Chapters 10 & 11 Blood and Cardiovascular System

Course of Study:9.) Identify structures and functions of the cardiovascular system. Tracing the flow of blood through the body Identifying components of blood Describing blood cell formation Distinguishing among human blood groups Describing common cardiovascular diseases and disorders Examples: myocardial infarction, mitral valve prolapse, varicose veins, arteriosclerosis

Chapters 10 & 11Blood and Cardiovascular SystemComponents of Blood

BloodThe only fluid tissue in the human bodyClassified as a connective tissueLiving cells = formed elementsNon-living matrix = plasma

Components of Blood:Although blood appears to be a thick, homogenous liquid, the microscope reveals it has both solid and liquid componentsBlood is a complex connective tissue (it is the only liquid tissue) in which living blood cells, the formed elements, are suspended in a nonliving fluid matrix called plasma.

Components of Blood:Blood in a centrifuge:The heavier formed elements are packed down The plasma rises to the topMost of the reddish mass at the bottom of the tube consists of erythrocytes, the red blood cells that function in oxygen transportAlthough, it is barely visible in there is a thin, whitish layer called the buffy coat at the junction between the formed elements and the plasma. This layer contains leukocytes (leuko=white), the white blood cells that act in various ways to protect the body, and platelets, cell fragments that function in the blood clotting process.Erythrocytes normally account for about 45% of the total volume of a blood samples, a percentage known as a hematocrit.White blood cells and platelets contribute less than 1%.Plasma makes up most of the remaining 55% of whole blood.

Figure 10.1 in your book, pg.329Physical Characteristics and VolumeBlood is a sticky opaque fluid with a characteristic metallic tasteDepending on the amount of oxygen it is carrying, the color of blood varies from scarlet (oxygen-rich) to a dull red (oxygen-poor)Blood is heavier than water and about five times thicker, or more viscous, largely because of its formed elements.Blood is slightly alkaline (basic) with a pH between 7.35 and 7.45.Its temperature is always slightly higher than body temperature (38C or 100.4F)Blood accounts for approximately 8% of body weight, and its volume in healthy males is 5-6 liters, or approximately 6 quartsso what is it in women? (2 point bonus)PlasmaIs approximately 90% waterIs the liquid part of the bloodOver 100 different substances are dissolved in this straw-colored fluid such as nutrients, salts (electrolytes), respiratory gases, hormones, plasma proteins, and various wastes and products of cell metabolismThe composition of plasma varies as cells remove or add substances to the bloodassuming a healthy diet, however, the composition is kept relatively constant by various homeostatic mechanisms of the body

Plasma ProteinsThe most abundant solutes in plasmaExcept for antibodies and protein-based hormones, most plasma proteins are made by the liver.Serve a variety of functionsAlbumin: contributes to osmotic pressure of blood, which acts to keep water in the bloodstreamClotting Proteins: Help stem blood loss when a blood vessel is injuredAntibodies: Help protect the body from pathogens (disease causing organisms)Plasma proteins are NOT taken up by cells to be used as food fuels or metabolic nutrients, as are other solutes such as glucose, fatty acids, and oxygen.Formed ElementsErythrocytesLeukocytesPlatelets

If you observe a stained smear of human blood under a microscope, you will see smooth, disc-shaped red blood cells, a variety of gaudily stained white blood cells, and most likely, some scattered platelets that look like debris.Erythrocytes vastly outnumber the other types of formed elements.

Erythrocytes: red blood cells (RBCs)Salmon-colored, biconcave disksFunction to ferry oxygen in blood to all cells of the bodyRBCs differ from other blood cells because they are anucleate meaning they lack a nucleus and they also contain very few organelles (which also means they cannot divide)Mature RBCs are literally sacs of hemoglobin moleculesHemoglobin: iron-bearing protein, transports the bulk of the oxygen that is carried in the bloodIn fact, because erythrocytes lack mitochondria and make ATP by anaerobic mechanisms, they do not use up any of the oxygen they transport, making them very efficient oxygen transporters indeed!RBCs live about 120 days and are then phagocytized by the liver and spleen

