Hematology: Introduction to Platelets

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Questions and Answers

What is the main function of platelets in the blood?

Transporting nutrients

Carrying oxygen

Clotting (correct)

Removing waste

What is the average volume of blood in the human body?

6 liters

3 liters

5 liters (correct)

4 liters

What are red blood cells (RBCs) primarily filled with to facilitate oxygen transport?

Hemoglobin (correct)

Platelets

Plasma

Carbon dioxide

Which of the following is a crucial test for predicting blood and systemic diseases?

Complete Blood Count (CBC) Signup and view all the answers

What is the normal appearance of red blood cells?

Pink to red with a central zone of pallor Signup and view all the answers

Which component of blood is involved in the removal of waste from tissues?

Plasma Signup and view all the answers

What is the significance of measuring hemoglobin using Drabkin reagent?

It converts to cyanmethemoglobin for absorbance measurement Signup and view all the answers

What is the size classification of red blood cells?

6-8 mm in diameter Signup and view all the answers

What does a high platelet count indicate in a patient?

A condition called thrombocytosis. Signup and view all the answers

Which sign must be present on containers dealing with potentially infectious specimens?

Biohazard sign. Signup and view all the answers

What condition is indicated by a low platelet count?

Thrombocytopenia. Signup and view all the answers

Which type of fire extinguisher is designated for use on energized electrical fires?

Type C. Signup and view all the answers

What is one of the primary functions of neutrophils?

Involved in bacterial infection response Signup and view all the answers

Which of the following is a potential consequence of thrombocytopenia?

Easy bruising. Signup and view all the answers

Which of the following diseases can be transmitted through potentially infectious specimens?

Syphilis. Signup and view all the answers

What distinguishes band neutrophils from mature neutrophils?

They are less mature and indicate a bacterial infection. Signup and view all the answers

What is the main method of indirect transmission for pathogens in a laboratory setting?

Touching contaminated surfaces and then the mouth. Signup and view all the answers

Which type of white blood cell is characterized by bright orange-red granules?

Eosinophils Signup and view all the answers

Which condition is associated with an increase in monocytes?

Infections and collagen-vascular diseases Signup and view all the answers

Why is it crucial to observe infection control policies in phlebotomy?

To prevent transmission of pathogens. Signup and view all the answers

What is the size range of platelets?

2 to 4 µm Signup and view all the answers

How do platelets contribute to hemostasis?

They form aggregates to plug damaged vessels. Signup and view all the answers

Which of the following is NOT a characteristic of platelets?

Diameter of 5 to 7 µm Signup and view all the answers

What is the role of basophils in the immune response?

Release histamines during allergic reactions Signup and view all the answers

What is the primary role of red blood cells (RBCs)?

Transport oxygen Signup and view all the answers

Which of the following best defines hematocrit (HCT)?

Volume of red blood cells in whole blood Signup and view all the answers

What condition is lymphocytosis often associated with?

Viral infections Signup and view all the answers

What is the function of monocytes in the immune system?

Phagocytose foreign particles Signup and view all the answers

Which of the following RBC indices reflects the diameter of red blood cells?

Mean Cell Volume Signup and view all the answers

What are the dark purple granules in certain white blood cells responsible for?

Releasing histamines Signup and view all the answers

Which type of white blood cell is primarily associated with humoral and cell-mediated immunity?

Lymphocytes Signup and view all the answers

What does the Red Blood Cell Distribution Width (RDW) indicate?

Variability in RBC volume Signup and view all the answers

What is the recommended fasting duration before a blood test?

8 to 12 hours Signup and view all the answers

What impact does smoking have on blood test results?

Increases white blood cell count Signup and view all the answers

How does a patient's posture affect test results?

Shifts body water from intravascular to interstitial space Signup and view all the answers

What should be done to maintain standard precautions during venipuncture?

Follow personal hygiene and use gloves Signup and view all the answers

What is a physiological factor that can cause preanalytical variation in test results?

Dietary habits Signup and view all the answers

What device can be used during venipuncture to help locate a vein?

Blood pressure cuff Signup and view all the answers

What is one effect of diurnal rhythm on physiological test results?

Fluctuations in body fluid dynamics Signup and view all the answers

What is the primary function of a tourniquet during venipuncture?

To provide a barrier to venous blood flow Signup and view all the answers

Study Notes

Introduction to Platelets

Platelets, also known as thrombocytes, play a vital role in blood clotting.

Hematology Overview

Hematology is the study of blood cells, including their staining, counting, and analysis.
Blood volume in an average adult is approximately 5 liters.

Functions of Blood

Transports oxygen from lungs to body tissues and removes carbon dioxide.
Facilitates transport of nutrients like glucose, proteins, and fats.
Removes waste products to liver and kidneys.
Plasma provides enzymes that protect blood vessels and maintain circulation.

Blood Components

Red Blood Cells (RBCs): Anucleate biconcave cells filled with hemoglobin (HGB) for oxygen and carbon dioxide transport; size is 6-8 µm.
White Blood Cells (WBCs): Defend against infection, comprised of several types including neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Hemoglobin and Hematocrit Measurements

Hemoglobin levels assessed using Drabkin reagent, with plasma absorbance evaluated at 540 nm.
Hematocrit (HCT) measures the ratio of packed RBC volume to whole blood volume.

Red Blood Cell Indices

Mean Cell Volume (MCV): Reflects diameter of RBCs.
Mean Cell Hemoglobin (MCH): Represents mass of hemoglobin in individual cells.
Mean Cell Hemoglobin Concentration (MCHC): Indicates staining intensity of RBCs.
RBC Distribution Width (RDW): Variability in RBC volume, important for diagnosing anemia and other disorders.

Types of White Blood Cells (WBCs)

Neutrophils: Phagocytic cells important for bacterial infections; band neutrophils indicate immature stages.
Eosinophils: Respond to allergies and infections with bright orange-red granules.
Basophils: Contain histamines, involved in allergic responses.
Lymphocytes: Crucial for immunity, with conditions like lymphocytosis and lymphopenia indicating various health issues.
Monocytes: Immature macrophages that assist in immune response; indicative conditions include monocytosis in infections.

Role of Platelets in Hemostasis

Platelets are crucial in sealing wounds, repairing blood vessel walls, and maintaining vascular integrity.
Size ranges from 2 to 4 µm; shape is round or oval and anucleate with a slightly granular appearance.

Clinical Significance of Platelets

Thrombocytosis: Elevated platelet count associated with inflammation or trauma; essential thrombocythemia is a serious condition.
Thrombocytopenia: Low platelet count linked to drug treatment can lead to easy bruising and uncontrolled bleeding.

Blood Collection and Patient Safety

Treat specimens as potentially infectious due to possible pathogens like Hepatitis and HIV.
Importance of hand hygiene and wearing gloves during blood collection.
Ensure proper disposal of contaminated sharps and use of biohazard containers.

Physiologic Factors Affecting Test Results

Body posture changes fluid distribution affecting blood test results.
Diurnal rhythm indicates that body fluid levels fluctuate throughout the day, impacting various analytes.

Equipment for Venipuncture

Tourniquet: Creates a barrier to venous blood flow, aiding vein location.
Types include Velcro straps and blood pressure cuffs, applied several inches above the venipuncture site.

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Description

Explore the pivotal role of platelets, or thrombocytes, in blood clotting and overall hematological function. This quiz covers blood volume, cell analysis, staining, and counting techniques essential for understanding hematology.