Study Guide for Exam 2- Heart and Circulatory System
Study Guide for Exam 2- Heart and Circulatory System Biol 2230-001
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This 31 page Study Guide was uploaded by Camryn Sartory on Tuesday February 16, 2016. The Study Guide belongs to Biol 2230-001 at Clemson University taught by Dr. John Cummings in Spring 2016. Since its upload, it has received 104 views. For similar materials see Human Anatomy & Physiology II in Biological Sciences at Clemson University.
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Date Created: 02/16/16
Lecture Objectives Blood 1. List the functions of blood. Delivers oxygen i. Also nutrients (sugar, glucose, etc.) Transports metabolic wastes i. Ex: CO 2 proteins, nitrogenous compounds Transports hormones Maintains body temperature Maintains body pH i. Slightly basic ii. Contains buffers that regulate pH Maintains fluid volume i. Fluid exchange between tissue and blood Prevents blood loss i. Clotting factors platelets Prevents infection i. Functions as part of the immune system ii. Immune cells, antibodies 2. Describe the composition of whole blood. Formed Elements i. Erythrocytes 1. Red blood cells 2. Carry oxygen 3. 45% of total blood volume 4. Not really living cells 5. Produced in bone marrow ii. Leukocytes 1. Living cells 2. Contain nuclei and organelles 3. Immunity 4. Less than 1% of total blood volume iii. Platelets 1. Fragments of other cells 2. Pieces of cytoplasm and membrane 3. Can contain proteins and other things 4. Involved in blood clotting Plasma i. Liquid portion ii. 55% of total blood volume iii. Mostly water (90%) iv. Also contains proteins – albumin =produced by liver, globulins, enzymes, amino acid based hormones v. Nitrogenous wastes 3. Describe the structure, function and production of erythrocytes. Structure Small Biconcave Anucleate Contains no nucleus Contain hemoglobin Transport oxygen Contain antioxidant enzymes No longer living o Production Hemocytoblast produces myeloid stem cell In bone marrow A pluripotent cell can give rise to a number of things (RBC or WBC) Myeloid stem cell is also pluripotent Myeloid stem cell becomes proerythroblast Committed cell, all it can become is a RBC Proerythroblast becomes early erythroblast Early erythroblast becomes late erythroblast Late erythroblast becomes normoblast Normoblast loses organelles and nucleus to become reticulocyte Loses nucleus Accumulates a lot of hemoglobin molecules Leaves bone marrow Reticulocytes mature in bloodstream to become erythrocytes 4. Describe the chemical makeup of hemoglobin. Globin protein bound to heme pigment i. Heme pigment makes our blood red o 4 polypetide chains 2 alphas 2 betas Each globin subunit has a heme attached to it o Contains oxygen binding iron Each heme carries 4 molecules of oxygen 4 molecules of oxygen per hemoglobin molecule About 250 million hemoglobin per red blood cell Each RBC can carry a billion oxygen molecules We carry a shit ton of oxygen o Carbaminohemoglobin Hemoglobin bound to carbon dioxide Oxygen binds to heme Co2 binds to globin 20% of co2 transport is in the form of hemoglobin, the rest is carried in plasma (bicarbonate HCO3) 5. Define diapedesis. The ability of a blood cell to leave the blood vessel and circulation RBC’s cant Some WBC’s can 6. List the classes, structural characteristics and functions of leukocytes. Complete cells with nuclei and organelles Display positive chemotaxis o Can be attracted to an area due to the release of some chemical Classes o Granulocytes Vesicles that contain things Neutrophils (top left in pic) o Most common 50%70% o Lobed nucleus o Phagocytic cells, function during inflammatory response Eosinophils (top right in pic) o 2 lobed nucleus o Make sure it has granules o 2%4% of WBCs o Contain enzymes in granules that digest parasitic worms Basophils (bottom right in pic) o 0.51% most rare o Contain histamine in granules dilates blood vessels, attracts other WBCs o Agranulocytes Lymphocytes (bottom right in pic) Most of cell is made up of nucleus Major immune cells (B (bacteria) & T (virus/ tumor) lymphocytes) In lymph tissue 25% of WBCs Monocytes 35% Largest, with a u shaped nucleus Phagocytic cells Can diapedesis ( leave circulation), then called a macrophage 7. Describe leucopoiesis. Granulocyte leukopoesis Myeloid stem cells become myeloblasts Committed cell, can only become a granulocyte Myeloblasts accumulate lysosomes to become promyelocytes lysosomes= granules Promyelocytes differentiate into myelocytes Cell division stops, and nuclei arch to form band cells Nuclei constrict and segment to become mature granulocytes Agranulocyte leukopoesis (monocyte) Myeloid stem cells become monoblasts Monoblast is a committed cell Monoblasts become promonocytes Promonocytes leave bone marrow and become monocytes in lymph tissues Agranulocyte leukopoesis (lymphocyte) Lymphoid stem cells become lymphoblasts Lymphoblasts