CONCEPTS 2025
, Module 9: Student Note Taking
Guide
Chapter 28:
Introduction
The hematologic system is responsible for producing and regulating blood components,
which are essential for oxygen transport, immune function, and
_coagulation . Disorders of this system can significantly impact a patient’s ability
to maintain _homeostasis and respond to injury or illness.
This chapter focuses on _hematopoiesis , oxygen transport, iron
metabolism, therapeutic phlebotomy, and _bone marrow function. Understanding
these processes is crucial for nurses to identify and manage hematologic disorders such as
anemia , _polycythemia , and clotting disorders.
Hematopoiesis and Blood Cell Formation
Hematopoiesis is the process of blood cell formation, occurring primarily in the bone
marrow . All blood cells originate from _hematopoietic stem cells , which
differentiate into three main types of blood cells:
• Red blood cells (RBCs): Transport _oxygen from the lungs to tissues and
remove carbon dioxide . They contain _hemoglobin , a protein
that binds oxygen for distribution throughout the body. A deficiency in RBCs leads to
_anemia , causing fatigue and reduced oxygenation.
, • White blood cells (WBCs): Provide immune defense by _fighting infections ,
_destroying pathogens , and _regulating the immune response .
There are different types of WBCs, including _neutrophils (bacterial
defense), _lymphocytes (viral defense and antibody production), and
monocytes (phagocytosis).
• Platelets: Contribute to _clot formation by adhering to damaged blood
vessels and releasing _clotting factors . Without adequate platelet
levels, patients are at risk for excessive bleeding and poor wound
healing.
The bone marrow regulates hematopoiesis based on the body’s _oxygen needs and
_immune demands demands. If oxygen levels drop, the kidneys release
erythropoietin , stimulating red blood cell production. Other regulatory
factors include _colony-stimulating factors for WBC production and
thrombopoietin for platelet production.
Certain conditions can lead to dysregulation of hematopoiesis, such as _leukemia
(excessive WBC production leading to abnormal immune function), _aplastic
anemia (bone marrow failure leading to pancytopenia), and myelodysplastic
syndromes (abnormal and ineffective hematopoiesis leading to blood cell
dysfunction).
Clinical Example:
A 68-year-old client with chronic kidney disease presents with fatigue and pallor. Blood tests
show a hemoglobin level of 8.2 g/dL. Why is this client at risk for anemia?