Exam 3- Structure And Function Of The Hematologic System Flashcards
Macrophages
Do active phagocytosis as part of the mononuclear phagocyte system. Process and present antigens. Participate in wound healing.
Dendridic cells
Process antigens and present them to lymphocytes
B lymphocytes (plasma cells)
Produce antibodies against specific antigens
Natural killer cells
Kill tumor cells and virus-infected cells
Monocytes
Precursor cells for macrophages
Neutrophils
The most abundant leukocytes.
Do phagocytosis early and inflammation. Kill bacteria.
When mature, have a multilobed nucleus.
Eosinophils
Defend against parasites
Erythrocytes
A fully mature red blood cell. Life span of four months.
When mature, do not have a nucleus or other organelles.
Have the capacity to be reversibly deformed, which enables them to squeeze through the sinusoids of the spleen and through the smallest capillaries
Hematopoiesis
Production of blood cells. Occurs primarily in the bone marrow after birth
Hematopoetic stem cells
In the bone marrow. In the vascular niche they are active. And the osteoplastic niche they are dormant.
Can differentiate only into the various types of blood cells
Hemoglobin A molecule
Each molecule consists of 4 globin chains and 4 hemes. In order to bind oxygen the iron portion of heme must be ferrous Fe2+
Hepcidin
Hormone that regulates absorption of dietary iron.
Iron
Red blood cells need iron to make hemoglobin. They use hemoglobin to carry oxygen from the lungs to the rest of the body.
After absorption iron circulates attached to transferrin and is stored inside cells attached to ferritin. Large amounts of this intracellular iron complex gather as hemosiderin.
Platelet adhesion and aggregation
Inhibited by nitric oxide and prostacyclin. Triggered by epinephrine, thrombin, and collagen.
Primary lymphoid organ
Examples: thymus, bone marrow
Secondary lymphoid organs
Examples: Spleen, lymph nodes, tonsils, peyer patches (in gut)
Sequence of blood cell differentiation
Multipotent stem cell Hematapoetic stem cell Common myeloid progenitor cell Progenitor cell Blast cell Fully differentiated blood cell
Platelets
Also known as thrombocytes, cytoplasmic fragments of large cells called megakaryocytes that are located in the bone marrow.
Store proteins like clotting and growth factors in granules so that they can be released rapidly.
When exposed to sub endothelial collagen, they adhere to the injured area. They will aggregate and form a platelet plug.
Platelet plug
Stabilized by strands of fibrin.
Platelets can expel the serum from the platelet plug to increase its strength by contracting the aggregated platelets.
Fibrin
Comes from the action of the thrombin on fibrinogen, an active precursor that circulates in the blood until the clotting system is activated.
Stabilizes platelet plugs.
Fibrin stability is inhibited by plasminogen activators.
Plasma
The liquid portion of blood with it’s dissolved substances.
Plasma cells= B cells
The most abundant plasma protein is albumin.
Serum
Plasma minus the clotting
Multipotent stem cell
Can differentiate into many different types of cells
Reticulocyte
And immature erythrocyte that has a nucleus, mitochondria, and ribosomes.
Increased reticulocyte count indicates that bone marrow is making new red blood cells.
Ferritin
A protein that binds in stores iron.
Apoferritin
Ferritin that does not have iron attached
Mitosis
Normal cell division that includes DNA replication, anaphase, and cytokinesis.
Endomitosis
A type of cell division done by megakaryocyte proginators in which DNA replication occurs, but anaphase and cytokinesis are blocked, that’s producing a cell with a large polyploid nucleus and numerous organelles that fragments into platelets.
Progenitor cell
Derived from hematopoetic stem cells (HSPs). like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its “target” cell. Differentiate in hematopoiesis.
Two types: myeloid and lymphoid
Progenitor cells can divide only a limited number of times.
Myeloid progenitor cells
Derived from hematopoietic stem cells (HSPs). Differentiate into different target blood cells in hematopoiesis.
Become erythrocytes, eosinophils, monocytes, neutrophils, basophils, and platelets.
Lymphoid progenitor cells
Derived from hematopoietic stem cells (HSPs). Differentiate into different target blood cells in hematopoiesis.
Become T cells, B cells (plasma cells), and natural killer cells.
Albumin
The most abundant plasma protein
Erythropoietin
Excreted by the kidneys. Stimulates bone marrow to produce more erythrocytes.
In chronic kidney disease, decreased erythropoietin production results in the bone marrow producing fewer red blood cells, causing anemia.
Thrombopoetin
Stimulates bone marrow to produce more platelets.
Tissue factor
Also called tissue thromboplastin. It triggers the extrinsic pathway of clotting.
Plasmin
An enzyme that degrades fibrin polymers. It’s in active precursor is plasminogen, which is produced by the liver.
Lymphocytes
Tend to have decreased function in older adults.
Nitric oxide
Inhibits platelet activation and aggregation
Clotting cascade
Inhibited by anti-thrombin III, thrombomodulin, protein C, and protein S.
Asplenia
A spleen usually remove the old red blood cells by using macrophages. Without a spleen, immune cells in the liver take over that job. Those liver cells are called Kupffer cells and are a type of macrophage.
Bilirubin
When red blood cells die there hemoglobin is taken apart, and a piece of the hemoglobin is changed to bilirubin.
D dimer
Our bodies make protective enzymes that chop up fibrin in clots. D-dimer is a fibrin degradation product, which means that it is a tiny piece of fibrin clot that a protective enzyme is trying to remove. And elevated D dimer can mean that there is a clot
