Hematologic Flashcards
The hematological system
4 main components
Plasma
Red blood cells
White blood cells
Platelets
Anemia
A condition in which the blood doesn’t have enough healthy red blood cells
Describe the composition of blood
Plasma is 55% of blood
(7% proteins; 92% water, 1% other solutes)
Formed elements are 45% of blood
(platelets; leukocytes; erythrocytes)
Leukocytes:
- neutrophils (40-60%)
- lymphocytes (20-40%)
- monocytes (2-8%)
- eosinophils (2-4%)
- basophils (0.5-1%)
Discuss the function of plasma and plasma proteins
Plasma is 55% of blood
(7% proteins; 92% water, 1% other solutes)
Function: Maintains BP and regulates body temperature, supplies proteins for blood clotting, immunity and maintains proper PH.
- Albumins function as carriers and control the plasma oncotic pressure
- Globulins are carrier proteins and immunoglobulins (antibodies)
- Clotting factors (mainly fibrinogen)
Discuss the structure and function of the cellular components of blood
Platelets:
- disk-shaped cytoplasmic fragments of megakaryocytes
- essential for blood coagulation and control of bleeding
- about a 10 day lifetime in blood (not true cells)
- Thrombopoietin is the main regulator (stimulating factor) for platelet formation; regulates platelets b/c bound by platelets
Cellular Components:
- Erythrocytes (RBCs) are the most abundant cell in the body; responsible for tissue oxygenation; bioconcavity and reversible deformity
- 120 day life cycle
- Leukocytes (WBCs):
Lymphocytes (B & T cells);
Monocytes;
Granulocytes (Basophils, Eosinophils, Neutrophils)
Identify the role of the mononuclear phagocyte system
Consists of monocytes that differentiate w/out dividing and reside in the tissue for months or years.
MPS cells ingest and destroy (phagocytosis) unwanted materials and foreign protein particles, circulating immune complexes, microorganisms, debris, defective/ injured erythrocytes, and dead neutrophils. Osteoclasts are multinucleate MPS that originate from monocyte cell lineage and specialize to allow function of lacunar bone resorption and are also known to be phagocytic.
Body’s main line of defense against bacteria in the blood.
Identify the process of hematopoiesis and the role of hematopoietic stem cells
Blood cell production.
Formed from stem cells in bone marrow(myeloid tissue).
Regulation by growth factors - controls for correct proportions of each cell type
Mesenchymal Stem Cells (MSCs):
- Stromal cells, that can differentiate into a variety of cells → incl. osteoblasts, adipocytes, and chondrocytes (produce cartilage), but from there cannot differentiate into other cell types any longer.
Hematopoietic stem cells (HSCs):
- Progenitors of all hematologic cells
Both populations of stem cells undergo self-renewal in the bone marrow to replace the ones that undergo differentiation.
Explain erythropoiesis, focusing on the role of erythropoietin in this process
Erythropoiesis is the process which produces RBCs (erythrocytes). It is stimulated by decreased O2 in circulation (hypoxia), which is detected by the kidneys causing the secretion of the hormone erythropoietin. This hormone stimulates proliferation and differentiation of red cell precursors, which activates increased erythropoiesis in the hemopoietic tissues, ultimately producing erythrocytes.
Erythropoietin → hormone that stimulates erythrocyte production; made in the kidney and its main stimulus is hypoxia, but also decreased RBCs, decreased Hb synthesis, decreased blood flow, hemorrhage and increased O2 consumption by tissues.
Explain the function of hemoglobin in the human body
o Oxygen carrier.
o Carbon dioxide carrier.
o Gives the red color to blood by Fe2+ ions
o Maintains the shape of the red blood cells.
o Acts as a buffer.
o Interacts with other ligands.
o Degradation accumulates physiologically active catabolites.
Explain how iron (as Fe2+, Fe3+, and bound to transferrin) is used, focusing on how hemoglobin can carry oxygen, including the cycle of oxy-, deoxy-, and met- hemoglobin
- Each globin subunit of the hemoglobin molecule can bind with one Fe 2+ ion.
- Affinity of hemoglobin towards oxygen is gained by the Fe2+ion. Each Fe2+ can bind with one oxygen molecule
- The binding of oxygen oxidizes Fe2+ into Fe3+. Oxyhemoglobin → oxygen-bound hemoglobin When blood reaches an oxygen deficient tissue, oxygen is dissociated from hemoglobin and diffused into the tissue. The O2 is the terminal electron acceptor in the process called oxidative phosphorylation in the production of ATP.
- The removal of O2 turns the iron into its reduced form. Deoxyhemoglobin → oxygen-unbound hemoglobin. Oxidation of Fe2+ into Fe3+ creates methemoglobin which cannot bind with O2.
- Methemoglobin Fe3+ loses O2 but can still oxidize → tissues
List several situations that lead to increased leukocyte production
An increased production of white blood cells to fight an infection
A reaction to a drug that increases white blood cell production
A disease of bone marrow, causing abnormally high production of white blood cells
Acute lymphocytic leukemia à an immune system disorder
Acute myelogenous leukemia (AML)
Allergy, especially severe allergic reactions
Chronic lymphocytic leukemia
Chronic myelogenous leukemia
Drugs, such as corticosteroids and epinephrine
Infections, bacterial or viral
Myelofibrosis (a bone marrow disorder)
Polycythemia vera
Rheumatoid arthritis (inflammatory joint disease)
Smoking
Stress, such as severe emotional or physical stress
Tuberculosis
Whooping cough
Describe the role of platelets in hemostasis
Platelet accumulation at the site of injury is considered the first wave of hemostasis and the second wave of hemostasis is mediated by the blood coagulation pathway. Platelets play a central role in a series of sequential events during the platelet accumulation (i.e. platelet adhesion, activation, and aggregation) and are also actively involved in cell-based thrombin generation, which markedly amplifies the blood coagulation cascade. Thus, platelets contribute to both the first and the second waves of hemostasis
Lab values for complete blood count (CBC)
WBC
WBC: 5,000 -10,000 /mm3
Lab values for complete blood count (CBC)
Hgl
Hgl: Male: 13.2-17.3 Female: 11.7-15.5 g/dL
Lab values for complete blood count (CBC)
Plt
150,000-400,000 /uL