become prolymphocytes Prolymphocytes leave bone marrow and become lymphocytes in lymph tissue 8. Describe the structure, function and formation of platelets. Structure Function formation 9. Give examples of disorders caused by abnormalities of each of the formed elements. o Erythrocyte disorders Anemias Any time our blood has a low oxygen carrying ability Insufficient number of RBCs Irregularly shaped blood cells sickle cell anemia Polycythemia Too many RBCs Blood is thicker and doesn’t circulate as well Blood is like a sludge Leukocyte disorders Leukemia Cancer of white blood cells Infectious mononucleosis In response to an infection from a virus (Epstein bar) Causes increase in production of Agranulocytes Leukopenia Deficiency in the number of white blood cells 10. Describe the process of hemostasis, differentiating the intrinsic pathway from the extrinsic pathway. Vascular spasm o When damaged, a blood vessel will constrict o Less blood is able to pass through, slowing the loss of blood Platelet plug formation o Platelets will collect at the site of damage o Due to a chemical signal o Don’t collect at undamaged sites o Damage to blood vessel exposes underlying collagen fibers (connective tissue) Causes accumulation of chemicals Also releases von Willebrand factor and thromboxane A o 2 Von is a plasma protein A2 is released by blood vessel itself Prostaglandin – local signaling molecule o Causes platelets to collect and adhere at site of damage Due to high accumulation of above factors Stick to collagen fibers o Once attached, thrombin activates platelets to breakdown and release chemical contents Coagulation Clotting o o Prevents loss of blood and stimulates the repair of a blood vessel Intrinsic Series of reactions in which clotting factors converted to active forms Ultimately aggregated platelets release PF 3 Platelet factor 3 PF 3activates other intermediates leading to activation of factor X Aka factor 10 Activated factor X complexes with calcium, PF and3factor V to form prothrombin activator Activates prothrombin Prothrombin activator catalyzes conversion of prothrombin to thrombin Thrombin is the active form Thrombin catalyzes polymerization of fibrinogen into fibrin Thrombin also activates factor XIII which links fibrin strands together Produces mesh Ultimately fibrin makes it stick There are 13 platelet factors Extrinsic i. Injured cells release tissue factor 1. Damaged blood vessel cells release chemicals ii. Tissue factor interacts with PF 3to allow shortcut to factor X activation 11. List factors that limit clot formation. Thrombopoietin i. Hormone ii. Communicates with bone marrow Intact endothelial cells secrete PGI 2(prostacyclin) and heparin i. Healthy cells produce PGI2 ii. Prevents sticking iii. Heparin prevents platelet action Vitamin E quinone i. Blood thinner Clotting factors carried away from site by circulating blood i. So clot doesn’t get to big Antithrombin III inactivates thrombin i. Plasma protein, it circulates in the blood normally Protein C inhibits intrinsic pathway events i. Limits size of the clot ii. Plasma protein, it circulates in the blood normally Heparin enhances activity of antithrombin III and inhibits intrinsic pathway events 12. Explain how the processes of retraction and fibrinolysis relate to the natural elimination of a blood clot. Clot Retraction Platelets contain contractile proteins Similar to actin and myosin Cause platelets to contract and squeeze out serum to compact clot This draws ruptured edges of vessel closer together Contraction of blood clot pulls blood vessel together PDGF stimulates vessel repair As platelets start to break down, they release platelet derived growth factor Stimulates cells to divide Fibrinolysis i. Clot produces plasminogen 1. Inactive 2. Tissue plasminogen activator (TPA) activates plasminogen ii. Plasminogen is activated to plasmin iii. Plasmin digests fibrin 13. Identify the hemostatic disorders. Thromboembolytic disorders too much clotting i. Thrombus 1. A blood clot that forms in healthy blood vessels 2. Stationary, and blocks the flow of blood Embolism i. Moving blood clot ii. Will find an area it cant pass through and it will clog up Bleeding disorders to little clotting i. Thrombocytopenia Insufficient amount of platelets in body Due to some sort of pathology/disease/infection Hemophilia Genetic disorder Cant produce one of the clotting proteins they don’t possess the gene to do it Any one of the 13 clotting factors Most important are factor 10, 13 14. Describe the ABO and Rh blood groups. Determined by presence of agglutinogens i. Markers on the surface of blood cells ii. Specifically ABO and Rh (D) 1. If a blood cell has A agglutinogen, its type A blood. Markers direct production of agglutinins i. If you have A agglutinogen, you produce B agglutinin Type O is a universal donor AB+ is the universal accepter Hemolytic disease of the newborn i. Woman is Rh negative and the