4.3 - Lecture - Blood/Immune Flashcards
Plasma
= serum + clotting factors
platelets
= thrombocytes
Erythrocytes
Red Blood Cells
Leukocytes
White Blood Cells
Diapedesis
- the mechanism in which leukocytes leave the circulation
- a squeezing through the membrane
Macrophages
- derived from circulating monocytes
- have primary role in phagocytosis of unwanted material
- mononuclear phagocytic system refers to all marcophages as they commonly exist in tissue-specific forms
Monocytes
- the premature macrophages
- will proliferate to form macrophages
Mononuclear Phagocytic System
- the collective term for macrophages
- used to describe them because they often occur in many tissue-specific forms
Neutrophils
- capable of chemotaxis
- specialized to kill phagocytosed microorganisms through respiratory burst RXNs
Respiratory Burst RXNs
- a rapid release of reactive oxygen species (commonly superoxide radical and hydrogen peroxide)
- a specialized mechanism of attack used by neutrophils
Three Types of Intracellular granules of Neutrophils
- Azurophilic (primary)
- Specific (secondary)
- Tertiary granules
What is NETosis
= “Neutrophil Extracellular Traps”
- A dying response of some neutrophils to invasion
- their death coincides with extravasation of stranded chromosomal material
- substances normally associated with the nuclear DNA then double as a bacteriotoxic agents when extracellular
Mast Cells
- contain histamine and heparin
- functionally similar to basophils
- but have a different lineage + distribution
Histamine is
- a mediator of inflammation
- found in mast cells
Heparin is
- an anticoagulant
- found in mast cells
Basophils
- functionally similar to mast cells with different lineage + distribution + appearance
Eosinophils
- mediate allergic responses
- are antihelminthic
- their granules contain numerous cationic proteins
(including major basic protein, which has a characteristic EM appearance)
What is major basic protein and what is the “Characteristic appearance” of it
- Major Basic Protein is one of the cationic proteins commonly found in eosinophilic granules
- in EM it is a dark granule with a line bisecting it?
Lymphocytes
- function in the adaptive immune response
- B-lymphocytes work via antigen-antibody recognition - undergo clonal expansion when antigen is recognized
- T-lymphocytes recognize self from non-self cells through MHC-molecule recognition via the T-cell receptor
Clonal expansion
- B-lymphocytes working under antigen-antibody recognition proliferate and amplify their population of relevant cells for an antigen once it is recognized
Plasma cells
- are the antibody-producing B-lymphocytes
- have a unique morphology
MHC-Molecule
- MHC = major histocompatibilty complex
- allows T-lymphocytes to recognize self from non-self cells
- recognition occurs via the T-cell receptor
T-cell receptor
- adhesion molecule on the membrane of T-lymphocytes
- allows MHC-molecule recognition of self vs. non-self
CT Cells of the Mesenchyme Include
- Fibroblast (dense irregular, loose)
- Tendenocyte (Dense regular)= a specialized fibroblast
- Adipocyte (adipose tissue)
- osteocyte (bone)
- chondrocyte (cartilage)
CT Cells of Bone marrow
- Macrophage
- Neutrophil
- Eosinophil
- Lymphocyte (B and T)
- Plasma Cell
- Mast Cell
Cytokines are
chemical messengers released by macrophages in response to the binding + phagocytosis of a pathogen
4 Cardinal Signs of inflammation
1) Calor (heat)
2) Rubor (redness)
3) Tumor (Swelling)
4) Dolor (pain)
Vascular response aspect of innate immune response:
- Cytokines cause vasodilation or arterioles –> increases blood flow to area (accounts for redness and heat)
- cytokines increase permeability of blood vessels –> disrupt intracellular linkages and allows fluid into extravascular CT space (Edema) - removes fluid, slows down RBCs, WBC contact endothelium
Neutraphils (PMN)
- highly prevalent in blood not found in CT (healthy)
- Contain 2-5 lobes of segmented nucleus
- 3 classes of granules
1) primary - lysosmes - kill things
2) secondary (specific) - antimicrobial agents
3) tertiary - gelatinase/cathepsins (collagenases) - break down GAGs for movement in CT
Rolling adhesion
- Neutraphils are marginated by slowing blood
- endothelial cells express selectin receptors in response to cytokines (chemotaxis)
- selectins on neutraphils bind receptors on endothelial cells (weak affinity binding) - serves to slow and stop neturaphil
- neutraphil then firmly binds integrin receptors
Diapedesis: Cellular response aspect of innate immune response
- neutraphils bind endothelium where selectins expressed, extend foot between endothelial cells (pierce basal lamina)
- once inside CT they migrate to source of cytokines (by using tertiary granules - cathepsins + gelatinases)
Describe Fast acting neutraphils actions (including peak concentration)
- invade quickly
- reach peak concentration around 24hrs
Describe delayed cellular immune response (including peak concentrations)
- monocytes enter tissue + transform into macrophages (have newable heterolysosomes- long term functioning)
- monocyte response peaks @ 36-48hrs
Lymphatic vessels
- endothelial lined
- begin in loose CT
- walls are highly permeable (unlike typical endothelial cells)
- transport fluid, substance + cells to lymph nodes
Macrophages
= antigen presenting cells
- attaches a digest piece of antigen to MHCII receptor - initiates highly specific immune response to any subsequent appearance of pathogen
2 types of Lymphocytes and difference in LM morphology
- T cells
- B cells
- indistinguishable on LM
Morphology of Lymphocytes
- small 6-8mm
- heterochromatic nucleus
- little cytoplasm
Function of t-cells
= cell mediated immune response
- recognize + destroy virally-infected cells or foreign cells
function of B-cells
= humoral response
- turn into plasma cells - responsible for producing antibodies
Diffuse Mucosa-Associated Lymphoid Tissue (MALT)
= tissue found in loose CT of epithelia (e.g. lamina propria of GI tract)
- contains lymphocytes + other non-resident cells of CT
- intercepts pathogens + conveys them to lymph nodes via lymphatic vessels
Plasma Cells
= activated B-lymphocytes
- secerte antibodies
LM appearance of Plasma Cells
- round nucleus
- cytoplasm = v. basophilic because of rER
- chromatin clumped in discrete locations around edge of nucleus (clock-face or spoke-wheel appearance)
- cytocentrum = clear spot on plasma cell - location of golgi apparatus
Antibody fxn
- bind pathogen (opsonizatoin) + prevent its interaction with body
- easily recognizable to macrophages, neutraphils, lymphocytes
Mast Cells
- very similar in fxn to basophils
- IgE antibodies binds receptors on mast cell plasma membrane
- high dense granulated morphology
- have pseudopodia?
Degranulation of mast cells
- compound exocytosis = granules fuse with each other + the plasma membrane causing release of all granule contents into pericelllular space
- causes a powerful + prompt inflammatory response (characteristic in extreme allergic rxns)
- recruits neutrophils + eosinophils to the site
Eosinophil
= blood born + attracted to sites of inflammation
- morphology = refractile eosinophilic granules (have line in center)
FXN = (-) feedback control for inflammatory RXNs, antiparasitic agent, phagocytic