Anemia & Sickle-Cell AnemiaAnemia: Decrease in the oxygen-carrying ability of the bloodMay be result of: 1) Lower than normal number of RBCs 2) abnormal or deficient hemoglobin content in the RBCs or Sickle-Cell Anemia (SCA):The abnormal hemoglobin formed becomes spiky and sharp when the RBCs unload oxygen molecules or when the oxygen content of the blood is lower than normal (like during exercise, anxiety, or other stressful situations). The deformed (crescent-shaped) erythrocytes rupture easily and dam up in small blood vessels. These events interfere with oxygen delivery and cause extreme pain.It is amazing that this havoc results from a change in just ONE of the amino acids in each of the beta chains of the globin molecule!SCA occurs chiefly in black people who live in the malaria belt of Africa and among their descendants.Apparently, the same gene that causes sickling makes RBCs infected by the malaria-causing parasite stick to the capillary walls and then lose potassium, an essential nutrient for survival of the parasiteHence, the malaria-causing parasite is prevented from multiplying within the RBCs, and individuals with the sickle gene have a better chance of surviving where malaria is prevalent!!! Cool.

Leukocytes: white blood cells (WBCs)Far less numerous than RBCsAre crucial to body defense against diseaseInclude: Granulocytes (neutrophils, eosinophils, basophils) & Agranulocytes (lymphocytes, monocytes)WBCs are the only complete cells in the blood; that is, they contain nuclei and the usual organellesWBCs form a protective, movable army that helps defend the body against damage by bacteria, viruses, parasites, and tumor cells.so they have special characteristics

More About Leukocytes (WBCs)RBCs are confined to the bloodstream and carry out their function in the bloodnot WBCsWBCs are able to slip into and out of the blood vessels - a process called diapedesis.The circulatory system is simply their means of transportation to areas of the body where their services are needed for inflammatory or immune responses (we will look more at this in ch.12)WBCs can also locate areas of tissue damage and infection in the body by responding to certain chemicals that diffuse from the damaged cells (they pick up the scent and move therepretty neat!) They pinpoint areas of tissue damage and rally round in large numbers to destroy microorganisms or dead cells.Whenever WBCs mobilize for action, the body speeds up their production, and as many as twice the normal number of WBCs may appear in the blood within a few hours. A total WBC count above 11,000 cells/mm3 is referred to as leukocytosis.this generally indicates that a bacterial or viral infection is stewing in the body. Leukopenia, the opposite condition, is an abnormally low WBC count. It is commonly caused by certain drugs, such as corticosteroids and anticancer agents.Leukocytosis & LeukemiaLeukocytosis: Normal and desirable response to infectious threats to the body.By contrast, the excessive production of abnormal WBCs that occurs in infectious mononucleosis and leukemia is distinctly pathological.Leukemia:Literally white bloodThe bone marrow becomes cancerous, and huge numbers of WBCs are turned out rapidlySeems like not a bad thing.but.the newborn WBCs are immature and incapable of carrying out their normal protective functions. So, the body becomes the easy prey of disease-causing bacteria and viruses.2 Major Groups of WBCs:GranulocytesGranule containingAgranulocytesLack visible granulesNeutrophilsAvid phagocytes at sites of acute infectionEosinophilsTheir number increases rapidly during allergies and infections by parasitic worms (like tapeworm)BasophilsRarest of WBCs that contain large histamine-containing granulesHistamine is an inflammatory chemical that makes blood vessels leaky and attracts other WBCs to the inflammatory site.LymphocytesTake up residence in lymphatic tissues, where they play an important role in the immune responseMonocytesLargest of all WBCsThey migrate into tissues, change into macrophages with huge appetites. Macrophages are very important in fighting chronic infections, such as tuberculosis

PlateletsReally arent cellsthey are fragments of bizarre multinucleate cells called megakaryocytes which pinch off thousands of anucleate platelet pieces that quickly seal themselves off from the surrounding fluidsPlatelets appear as darkly staining, irregularly shaped bodies scattered among the other blood cellsThe normal platelet count in blood is about 300,000/mm3.Platelets are needed for the clotting process that occurs in plasma when blood vessels are ruptured or broken

