Anatomy-Chapter 17,18,19

Chapter 18, LO #4, PART 2

-3. ARTERIOLES: smallest arteries, contains all 3 layers of blood vessel wall, but layers are extremely thin, and tunica media contains only 1-3 layers of smooth muscle cells, METARTERIOLES: smallest arterioles and directly feed capillary beds in most tissues, smooth muscle cells of the metarterioles are confined mostly to circular PRECAPILLARY SPHINCTER that encircles metarteriole-capillary junction.. certain arteries also play important role in monitoring BP and detecting concentration of certain chemicals in blood -pressure receptors (BARORECEPTORS) are found in aorta, as well as in common carotid artery, located in neck, also in carotid artery and aorta are groups of CHEMORECEPTORS; detect blood oxygen, carbon dioxide, and hydrogen ion concentrations

Chapter 18, LO #8, PART 2

-3. BLOOD VESSEL LENGTH: the longer the blood vessel the greater resistance; more pressure is needed to propel blood through a long vessel than a short one; 1 reason why resistance in pulmonary circuit is so much lower than in a systemic circuit -a 4th factor that influences peripheral resistance is the presence of obstructions within the blood vessels, tumors, fatty plaques, blood clots, etc. -LAMINAR: blood flow within a vessel should be this or layered: the layer of blood nearest the vessel wall adheres to the wall due to friction (resistance) but blood in the center of the vessel flows more freely

Chapter 19, LO #12, PART 2

-3. COAGULATION: process that forms molecular glue; binds platelets, endothelial cells, and other formed elements together, cascade of events proceeds down 2 pathways: intrinsic: involving components within the blood itself, extrinsic: involving components from damaged cells and surrounding tissues, both converge at a common pathway; leads to activation of fibrin- threadlike protein that converts a soft, liquid platelet plug into a more substantial solid mass -FIBRIN: is found circulating in plasma and in platelets in an inactive form called fibrinogen: is converted into fibrin by a series of reactions that occur at surface of platelets and/or damaged endothelial cells; called coagulation cascade, thrombin: is produced by the platelets which convert soluble fibrinogen into insoluble fibrin- making a clot or scab, cascade depends on clotting factors; mostly enzymes synthesized in liver; circulate in blood in an inactive form

Chapter 19, LO #12, PART 3

-4. CLOT RETRATION: occurs as coagulation cascade nears its completion, actin and myosin fibers in involved platelets contract; brings edges of wounded vessel closer together, serum-fluid consisting of plasma without clotting proteins; forced out of clot during clot retraction -5. THROMBOLYSIS: process that begins after injury has healed and blood clotting is no longer necessary, FIBRINOLYSIS: process that breaks down fibrin glue; tPA activates plasminogen: tPA converts bound inactive plasminogen to active enzyme plasmin, plasmin degrade fibrin and clots dissolves; remaining components of clot dissociate from endothelium and process is complete

Chapter 17, LO #4, PART 3

-ANASTOMOSES: coronary arterial supply is complicated by formation of these which are system of channels formed between blood vessels, coronary arteries may form these with one another with branches from pericardium or even with arteries outside coronary circulation -COLLATERAL CIRCULATION: when blood flow to myocardium is insufficient, occasionally new anastomoses will form to provide alternate routes of blood flow or this to myocardium, collaterals formed in this manner help help to protect muscle cells from damage that could result from blocked vessels -CORONARY VEINS: generally, majority of heart's veins empty into a large venous structure on posterior of heart called CORONARY SINUS; drains into posterior right atrium... coronary sinus receives blood from 3 major veins: -GREAT CARDIAC VEIN: large, ascends along anterior interventricular sulcus and then travels to posterior side of heart along left atrioventricular sulcus; drains left atrium and much of both ventricles -SMALL CARDIAC VEIN: travels along right atrioventricular sulcus, drains right atrium and parts of right ventricle -MIDDLE CARDIAC VEIN: travels along posterior interventricular groove; drains mostly posterior left ventricle

Chapter 18, LO #2, Define and compare the basic functions of the 3 types of blood vessels: arteries, capillaries, and veins

-ARTERIES: distribution system of the vasculature; as they travel away from the heart, they branch into vessels of progressively smaller diameter that supply most tissues in the body with blood, big to small -CAPILLARIES: exchange system of vasculature; very small-diameter vessels that form branching networks called CAPILLARY BEDS; gas, nutrients, waste, and other molecules are quickly exchanged between tissue cells and blood through capillary walls, many of which are only a single cell thick- single layer -VEINS: collection system of vasculature; drain blood from capillary beds and return it to heart; follow opposite pattern of arteries- small veins merge with other veins to become progressively larger vessels as they progress toward the heart- small to big

