Human Blood Quiz

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Questions and Answers

What is the primary function of blood in the body?

Transport of oxygen and carbon dioxide (correct)

Production of hormones

Storage of nutrients

Protection against infectious diseases

What is the typical volume of blood drawn for clinical testing?

20 mL

15 mL

5 mL (correct)

10 mL

Which component makes up the majority of blood plasma?

Water (correct)

Glucose

Proteins

Lipids

What does the hematocrit (HCT) measure in blood?

Volume of packed erythrocytes Signup and view all the answers

What is a common method of collecting blood from newborns?

Heelstick blood collection Signup and view all the answers

What triggers thrombocyte aggregation upon injury to a blood vessel?

Contact with collagen Signup and view all the answers

Which of the following components is NOT part of a thrombus?

Serotonin Signup and view all the answers

Which granule contents are released during the thrombocyte release reaction?

Serotonin and ATP Signup and view all the answers

What is thrombosis primarily characterized by?

Blood clot formation in intact vessels Signup and view all the answers

Which substance helps to neutralize heparin in the context of blood clotting?

Heparin neutralizing factor Signup and view all the answers

Which function is primarily associated with neutrophil granulocytes?

Degranulation Signup and view all the answers

What is the primary role of the major basic protein (MBP) found in eosinophil granules?

Contributing to the eosinophilic staining Signup and view all the answers

What distinguishes specific granules in eosinophils from primary granules?

Presence of crystalloid bodies Signup and view all the answers

What is the normal percentage of eosinophils in a differential blood count?

2-4 % Signup and view all the answers

What type of granules do neutrophils primarily contain that are responsible for hydrolytic activity?

Lysosomal acid hydrolases Signup and view all the answers

What is the normal range for erythrocyte count in blood?

4.5 – 5.5 T/l Signup and view all the answers

What is the life span of a platelet?

7-12 days Signup and view all the answers

What protein is responsible for oxygen transport in erythrocytes?

Hemoglobin Signup and view all the answers

Which of the following components is typically missing in erythrocytes?

Nucleus Signup and view all the answers

What method is traditionally used to count different types of blood cells?

Bürker chamber Signup and view all the answers

What is the diameter range of a typical erythrocyte?

7.2 – 7.8 μm Signup and view all the answers

What is the function of ɑ (alpha) granules in platelets?

Contain bioactive substances Signup and view all the answers

Which blood group system is associated with erythrocyte membrane antigens?

AB0 blood group system Signup and view all the answers

What is the normal percentage range of neutrophil granulocytes in the blood?

60-70% Signup and view all the answers

Which type of white blood cell is primarily responsible for responding to bacterial infections?

Neutrophil granulocyte Signup and view all the answers

What is the life span of neutrophil granulocytes in the body?

7-12 days Signup and view all the answers

How do leukocytes exit the bloodstream to reach tissue during an inflammatory response?

By extravasation through postcapillary venules Signup and view all the answers

What is the typical percentage range of lymphocytes in normal blood differential counts?

20-40% Signup and view all the answers

Which type of granule is found in neutrophil granulocytes and contains antibacterial agents?

Specific (secondary) granules Signup and view all the answers

What is the main function of azurophil granules in leukocytes?

Contain hydrolytic enzymes for digestion Signup and view all the answers

Which type of leukocyte is least abundant in a differential blood count?

Basophil granulocyte Signup and view all the answers

What is the primary function of basophil granulocytes in peripheral tissues?

Allergic reactions Signup and view all the answers

Which type of cell serves as a professional antigen presenting cell?

Monocyte Signup and view all the answers

The diameter of a small lymphocyte is approximately how many micrometers?

5-7 µm Signup and view all the answers

Which cell type is primarily responsible for cell-mediated immunity?

Cytotoxic T-lymphocyte Signup and view all the answers

What is the lifespan of a monocyte?

Months to years Signup and view all the answers

What indicates the presence of immature cells in the blood, often associated with inflammation?

Left shift Signup and view all the answers

Natural killer cells are primarily associated with which type of immunity?

Innate immunity Signup and view all the answers

What specific granules are present in basophils?

Histamine and interleukins Signup and view all the answers

Study Notes

Blood - Histology

Blood is a fluid connective tissue
Functions include transporting oxygen (O2), carbon dioxide (CO2), nutrients, metabolites, hormones, and other regulatory substances
Maintains homeostasis (buffering, thermoregulation, blood clotting)
Transports humoral agents and immune system cells

Blood Collection for Clinical Testing

Blood is commonly drawn from a vein in the arm directly into evacuated tubes
Tubes typically hold 5 mL of blood, enough for many clinical chemistry tests
Automated analyzers require small amounts (2-100 µL) per test
Capillary blood collection is used when venous collection is difficult, e.g., in newborns using a heel stick
Phlebotomy is the act of drawing blood, venipuncture specifically refers to drawing blood from a vein.