Hemostasis (hem=blood; stasis=standing still)The process of stopping bleedingCoagulation causes the formation of a blood clot3 Key Events:1. Blood vessel spasm - damaged or broken vessels stimulate muscle tissue in the walls of the blood vessels to contract. This slows or stops blood flow, lasts for several minutes. Also, platelets release serotonin, a vasoconstrictor which maintains the muscle spasm even longer.2. Platelet plug formation - platelets stick to surfaces of damaged blood vessels and to each other to form a "plug"3. Blood coagulation - most effective, forms a blood clot (hematoma). Injury causes an increase in the release of coagulants. Main event - conversion of fibrinogen into long protein threads called fibrin.Blood clotting - Animation - YouTube

Undesirable Clotting:Sometimes clots form in intact blood vessels, particularly in the legsA clot that develops and persists in an unbroken blood vessel is called a thrombusIf large enough, it may prevent blood flow to the cells beyond the blockagefor exampleif a thrombus forms in the blood vessels serving the hearth (coronary thrombosis), the consequences may be death of heart muscle and a fatal heart attackIf a thrombus breaks away from the vessel wall and floats freely in the bloodstream, it becomes an embolus. An embolus is usually no problem unless or until it lodges in a blood vessel too narrow for it to pass throughfor examplea cerebral embolus may cause a strokeA number of anticoagulants, most importantly aspirin, heparin, and dicumarol, are used clinically for thrombus-prone patients

Cool Picture from your TextReads: Fibrin Clot. Scanning electron micrograph of red blood cells trapped in a mesh of fibrin threads.Blood Cell Formation (Hematopoiesis)Blood Cell FormationOccurs in red bone marrowIn adults, this tissue is found is found chiefly in the flat bones of the skull and pelvis, the ribs, sternum, and proximal epiphyses of the humerus and femurEach type of blood cell is produced in different numbers in response to changing body needs and different stimuliafter they mature, they are discharged into the blood vessels surrounding the area.All formed elements arise from a common type of stem cell: the hemocytoblast, which resides in the red bone marrowErythrocyte Development:Because RBCs are anucleate (have no nucleus) they are unable to synthesize proteins, grow, or divideAs they age, RBCs become more rigid and begin to fragment, or fall apart, in 100-120 days. Their remains are eliminated by phagocytes in the spleen or liver.Lost cells are replaced by the division of hemocytoblasts in the red bone marrow.The developing RBCs divide many times and then begin synthesizing huge amounts of hemoglobinsuddenly when enough hemoglobin has been accumulated, the nucleus and most organelles are ejected and the cell collapses inward.The result is the young RBC, called a reticulocyte because it still contains some rough endoplasmic reticulum (ER)The reticulocytes enter the bloodstream to begin their task of transporting oxygen.within 2 days of release, they have ejected the remaining ER and have become fully functioning erythrocytes. The entire developmental process from hemocytoblast to mature RBC takes 3-5 days.Erythrocyte Development:Rate of production is controlled by a hormone (not so surprisingly!) called erythropoietinNormally a small amount of erythropoietin circulates in the blood at all times, and the red blood cells are formed at a fairly constant rateAlthough the liver produces some, the kidneys play the major role in producing this hormone.When blood levels of oxygen begin to decline for any reason, the kidneys step up their release of erythropoietinthe erythropoietin targets the bone marrow, prodding it into high gear to turn out more RBCs.As you might expect, and overabundance of erythrocytes, or an excessive amount of oxygen in the bloodstream, decreases erythropoietin release and red blood cell production.Leukocyte and Platelet DevelopmentAlso stimulated by hormones like erythrocytesThese colony stimulating factors (CSFs) and interleukins not only prompt red bond marrow to turn out leukocytes, but also marshal up an army of WBCs to ward off attacks by enhancing the ability of mature leukocytes to protect the bodyThey are released in response to specific chemical signals in the environment such as inflammatory chemicals and certain bacteria or their toxinsThe hormone thrombopoietin accelerates the production of platelets, but little is known about how that process is regulated