baby is Rh positive ii. Can get a shot of RhoGAM suppresses the production of Rh antibodies iii. First baby is fine iv. Second baby isn't 1. As soon as its born the blood coagulates and dies Lecture Objectives The Heart 1. Describe the location and orientation of the heart. Size of fist in middle of chest Mediastinum i. Cavity in chest that the heart is in Base i. Top of the heart Apex i. the bottom of the heart ii. Part that kind of learns to the left iii. While developing the apex is at the top, but it twists and reverses position 2. Name the coverings of the heart. o Fibrous pericardium Sac like structure Outermost layer Made of dense irregular connective tissue Protects heart Anchors heart to thoracic cavity wall o Serous pericardium 2 layer sac Outermost layer of heart Parietal layer Belongs to the cavity Visceral layer Belongs to the organ Aka epicardium outermost layer of heart o Pericardial cavity Between the 2 layers Filled with pericardial fluid Protects the heart, prevents friction, dissipates heat so heart muscle doesn’t fatigue 3. Describe the structure and the function of the three layers of the heart. a. Epicardium i. Same thing as the visceral layer of the serous pericardium b. Myocardium i. Muscle layer that does the beating c. Endocardium i. Layer on the inside of heart ii. Squamous epithelial tissue iii. Same lining covers the blood vessels 4. List the chambers and anatomical landmarks of the heart. o Atria Separated by interatrial septum After birth they are complete separated. Before birth they are connected because baby isn't breathing Pectinate muscles Muscles in the atria Help contract and push blood into atrium Fossa ovais Used to be foramen ovale Used to be an opening Used to be shortcut between atriums Closed after birth Auricles External extensions of atrial chambers Purpose is to increase surface area, allowing them to hold more blood o Ventricles Trabeculae carneae Bundles of muscles in the walls of the ventricles Papillary muscles Individual muscles extending into the ventricle Extend off the wall Connected to the valves Important in regulating blood flow through the heart Purpose(s): keeps valves from being turned inside out and pushed into atria o Interatrial septum Separate atriums o Interventricular septum Separate ventricles o Coronary sulcus Runs diagonal Anterior side Atrial ventricular groove Runs at the point that separates the atria from the ventricles Blood vessels and lipid layer protecting the vessels o Interventricular groove Straight up and down posterior Arteries and veins travel through this Between right and left ventricles 5. Describe the structure and composition of the heart chambers. a. Chamber related blood vessels i. Vena cava 1. Largest vein in body 2. Empty into right atrium 3. Superior: returns blood to heart from everything superior to diaphragm 4. Inferior: returns blood from everything below diaphragm ii. Coronary sinus 1. Receives blood from heart or myocardium 2. Feed myocardium 3. Empty into the right atrium iii. Pulmonary veins 1. Empty into left atrium 2. Only vein that is oxygen rich 3. Brings blood back to heart from lungs 4. Most oxygen rich blood vessel in body iv. Pulmonary artery 1. Takes blood to the lungs 2. From right ventricle to lungs 3. Oxygen poor blood v. Aorta 1. Largest artery in the body 2. BV under the greatest pressure 3. Connects to Left ventricle 4. Takes blood to the body 6. Trace the pathway of blood flow through the heart, including the major blood vessels. a. Right atrium b. Tricuspid valve (right AV valve) c. Right ventricle d. Pulmonary semilunar valve e. Pulmonary arteries f. Lungs g. Pulmonary veins h. Left atrium i. Bicuspid valve (mitral valve) j. Left ventricle k. Aortic semilunar valve l. Aorta m. Body n. Vena Cava 7. Differentiate the pulmonary and systemic circuits. a. Pulmonary circuit i. Right side of heart ii. Blood to lungs iii. Back to left side of heart iv. Gas exchange in lungs v. Oxygen in, CO2 out b. Systemic circuit i. Left side of body ii. Blood to body iii. Back to right side of heart iv. O2 out, co2 in 8. List the major coronary arteries and veins. a. Coronary arteries i. Blood supply to the heart b. Cardiac veins i. Receives hearts blood and empties in coronary sinus c. Coronary sinus i. Receives blood in cardiac veins and empties into the right atrium 9. Identify the name and location of the valves that control the flow of blood through the heart. a. The movement of blood through the heart is based on pressure differences b. As the atria contracts, pressure in the atria increase, and is greater than pressure in the ventricles i. High pressure low pressure Atrioventricular valves: valves between the atrium and ventricle on both the ride and left side of heart. Forced open during contraction o Tricuspid Three flaps Right side of heart Prevent backflow of blood into the atria Connected to papillary muscles that pull on the valve ro prevent