Functions of Blood
Transportation: O2 and CO2, nutrients, heat, and waste
Regulation: homeostasis of body fluids, regulates pH, adjusts body temperature, blood osmotic pressure
Protection: ability to clot, white blood cells carry on phagocytosis, blood proteins include antibodies
Plasma
straw-colored liquid, 91.5% water and 8.5% solutes (mostly proteins); makes up the largest percentage of total blood volume
Plasma Proteins
synthesized by hepatocytes (liver cells); includes albumins, globulins, and fibrinogen
Platelets
fragments of cell that don’t have a nucleus, release chemicals that promote blood clotting, originate from the cytoplasm of a megakaryocyte
White Blood Cells
protect the body from invading pathogens and other foreign substances
Red Blood Cells
transport oxygen to the body cells and transport CO2 to the lungs
Hematopoiesis
process of blood developing
before birth: umbilical vesicle of an embryo → liver, spleen, thymus, and lymph nodes
last 3 months of gestation and on: red bone marrow
Erythrocytes (Red Blood Cells)
biconcave discs, lack a nucleus, can’t reproduce or carry on extensive metabolic activities, contain hemoglobin (oxygen-carrying protein that makes it red); phagocytosed by macrophages in the spleen; broken down into globin, heme, and biliverdin
Function of Transferring and Ferritin
Transferrin: transporter of Fe3+ in the bloodstream, in bloodstream
Ferritin: protein that stores iron in cells, in liver
act as protective “protein escorts” during transport and storage of iron ions
Neutrophil
60-70%
phagocytic → eat and die creating pus
small, purple granules and multi-lobed nucleus
Lymphocyte
20-25%
long-term immunity
minimal cytoplasm, nucleus takes up most space
Monocyte
3-8%
blood macrophages (big eaters)
large, kidney-bean nucleus
Eosinophil
2-4%
parasite fighter, mildly phagocytic
big, reddish-orange granules
Basophil
0-1%
allergic reaction (release histamine)
large, purple granules
Megakaryocyte
huge cells that splinter into 2000-3000 fragments
Platelet
each fragment of a megakaryocyte enclosed by a piece of plasma membrane
break off from megakaryocytes in red bone marrow and enter the blood circulation
Pluripotent Stem Cell
give rise to all of the cell types that make up the body
Hemostasis
sequence of responses that stops bleeding
Vascular Spasm
contraction of circularly arranged smooth muscle in the walls of arteries or arterioles when they are damaged
Platelet Plug Formation
Platelet Adhesion: platelets stick to exposed collagen
Platelet Release Reaction: become activated → release chemicals that release more platelets
Platelet Aggregation: platelets become sticky (due to ADP) → platelet plug forms
Clotting (Coagulation)
formation of fibrin network
blood clot: formation of insoluble protein fibers (fibrin) where the formed elements of blood are trapped
extrinsic pathway: occurs rapidly, leaks into blood from cells outside blood vessels
intrinsic pathway: occurs slower, activators are in direct contact within blood
Thrombin
positive feedback on clotting, converts fibrinogen into fibrin, 2 loops:
accelerates the formation of prothrombinase → prothrombinase accelerates production of thrombin
activates platelets → reinforces their aggregation and the release of platelet phospholipids
Fibrinogen
blood plasma protein formed in the liver, generates fibrin
Fibrin
forms the threads of the clot
Thrombus
blood clot
Embolus
blood clot that has moved from original location
Fibrinolytic System
dissolves small, inappropriate clots and clots at site of damage once damage is repaired
Plasminogen
inactive blood plasma enzyme that generates plasmin
Plasmin
digests fibrin, initiates destruction of blood clot
Landsteiner’s Rule
“You contain the antibody for the antigen you lack”
anti-Rh
an Rh- person will develop anti-Rh if and only if an Rh- person receives an Rh+ blood transfusion
a second transfusion of Rh+ will cause agglutination and hemolysis of the RBCs
Hemolytic Disease of the Fetus
Rh- parent and Rh+ baby, anti-Rh can cross placenta and parent is exposed during birth, okay if untreated for first pregnancy but not for second
prevention: RhoGam or RhIg → anti-Rh antibodies given at 28 weeks and delivery which prevents parent’s own anti-Rh creation
treatment: intrauterine transfusion and exchange transfusion at birth
Reticulocyte
immature RBC that moves from the red bone marrow into the blood and matures into an RBC within 1-2 days
Erythropoiesis
production of RBCs in the red bone marrow
proerythroblast → reticulocyte → RBC
increased during: training at high altitudes, injection of erythropoietin, hemorrhage, anemia
Hormones that Stimulate Hematopoiesis
Erythropoietin (EPO): stimulates production of RBCs
Thrombopoietin (TPO): stimulates the formation of platelets from megakaryocytes
Cytokines: regulate development of blood cell types
Erythropoietin
Increases the number of circulating reticulocytes, oxygen carrying capacity, and bone marrow cell division