Unit 4 - Part 2 Flashcards
Plasma
The fluid portion of blood (55%). Contains water, proteins, nutrients, and hormones.
Leukocytes
White blood cells. Function in immune response.
Erythrocytes
Red blood cells. Biconcave in shape. Most abundant cell in the blood. Contains hemoglobin. The major function is gas transport (O2 and CO2). For mammals it lacks a nucleus and mitochondria.
Thrombocytes
Platelets. Involved in blood clotting. Derived from megakaryocytes (pinched off and have no nucleus).
Haematopoiesis
The creation of blood cells. Occurs in the red bone marrow.
Haemoglobin
Required for red blood cells to bind oxygen. A large complex molecule made up of 4 protein chains/globins. Each subunit contains a certain iron molecule.
Red Bone Marrow
Where all blood cells are produced.
Erythropoietin
Regulates erythropoiesis. Is usually called a hormone but it is a cytokine. A glycoprotein made and released primarily in the kidneys. Its synthesis and release is regulated by hypoxia (low oxygen).
Cytokines
Released by leukocytes that further regulate leukocyte production. Are released into the venules.
Colony Stimulating Factors (CSFs)
Regulate the formation of leukocytes. Are released by endothelial cells, marrow fibroblasts, and white blood cells. They induce cell division and cell maturation in stem cells. Are released into the venules.
Megakaryocytes
Parent cells that produce platelets (thrombocytes). Undergo mitosis up to 7 times without undergoing nuclear or cytoplasmic division. Results in a polyploid cell with a lobed nucleus. Reside in the bone marrow and extend their outer edges through the endothelium (cells lining the blood vessels) into the blood stream.
Platelet
Small cell fragments in the blood that are essential for blood clotting, preventing excessive bleeding, and wound healing. Formed from megakaryotes.
Haemostasis
The process of fixing damaged blood vessels.
Haemorrhage
Blood leaving from a broken blood vessel.
Platelet Plug
Formed by activated platelets sticking together.
Thrombin
Converts fibrinogen into fibrin.
Factor XIII
Used in the cross-linking of fibrin to form the clot.
Fibrinogen
The inactivated form of fibrin.
Fibrin
What forms the cross-linked structure for the clot.
Plasmin
An enzyme used to dissolve blood clots.
Fibrinolysis
When the enzyme plasmin dissolves the blood clot.
Platelet Activation
Occurs when there is damage to the walls of the circulatory system.
Regulation of Blood Cell Production
White Blood Cells - regulated by colony-stimulating factors.
Platelets - regulated by cytokine thrombopoietin.
Red Blood Cells - regulated by erythropoietin.
Haemoglobin Oxygen Saturation Curves
Shows the relationship between the partial pressure of oxygen and the percent saturation of hemoglobin.
Blood
The circulating component of extracellular fluid responsible for carrying substances around the body.
Components of Blood
1) Plasma
2) Red Blood Cells/Erythrocytes
3) White Blood Cells/Leukocytes
4) Platelets/Thrombocytes
Types of Leukocytes
1) Lymphocytes
2) Monocytes/Macrophage
3) Granulocytes
3a) Neutrophils
3b) Eosinophils
3c) Basophils (mast cells)
Granulocytes
3 types. Full of proteins.
Buffy Coat
1% of blood. Contains white blood cells and platelets.
Hematocrit
45% of blood. Contains red blood cells.
Anemia
A lack of hemoglobin synthesis due to low dietary iron consumption.
Right Shift
Increase in temperature, increase in partial pressure of CO2, and decrease in pH. Causes lower binding affinity.
Left Shift
Decrease in temperature, decrease in partial pressure of CO2, and increase in pH. Causes higher binding affinity.
Pluripotent Haematopoietic Stem Cell
The precursor of all blood cells (the starting stem cell).
Progenitor Cells
The daughter cell of a stem cell that becomes differentiated.
Leukopoiesis
The formation of leukocytes which is regulated by the colony-stimulating factors (CSFs).
Cytokine Thrombopoietin (TPO)
Regulate the growth and maturation of megakaryocytes.
Thrombopoiesis
The process of the ends of megakaryocytes being pinched off to form platelets.
Erythropoiesis
The formation of red blood cells.
Vascular Spasm
Similar to putting pressure on a bleeding wound. Done by vasoconstrictive paracrines released by damaged endothelium of the blood vessel.
Stages in Haemostasis
1) Vascular spam which decreases blood flow by increasing resistance which promotes the formation of the platelet plug.
2) Exposed collagen from the sub-endothelial layer allows platelets to stick and become activated. Cytokines are released activating more platelets. Activated platelets form the platelet plug.
3) A blood clot is formed by the coagulation cascade.
Coagulation Cascade
Starts with two pathways, the intrinsic and extrinsic, and ends up merging into the final common pathway.
Intrinsic Pathway
Activated by damage to the vessel wall. Inactive plasma proteins are activated by exposure to factor XII to collagen. Ends with factor X.
Extrinsic Pathway
Activated by trauma to extravascular cells. Inactive plasma proteins are activated by exposure to tissue factor III released from damaged cells. Ends with factor X.
Common Pathway
Factor X leads to the activation of thrombin from prothrombin which cleaves fibrinogen into fibrin. Thrombin also activates factor XIII which cross-links the fibrin into long fibres that intertwine to form a fibrin network. Intertwined fibres reinforce the platelet plug making it a clot. Excessive clotting produces a thrombus, a clot which can block blood vessels.
Healing From a Damaged Blood Vessel
Plasminogen is converted into plasmin by either thrombin or tissue plasminogen activator (tPA). The enzyme plasmin dissolves the clot by fibrinolysis. As repairs progress the clot slowly shrinks.
