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153 Cards in this Set
- Front
- Back
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The inner most layer of a blood vessel. Made up of endothelium cells and the basement membrane. |
What is the tunica intima? |
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Second layer of a blood vessel made up of smooth muscle. |
What is the tunica media? |
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What is the basement membrane comprised of? |
Proteins |
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The outer most layer of a blood vessel (also comprised of protein). |
What is the tunica externa |
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The outer most part of the tunica interna. Forms the boundary between the tunic internal and the tunica media. |
What is the internal elastic lamina? |
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2nd component of tunica interna. Provides physical support base for epithelial layer. Anchors endothelium to underlying connective tissue. |
what is the basement membrane? |
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The inner most layer of tunica internal. Which is continuous with endocardial lining of the heart. |
What is the endothelium? |
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The smooth muscle cells of the tunica media do what? |
Regulate the diameter of the lumen. |
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Is the interior opening of a blood vessel. |
What is the lumen? |
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Increase in sympathetic stimulation stimulates smooth muscle to do what? |
Contract or vasoconstriction |
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Vasoconstriction causes what? |
The narrowing of the lumen. |
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Decrease in sympathetic stimulation or the presence of certain chemicals cause smooth muscle fibres to relax. |
What is vasodilation? |
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Also causes smooth muscle to relax when an artery or arteriole is damaged. This helps limit the loss of blood through injured vessel. |
What is a vascular spasm? |
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What is the most variable of the tunics? |
The tunica media |
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Separating tunica media from tunica external is a network of elastic fibres. |
What is the external elastic lamina? |
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Consists of elastic fibres and collagen. Outer covering of a blood vessel. Contains numerous nerves. |
What is the tunica externa? |
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The tiny blood vessels that supply blood to the tissue of the vessel wall. |
What are vasa vasorum? |
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Which layer of a blood vessel can you find the vasa vasorum? |
The tunica externa |
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What are the three layers of a blood vessel? |
Tunica intma, tunica media, and tunica externa |
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What is different about the tunica media in
large and medium sized arteries? |
The smooth muscle layer is bigger and have the presence of elastin (which is a protein). |
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What does elastin do to an artery? |
Helps make them more elastic. |
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Arteries are high compliance which means what? |
Their walls stretch easily without tearing in response to small increases in pressure. |
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Characterized by well defined internal and external elastic laminae, along with thick tunica media that is dominated by elastic fibres. |
What are elastic arteries? |
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The two major elastic arteries? |
Aorta and pulmonary trunk (also the 2 major trunks that exit the heart). |
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Elastic arteries are? |
The largest in the body and have largest diameter but their vessel walls are relatively thin compared with the overall size of the vessel. |
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Why is being elastic so important for certain arteries? |
They can with stand pressure of blood at ventricle systole because the elastic fibre allows them to expand with the pressure. |
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A thick tunica media that is dominated by elastic fibres. |
What is the elastic lamella? |
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Smooth muscle makes the walls of this vessel thick. These tend to be medium sized and their tunic media contains more smooth muscle and less elastic fibres. |
What are muscular arteries? |
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Smooth muscle does what to muscular arteries? |
Makes them capable of greater vasoconstriction and vasodilation to adjust rate of blood flow. |
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Ability of muscle to contract and maintain a state of partial contraction. |
What is vascular tone? |
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Muscular arteries are also called? |
Distributing arteries because they continue to branch and distribute blood to various organs. |
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As they stretch, elastic fibres momentarily store mechanical energy and function as a ____________________. |
Pressure reservoir (remember arteries are HIGH pressure and LOW volume). |
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Systemic veins and venules fuction as _______________. |
Blood reservoirs (remember veins are LOW pressure and HIGH volume) |
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Is the union of the branches of two or more arteries supplying the same body region. |
What is anastomosis? |
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What is collateral circulation? |
Anastomoses between arteries provides alternative routs for blood to reach a tissue or organ. |
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Arteries that do not anastomose. |
What are end arteries? |
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Obstruction of an end artery interrupts blood supply to whole segment of an organ which leads to death of that segment. |
What is necrosis? |
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Are abundant microscopic vessels that relate the flow of blood into the capillary network. |
What are arterioles? |
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Terminal end of arteriole, tapers towards the capillary junction. |
What is a metarteriole? |
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Monitors the blood flow into the capillary. |
What is the precapillary sphincter? |
