Blood & Bone Marrow Histology Flashcards
Components of Blood
- Erythrocytes (RBCs)
- Leukocytes (WBCs)
- Platelets
- Plasma
What leukocytes are agranulocytes?
Monocytes and Lymphocytes
- Contain only azurophilic granules
What is the size of an erythrocyte?
Roughly 6-8 um
Describe an erythrocyte
A round, anucleate, biconcave cell with no organelles but filled with hemoglobin that carry oxygen.
- It has a life span of 120 days.
- It’s cell membrane has determinants for the blood type.
What are cytoskeletal proteins of RBCs that help maintain the shape?
- ankyrin
- band 4.1
- 3 band proteins (spectrin & actin)
Hematocrit
Number of RBCs per unit volume of blood.
What suggests lead poisoning?
Basophilic stippling (aggregates of rRNA) of RBCs
What leukocytes are granulocytes?
Neutrophils, basophils, and eosinophils
- Contain both azurophilic granules and specific granules
Azurophilic Granules
Lysosomes containing hydrolytic enzymes.
Specific Granules
Granules filled with specific type enzymes such as lysozymes, alkaline phosphate, collagenase, and lactoferrin.
Two Mechanisms of Neutrophilic Phagocytosis
- Merging of azurophilic granules and into phagosomes.
- Respiratory Burst through reactive O2 compounds.
* Neutrophils use C3b and Fc receptors to form phagosomes.
Describe Eosinophils
A granulocyte with a bi-lobed nucleus that moderate inflammatory reactions and helminthic infections by inactivating histamine and leukotriene C
- Has Large red specific granules with no lysozyme
Describe Basophils
A granulocyte with large blue specific granules (histamine and heparin) that mediate inflammatory responses of allergic reactions in a manner similar to mast cells.
What are two types of lymphocytes and what are their functions?
- T-Cells: generate cell-mediated immune response; secrete growth factors.
- cannot further differentiate like b-cells
- Mature in Thymus
- B-Cells: generate humoral immune response.
- become plasma cells
- Mature in Bone Marrow (Bursa of Fabricius)
Describe Monocytes
Largest leukocytes that become macrophages in CT.
- Has a kidney-shape nucleus.
Describe Diapedisis
The process in which leukocytes leave the bloodstream to the tissues by breaking intercellular junctions.
- It is uni-directional except for lymphocytes.
Describe Platelets
It is anucleated disk-shaped fragments from megakaryocytes in bone marrow.
- Composed of Hyalomere (clear region) & Granulomere (purples granules region with factors for clot formation).
What is another name for platelets?
Thrombocytes
Two Types of Bone Marrow
- Yellow BM
2. Red BM
Describe Yellow BM
- Located in the long bones.
- It is fatty (why yellow) and not hemopoietic.
Describe Red BM
- Located in the epiphyses (end) of long, flat, irregular, and short bones.
- It is highly vascular with large sinusoids (large capillaries).
- Site of Hemopoiesis and contains megakaryocytes.
Hemopoiesis
aka. Hematopoiesis
Formation of blood cellular components.
Stages of Prenatal Hemopoiesis
Yolk Sac –> Liver –> Spleen –> Bone Marrow
Three Classes of Postnatal Hemopoiesis
- Hemopoiesis now only occurs in the bone marrow after birth.
stem cells –> progenitor cells –> precursor cells