backflow of blood into the atria Aka AV valve o Bicuspid Two flaps Left side of heart Most important valve in the heart because its under much higher pressure Aka mitral valve Cordae tendinae o Attached to the atrioventricular valves o Anchors the valves to the papillary muscles Tensions so the flap doesn’t turn inside out Semilunar valves: valves between the ventricles and arteries that are forced open during contraction o Aortic Left side of heart Between left ventricle and aorta o Pulmonary Right side of the heart Between right ventricle and pulmonary trunk 10. Describe the structural and functional properties of cardiac muscle, contrasting it from skeletal muscle. a. Striated b. Uninucleate c. Sliding filament mechanism of action d. Adjacent cells locked by desmosomes and gap junctions e. Intercalated disks i. Desmosomes that lock adjacent cells together ii. Rapid communication that allows cells to contract in unison f. Branches i. Help spread signal to help the heart function as one unit Lecture Objectives Heart Physiology 1. Name the components of the conduction system of the heart, and trace the conduction pathway. a. Intrinsic conduction i. Autorhythmic cells have unstable resting membrane potentials ii. Initiate and distribute impulses 1. Sodium passes through easily and causes these cells to depolarize which stimulates heart muscles to contract à distribute and issue impulses iii. We have nervous connection though, that changes the rate of heart contraction 1. Autonomic (Sympathetic and Parasympathetic) a. sympathetic à rate increases (fight or flight) b. Parasympathetic impulses sent à rate decreases iv. Heart doesn’t need nervous signal to contract, it stimulates itself b. Autorythmic cell location i. Sinoatrial node 1. Collection of autorhythmic cells in the upper portion of the right atrium 2. Pacemaker of the heart = Establishes rate of contraction ii. AV node 1. Sits on top of the interventricular septum 2. This signal shoots all the way down to the apex to the heart iii. Bundle of His 1. Splits to right and left branches iv. Bundle branches 1. Branches v. Atria are stimulated from the top, squeeze toward ventricles but the contraction … vi. Purkinje fibers 1. Go to heart muscle to stimulate change (depolarize) 2. Some go to capillary muscles a. Signal is sent to capillary muscles à contract before ventricles à close vii. Heart rate is due to these automatically depolarizing cells, extrinsic pathway changes heart rate c. Extrinsic innervation i. Brain stem activity from the medulla (autonomic) modifying heart rate ii. Two different centers in the medulla: 1. Cardioacceleratory center a. Sympathetic: Speeds up heart rate 2. Cardioinhibitory center a. Parasympathetic: slows down heart rate i. Parasympathetic impulse travels along the vagus nerve 3. Vagal Tone a. Intrinsic conduction of the heart wants the heart rate to beat at about 100 bpm à parasympathetic pathway is slowing down heart rate b. Extrinsic system therefore modifies the intrinsic c. On average someone our age’s heart beats at about 70 bpm 2. Explain how heart rate is maintained and how it can be modified. Include a discussion of vagal tone. a. Vagal Tone i. Intrinsic conduction of the heart wants the heart rate to beat at about 100 bpm à parasympathetic pathway is slowing down heart rate ii. Extrinsic system therefore modifies the intrinsic iii. On average someone our age’s heart beats at about 70 bpm iv. Autorhythmic cells want the heart to rest around 100 bpm v. Parasympathetic impulses being sent to the heart to slow it down vi. Nervous system slows down resting heart rate à allows you to increase heart rate more if you need to respond to stress (emergency situation) 3. Draw a diagram of a normal ECG, name the waves and intervals, and describe the electrical events associated with each. o Depolarization events detected by electrodes attached to the heart can be represented in an Electrocardiogram (ECG) or EKG in Europe o Graphic recording of electrical events of the heart Deflection waves Three types: o P wave: represents the depolarization of the atrium (sinoatrial node à AV node) o QRS complex: (the big wave) depolarization of the ventricles that masks a smaller event repolarization of the atrium o T wave: repolarization of the ventricle o Diagnostic tool that looks at interruptions in electrical conductivity of the heart Ex: PR interval: time lag in getting impulse from sinoatrial node down the bundle of his If it is too long à conduction has slowed and there is a problem in that part of the heart ST interval: bundle of his à perkinje fibers Doesn’t show anything about contraction strength 4. Identify what causes normal heart sounds and heart murmurs. a. AV valves closing (lub) b. SL valves closing (dub) c. Head with a stethoscope (an amplifier) d. Murmur i. Potential heart sound ii. Innocent heart murmur can be the result of incorrect anatomical arrangement can iii. Other