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What helps to alter the diameter of arterioles and varies the rate of blood flow/resistance through the vessel? |
The tunica external of arteriole consists of areolar connective tissue containing unmyelinated sympathetic nerves. |
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The opposition to blood flow. |
What is resistance? |
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In blood vessels what is resistance caused by? |
Due to the friction between blood and the inner walls of blood vessels. When diameter is smaller friction is greater which equals more resistance. |
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The flow of blood from a met arteriole through capillaries and into a post-capillary venuel. |
What is microcirculation? |
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The smallest of blood vessels that form "u-turns" that connect arterial outflow to the venous return system. |
What are capillaries? |
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Plasma membrane of endothelial cells form a continuous tube that is interrupted only by an intercellular cleft. |
What is a continuous capillary? |
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Plasma membrane has many small pores. These capillaries are found in small intestine, brain, and endocrine glands. |
What are fenestrated capillaries? |
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Wider and more winding, endothelial cells may have unusually large fenestrations. Have an incomplete or absent basement membrane. Very large intercellular clefts that allow proteins to pass from tissue into bloodstream. |
What are sinusoids (discontinuous capillaries)? |
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Venues that initially receive blood form capillaries. Smalles vein and have loosely organized intercellular junctions. |
What are post capillary venules? |
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Very porous, function as significant sites of exchange of nutrients and waste of white blood cell emigration. |
Post capillary venules |
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Have thick walls so exchanges with interstitial fluid can no longer occur. As postcapillary venues move away from capillary they acquire one or two layers of smooth muscle. |
What are muscular venules? |
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Thin folds of tunica interna that form flaplike cusps. These project into the lumen, pointing toward the heart. |
What are the vein valves? |
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A vein with a thin endothelial wall that has no smooth muscle to alter its diameter. Surrounding dense connective tissue replaces the tunica media and externa providing support. |
What is the vascular (venous) sinus? |
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Leaky venous valves that can cause veins to become dilated and twisted in appearance. |
What are varicose veins? |
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What makes a metarteriole different from the true capillaries? |
It's layer of smooth muscle. |
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Where is the largest portion of blood volume when the body is at rest? |
In systematic veins and venules (about 64%). |
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What are the principal blood reservoirs? |
The veins of the abdominal organs. |
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Most important mechanism for exchange of nutrients. 02, C02, glucose, amino acids, and hormones. |
What is diffusion? |
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How does 02 and other nutrients diffuse? |
They are normally present in higher concentrations in blood then in cells. So they diffuse down their concentration gradients into interstitial fluid. |
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How does C02 and wastes diffuse? |
Are present in higher concentration in interstitial fluid so they diffuse down their concentration gradient into the blood. |
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How do glucose and amino acids pass into blood or cells? |
Can diffuse through intercellular clefts or fenestrations. |
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Endothelial cells of the brain capillaries are sealed together with tight junctions. Resulting in a blockade to movement of materials. |
What is the blood brain barrier? |
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What areas of the brain lack a blood brain barrier? |
Hypothalamus, pineal gland, and pituitary gland. These undergo capillary exchange. |
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In this process, substances in the blood plasma become enclosed within tiny pinocytic vessels that enter endothelial cells via endocytosis. |
What is transcytosis? |
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Transcytosis important for what? |
Mainly for large, lipid-insoluble molecules that cannot pass through capillary walls. |
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What is a good example of transcytosis? |
The hormone insulin-- passes from maternal circulation into fetal circulation. |
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Passive process in which large # of ions and molecules move together in same direction. Move at rates that are to great for diffusion alone. |
What is bulk flow? |
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____________ occurs in an area of higher pressure to an area of lower pressure and will continue as long as pressure difference exists. |
Bulk flow |
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Pressure driven movement of fluid and solutes from blood capillaries into interstitial fluid. |
What is filtration? |
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Pressure driven movement from interstitial fluid into blood capillaries. |
What is absorption? |
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What two pressures promote filtration? |
1) Blood hydrostatic pressure (BHP) 2) Blood colloid osmotic pressure (BCOP) |
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The balance of blood hydrostatic pressure and blood colloid osmotic pressure. |
What is net filtration pressure (NFP)? |
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Convert potential energy to mechanical energy. |
What are pressure reservoirs (or arteries) |
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Pressure reservoirs do what during ventricular diastole? |
Keep blood moving through arteries. |
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Sympathetic stimulations does what to veins? |
Can constrict them quickly moving blood into areas of the circulatory system where it is needed. |
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If a blood vessel is blocked, blood may still flow through the body area through an _________________ or union of branches of two or more arteries supplying a body region. This process is called ___________________. |
