BISC104 Lecture Notes - Lecture 23: Varicose Veins, Sinoatrial Node, Bone Marrow
11 May 2018
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●Three main components
○Circulating fluid (blood)
○Pump (heart)
○Vascular system (blood vessels and capillaries)
●Blood
○Moving liquid tissue
■Cells suspended in an aqueous solution (plasma)
○Adults have ~5 liters
○Composition
■Fluid (plasma) → mostly H2O material dissolved in H2O
■Cells (red, white, platelets)
●Red → packed with hemoglobin, oxygen transport, remove CO2
●White → immune defense, housekeeping, attack infection
●Platelets → clot formation
●Blood Cells
○Produced by stem cells in blood marrow
○Bone marrow can produce two differentiated blood stem cells
●Platelets and Blood Clotting
○Vessels constrict
○Platelets stick to damage vessels
○Fibrin clot
■Fibrinogen
●The Heart
○Muscular pump
■Systole → contraction
■Diastole → relaxation
○4 chambers → 2 atria, 2 ventricles
■2 pumps
○Valves
■(AV) bicuspid, (AV) tricuspid, semilunar
■Prevent backflow of blood
○Sinoatrial node
■Pacemaker
■Brain hormones
●Blood vessels
○Arteries
■Move blood away from the heart
■Thick, muscular, elastic walled tubes (expand and contract)
○Capillaries
