- Slides: 15
Blood and Blood Cells • Whole blood is slightly heavier and three to four times more viscous than water. • A blood sample is usually about 45% cells by volume. • Hematocrit - % of cells contained in a blood sample.
Blood Cells • Most blood cells are red cells • The remaining 55% of a blood sample is clear, straw-colored liquid called plasma. • Plasma is a complex mixture of water, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes.
Red Blood Cells • Also called erythrocytes. • Bioconcave discs in order to transport gases. • Each red blood cell is about 1/3 hemoglobin by volume. • Hemoglobin carries oxygen.
Hemoglobin • When it combines with oxygen = oxyhemoglobin(bright red) • When oxygen is released = deoxyhemoglobin (darker)
White Blood Cells • Also called leukocytes. • Function to protect against diseases. • Develop from hemocytoblasts in response to hormones. – Hormones fall into two groups: • Interleukins • Colony-stimulating factors (CSFs)
Function of White Blood Cells • Protect against infection in various ways – Some phagocytize(eat) bacterial cells in the body – Others produce proteins(antibodies) that destroy or disable foreign particles
Neutrophils and Monocytes • Most mobile and active phagocytic leukocytes. • Monocytes can engulf large objects • Neutrophils engulf same-sized or smaller objects. • Both contain many lysosomes
Lymphocytes • Are important in immunity. • Produce antibodies that attack specific foreign substances that enter the body.
White Blood Cell Counts • A total number of white blood cells exceeding 10, 000 per cubic mm of blood is called leukocytosis = an acute infection somewhere in the body. – Example: appendicitis.
Leukopenia • A total white blood cell count of 5000 per cubic mm of blood. • Indicates typhoid fever, influenza, measles, mumps, chicken pox, AIDS, or poliomyelitis.
DIFF • Differential White Blood Cell Count – Lists percentages of the types of leukocytes in a blood sample. – Useful because the relative proportions of white blood cells may change in a particular disease. • For example, the number of neutrophils usually increases during bacterial infections. The number of eosinophils increases during parasitic infections and allergic reactions. In AIDS, the number of a certain type of lymphocyte drops sharply.
Blood Platelets • Also called thrombocytes. • Are not complete cells. • Arise from very large cells in red bone marrow called megakaryocytes. • Platelets help close breaks in damaged blood vessels and initiate formation of blood clots.
Blood Plasma • We will go through this on Friday. • Assignment: – Pg. 325, 1 -3, 8, 9, 10, 11, 12, – Critical thinking #1
5 Types of White Blood Cells Differ in size, nature of their cytoplasm, shape of their nucleus, and staining characteristics. 1. Neutrophil-lobed nucleus 2. Eosinophil-stains red 3. Basophil- stains deep blue 4. Monocyte- largest blood cells 5. Lymphocyte- large, round nucleus