Anastomosis, collateral circulation. |
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Blood reaches the cells that make up large blood vessels by way of tiny capillaries called the __________________ in the outer layer of the vessel. |
Vasa vasorum |
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Which type of blood vessel hold the smallest amount of blood? |
Capillaries |
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Endothelium makes up the layer of the arteries called the _____________________. |
Tunica interna |
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The property that contributes to a pressure reserve is the ______________________. |
Elastic recoil of the large arteries |
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Material enteres and leaves blood vessels through? |
Diffusion, transcytosis, and bulk flow |
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An abnormal increase in interstitial fluid volume or ______________ may result from either excess filtration or inadequate absorption. |
Edma |
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Pressure against the wall of capillaries due to water in the blood. |
What is blood hydrostatic pressure (BHP)? |
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At the venous end of capillaries, fluid moves from the interstitial spaces into capillaries because? |
The net filtration pressure is about -9 mmHg |
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When amino acids are broken down they form what ________________ which is then converted into____________________ by the liver. |
Ammonia and urea |
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What breaks up blood clots? |
Heprin |
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What can be found in your blood stream? |
Minerals, waste products, and blood clotting factors. |
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Minerals are also called what? |
Electrolytes |
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What is the difference between HDL and LDL? |
LDL takes cholesterol and deposits it in arteries. HDL take cholesterol out of arteries and back to liver. |
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Too much bilirubin causes what? |
Jaundice |
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The major electrolyte in our blood and extracellular fluid is? |
Sodium Ions (Na+) |
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What two minerals are important for membrane potentials and action potentials? |
Na+ and K- (sodium and potassium) |
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What is calcium important for? |
Muscle contraction and blood clotting |
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What is our major buffer when it comes to minerals? |
Bicarbonate |
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Cells are also called what in regards to blood? |
Formed elements |
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How much of the blood is comprised of formed elements? |
45% and the remaining portion is plasma |
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What is plasma made up of? |
Primarily water but 7% is protein |
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How do the proteins of plasma break down? |
Albumin (60%), alpha/beta globulins (transport fats/minerals), gammaglobulins (antibodies), and blood clotting proteins. |
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What is another name for platelets? |
Thrombocytes |
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RBCs are also known as? |
Erythrocytes |
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What is the only cell smaller than an RBC? |
A sperm |
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Why are RBCs so small? |
So that they can pass through capillaries |
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What happens to RBCs because they lack a nucleus? |
They lack genetic material and therefore cannot remake themselves. |
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Two major MHC (recognition sites), they are? |
ABO group and Rh group |
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MHC stands for? |
Major histocompatibility complex |
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What organ secretes erythropoietin? |
Kidneys |
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What does erythropoietin do? |
Stimulates erythropoiesis or the production of RBCs |
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How are dead RBCs removed from the blood stream? |
Via macrophages phagocytic cells primarily found in the liver |
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What is an important vitamin needed to make RBCs? |
Vitamin B12- can have anemia based on lack of this vitamin |
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Are little pieces of cells released by bone marrow (break off of megacryocytes) |
What are platelets? |
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Thrombycyteopenia |
Reduce blood platelet count |
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Hemostasis |
The control of bleeding |
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Three main steps of hemostasis |
a) Tissue spasm (thromboxin), b) formation of a platelet plug, and c) formation of fibrin clot (coagulation) |
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What happens when platelets form a plug? |
They aggregate and release a chemical PF (platelet factor). |
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Thrombosis |
A blood clot in blood vessel (not good) |
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What do the walls of an injured tissue release? |
Tissue factor (TF) which also activates prothrombynase (clotting). |
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What serves as a coenzyme to prothrombynase? |
Calcium |
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Common pathway for clotting? |
Prothrombin--> prothrombinase + Ca---> fibrinogen= fibrin clot |
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What is fibrinolysis? |
The result of plasmin, dissolving a clot |
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Three mech- anisms reduce blood loss: (1)
vascular spasm, (2) platelet plug formation, and (3) blood clotting (coagulation). |
What are the three mechanisms of hemostasis? |
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Is a sequence of responses that stops bleeding. When blood vessels are damaged or ruptured, this response must be quick,
localized to the region of damage, and carefully controlled in order to be effective. |
What is hemostasis? |
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When arteries or arterioles are damaged, the circularly arranged smooth muscle in their walls contracts immediately. This reduces blood loss for several min-utes to several hours, during which time the other hemostatic mechanisms go into operation.