Fractionation of Blood Components

Blood is fractionated into plasma and formed elements
Plasma (55% of whole blood) is the least dense component
Buffy coat: leukocytes and platelets (<1% of whole blood)
Erythrocytes (45% of whole blood) are the most dense component
Hematocrit (HCT) measures the volume of packed erythrocytes in %, a normal value is ~45%

Composition of Blood

~90% water
~8% protein
~1% inorganic salts, 0.5% lipids, 0.1% glucose, and other minor components

Blood Smear (May-Grünwald-Giemsa Staining)

A blood smear allows for examination of blood cells
Stained using May-Grünwald-Giemsa stain
Blood Smear: preparation technique and overview photomicrographs are used

Counting Blood Cells

Traditional method: Bürker chamber (haemocytometer)
Modern method: Hematology Analyzer

Complete Blood Count (CBC)

Quantitative blood count of formed elements.
Erythrocytes (red blood cells, RBC): 4.5-5.5 T/L
Thrombocytes (platelets, Thr): 0.15-0.3 T/L
Leukocytes (white blood cells, WBC): 4-11 G/L

Erythrocyte (Red Blood Cell, RBC)

Anucleate cells, typically missing cellular organelles
Biconcave disc shape, maximizing cell surface area for gas exchange
~7.2 - 7.8 µm in diameter
~120-day lifespan
Normal number: 4.5-5.5 T/L
Contains hemoglobin, which carries oxygen throughout the body

Erythrocyte Membrane Structure

Special cytoskeletal network and cell membrane provide flexible cell shapes allowing passage in small capillaries

Erythrocyte Function

Transports oxygen and carbon dioxide

Blood Typing and Transfusion

Erythrocyte membranes contain blood group antigens important in transfusions
ABO blood grouping system is a common example for recognizing blood groups

Platelet (Thrombocyte)

Diameter ~ 2-4 μm
Cytoplasmic fragments of megakaryocytes
Lifespan: 7-12 days
Normal number in peripheral blood: 0.15-0.3 T/L
Removal of aged forms: spleen, liver
Granules contain bioactive substances like mitogen growth factor, etc.

Platelet Release Reaction

Upon injury, platelets contact connective tissue (collagen) which triggers aggregation and release of granule content, initiating blood clotting

Thrombosis

Blood clots (thrombus) forming in intact blood vessels, preventing proper blood flow
Thrombi have two components: aggregated platelets and red blood cells forming a plug, and a mesh of cross-linked fibrin protein

### Leukocyte (White Blood Cell, WBC) Differential

Percentage ration of different leukocyte types
Neutrophil granulocytes (60-70%)
Lymphocytes (20-40%)
Monocytes (3-8%)
Eosinophils granulocytes (2-4%)
Basophils granulocytes (0.5%)

Leukocytes (WBC) Types

Granulocytes:
- Neutrophils
- Eosinophils
- Basophils
Agranulocytes:
- Lymphocytes (small and large)
- Monocytes

Granulocytes (WBCs) Description

Contains primary and secondary granules, with specific functions
primary (azurophilic) granules are lysosomes (primarily digestive enzymes)
secondary (specific) granules include different types of enzymes for specific granulocytes (enzymes for digestion and/or killing)

Leukocyte Extravasation

White blood cells exit blood vessels into tissues, responding to signals of inflammation

Neutrophil Granulocyte Function

Phagocytosis (engulfing of pathogens)
Degranulation (releasing enzymes from granules)
NETosis (releasing chromatin traps to capture pathogens)

Eosinophil Granulocyte

Diameter: 12-14 µm
Bi-lobed nucleus
8-12 day lifespan
2-4% in differential count
Granules: contain lysosomal acid hydrolase, and specific crystalloid bodies - major basic protein, histaminase, collagenase, cathepsins
Function in tissues: attacking parasitic infections

Basophil Granulocyte

Diameter: 10-12 µm
Less segmented nucleus, covered by basophilic granules
8-12 day lifespan
~0.5% in differential count
Granules contain: lysosomal acid hydrolase, heparin, histamine, leukotrienes, interleukins.
Function in tissues: dealing with allergic and inflammatory reactions

Monocyte

Diameter: 15-20 µm
Kidney-shaped nucleus
Months-years lifespan
~3-8% in differential count
Functions: Phagocytosis, professional antigen-presenting cell, cytokine production, differentiate to macrophages (MPS = Mononuclear Phagocytic System)

Small Lymphocyte

Diameter: 5-7 µm
Thin cytoplasm, containing azurophilic granules
Years lifespan (longer for memory cells)
40-60% in differential count
Two Major types: T-lymphocyte (thymus-dependent), B-lymphocyte (bursa-dependent)
Functions: Cellular (T-cells) and humoral (B-cells) immunity

Large Granular Lymphocytes

Diameter ~15 μm
Numerous azurophilic, large granules
~5-10% of lymphocytes
Functions: Natural Killer (NK) cells; recognizing and killing tumor and virus-infected cells. Innate immunity

Left Shift in Blood Count

Indicates presence of immature leukocytes (e.g., myelocytes, metamyelocytes, band neutrophils) in the blood
Suggests an inflammatory response or acute infection
Increased release of immature neutrophils into the blood due to demand
Driven by the variety of growth factors and cytokines - G-CSF, GM-CSF, IL-3, and IL-5

Literature

Includes various books on Functional Histology and Concise Histology, along with scientific papers and internet resources

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Description

Test your knowledge about the functions and components of human blood. This quiz covers topics like blood volume, plasma components, and clotting mechanisms. Perfect for biology students or anyone interested in human physiology.