murmur can result from the movement of blood backwards through the valves, indicating malfunctioning valves (lubshdub) 5. Describe the events of the cardiac cycle. a. One complete beat of the heart b. Atria contracting and relaxing, ventricle contracting and relaxing i. Systole and diastole of both atria plus systole and diastole of both ventricles 1. Systole phase of contraction 2. Diastole phase of relaxation 3. All of this is one cardiac cycle ii. As chambers contract the impart pressure on the blood 1. Blood pressure a. Can be measured directly in the heart through a catheter b. 24/8 is normal c. Can use arm to detect ventricular blood pressure d. 120/80 mm Hg systolic over diastolic pressure is normal i. Blood is still there pushing against the wall à why diastolic isn’t 0 2. Difference between systolic and diastolic pulse pressure a. 40 mmHg average b. 0 dead person, but the blood pressure isnt 0 because there is still blood iii. Controls the movement of blood through the chambers of the heart through contraction 6. Define cardiac output, identify the normal cardiac output, and describe factors that can affect cardiac output. a. Cardiac Output i. Amount of blood that passes through the heart per minute ii. Two factors determining this amount: 1. amount pumped out of the ventricles per beat = stroke volume 2. Stroke volume x beats per minute = mL per minute à cardiac output iii. Product of stroke volume and heart rate 1. CO = 75 bpm x 70 ml/b 2. CO = 5250 ml/min a. Every ounce of blood in your body is pumped through your heart every minute (at rest) iv. Cardiac reserve 1. Difference between the maximum cardiac output and the rest cardiac output 2. For healthy people our age = 2025 L a. All blood in our body 45 times per minute when oxygen requirements increase b. Stroke volume i. Difference between amount of blood in ventricles before and after systole (contraction) 1. End diastolic volume (amount before contraction) – (amount remaining after contraction) end systolic volume= stroke volume 2. 120 ml 50 ml = 70 ml c. Factors affecting stroke volume i. Stretch of cardiac muscle 1. The stretch of the wall of the heart as blood enters the heart, it pushes against the wall of the heart, greater push = more stretch à contract harder 2. Starling Law of the heart a. Rubber band b. Preload phenomenon i. Vena cava and pulmonary veins passively dump blood into the chambers 1. If the amount coming in (stretches more) à greater contraction ii. Slower heart rate à preload phenomenon ii. Contraction strength not due to stretch 1. Excess calcium influx into the heart muscle cells a. Faster heart rate with a reduced preload à increase contraction strength iii. Arterial pressure 1. Pressure of blood in the arteries 2. Afterload heart has filled with blood but higher arterial pressure resists the output of blood 7. List and describe pathologies related to cardiac output. Tachycardia o Abnormally high resting heart rate (<100 bpm) Bradycardia o Abnormally low resting heart rate (>60 bpm) o Being very athletic can slow this down Congestive heart failure o Anything that causes a dangerously low cardiac output Coronary atherosclerosis Coronary arteries feed myocardium, the blood is rich in O2. anything that blocks the coronary artery ( cholesterol, plaque, etc) High blood pressure Reduce cardiac output. diastolic pressure greater than 90 mmHg Myocardial infarctions Heart attack. Insufficient blood supply to muscles of the heart. Muscle scars over and loses contracting abilities Dilated cardiomyopathy If one has high bp for a long time, the extra stretch of the chambers of the heart (mainly ventricles) makes them flabby and hard to beat. 8. Discuss the process of fetal heart development. Derived from mesoderm Embryonic mesoderm Originates as two endothelial tubes (right and left, completely separated) Tubes fuse into single chambered “heart” by day 23 post conception (3 weeks) Early chambers formed by day 25 Dlooping and structural changes divide heart into separate chambers and change orientation by day 46 o Bottom on top and top on bottom (why apex is on bottom of heart) o D loop to the right Foramen Ovales Connection of two atria through interatrial septum o Gaseous exchange is not occurring in babies lungs, gas exchange occurs across the placenta o Capillary bed in the lining of the bed of the endometrium of the uterus run close to the capillaries in the baby o When this hole closes it becomes the fossa ovales Ductus Arteriosus o Connection between pulmonary trunk and aorta Some blood made it into the right ventricle >lungs> direct connection between the pulmonary trunk and aorta. Most of blood will take shortcut Lungs will receive some of this blood from the pulmonary trunk so they can be nourished o Becomes ligamentum arteriosum Closes immediately after birth Vestigial element of this sealed shut pathway 9. Provide examples of agerelated changes in heart function. a. Valve