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What is a vascular spasm? |
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What are the chemicals stored inside platelets? |
Clotting factors, ADP, ATP, Ca2, and serotonin. Also present are enzymes.
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Also within platelets , a hormone that can cause proliferation of vascular endothelial cells,
vascular smooth muscle fibers, and fibroblasts to help repair damaged blood vessel walls. |
What is is platelet-derived growth factor (PDGF)? |
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Initially, platelets contact and stick to parts of a damaged blood vessel, such as collagen fibers of the connective tissue underlying the damaged endothelial cells.
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What is platelet adhesion (STEP 1Platelet Plug Formation)? |
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Due to adhesion, the platelets become
activated, and their char- acteristics change dramatically. They extend many projections that enable them to contact and interact with one another, and they begin to liberate the contents of their vesicles. |
What is platelet release action (STEP 2)? |
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What happens with the enzymes and chemicals within platelets during step 2? |
Liberated ADP and thromboxane A2 play a major role by activating nearby platelets. Serotonin and thromboxane A2 function as vasoconstrictors, causing and sustaining contraction of vascular smooth muscle, which decreases blood flow through the injured vessel.
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The release of ADP makes other platelets in the area sticky, and the stickiness of the newly
recruited and activated platelets causes them to adhere to the originally activated platelets. |
What is platelet aggregation (STEP 3)? |
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Is a series of chemical reactions that culminates in formation of fibrin threads.
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What is a clot or coagulation? |
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Clotting in an undamaged blood vessel.
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What is thrombosis? |
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Has fewer steps than the intrinsic pathway and occurs rapidly—within a matter of seconds if trauma is severe.
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What is the extrinsic pathway? |
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Is a complex mixture of lipoproteins and
phospholipids released from the surfaces of damaged cells. |
What is TF (tissue factor)? |
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Is more complex than the extrinsic pathway, and it occurs more slowly, usually requiring
several minutes. Is so named because its activators are either in direct contact with blood or contained within (intrinsic to) the blood; outside tissue damage is not needed. |
What is the intrinsic pathway? |
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Thrombin is also known as what? |
Clotting factor II (in the intrinsic pathway) |
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What is the sequence of the intrinsic pathway? |
XII (when activated)--> XI--> IX--> X--> II (thrombin)--> I |
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What is factor I? |
Fibrin |
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Once factor X is activated, it combines with
factor V in the presence of Ca2 to form ______________ |
Prothrombinase (completing extrinsic pathway)
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What does factor Xiii do? |
Helps strengthen fibrin threads |
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What does thrombin activate? |
Clotting factors V, VII, VIII, XI, XIII |
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What happens with fibrin at the end of these pathways? |
Fibrin becomes fibrin strands which become interlaced fibrin strands. |
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What are the five major categories of WBCs? |
Neutrophils, lymphocytes, monocytes, esoniphils, and basophils. |
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Process by which formed elements of the blood develop. |
What is hemopoiesis? |
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Small glycoproteins that act as local hormones (pancreas) and stimulates proliferation of progenitor cells in red marrow. |
What is cytokines? |
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Produced by liver and stimulates formation platelets of thrombocytes. |
What is thrombopoietn (TPO)? |
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Platelet formation: |
Pluripotent stem cells--> myeloid stem cell--> CFU-Meg--> megakaryoblasts--> megakaryocytes--> thrombocytes |
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Also called hemocytoblasts and are important part of red bone marrow cells. Can develop into many different type of cells. |
What are pluripotent stem cells? |
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Begin development in red bone marrow and give rise to RBCs. |
What are myeloid stem cells? |
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Are no longer capable of reproducing themselves and are committed to giving rise to more specific elements of the blood. |
What are progenitor cells? |
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Some progenitor cells are also known as what? |
Colony forming units (CFU) |
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Over several divisions they develop into actual formed elements of the blood. |
What are precursor cells or "blasts"? |
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Chemicals released by microbes and inflamed tissue that attracts phagocytes. |
What is chemotaxis? |
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An increase in the # of WBCs in a normal protective response to stresses such as invading microbes or exercise. |
What is leukocytosis? |
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Is a count to determine the % of the 5 types of WBCs in a sample. Helps doctors to detect infection. |
What is a differential WBC count? |
