Blood Cells 12.2 Cheri Hines Bianca Vanderipe Zachary Moser Austin Ashley Sami Booker

Red Blood Cells  Red blood cells, also known as erythrocytes, are biconcave discs  The concave shape has a lot to do with the red blood cells function.  It is adapted to carry gasses and place the cell membrane closer to oxygen carrying hemoglobin within the cell  Red blood cells have nuclei but lose it as they mature in order to make room for hemoglobin  They are unable to synthesize or divide  A red blood cell has a life span of around 120 days  Red blood cells lack mitochondrion and produce ATP through glycolysis

Red Blood Cell Count Typical red blood cell count: Adult Male: 4,600,000-6,200,000 per microliter(µL) Adult Female: 4,200,000- 5,400,000 per µL When red blood cell count (RBCC) increases, so does your oxygen-carrying capacity. Changes in RBCC can affect a person’s health. The RBCC is often consulted to help diagnose & evaluate courses of various diseases.

Red Blood Cell Production & Its Control  The average lifespan of a red blood cell is 120 days.  Red blood cell formation (erythropoiesis) occurs in your yolk sac, liver, and spleen.  Erythropoietin: controls the rate of red blood cell formation through negative feedback. Fun Fact: The combined surface area of all red blood cells in the human body is roughly 2,000 times as great as the body’s exterior surface.

Dietary Factors Affecting Red Blood Cell Production  The availability of Vitamin B 12 and folic acid influence red blood cell production in the body.  The process of hemoglobin synthesis requires iron.  Anemia is when someone has too few red blood cells or too little hemoglobin. (.e. Bianca)

Destruction of Red Blood Cells  Macrophages in the liver and spleen phagocytize damaged red blood cells  When hemoglobin molecules are decomposed, some of the iron they contain are recycled  Hemoglobin releases biliverdin and bilirubin pigments.

White Blood Cells  White blood cells, or leukocytes, protect against disease.  Leukocytes develop from hemocytoblasts in red bone marrow as a result of hormone stimulation.  There are normally five types of white blood cells circulating in the blood.  They fall into two categories depending on the presence of granular cytoplasm.  Those with granular cytoplasm are called granulocytes, these include:  Neutrophils-they have fine cytoplasmic granules and make up 54-62% of the leukocytes in a typical adult.  Eosinophils-contain coarse, uniformly sized cytoplasmic granules with a two lobed nucleus. They make up 1-3% of the circulating leukocytes.  Basophils-Similar to eosinophils in size in the shape of the nucleus, but have fewer and more irregularly shaped granules. They make up less than 1% of circulating leukocytes. The other classification of leukocyte lacks granular cytoplasm, these include: Monocytes-These are the largest blood cells (2-3 times larger than red blood cells). They have round, oval, kidney shaped, or lobed nuclei. They make up 3-9% of circulating leukoctes. Lymphocytes -Slightly larger than a red blood cell with a large round nucleus. They account for 25-33% of circulating leukocytes. They may live for years

Functions of White Blood Cells  White blood cells help to fight infections in many ways.  Some phagocytize bacterial cells while others produce antibodies that destroy or disable foreign particles.  The most mobile and active phagocyic leukocytes are neutrophils and monocytes.  Neutrophils can't ingest particles much larger than bacterial cells  Monocytes can engulf larger objects  Both phagocytes, neutrophils and monocytes, contain many lysosomes.  Lymphocytes are important in immunity.

White Blood Cell Counts  White blood cell count is usually 4,500-10,000 per microliter  A total white blood cells count below 5,000 per mm3 of blood is called leukopenia.  A total number of white blood cells exceeding 10,000 per mm3 constitutes leukocytosis indicating acute infection.  Leukocytosis is seen when dealing with appendicitis or leukemia.  Leukopenia -such deficiency may accompany diseases like measles, chicken pox, and aids.

Blood Platelets  Blood Platelets are made by megakarocytes.  Megakarocytes - large cells in red marrow, they fragment and release small sections of platelets into the circulation.  They develop from hemocytoblasts in response to the hormone thrombopoietin.  Each Platelet lacks a nucleus and is less than half the size of a red blood cell.  It is capable of amoeboid movement and may live for about ten days.  In normal blood, the platelet count varies from 130,000 to 360,000 per microliter.  Platelets help close breaks in damaged blood vessels and initiate the formation of blood clots.