Med Surg Hema Ch. 33 Flashcards
The hematological system includes?
blood, blood cells, lymph, and organs involved with blood formation or blood storage
Blood is a
specialized connective tissue that acts as a transport vehicle of materials between the external environment and the body’s cells
Blood consists of
plasma (a clear yellow, protein-rich fluid); solutes (proteins, electrolytes, and organic elements); red blood cells (RBCs), white blood cells (WBCs); and platelets (which are fragments of cells).
The hematological system is important in
helping the body by circulating oxygen, nutrients, hormones, and metabolic wastes; protecting against invasion of pathogens; maintaining blood coagulation; and regulating fluids, electrolytes, acids, bases, and body temperature
Bone marrow is the primary site for
Blood formation and maturation (hematopoiesis)
Bone marrow is
network of flexible connective tissue that produces stem cells
Stem cells are
Fxn?
are immature, undifferentiated cells that have the ability to become any one of several types of blood cells.
**Can become whatever cell you need and can divide over and over again to produce new cells
Lymphoid stem cells produce
either T or B lymphocytes, which are the main functional cells of the immune system
Myeloid stem cells differentiate
into three cell types: RBCs (erythrocytes), WBCs (leukocytes), and platelets (thrombocytes)
Which is the most abundant of the formed elements?
RBCs
aka = erythrocytes
RBC’s characteristics
small, biconcave disk with no nucleus
Are RBCs rigid or flexible?
Flexible- that it can move through small capillaries of the circulatory system
Are RBCs thin or thick?
Very thin so that O2 and CO2 gases easily diffuse across
RBCs fxn
- to pick up O2 from the lungs and transport it to systemic tissues
- to pick up CO2 from the tissues and deliver it in the lungs
What affects RBCs ability to perform fxns?
Shifts in the:
- Amount
- Size
- Shape
- Composition
**Think about sickle cells
Where are RBCs formed?
Bone marrow
What is the lifespan on RBCs?
120 days
RBC normal range
3.61 to 5.81 million/mm3
Erythropoiesis
the selective maturation of stem cells into mature erythrocytes
RBCs produce
Hemoglobin
Hemoglobin is
-the oxygen carrying component of an RBC
**Needs iron
Hemoglobin is composed of
Pigment (heme) that contains iron (Fe2+) and a protein (globin)
Hgb molecule is made up of
4 globins with a heme molecule attached to each globin
The heme molecule has what at the center?
How many O2 molecules can be carried?
iron at the its center which binds with O2
-This makes Hbg capable of transporting up to four molecules of O2; therefore, iron is a significant component of Hgb
Hematopoiesis
Making of blood cells
Why are erythrocytes critical for survival?
because a severe deficiency of erythrocytes in the case of major trauma or hemorrhage, can be fatal within a few minutes because of the lack of oxygen.
WBCs are called
leukocytes
WBCs fxn
Components of the body’s defense system against infection and disease
What is the least abundant formed element?
WBCs
yet they are required for life to provide protection against infectious microorganisms and other pathogens.
Normal number of WBCs
4500-11,000 WBCs per cubic mm of blood
Where can RBCs and WBCs travel?
RBCs= stay in the vascular space (w/in blood vessels) WBCs = travel anywhere
WBCs: Granulocytes
- Neutrophil
- Eosinophils
- Basophils
WBCs: Agranulocytes
- Lymphocytes
- Monocytes
Neutrophil fxn:
phagocytosis (engulfing and digesting bacteria)