sclerosis i. Valves in the heart can often harden due to deposits (calcium) ii. Deposits on the flaps, so they don’t open and close the way they are supposed to iii. Esp problematic on mitral valve. Reduces cardiac output by back flowing into left ventricle b. Decreased cardiac reserve i. Don’t have the ability to respond to stresses by increasing cardiac output as much c. Fibrosis of myocardium i. Skeletal muscle atrophies if not used, it will convert from skeletal tissue to fibrous connective tissue (not contractile) ii. Same thing happens with cardiac tissue d. Atherosclerosis i. The arteries are having deposits laid down on the inside (cholesterol) ii. Lumen of the vessel is shrinking (changes bp and flow) iii. Elasticity changes Lecture Objectives Blood Vessels 1. Identify the blood vessels of the human body, and indicate their direction of flow. a. Arteries i. Leave the heart ii. Elastic 1. Arteries with largest diameter 2. Least amount of resistance to blood 3. Close to heart 4. Sheets of elastic connective tissue 5. Allows vessels to stretch and rebound when heart beats iii. Muscular 1. Smooth muscle 2. Smaller diameter 3. Distal to elastic arteries and heart 4. Deliver blood toward organs b. Arterioles i. Empty into capillaries c. Capillaries i. Where gas exchange occurs d. Venules i. Capillaries empty into venules e. Veins i. Carry blood back through heart 2. Describe the three layers that make up the wall of most blood vessels, and state the function of each layer. a. Tunica interna i. Layer closest to lumen of BV ii. Made up of simple squamous epithelium iii. Also called vessel endothelium iv. Same tissue and purpose of endocardium b. Tunica media i. Deep to tunica interna ii. Made of smooth muscle iii. Allows BV to change diameter iv. Change in diameter due to stimulation of sympathetic nervous system or chemically through norepinephrine v. Change in diameter changes the flow of blood through vessels and directs blood flow vi. Thicker in arteries c. Tunica externa i. Full of collagen, which anchors the BV in place ii. Vasa vasorum d. Lumen i. Space in the middle of the tube ii. Collapses in veins 3. Differentiate the three categories of capillaries discussed in class, and identify where each could be found. a. Continuous i. Most are continuous ii. Tight junction iii. Intracellular cleft very small iv. Vesicles that aid in exchange can pass through the clefts v. Lining is smooth, little resistance to blood flow b. Fenestrated i. Small pores in walls of capillary ii. Have clefts and pores iii. Increases permeability of capillaries iv. Lots of absorption like in small intestine, lots of filtration like in kidneys, endocrine organs which secrete hormones c. Sinusoidal i. Leaky capillaries ii. Have big gaps called sinusoids iii. Fewer tight junctions gaps between cells are larger iv. Molecules and blood cells can pass through them v. In bone marrow, in liver 4. Describe the structure and function of a capillary bed. a. Terminal arteriole i. Larger arteriole that takes blood to the capillary bed b. Metarteriole i. Branches of the terminal arteriole ii. Leads to capillary bed c. Thoroughfare channel i. Metarteriole joins with the vein on the other side (veins is the throughfare channel) d. Postcapillary venule i. Blood will always pass through this circuit up until now ii. Collects blood from capillary bed. Takes blood back to heart. e. Vascular shunt i. Shourtcut through capillary bed ii. Always goes through. If it only goes through vascular shunt it wont go through true capillaries. f. True capillaries i. When there is a need within the tissue for blood it will pass through this capillary bed, not through the short cut g. Precapillary sphincters i. Sphincter that opens and closes regulating the flow of blood 5. Identify some significant differences between arteries and veins. a. Artery i. Thick walls ii. Small lumen iii. Thicker tunica media iv. Lower blood volume v. Higher blood pressure vi. No valves b. Vein i. Thin walls ii. Large lumen iii. Thinner tunica media iv. Higher blood volume v. Lower blood pressure vi. Venous valves 6. Explain the relationship between blood flow, blood pressure and blood resistance. Relatively constant flow, but where it goes is different Heart generates the pressure that pushes the blood. Blood closest to heart has the highest pressure, and vice versa Directly proportional to differences in blood pressure Greater the difference greater the flow Inversely proportional to peripheral resistance Peripheral resistance goes up, flow goes down F=P/R 7. Identify factors that could alter blood resistance, then identify the factor that exerts the most control. a. Blood viscosity i. Measurement of slipperiness or ease of flow ii. Internal resistance of blood due to makeup of blood itself iii. Higher viscosity, lower its flow iv. Blood viscosity can be changed but not often, it is usually constant 1. Ex: polyecthemia excess