2. Several Functions of Blood
•Transportation of dissolved gases, nutrients,
hormones, and metabolic waste.
•Protection against toxins, pathogens, and blood
loss injuries.
•Stabilization of body temperature.
•Regulation of the pH through the blood buffering
system and electrolyte composition of interstitial
3. WHITE BLOOD CELLS
•white blood cells (leukocytes) are immune system cells that
protect the body against diseases and foreign invaders. while
they vary in size, they are generally the largest cell type
found in the blood. white blood cells reside throughout the
body, including in the lymphatic system and in the blood.
they make up less than 1 percent of total blood volume. the
lifespan of a white blood cell varies from 18 hours to many
years.
4. formation
• white blood cells begin in the bone marrow in a process called hematopoiesis. all blood cells,
including white blood cells, red blood cells, and platelets, descend from a common
hematopoietic stem cell, or "pluripotent" stem cell. these stem cells evolve (differentiate) in
different stages.
• the hsc cell first separates into the lymphoid cell line, via a lymphoid stem or progenitor cell
and into the myeloid cell line, via myeloid stem or progenitor cell. the lymphoid stem or
progenitor cell gives rise to lymphocytes specifically b lymphocytes or "b cells" and t
lymphocytes (t cells).
• the myeloid stem or progenitor cells give rise to myeloblasts, which further differentiate into
macrophages, monocytes, neutrophils, basophils, and eosinophils and into the precursors of
red cells and platelets.
5. LAB VALUES
• a normal white blood cell count is usually between 4,000 and 10,000
cells/mcl.
Conditions Involving Elevated White Blood Cell Counts
• Though you may think of infections, there are many causes of an elevated
white blood cells count. These can be increased by overproduction, or
rather by the body releasing white blood cells early from the bone marrow.
Stress of any form can also result in this release of white blood cells. Some
causes of an increased white blood cell count include:
• Infections
• Cancers such as leukemias, lymphomas, and myelomas in which a greater
number of white blood cells are manufactured.
• Inflammation such as inflammatory bowel disease and autoimmune
6. Trauma ranging from fractures to emotional stress
Pregnancy - In pregnancy, the number of white cells is "normally" elevated
Asthma and Allergies - With allergies, you will often see an increase in the
type of white blood cells known as eosinophils
Exercise
Conditions With Low White Blood Cell Counts
Conditions which may result in a low white blood cell count include:
Severe infections
Bone marrow damage or disorders including aplastic anemia, bone marrow
"takeover" by blood cancers or metastatic cancer, or drug or chemical-related
damage to the bone marrow
Autoimmune diseases such as lupus
7. Symptoms of a Low White Blood Count
The symptoms of a low white blood count can be understood by knowing the
function of white blood cells. Our white blood cells are our bodies defense against
infections. Some of the cells are part of our innate immune system, meaning they
know from birth to attack foreigners, and others are part of our humoral, or learned
immune system, and manufacturer antibodies after "seeing" a germ in order to be
prepared for another attack by that germ ahead of time. Symptoms of infection may
include:9
Fever
Cough
Pain or frequency of urination
Blood in the stools
Diarrhea
8. • CHEMOTHERAPY
• ONE OF THE MOST COMMON AND DANGEROUS SIDE EFFECTS OF CHEMOTHERAPY IS DUE TO
ITS EFFECT ON WHITE BLOOD CELLS, PARTICULARLY THE TYPE OF WHITE BLOOD CELLS
KNOWN AS NEUTROPHILS. NEUTROPHILS ARE ESSENTIALLY THE "FIRST RESPONDERS" OF OUR
IMMUNE SYSTEM. A DECREASE IN NEUTROPHILS DURING CHEMOTHERAPY, KNOWN AS
CHEMOTHERAPY-INDUCED NEUTROPENIA, CARRIES THE RISK OF SERIOUS INFECTION.10
• NOT ONLY IS IT MORE DIFFICULT FOR THE BODY TO FIGHT OFF INFECTIONS RELATIVE TO
SOMEONE WITHOUT NEUTROPENIA, BUT BACTERIA WHICH ARE NORMALLY NOT TERRIBLY
HARMFUL CAN CAUSE SERIOUS INFECTIONS.
9. TYPES OF WHITE BLOOD CELLS AND THEIR
FUNCTIONS
• Basophils are the cells mainly responsible for allergic reactions.
they defend against parasites and bacteria by excreting two
chemicals: heparin and histamine. Heparin is a blood-thinning
substance. Histamine widens blood vessels and increases blood
flow to infected tissues. Basophils are not antigen specific. This
means they don't have to determine the identity of the invading
substance before taking action against it.
• Neutrophils mainly target bacteria and fungus. They are the most
abundant type of white blood cell in most mammals. They usually
respond and multiply quickly. Neutrophils are formed from stem
10. • eosinophils target larger parasites, such as worms, and modulate allergic
inflammatory responses. for most individuals, eosinophils make up about 1
to 6 percent of all white blood cells.
• monocytes are the largest type of white cell. there are at least three types
of monocytes in human blood and they differentiate into macrophages,
dendritic cells, and foam cells. monocytes are produced by bone marrow
and circulate in the bloodstream for about one to three days prior to
moving into tissues throughout the body. they make up about 3 to 8 percent
of white cells. Monocytes are the garbage trucks of the immune system.
Around 5 to 12 percent of white blood cells in your bloodstream are
monocytes, but their most important function is to migrate into tissues and
clean up dead cells
11. • Lymphocytes work the front lines to identify and destroy foreign
invaders. they are the main type of cell found in lymph, the fluid that
circulates through the lymphatic system. There are three primary types of
lymphocytes: b cells, t cells, and natural killer cells. b cells make up 10
percent of the lymphocytes. They circulate in the front lines of our blood
and work to identify foreign invaders. t cells make up 75 percent of
lymphocytes. They mature in the thiamin, which is a part of the lymph
system, and then migrate to the point of invasion. t cells surround, bind,
and help kill foreign invaders. Natural killer cells function to defend
against tumors and viruses.
