NHA MOD 2

MODULE 2: NHA CPT Exam 1 — Chapter 6: The Cardiovascular System

Content Overview

  • The Circulatory System

  • Blood Components

- Hemostasis & Complications

Career Development.

  • Building a Professional Resume

Laboratory Skills.

- Vein Identification & Mock Blood Draws

© McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. October 20-22, 2025

Subject Focus

  • Anatomy & Physiology for the Phlebotomist

Learning Outcomes

  1. Describe circulation and the purpose of the vascular system.

  2. Identify and describe the structures and functions of the different types of blood vessels.

  3. Locate and name the veins most commonly used for phlebotomy procedures.

  4. Identify the major components of blood and describe the major functions of each component.

  5. Define hemostasis and describe the basic coagulation process.

  6. Describe how A B O and Rh blood types are determined.

Why Anatomy & Physiology Matters in Phlebotomy

  • This week bridges biology and practice.

  • Understanding how the circulatory system works (blood travel, composition, clotting process) aids in:

    • Safely drawing blood

    • Minimizing errors

    • Interpreting patient reactions

Key Definitions

  • Anatomy: The study of the structure of the body.

  • Physiology: The study of how those structures function.

Importance

  • Together, anatomy and physiology provide the scientific foundation for

    • Every draw

    • Every test

    • Every patient encounter

Clinical Relevance

  • Knowledge of anatomy is essential to avoid injury during venipuncture (e.g., hitting arteries, nerves, or tendons).

  • Inadequate knowledge can lead to errors like specimen mislabeling or incorrect interpretations of blood characteristics.

Discussion Prompt

  • Describe how understanding the structure of veins and arteries affects confidence during venipuncture.

The Circulatory System: The Body’s Transportation Network

  • The circulatory system connects every organ, tissue, and cell.

  • It delivers:

    • Oxygen

    • Nutrients

    • Hormones

  • Removes carbon dioxide and waste products through:

    • A network of over 70,000 miles of interconnected vessels known as the vascular system, functioning continuously (24/7), from birth to death.

Main Structures

  • Heart: Muscular pump that maintains unidirectional blood flow.

  • Blood Vessels:

    • Comprising arteries, veins, and capillaries.

  • Blood: Connective tissue that carries essential elements.

Circulatory Pathways

  • Pulmonary Circuit:

    • Pathway: Right heart → Lungs → Left heart (functions in gas exchange).

  • Systemic Circuit:

    • Pathway: Left heart → Body → Right heart (delivers oxygen and nutrients).

Blood Volume

  • The average adult has 8–12 pints of blood—approximately the volume of a gallon of milk.

Clinical Relevance for Phlebotomists

  • Phlebotomists typically collect systemic venous blood (blood returning to the heart containing metabolic by-products).

  • Understanding circulatory pathways explains the darker color of venous blood compared to arterial blood.

    • Most laboratory tests utilize venous blood due to its insights into body metabolism and organ function.

Discussion Prompt

  • Why is venous blood typically collected instead of arterial blood?

    • Arterial blood reflects what the lungs have just oxygenated, not what tissues have utilized.

The Heart: Structure, Function, and Flow

  • The heart is a strong, hollow muscle approximately the size of a fist, located centrally in the chest, slightly left of midline.

  • Functions as a double pump:

    • Right Side: Sends deoxygenated blood to the lungs.

    • Left Side: Distributes oxygen-rich blood throughout the body.

  • Every heartbeat pumps about 70 mL of blood, which generates the pulse.

Heart Structure

  • Chambers:

    1. Right Atrium

    2. Right Ventricle

    3. Left Atrium

    4. Left Ventricle

  • Septum: The wall that divides the right (oxygen-poor) and left (oxygen-rich) sides of the heart.

  • Valves:

    • Tricuspid (between Right Atrium and Right Ventricle)

    • Pulmonary (between Right Ventricle and pulmonary artery)

    • Mitral/Bicuspid (between Left Atrium and Left Ventricle)

    • Aortic (between Left Ventricle and aorta)

Heart Function

  • The heart's dual pump system ensures proper circulation:

    • Atria: Upper chambers that receive blood.

    • Ventricles: Lower chambers that pump blood out.

Blood Flow Pattern

  • Pathway:
    Body → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Valve → Lungs → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve → Aorta → Body.

Clinical Relevance

  • Arterial blood, which is oxygen-rich, appears bright red and pulsatile.

  • Venous blood, collected by phlebotomists, returns to the right atrium and appears darker.

  • If an artery is accidentally punctured, it results in a high-pressure system where blood spurting may occur, requiring at least five minutes of pressure to control.

Vein Identification Techniques and Tourniquet Use

  • Successful phlebotomy is 90% preparation. Proper techniques in palpation and tourniquet control are critical.

Techniques

  • Tourniquet Placement:

    • Apply 3–4 inches above the venipuncture site, no longer than 1 minute.

  • Palpation:

    • Feel for bounce, direction, and depth of veins.

  • Preparation:

    • Cleanse the area and anchor the skin below the site.

Clinical Relevance

  • Applying a tourniquet for more than 60 seconds can lead to hemoconcentration, affecting laboratory results for proteins, calcium, and potassium levels.

Selecting a Vein

  • The choice of vein impacts the success and safety of blood draws.

Vein Patterns

  • H-Pattern:

    1. Median Cubital (ideal site)

    2. Cephalic

    3. Basilic (used with caution)

  • M-Pattern:

    • Median Basilic, Median Cephalic

Examples & Considerations

  • Cephalic vein: Often most accessible in obese patients.

  • Basilic vein: Closest to the brachial artery; should be used as a last resort due to complications.

  • Avoid drawing blood from the side of a mastectomy to reduce the risk of lymphedema.

Clinical Relevance

  • Choosing an inappropriate site can lead to nerve damage or inaccurate test results.

Vein Identification in the Antecubital Fossa

  • Subclavian vein, Cephalic vein, Basilic vein, Median cubital vein, Accessory cephalic vein, Median basilic vein, Median vein.

Identification Diagram

  • Understanding the layout and relation of these veins is crucial for successful venipuncture and avoiding complications.

Selecting A Vein: Artery vs. Vein

  • At a venipuncture site,

    • A vein will feel bouncy and resilient.

    • An artery will feel firm and pulsate.

Post-selection Procedures

  • After selecting a vein:

    • Use proper phlebotomy techniques.

    • Avoid probing at the site to minimize risks.

    • Accidental nerve puncture can lead to temporary or permanent loss of function and may be seen as an act of negligence.

  • In the case of accidental arterial puncture:

    • Withdraw the needle immediately.

    • Apply firm pressure for at least 5 minutes.

Veins in the Back of the Hand

  • Dorsal venous arch

  • Metacarpal plexus

Importance

  • Knowledge of these veins increases options for venipuncture and enhances the ability to collect blood samples effectively and safely.

  • Understanding the structure and accessibility of veins in various body locations is fundamental to phlebotomy and clinical practice.