RBC’s b. Vessel length i. Longer the vessel, the greater the resistance of flow ii. Relatively constant, but bigger people have longer vessels. Really only changes from person to person iii. Not a major factor c. Vessel diameter i. Major factor that determines resistance ii. Larger diameter, lower the friction iii. As friction increases, resistance increases iv. We can change the diameter of vessels 8. Contrast the blood pressure at various points through the circulatory system. Farther from heart, less pressure there is Loss of pressure begins in the muscular arteries Pulse pressure is eliminated in arterioles Huge drop in capillaries because they are microscopic, if the pressure was high they would explode things also move through more slowly, making exchange more efficient Less pressure in venules, due to same pressure but in larger diameters Blood pressure very low in veins, hard to get blood back to the heart 9. Define mean arterial pressure, and discuss the usefulness of this term in discussing blood circulation. a. Pressure that propels blood to tissues b. MAP = diastolic pressure + (pulse pressure/3) c. Below the mathematical average because we stay in diastole longer than systole 10. List and explain factors that respond to changes in blood pressure, and describe the control that each exerts. a. Epinephrine and norepinephrine i. Epinephrine increases CO2 ii. Causes vasoconstriction iii. Increases BP iv. Stress can cause in increase in BP b. Atrial natriuretic peptide i. If pressure of walls against atria of heart increases, the heart secretes ANP ii. Acts on the kidneys iii. Causes a change in water reabsorption iv. Shuts off aldosterone v. Lose water as urine, water isn't in blood so blood volume decreases vi. Lower BP c. Antidiuretic hormone i. Released from posterior pituitary ii. Promotes aldosterone production iii. Conserve waster iv. Increased blood volume and pressure v. Can also cause vasoconstriction, but only during times of extreme hemorrhage d. Angiotensin II i. When stimulated, kidneys will release renin with causes the production of angiotensin ii. Linked with production of aldosterone. iii. Increase BP iv. Functions as a vasoconstrictor e. Endotheliumderived factors i. Class of chemicals that can change BP ii. Blood vessel itself releases it iii. Stretch of vessel causes release of chemical iv. Vasoconstriction and some vasodilation f. Inflammatory chemicals i. During breech to immune system ii. Histamine is a vasodilator iii. Increases permeability across the vessel wall iv. Reduce BP g. Alcohol i. Inhibits ADH ii. More urination iii. Less water in blood iv. Reduce BP and blood volume v. Inhibits vasomotor center> vasodilation causes BP to decrease vi. Also directly causes vasodilation h. Nicotine i. Functions like epinephrine and norepinephrine ii. Increases BP i. Difference between localized and systemic effects i. If you constrict systemically, there is a big difference in BP ii. Short term= localized, don’t affect the whole body 11. Contrast the direct vs. the indirect renal mechanism, and identify the purpose of each. a. Direct i. Increase in blood pressure or blood volume speeds up filtration rate in kidneys 1. As blood passes thru capillary, a large portion of plasma will leak out and collect in collection tubule 2. Functions to keep or return things back into circulation (water, minerals, etc) wastes are excreted 3. If high BP or blood volume, filtration rate will increase, and urine production will increase b. Indirect i. Proteins from liver used (why its indirect) ii. Decrease in BP causes kidneys to release renin iii. Renin stimulates angiotensin II production iv. Angiotensin II stimulates aldosterone production 1. Aldosterone causes more water to be reabsorbed v. Blood pressure rises Lecture Objectives Circulation 1. Relate the vital signs to the cardiac cycle. a. Pulse i. Pressure due to expansion and recoil of arteries as blood passes through it ii. Most common is radial artery (wrist) iii. Where an artery is near the skin iv. Femoral (behind the knee) v. Carotid (neck) b. Blood pressure i. Measured using a BP cuff ii. Radial artery running through upper arm iii. Inflating cuff and compressing radial artery iv. 120/80 v. Inflate to about 180, and then you will hear nothing. As you start to deflate, you will hear the artery reopen, and blood will rush through. vi. First sound is systolic pressure vii. Continue to deflate cuff, and then the sound will stop. The last sound you hear is diastolic pressure. 