Human Blood Groups

AntigensBlood transfusions can save lives, but people have different blood groups, and transfusing incompatible or mismatched blood can be fatalThe plasma membranes of RBCs, like those of all body cells have genetically determined proteins (antigens), which identify each person as unique!An antigen is a substance that the body recognizes as foreign; it stimulates the immune system to release antibodies or use other means to mount a defense against itAntigens & AntibodiesMost antigens are foreign proteins like viruses or bacteria that have managed to invade the bodyEach of us tolerates our own cellular (self) antigens, but one persons RBC proteins will be recognized as foreign if transfused into another person with different RBC antigensThe recognizers are antibodies present in the plasma that attach to RBCs bearing surface antigens different form those on the patients RBCsAntibodies and AgglutinationAt this point of recognition of foreignerbinding of antibodies causes the RBCs to clump, called agglutinationThis leads to clogging of small blood vessels throughout the bodyDuring the next few hours, the foreign RBCs are ruptured and the hemoglobin is released into the blood streamAlthough the transfused blood is unable to deliver the increased oxygen-carrying capacity hoped for and some tissue areas may be deprived of blood.the most devastating consequenceNegative Consequences of Transfusion of Mismatched BloodThe most devastating consequence of severe transfusion reactions is that the freed hemoglobins block the kidney tubules and cause kidney failureTransfusion reactions can also cause fever, chills, nausea, and vomiting, but in the absence of kidney shutdown these reactions are rarely fatalTreatment is aimed at preventing kidney damage by infusing alkaline fluids to dilute and dissolve the hemoglobin and diuretics to flush it out of the body in urineABO and Rh GroupingThere are over 30 common RBC antigens in humans, allowing each persons blood cells to be classified into different blood groupsHowever, it is the antigens of the ABO and Rh blood groups that cause the most vigorous transfusion reactions

ABO Blood GroupsBased on which of two antigens, type A or type B, a person inheritsAbsence of both antigens results in type O bloodPresence of both antigens leads to type ABPossession of type A gives type A blood and possession of type B gives type B bloodIn the ABO blood group, antibodies are formed during infancy against the ABO antigens not present on your own RBCsFor example: a baby with neither the A nor the B antigen (O) forms both anti-A and anti-B antibodies, while those with type A antigens (A) form anti-B antibodies

Summary of ABO(from your text, pg.340)*Just remember, the antigens on the surface of your cells (or donated cells) will cause a reaction if your immune system does not recognize them as being part of you. Hence, if you are Type A, and transfused with Type B, your body will mobilize a massive immune response against the "invading" blood. This will cause coagulation of blood and death.Rh blood groupsNamed because 1 of the 8 Rh antigens was originally identified in Rhesus monkeys!Later the same antigen was discovered in human beingsMost Americans are Rh+, meaning that their RBCs carry the Rh antigenif you are negative, then you do not carry the Rh antigenUnlike the antibodies of the ABO system, anti-Rh antibodies are not automatically formed and present in the blood of Rh- people.However, if an Rh- person receives mismatched blood (Rh+), shortly after the transfusion his or her immune system becomes sensitized and begins producing antibodies (anti-Rh+) against he foreign blood type.Hemolysis (rupturing of the RBCs) does not occur with the first transfusion because it takes time for the body to react and start making antibodieshowever, the second time and every time after, a typical transfusion reaction occurs in which the patients antibodies attack and rupture the donors Rh+ RBCs

Important Rh Related ProblemOccurs in pregnant Rh- women that are carrying Rh+ babiesThe first pregnancy usually results in the delivery of a healthy babybut because the mother is sensitized by Rh+ antigens that have passed through the placenta into her bloodstream, she will form anti-Rh+ antibodiesUnless she is treated with RhoGAM shortly after giving birth..RhoGAM is an immune serum that prevents this sensitizationIf she is not treated and becomes pregnant again with an Rh+ baby, her antibodies will cross through the placenta and destroy the babys RBCs, producing a condition known as hemolytic disease of the newborn.The baby is anemic and becomes hypoxic (deficiency of oxygen) and cyanotic (the skin takes on a blue cast). Brain damage and even death may result unless fetal transfusions are done before birth to provide more RBCs for oxygen transport.Blood TypingThe importance of determining the blood group of both the donor and the recipient BEFORE blood is transfused is glaringly obvious!Essentially in blood typing, it involves testing the blood by mixing it with 2 different types of immune serum: anti-A and anti-B.Agglutination occurs when RBCs of a group A person are mixed with the anti-A serum, but not when they are mixed with the anti-B serum (& vise versa)Because it is critical that blood groups be compatible, cross matching is also done.involves testing for agglutination of donor RBCs by the recipients serum and of the recipient's RBCs by the donor serumTyping for Rh factors is done in the same manner as ABO blood typingBlood Typing From your text.Page 341

