blood vessels Flashcards
What is polycythemia, and what are its causes and consequences?
Polycythemia: An excessive or abnormal increase in the number of erythrocytes (red blood cells) in the blood.Causes:
Polycythemia Vera: A condition that may result from bone marrow cancer.
Secondary Polycythemia: A normal response to living at high altitudes, where there is less oxygen available.
Blood Doping: An illegal practice in which athletes infuse their own red blood cells back into their bloodstream to artificially raise oxygen-carrying capacity.
Consequences:
The major issue with excessive RBCs is increased blood viscosity, which causes the blood to flow more sluggishly.
This can impair circulation and oxygen delivery to tissues in the body.
What are leukocytes, and what role do they play in the body?
Leukocytes (White Blood Cells - WBCs):
Less numerous than red blood cells, but crucial for body defense.
Normal Range: There are about 4,800 to 10,800 WBCs/mm³ of blood.
Percentage of Blood: WBCs account for less than 1% of total blood volume.
Characteristics:
White blood cells contain nuclei and the usual organelles, making them the only complete cells in the blood.
and how do they function differently from red blood cells?
Back (Answer):
Leukocytes (White Blood Cells - WBCs):
Act as a protective, movable army to defend the body against bacteria, viruses, fungi, parasites, and tumor cells.
Special Characteristics:
Unlike red blood cells (RBCs), which stay confined to the bloodstream, WBCs can move in and out of blood vessels through a process called diapedesis (meaning “leaping across”).
The circulatory system serves as the transportation system for WBCs, taking them to areas of the body where their services are needed for inflammatory or immune responses.
wbc can locate
In addition, WBCs can locate areas of tissue damage and infection in the body by responding to certain chemicals that diffuse from the damaged cells. This capability is called positive chemotaxis (ke″mo-tax′is). Once they have “caught the scent,” the WBCs move through the tissue spaces by amoeboid (ah-me′boid) motion (they form flowing cytoplasmic extensions that help move them along). By following the diffusion gradient, they pinpoint areas of tissue damage and rally round in large numbers to destroy microorganisms and dispose of dead cells.
What is leukocytosis and leukopenia, and what causes these conditions?
Leukocytosis: An increase in the number of white blood cells (WBCs), typically above 11,000 cells/mm³.
Causes: It generally occurs when the body speeds up WBC production in response to bacterial or viral infections.
Meaning: Leukocytosis indicates that an infection is likely present in the body.
Leukopenia: An abnormally low WBC count (often below the normal range of 4,800–10,800 WBCs/mm³).
Causes: It is commonly caused by certain drugs, such as:
Corticosteroids
Anticancer agents
What is the difference between leukocytosis and the abnormal production of WBCs in infectious mononucleosis and leukemia?
Leukocytosis: A normal and desirable response to infections, where the body increases the production of mature white blood cells (WBCs) to fight off threats.
Abnormal WBC Production:
Infectious Mononucleosis: An infection that can cause an abnormal increase in certain types of WBCs, though the WBCs are usually functional.
Leukemia: A pathological condition where the bone marrow becomes cancerous and produces large numbers of immature WBCs.
These immature WBCs are incapable of performing normal protective functions, making the body more susceptible to infections.
Additionally, the overproduction of WBCs crowds out other blood cell lines, leading to severe anemia and bleeding problems.