2. Define tissue perfusion, and discuss how it is altered based on tissue needs. a. The passage of blood through tissues b. As blood passes through tissues, it delivers oxygen and nutrients to tissues c. Removes wastes from tissues d. Exchanges gases in lungs e. Forms urine in kidneys f. Blood delivery to different tissue organs differs based on needs g. Not constant to all areas of the body 3. Relate the velocity of blood flow to the different types of blood vessels, and explain why the pattern you describe exists. a. b. At any given time, there is more blood in veins than any other vessel c. Inversely related to crosssectional area of vessels i. Lowest velocity in most area d. Regulated locally by modifying diameter of arterioles i. More constricted, higher velocity e. velocity– steady in arties, slows in capillaries, speeds back up in veins f. Total area low in arteries, most in capillaries, drops again in veins g. BP highest in arteries, lowest in veins 4. Identify factors that could result in a change in blood velocity. a. Regulated by individual tissues based on tissue needs i. Intrinsic mechanism b. Low levels of nutrients or oxygen cause vasodilation and relaxation of precapillary sphincters (so blood will go thru capillaries and not just shunt) i. Dilate, deliver more blood to that area ii. Metabolic effect c. Changes in stretch of vessel causes response in smooth muscle of vessel i. Myogenic effect ii. More stretch, more contraction of smooth muscle, more constriction iii. Less blood flow, higher blood velocity d. Angiogenesis increases number and size of vessels i. Production of new blood vessels ii. Athlete= increased demand for oxygen, body will create more vessels 5. Explain how gases, lipidsoluble molecules, watersoluble solutes, large molecule and fluids pass through capillaries into interstitial fluids. a. Respiratory gases and lipidsoluble molecules pass via direct diffusion i. From areas of high concentration to low concentration ii. Pass directly thru plasma membrane b. Watersoluble solutes pass through intercellular clefts and fenestrations c. Large molecules pass through caveoli i. Structures within vesicles that allow for active passage d. Fluids pass through pinocytic vesicles i. Form of active transport ii. Requires energy 6. Identify the pressures that work in opposition to one another to regulate movements in/out of capillaries. Explain how these forces operate. a. Fluid forced out through clefts at arterial end i. Higher pressure in arteries b. Most returns at venous end i. Lower pressure in veins c. Flow regulated by balance between hydrostatic pressure and colloid osmotic pressure i. 2 forces hydrostatic pressure (fluid pressure) ii. 2 forces colloid osmotic pressure d. Hydrostatic Pressure i. Force exerted by fluid pressing against a wall 1. 2 forces one internal and one external ii. Capillary hydrostatic pressure drops along length of capillary bed 1. Same as capillary BP 2. External> blood will move out 3. Internal> blood will move in e. Colloid Osmotic Pressure i. Force created by presence of large, nondiffusible molecules 1. Ex: proteins ii. Functions in opposition to hydrostatic pressure 1. Hydrostatic wants to push things out 2. Colloid wants to suck things in iii. Does not vary along length of capillary bed f. Net filtration pressure i. Interaction between hydrostatic and colloid osmotic pressures 1. Interaction of all 4 pressures 2. Capillary hydrostatic pressure plays the most important role 3. Capillary pressure high, things move out 4. Capillary pressure is low, things move in ii. Determines if there is a net gain or loss of fluid from capillaries 7. Define a portal system. a. Capillary bed between 2 veins b. Veins to capillaries to veins i. Specialized exchange structure that existed between 2 veins 1. Important one is in liver 2. Blood cells get recycled and exchanged in low pressure 3. Detox occurs in liver c. Serves specific regional tissue needs 8. Define circulatory shock, and identify possible sources. a. Any condition that prevents blood from circulating properly b. Hypovolemic shock i. Occurs from massive blood loss ii. Blood volume is so low that it cant be pushed through system c. Vascular shock i. Blood volume is normal ii. Poor circulation due to extreme vasodilation iii. Ex: sunburn dilate vessels to cool tissue, being in a hot tub too long iv. Can occur in anaphylaxis d. Cardiogenic shock i. Post heart attack ii. Loss of blood supply to part of the heart. Converts to fibrous connective tissue and cant be contracted iii. Heart cant pump 9. Explain how blood vessels develop in the fetus. a. Mesoderm cells form endothelial lining of blood vessels i. Form from the inside out b. These collect as blood islands i. Collections of blood vessels c. These connect to form vascular tubes i. Tubes connected that have yet to differentiate d. Plateletderived growth factor signals mesenchymal cells to form muscular and fibrous coats e. Starts everywhere, connects, then modifies 10. Provide examples of agerelated blood vessel changes. a. Atherosclerosis i. The build up of plague deposits in the lining of blood vessels ii. Usually remnants of cholesterol iii. Diet contributes iv. Inhibits flow of blood v. Men form more plaques than women, because estrogen helps prevent plaque formati
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