Today:1. Heart Labeling Quiz2. Complete PP Notes3. Disorders with Nooks

Remember: Monday Heart Dissection!Tracing the Flow of Blood through the Body (Chapter 11)Looking specifically at the heart, veins, and arteries

The Cardiovascular SystemA closed system of the heart and blood vesselsThe heart pumps bloodBlood vessels allow blood to circulate to all parts of the bodyThe function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

The HeartLocationThorax between the lungsPointed apex directed toward left hipAbout the size of your fistThe Heart: CoveringsPericardium a double serous membrane that covers the heart like a bag, but has two layers with fluid in betweenVisceral pericardiumNext to heartParietal pericardiumOutside layer

Serous fluid fills the space between the layers of pericardium-reduces friction!

The Heart: Heart WallThree layersEpicardiumOutside layerThis layer is the parietal pericardiumConnective tissue layerMyocardiumMiddle layerMostly cardiac muscleEndocardiumInner layerEndothelium

Physiology of the HeartAs the heart beats or contracts, the blood makes continuous round trips-into and out of the heart, through the rest of the body, and then back to the heart-only to be sent out againThe amount of work that a heart does is almost too incredible to believeIn one day it pushes the bodys supply of 6 quarts or so of blood (6Liters) through the blood vessels over 1,000 times!Meaning that it actually pumps about 6,000 quarts (or liters) of blood every single day!

Blood CirculationThe systemic (to the body) and pulmonary (to the lungs) circuits are shown hereThe left side of the heart is the systemic pumpsupplies oxygen & nutrient rich blood to all body organsThe right side of the heart is the pulmonary circuit pumpreceives relatively oxygen poor blood from the veins of the body and pumps it out to the lungs where oxygen is picked up and carbon dioxide is unloaded

Figure 11.3Path of Blood Through the HeartQuick OverviewGive Handout!1. Deoxygenated blood enters right atrium through the vena cava2. Blood moves into the right ventricle3. Blood goes out the pulmonary arteries and heads to the lungs4. Blood returns from the lungs and enters the left atrium5. Blood moves into the left ventricle6. Oxygenated blood moves out of the left ventricle through the aorta and to the body

The Heart: ValvesAllow blood to flow in only one directionValves open as blood is pumped throughHeld in place by chordae tendineae (heart strings)Close to prevent backflow

The Heart: ValvesFour valvesAtrioventricular valves between atria and ventriclesBicuspid valve (left)Tricuspid valve (right) Semilunar valves between ventricle and arteryPulmonary semilunar valveAortic semilunar valve

Sounds of the HeartWhen using a stethoscope, you can hear two distinct sounds during each cardiac cycleThese heart sounds are often described by the two syllables lub and dup, and the sequence is lub-dup, pause, lub-dup, pause, etcThe first sound lub is caused by the closing of the AV valvesThe second sound dup is caused by the closing of the semilunar valves at the end of systole

The Heart: Associated Great VesselsAortaLeaves left ventricleLarge vessel that delivers blood to the bodyPulmonary arteriesLeave right ventricleLarge vessel that splits into the left and right pulmonary arteries, these are the only arteries that carry deoxygenated bloodVena cavaEnters right atriumSuperior Vena Cava - vessel the returns blood to the heart from the upper bodyInferior Vena Cava - vessel the returns blood to the heart from the lower bodyPulmonary veins (four)Enter left atriumPulmonary Veins - returns oxygenated blood from the lungs

