb in sickle cell disease
HbC
Haemoglobin where glutamic acid is replaced by lysine and asymptomatic
HbE
Haemoglobin E disease which is a mild anaemia
When are iron supplements contraindicated?
During infection. It can cause vomiting, haemhorrage, diarrhoea
Types of vone marrow tissue
Fatty tissue and myeloid
What do mesenchymal stem cells produce?
Fat, cartilage and bone cells
When does yellow marrow become red?
During fever or severe blood loss
What are the platelet agonists?
ADP, adrenaline, collagen
What is the form of animal diet iron?
Haem iron which is more easily absorbed than non haem iron.
Where is pepsinogen produced?
Fundus in chief cells
What is the precursor to bilirubin?
Haem -> biliveridin
How does urobilinogen form?
Bilirubin -> urobilinogen
What facillitates b12 absorption?
Pancreatic protease
WHat is the effect of gastrectomy?
Reduced B12 and iron absorption. Stomach acid causes Fe3+ -> Fe2+ and produces parietal cells. There is also osteoporosis because pareital cells produce Ca2+
What is the form of vegeterian based iron?
Non haem iron
What triggers organ/graft rejection?
HLA
Where is trypsin activated?
In duodenum into trypsin via enterokinase. it activates pacreatic proteases
Where do the testes drain?
Into the para-aortic lymph nodes
What drains into the external iliac lymph nodes in males?
Glans penis and prostate
Where does scrotum drain?
Inginal lymph nodes
Where does scrotum drain?
Inginal lymph nodes
Phrenic nerve
Anterior to lung hilum. C3, C4, C5
What suppleies the left atrium?
Left coronary artery and circumflex.
What supplied by the LAD?
Left ventircle
What is supplied by posterior descending artery?
Posterior third of interventricular septum
What is supplied by left marginal?
left ventircle
Where is the vasa vasorum located?
Tunica advetitia- contains fibroblast, collagen, vasa vasorum in outermost layer
Where does superior mesenteric vein drain?
Portal vein
What is the cause of Goodpasture’s syndrome?
Type 2 hypersensitivity against type 4 collagen in basement membrane of kidneys that reduces kidney function for urine
What is thiamine?
Vitamin B1
What is riboflavin?
Vitamin B6/FOLATE
Aspirin
Irreversibly blocks thromboxane A2 formation
Role of vitamin K
Carboxylation of factor 2, 7, 9 and 10
Role of lipoxygenase
Converts arachidionic acid to leukotrienes
Role of prostaglandin?
Decreases platelet aggregation
Where is the amjoirty of iron found in the body?
Bound to haemoglobin. Plasma iron is the lowest store.
Where is oxygen stored in muscles?
Myoglobin- monomeric protein found in muscle tissue. This contains iron.
Action of heparin
Activates anti thrombin which inhibits thrombin and Factor Xa
Effect of thromboxane?
Derived from prostaglandin and causes vasoconstriction, hypertension and platelet aggregation
Haemophilia
Factor 8 deficiency
Role of B12
Regenerate folic acid
What reduces uterine tone?
Prostacyclin
Which clotting factor reduces first in vitamin K deficiency?
Factor VII
How do inflmamatory mediators form?
Phospholipids are freed by phospholipase A2 and form arachiodionic acid. Arachidionic acid forms prostaglandin via COX-1/2. Prostaglandin becomes thromboxane A2 by COX-1 enzyme or propstacyclin by COX-1 or COX-2.
WHat do prostaglandins form in vascualr
endothelium?
Prostacyclin that causes vasodilation and reduces platelet aggregation via COX-2 or COX-1.
What do prostaglandins form in platelets?
Thromboxane A2 that causes vasoconstriction and increases platelet aggregation via COX-1 only.
Role of COX-2?
Formation of prostacyclin from prostaglanidn and activated by inflammation.
Role of COX-1
Always active and causes formation of prostacyclin or thrombooxane.
Role of steroids?
Inhibit phospholipase A2 for arachidionic acid -> prostaglandin.
Role of NSAIDS?
Inhibit COX-1 or COX-2 for inflammatory mediators.
Effect of leukotrienes?
Produced from arachidionic acid by 5-lipooxygenase (LOX) Causes chemotaxis of neutrophils adn bronchoconstriction of airways.
Effect of COX-2 selective inhibitors?
Reduces risk of peptic ulcers because prostaglandin is not inhibited but increases bleeding.
What medication should not be given after surgery?
Aspirin because it is a COX-1 ihibtior which prevents wound healing via clotting throug thromboxane A2.
What is transcyotsis?
Uptake of substance by forming a vesicle, stabilised with clathrin protein. Clathrin transcytosis is used by epithelial cells for pathogen defenese and passive immunity for IgG upake
Where do continuous capillaries not have gaps?
Brain
Location of continuous capillaries?
Lungs, skin, blood-brain barrier
Location of fenestrated capillaries?
Kidneys and small intestine
Effect of folate
MAY REDUCE b12
Effect of corticosteroids
Increase BP and stimulate sodium retenion and water
Effect of corticosteroids
Increase BP and stimulate sodium retenion and water
