FINAL EXAM-Ch.12 Flashcards
(15 cards)
Cellular Component
Formed Elements
Liquid Component
Fluid element that suspends cellular component (Plasma)
Hematocrit
the percentage of the blood volume that consists of erythrocytes or RBCs
Unusual features of RBCs and Platelets
- Not true cells-RBC lack nuclei and organelles, and platelets are cell fragments
- Cannot divide and survive in the blood stream for only a short time (few hours to months) before being replaced by new cells or broken down and recycles
Spectrin
Plasma membrane Protein
Give Erythrocytes their Flexibility
Allow them to change shape as necessary
Hemoglobin
- cytoplasm is packed with hemoglobin
- hemoglobin reversibly binds with oxygen
- hemoglobin is composed of the protein glob in, made up of two alpha and two beta chains, each bound to a heme group
- each heme group bears an atom of iron, which can bind to one oxygen molecule
- each hemoglobin molecules can transport four molecules of oxygen
- oxidation of iron on the hemoglobin gives blood its red color
White Blood Cells
- complete cells, with organelles and nuclei
- protect the body from infectious microogranisms fight infections
- function outside the blood stream in loose connective tissue
- varius chemicals produced or released at infection sites attract circulating WBCs
Diapedesis
circulating leukocytes leave the capillaries (white blood cells)
Leukocytosis
the white blood cell count above the normal range in the blood
Neutrophils
- bacteria slayers
- give cytoplasm a lilac color
- take up both acidic and basic dyes
- contain peroxidases, hydrolytic enzymes, and defensins
- 60-70% of WBCs
Eosinophils
- red staining, bobbed nuclei connected via a broad band of nuclear material
- lead the body’s counterattack against parasitic worms
- lessen severity of allergies by phagocytizing immune complexes
Macrophages
- they leave the circulation, enter tissue, and differentiate into macrophages
- Are highly mobile and actively phagocytic
- Activate lymphocytes to mount an immune response
Lymphocytes
- Large, dark-purple, circular nuclei with a thin rim of blue cytoplasm
- Found mostly enmeshed in lymphoid tissue (some circulate in the blood)
Two types of Lymphocytes: T cells and B cells
T cells: function in the immune response
B cells: give rise to plasma cells, which produce antibodies
Platelet Actions
- result from fragmentation of megakaryocytic (giant cells) in bone marrow.
- involved in coagulation or blood clotting
- plug small tears in the walls or blood vessels to limit bleeding
- adhere to exposed collages at edges of tear and secreting substance that: 1. signal more platelets to arrive 2. initiate inflammation at the injury site 3. cause vessel to constrict, limiting blood flow
Thrombin
Acts as an enzyme severing amino acid chains from fibrinogen molecules to form fibrin threads
