Lecture 12 Flashcards
(29 cards)
What are the 6 types of blood cells?
Erythrocytes
Neutrophils
Basophils
Eosinophils
Monocytes
Lymphocytes
For Erythrocytes, list their characteristics and functions.
classic RBC that carries oxygen
Characteristics: devoid of granules and organelles
Composed of about 50% integral membrane proteins (spectrin and actin bound to ankyrin)
For Neutrophils, list their characteristics and functions.
active amoeboid phagocytes that secrete enzymes that destroy certain bacteria by the formation of free radicals (superoxide); also create lysozyme and lactoferin to destroy bacterial cell walls
Characteristics: 3-5 nuclear lobes with connecting strands
Their small, numerous granules contain lysozyme and other proteases
Their larger, less numerous granules contain elastase and myeloperoxidase
For Basophils, list their characteristics and functions.
express IgE on their surface and release histamine, when activated by antigen binding, to mediate allergic reactions
Characteristics: large, membrane-bound basophilic granules with a bilobed nucleus
For Eosinophils, list their characteristics and functions.
primarily go after parasites but can also lead to allergic reactions
Characteristics: larger than basophils/neutrophils
Found with basophils usually
Bilobed nucleus
Have the following specific granules:
Major basic protein (MBP): disrupts parasite membranes and causes basophils to release histamine
Peroxidase
Cationic Protein: neutralizes heparin and is anti-parasitic
For Monocytes, list their characteristics and functions.
largest of the RBC’s that serves as a precursor of macrophages and osteoclasts
Characteristics: eccentrically located, kidney-shaped nucleus
Granular cytoplasm due to small lysosomes
For Lymphocytes, list their characteristics and functions.
Characteristics: large and round with a slightly indented nucleus that fills most of the cell
Occur in small, medium, and large sizes
Explain how basophils can increase vascular permeability. What other effect does this function have?
they can produce leukotrienes to increase vascular permeability and slow the contraction of smooth muscles
Basophils contain vasoactive substances such as heparin and Kallikren. What do these subtances induce when released?
Heparin is an anticoagulant
Kallikrein: attracts eosinophils
Basophils contain vasoactive substances such as heparin and Kallikren. What do these subtances induce when released?
Heparin is an anticoagulant
Kallikrein: attracts eosinophils
How many types of monocytes are there? what do these do?
2 types
B Monocytes are precursors of plasma cells
T lymphocytes mature later in the thymus
How many types of monocytes are there? what do these do?
2 types
B Monocytes are precursors of plasma cells
T lymphocytes mature later in the thymus
What are platelets derived from and why do they release thromboxane?
cells derived from megakaryocytes that enhance aggregation by the release of thromboxane
The adhesion of platelets involves ________
integrins
What promotes clot formation, retraction, and dissolution?
platelets
What promotes clot formation, retraction, and dissolution?
platelets
What are the 5 stages of hemostasis?
Constriction of smooth muscles around cells
Constriction of vessels
Slowing of blood
Formation of platelet plug
Blood clotting (coagulation)
List the steps involved in the formation of the platelet plug
underlying collagen fibers of the damaged epithelial tissue are exposed
Platelets adhere to the exposed collagen fibers and release the contents of their secretory vesicles (including ADP) and cause the conversion of arachidonic acid (in the platelet plasma membrane) to thromboxane A2 which further stimulates platelet aggregation.
ADP and other factors cause platelet aggregation in order to form the platelet plug
Where is Von Williebrand factor released from, and what is it’s function?
Von Willebrand factor is released from Weibel-Palade bodies in endothelial cells
It facilitates the adherence of platelets to the walls of the damaged blood vessel
Compare the intrinsic and extrinsic clotting pathways
Intrinsic Pathway: everything necessary for it to occur is already within the blood and it is triggered during injury to the epithelial tissues of the vessel being damaged, exposing their collagen fibers
Extrinsic Pathway: involves the formation of tissue factor (thrombin or Factor III)
describe the steps that form a blood clot (include both factors, prothrombin, fibrinogen, plasminogen activator cascade, and t-PA)
Factor XII is activated when it contacts the exposed collagen of a damaged vessel wall
Factor XII activates prothrombin to become thrombin
Thrombin splits fibrinogen into fibrin polypeptides
A fibrin meshwork forms by the enzymatic action of Factor XIII which traps erythrocytes and other cells to become a clot
Describe the process of the dissolution of a blood clot. What activates this process?
Fibrinolysis (dissolution of fibrin) occurs when plasminogen is converted to it’s enzymatic form, plasmin. (plasmin and t-PA both dissolve the clot)
Fibrin activates this process
What are the 2 cell adhesion proteins involved in extravasation?
Selectin and Integrins
Describe Selectin’s role in Extravasation.
P-selectin appears on the cell surface when endothelial cells are activated by inflammatory signaling
Oligosaccharide ligands on leukocytes bind to carbohydrate recognition domains (CRD’s) on the P-selectins (which are from Weibel-Palade bodies)
Binding of ligands to the P-selectins causes leukocytes to roll along the endothelium