Chapter 18, LO #18, Define autoregulation and discuss the myogenic mechanism and metabolic controls that regulate tissue perfusion

-AUTOREGUALTION: self-regulating, tissue perfusion is regulated by local factors within each individual tissue, ensures that correct amount of blood is delivered to match a tissue's level of activity, 2 types of local autoregulatory control- myogenic and metabolic -MYOGENIC MECHANISM: vascular smooth muscle in arterioles will respond to increases in arteriolar pressure, opens stretch-sensitive channels that allows contraction without NS stimulation, mechanism slows blood flow by increasing resistance when arteriolar pressure rises; mechanism speeds up blood flow by decreasing resistance when arteriolar pressure lowers, both changes maintain local tissue perfusion at a constant level; ensure that gases and other substances continue to be exchanged in adequate amounts even in face of fluctuating BP

Chapter 19, LO #7, PART 3

-BASOPHILS: least common leukocyte, have S-shaped nucleus and appear dark purple due to uptake of methylene blue dye, chemicals in granules mediate inflammation, not phagocytic- mobile hormone factory -AGRANULOCYTES: include lymphocytes and monocytes both of which lack visible cytoplasmic granules; do contain lysosomes -LYMPHOCYTES: second most common leukocyte in blood, large, spherical nuclei and a light blue rim of cytoplasm, 2 basic types: similar in appearance but different functions; both types are activated by cellular markers found on all cells called antigens -B LYMPHOCYTES (B CELLS): when activated, produce antibodies which bind to and remove antigens from tissues, each population of B lymphocytes secretes antibodies that bind only to a specific unique antigens -T LYMPHOCYTES: (T CELLS): also activated by specific antigens; do not produce antibodies; have membrane-bound receptors for individual antigens, T lymphocytes activate other immune system components and directly destroy abnormal body cells such as cancer cells or virally infected cells, antibodies and T cell receptor cells both bind to only 1 unique antigen based on structure- specific immunity

Chapter 18, LO #7, Define blood pressure, describe how blood pressure is expressed and list 3 main factors that determine BP

-BLOOD PRESSURE: outward force that blood exerts on walls of blood vessels, expressed in unite millimeters of mercury or mm Hg; force exerted by a column of mercury 1 millimeter in height, varied in different parts of vasculature; highest in large systemic arteries and lowest in large systemic veins -3 main factors that influence blood pressure: resistance, cardiac output, and blood volume

Chapter 19, LO #14, Explain the role of surface antigens (agglutinogens) on erythrocytes in determining blood types. List the type of antigen and the type of antibodies (agglutinins) present in each ABO and Rh blood type

-BLOOD TRANSFUSION: blood taken from a donor is given to the recipient; commonly used treatment modality in today's medicine, but mot always the case -ANTIGENS: discovery of these surface markers, found on most biological molecules and all cells, including erythrocytes; lead to development of safer transfusion practices, immune system recognizes foreign antigens; responds by trying to remove them, response was responsible for many fatalities in early transfusion patients -ANTIGENS OR AGGLITINOGEN: part of the plasma membrane of cells-what out immune system cells 'read' to identify 'self' from 'non-self' or foreign cells -ANTIBODY OR AGGLITNIN: chemicals (large proteins with specific shapes), produced y our liver or our B lymphocytes that are specific shapes that complement specific antigen- they circulate in our blood plasma

Chapter 18, LO #1, State the general functions of blood vessels

-BLOOD VESSELS: transport blood to tissues, where gases, nutrients, and wastes are exchanged, and then transport it back to heart, regulate blood flow to tissues, control blood pressure, secrete a variety of chemicals

Chapter 18, LO #16, Explain the 3 mechanisms of capillary exchange

-CAPILLARY EXCHANGE: nutrients, gases, ions, and wastes must be able to cross wall and travel between blood in capillary and tissue cells; movement of materials is known as this; materials are generally exchanged by 3 mechanisms, including 2 types of diffusion and transcytosis -DIFFUSION AND OSMOSIS THROUGH GAP PORES: some capillaries have small pores within their endothelial cells, called fenestrations, water, as well as small substances (such as monosaccharides and amino acids) that are dissolved in water, are able to move freely through these pores when a gradient exists

Chapter 18, LO #9, Explain how cardiac output and peripheral resistance determine the pressure gradient that drives circulation and the what blood volume is

-CARDIAC OUTPUT (CO): product of SV(amount of blood pumped with each beat) times heart rate(number of beats per/min), cardiac output, and peripheral resistance are 2 factors that determine pressure gradient that drives circulation; the relationship is expressed by a simple equation: deltaP=CO(PR)... pressure change is caused by altering cardiac output (CO) and/or peripheral resistance (PR), when cardiac output increases, BP increases, and vice versa -BLOOD VOLUME: a final factor that determines overall BP is this in the circulatory system, the total volume of blood is directly linked to the amount of water in the blood, when the blood contains more water, blood volume increases; as blood volume increases, BP increases

