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Chapter 15 Lecture 2 (Defensive blood cells: Leukocytes (Granulocytes…
Chapter 15 Lecture 2
Defensive blood cells: Leukocytes
Granulocytes
Contain large granules that stain different colors
Three types
Basophils—stain blue with basic dye
methylene blue
Eosinophils—stain red/orange with acidic dye eosin– these are involved with defending the body against parasitic worms!!!
Neutrophils- Also known as polymorphonuclear leukocytes)—stain lilac with mix of acidic and
basic dyes
Neutrophils and eosinophils
Phagocytize pathogens
Capable of diapedesis- exit the blood to attack invading microbes in the tissues by squeezing between the cells lining capillaries
Agranulocytes
Cytoplasm appears uniform under a light microscope
Two types
Lymphocytes
Most involved in adaptive immunity
Natural killer lymphocytes
Monocytes
Leave the blood and mature into macrophages (which are phagocytic cells) by diapedesis
Phagocytic cells that devour foreign objects including bacteria, fungi, spores and dust as well as dead body cells
Macrophages
Often named for their location in the body
Wandering macrophages leave the blood and perform a scavenger function traveling through the body
Other macrophages are fixed like:
Alveolar macrophages of the lungs
Microglia of the CNS
Lab analysis of leukocytes
Differential white blood cell count can signal disease
An Increased percentage of eosinophils can indicate allergies or a parasitic worm infection
Bacterial diseases often show increase in leukocytes and neutrophils
Viral infections show increase in lymphocytes
An increase in the number of certain leukocytes over normal can indicate cancer
A decrease in the number of certain leukocytes can indicate immunodeficiency
Phagocytosis
Cells capable of phagocytosis are called phagocytes
Phagocytosis is not completely understood but used to rid the body of pathogens
Means “eating by a cell”
Can be divided into six stages
Chemotaxis
Adhesion
Ingestion
Maturation
Killing
Elimination
Defense Components of Blood
Plasma
Mostly water containing electrolytes, dissolved gases, nutrients, and most importantly -- proteins
Serum is the fluid remaining when clotting factors are removed
Contains iron-binding compounds
Iron needed for metabolism
Some microbes produce proteins that bind iron
Complement proteins and antibodies are also found in plasma
Plasma proteins called antibodies or immunoglobulins are a part of adaptive immunity
Defensive blood cells: Leukocytes
Cells and cell fragments in plasma called formed elements
Three types of formed elements
Erythrocytes
Carry oxygen and carbon dioxide in the blood
Platelets these are pieces of large cells called megakaryocytes
Involved in blood clotting
Leukocytes commonly called white blood cells
Involved in defending the body against invaders
Divided into two groups: granulocytes and agranulocytes
Through hematopoiesis, blood stem cells (in bone marrow) form :
Erythroid stem cells form erythrocytes
Myeloid stem cells produce platelets and 4 kinds of leukocytes
Lymphoid stem cells produce the 5th kind of leukocyte
The Body’s Second Line of Defense
Operates when pathogens penetrate the skin or mucous membranes
Has no barriers like the first line, so it is made up of cells, antimicrobial chemicals( peptides, compliment interferons), and processes (inflammation and fever)
Many of these components are contained in or originate in the blood