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Unformatted text preview: 1 Anatomy of Circulatory Systems Basic components of closed circulatory and respiratory systems: Heart pumps blood around body Vessels carries blood to all cells in body Blood & Respiratory pigments (RPs) transport medium and RPs increase the capacity of blood to carry many times more O 2 than without RPs Lungs/Gills/ventilation surface designed to take in O 2 and release CO 2 efficiently and load/offload respiratory pigments Oxygen transport Not enough oxygen dissolves into blood to support metabolic needs Respiratory pigments increase the amount of gas carried in solution May be contained within red blood cells or in plasma Proteins with one or more metal ions (Iron or Copper are most common) Hemoglobin Found in RBC Special protein made up of four sub-units Each sub-unit has heme molecule that contains an iron ion (Fe 2+) Oxygen binds reversibly to iron core Each hemoglobin can bind to four oxygen molecules Formed in stem cells within bone marrow Brooker Fig. 47.7 or Campbell 42.28 The transport of oxygen is governed by partial pressure gradients. Partial pressure of O 2 at lungs: HIGH ~104 mmHG Partial pressure of O 2 at tissue: LOW~40 mmHG Gases diffuse DOWN their pressure gradient. To be an effective carrier of O 2 and CO 2 hemoglobin must reversibly bind O 2 & CO 2 . The partial pressure of the gas (O 2 or CO 2 ) at different locations in the body allow hemoglobin to diffuse into the red blood cell or away from the red blood cell. Oxygen-hemoglobin dissociation curve The conditions under which hemoglobin will bind to or release oxygen are described by an oxygen-hemoglobin dissociation curve . Partial pressure of O 2 mm HG % Saturation of Hb 100 100 20 40 60 80 20 40 60 80 Tissues (Rest) Tissues (Exercise) Lungs Partial pressure of O 2 mm HG % Saturation of Hb 100 100 20 40 60 80 20 40 60 80 Tissues At rest Lungs Amount of O 2 unloaded during normal metabolism Tissues At exercise Amount O 2 available to highly metabolic tissues 2 Oxygen-hemoglobin dissociation curve When P O2 is high, more O 2 binds to hemoglobin When P O2 is low, less O 2 binds to hemoglobin Sigmoidal curve due to cooperation shape of hemoglobin changes as oxygen loads and unloads- Active metabolic tissues generate products that can shift the curve...
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- Winter '08