The Heart: Cardiac CycleAtria contract simultaneouslyAtria relax, then ventricles contractSystole = contractionDiastole = relaxation

The Heart: Regulation of Heart RateIncreased heart rateSympathetic nervous systemCrisisLow blood pressureHormonesEpinephrineThyroxineExerciseDecreased blood volumeDecreased heart rateParasympathetic nervous systemHigh blood pressure or blood volumeDecreased venous returnBlood Vessels: The Vascular SystemTaking blood to the tissues and backArteries and ArteriolesCarry blood Away from the heart (arterioles are just smaller arteries)CapillariesAre only one cell layer thickallows easy exchanges between the blood and tissue cellsVeins and Venules Carry blood To the heart (venules are just smaller arteries)

Differences Between Blood Vessel TypesWalls of arteries are the thickestThis is because arteries are much closer to the heart and must be able to expand as blood is forced into themtheir walls must be strong and stretchy enough to take these extreme changes in pressureArterial blood is pumped by the heartLumens (opening in middle) of veins are largerVeins are far from the heart in the circulatory pathway and the pressure tends to be low all of the time, so veins have thinner wallsSince the blood pressure is usually too low to force blood back to the heartveins are modified to ensure that the amount of blood returning to the heart equals the amount being pumped out of the heart at any time1) The larger veins even have valves that prevent backflow of blood2) Skeletal muscle activity enhances venous return (milks the blood back to the heart)3) Finally, when we inhale, the drop in pressure that occurs in the thorax causes the large veins near the heart to expand and fill helping return blood to the heart.The Vascular System

Capillary BedsCapillary beds consist of two types of vesselsVascular shunt Directly connects an arteriole to a venuleTrue capillariesexchange vessels, usually branch off the proximal end of the shunt and return to the distal endOxygen and nutrients cross to cellsCarbon dioxide and metabolic waste products cross into blood

Sphincters act as a valve to regulate the flow of blood into the capillary.PulsePulse pressure wave of bloodMonitored at pressure points where pulse is easily palpated

Figure 11.16Blood PressureMeasurements by health professionals are made on the pressure in large arteriesSystolic pressure at the peak of ventricular contractionDiastolic pressure when ventricles relaxPressure in blood vessels decreases as the distance away from the heart increases

Systolic pressure / diastolic pressure

Systolic occurs when blood is forced out of the left ventricle, and the aortic valve OPENS...this is the high number on a blood pressure readingDiastolic occurs when the aortic valve closes and the ventricle relaxes, this is the lower number of the blood pressure reading.Average (Normal) Blood Pressure = 120/80 & Average heart rate = 72 bpm The device used to measure blood pressure is a SPHYGMOMANOMETER

Developmental Aspects of the Cardiovascular SystemA simple tube heart develops in the embryo and pumps by the fourth weekThe heart becomes a four-chambered organ by the end of seven weeksFew structural changes occur after the seventh week

Disorders/Diseases Associated with the Cardiovascular SystemMyocardial infarctionMitral valve prolapseVaricose veinsArtherosclerosis/ArteriosclerosisChronic hypertensionMurmursHemophiliaThrombocytopenia

*Include a 1 Paragraph Summary of your assigned disorder/disease with your Homework!WITHOUT LOOKING!!do the best you can.Write the Flow of Blood through the Heart, Lungs and Body!

Todays Plans*Remember we are learning about tracing the flow of blood through the body!1. Heart Walk Through Practice (Quiz Tomorrow!)2. Review Assignment from Book (on the board)Due at the End of Class!3. Tomorrow we will be taking the Heart Walk-Through Quiz and also Reviewing for your Ch.10& 11 TEST on Thursday!

Todays PlansReview for Ch.10&11 Blood and Cardiovascular TestYou will work with a partner using a study guide handout to highlight/mark your notes on what to studyYou will not be able to take the study guide handout out of the roomOnce you have marked your notes, begin reviewing for your test tomorrow!Heart Walk-Through QuizI will draw names from the hat to see what order we will go inThis quiz will be given in the hallwayWhen you hear your name report to the hall!