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Questions and Answers
What is the primary function of white blood cells in the body?
What is the primary function of white blood cells in the body?
Which of the following best describes white blood cells?
Which of the following best describes white blood cells?
Leukocytes are primarily involved in which bodily system?
Leukocytes are primarily involved in which bodily system?
Which of the following statements about white blood cells is NOT true?
Which of the following statements about white blood cells is NOT true?
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What alternative name is commonly used for white blood cells?
What alternative name is commonly used for white blood cells?
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What is the primary function of white blood cells (WBCs)?
What is the primary function of white blood cells (WBCs)?
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What is the average number of white blood cells per microliter in a normal adult body?
What is the average number of white blood cells per microliter in a normal adult body?
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Why do white blood cells circulate in the blood?
Why do white blood cells circulate in the blood?
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Which statement best describes the normal range for WBC count in an adult body?
Which statement best describes the normal range for WBC count in an adult body?
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What happens when the number of white blood cells exceeds the normal range?
What happens when the number of white blood cells exceeds the normal range?
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What is the significance of having an average WBC count of around 7,000?
What is the significance of having an average WBC count of around 7,000?
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In what condition would you expect WBC count to be lower than the normal range?
In what condition would you expect WBC count to be lower than the normal range?
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What unit is used to express the concentration of white blood cells in the bloodstream?
What unit is used to express the concentration of white blood cells in the bloodstream?
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Which condition is likely indicated by a significantly high WBC count?
Which condition is likely indicated by a significantly high WBC count?
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Study Notes
White Blood Cells (WBCs)
- WBCs, also known as leukocytes, are part of the immune system
- They defend the body against infections by traveling to affected areas
- A normal adult has 4,500 to 11,000 WBCs per microliter of blood (average 7,000)
Hematopoiesis
- Hematopoiesis is the process of blood cell formation
- Two main types of tissues are involved myeloid and lymphoid
Myeloid Tissue
- Bone marrow is the main site
- Erythrocytes (red blood cells), platelets, granulocytes (eosinophils, basophils, neutrophils), and monocytes are produced in the bone marrow
Lymphoid Tissue
- Thymus, lymph nodes, and spleen are the primary sites
- Lymphocytes (B cells and T cells) are produced here
Granulocytes
- Comprise neutrophils, eosinophils, and basophils
- Characterized by cytoplasmic granules
- Neutrophils: 60-70%, life span 6-10 hours, 3-5 segments, important role in fighting bacterial infections
- Eosinophils: 2-4%, combat parasitic infections, and allergic reactions, have bi-lobed nuclei, cytoplasmic granules stain pink-orange
- Basophils: <1%, release histamine and heparin, have a bi-lobed nucleus, found in allergic reactions
Agranulocytes
- Lymphocytes and monocytes
- Lymphocytes: 25-33%, vital part of the adaptive immunity, recognizes specific antigens through antigen presentation, may be small or large
- Monocytes: 3-8%, Largest WBC, unilobed nucleus, often kidney or bean-shaped, abundant vacuoles, found in chronic infections and inflammation
White Blood Cells Proliferation
- Myeloblast cells divide, making up ~2% of nucleated cells in bone marrow
- 8-13 µm diameter
- Cytoplasm is basophilic (contains many free ribosomes)
- Nucleus is undifferentiated, round to ovoid, and has coarse nucleoli appearing sieve-like
Promyelocyte
- Divides, a little over 5% of nucleated bone marrow cells
- Cytoplasm stains deep blue, possessing abundant specific azurophilic granules, and containing numerous ribosomes, well developed Golgi apparatus
- Indented round to ovoid nucleus
- Prominent nucleoli
Myelocyte
- Significant granular development with decreased basophilia
- Nucleus is oval-shaped, irregularly-shaped due to disappearing nucleoli, chromatin dense and compact
- 5-20% of nucleated bone marrow cells
Metamyelocyte
- Cell division stops
- Nucleus is slightly indented, kidney bean-shaped, dense chromatin, no nucleolus
- ~22% of nucleated cells in bone marrow
- Size: 10-18 μm (slightly larger than mature PMN)
Granulocyte Maturation
- Stepwise progression from stem cells to mature granulocytes through distinct stages, involving cell division, cytoplasmic development, and the formation of granules
- Includes myeloblast, promyelocyte, myelocyte, metamyelocyte stages
Neutrophils (detailed)
- Makes up 60-70% of WBCs
- Short lifespan (6-10 hours)
- Crucial role in fighting bacteria infections
- Segmented nucleus with 3-5 lobes
- Hypersegmentation (more than 5 lobes) can be a sign of Vitamin B12 deficiency
Eosinophils (detailed)
- 2-4% of WBCs
- 12-17 µm diameter
- Bi-lobed nuclei connected by thin strands
- Pink-orange granules from eosin staining
- Fight parasitic infections and allergic responses.
Basophils (detailed)
- 0.5-1% of WBCs
- Bi-lobed nucleus (difficult to visualize)
- Dark cytoplasmic granules containing histamine and heparin
- Involved in allergic reactions
- 3-4.5 day life span
Monocytes (detailed)
- Largest WBC (15-20 µm)
- 3-8% of WBCs
- Kidney or bean-shaped nucleus
- Blue-gray cytoplasm with fine vacuoles (ground-glass appearance)
- Important in chronic infections and inflammation
- A significant proportion reside in the spleen
Lymphocytes (detailed)
- 2nd most abundant WBC (25-33%)
- Crucial in adaptive immunity
- Small or large, approximately 7µm in diameter
- Their function is to recognise specific non-self antigens during a process known as antigen presentation
- Hard to differentiate between T cells and B cells in a peripheral blood smear
Hematopoietic Response
- Hypoxia stimulates RBC production
- Infection or inflammation triggers granulocyte/monocyte production
- Antigens stimulate lymphocyte production
- Hemorrhage promotes platelet production
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Description
Explore the fascinating world of white blood cells and their crucial role in the immune system. This quiz delves into hematopoiesis, the formation of blood cells, and the various types of tissues involved. Test your knowledge on granulocytes, myeloid and lymphoid tissues, and their functions in defending the body.