Chapter 17, LO #1, PART 2

-CHAMBERS: consists of right and left ATRIUM (upper) and VENTRICLES (lowers), both right and left receive blood from VEINS (blood vessels that bring blood to the heart). -blood drains from atria to ventricles; ventricles pump blood into blood vessels called ARTERIES (carry blood away from the heart)... many veins and arteries that bring blood to and from the heart known as GREAT VESSELS

Chapter 18, LO #10, Explain the relationship between blood volume and BP. Define compliance

-COMPLIANCE: small increases in blood volume are offset by ability of vessels to stretch, a property known as this -veins are most compliant vessels; stretch to accommodate added fluid when BP increases, with only a small rise in pressure, BP remain fairly low throughout pulmonary circuit; however, BP changes significantly as blood travels through systemic circuit, BP in the 2 circuits are dramatically different, averaging about 15mm Hg in pulmonary circuit and about 95 mm Hg in systemic circuit, pressure declines even further in venules and veins, dropping to only about 4 mm Hg in inferior vena cava ad as low as 0 in right atrium; low pressure is largely due to high compliance of veins and declining resistance as vessels merge and become larger: venous blood must be returned to the heart at same rate that it is pumped into arteries, venous circuit is under such low pressure that there is not much of a driving force to propel venous blood back to the heart

Chapter 17, LO #19, PART 2

-CONTRACTIBILITY: in heart's intrinsic pumping ability, or ability to generate tension; difficult to measure directly; however, it can be estimated clinically by examining velocity of blood being ejected from ventricles, increasing contractibility will increase SV and decrease ESV, decreasing contractibility will do opposite; decreasing SV and increasing ESV (assuming that preload and afterload remain constant) -AFTERLOAD: refers to force that right and left ventricles must overcome in order to eject blood into their respective arteries, largely determined by BP in arteries of both pulmonary and systemic circuits, as afterload increases, ventricular pressure must be greater to exceed pressure in arterial pulmonary and systemic vessels and open semilunar valves, an increase in afterload therefore generally causes a decrease in SV and so a rise in the ESV of ventricles; conversely, a decrease in afterload generally corresponds to a higher stroke volume and a lower ESV

Chapter 17, LO #4, Define coronary circulation, anastomoses, and collateral circulation

-CORONARY CIRCULATION: blood vessels that feeds the heart itself, has nothing to do with the big area that pumps to the body, the reason this is necessary is because the heart's chamber are filled with blood, but myocardium is too thick for oxygen and nutrients to diffuse from inside chambers to all of organ's cells -parts of this circulation: right after the ascending aorta emerges from the left ventricle two branches arise : RIGHT AND LEFT CORONARY ARTERIES, which travel in the right and left ATRIOVENTRICULR SULCI

Chapter 17, LO #17, Define diastole and systole. Describe the phases of the cardiac cycle. Define end-diastolic and end-systolic volumes and give their normal amounts

-DIASTOLE: each cardiac cycle consists of 1 period of relaxation called this -SYSTOLE: and a period of contraction called this for each chamber of the heart -atrial and ventricular diastoles and systoles occur at different times as a result of AV node delay; both sides of heart are working to pump blood into their respective circuits simultaneously -cycles are divided into 4 phases that are defined y their action of ventricles and position of valves: FILLING, CONTRACTION, EJECTION, RELAXATION

Chapter 18, LO #16, PART 2

-DIFFUSION THROUGH MEMBRANES OF ENDOTHELIAL CELLS: lipid-soluble substances such as oxygen, carbon-dioxide, and certain lipids can generally enter and exit capillary by diffusing across membrane of 1 side of endothelial cell and out membrane on other side, substances then enter interstitial fluid or blood -TRANSCYTOSIS: larger molecules must cross the endothelial cells by this, molecules are taken into cell by endocytosis and then are moved out other side of cell by exocytosis, both diffusion and transcytosis involve a substance crossing entire width of endothelial cells

Chapter 17, LO #19, Define ejection fraction. Describe the factors that influence stroke volume, and explain how they affect cardiac output. Explain the significance of the Frank- Starling Law of the heart

-EJECTION FRACTION: although stroke volume averages about 70 mL per beat, it may range from 50-120 mL; exact SV may be difficult to measure directly, and often a measurement called this is used in it place, percentage of blood that is ejected with each ventricular systole and is divided by EDV, normal ejection fraction is about 50-65%, and this value should be equal for each ventricle, three factors that influence SV: preload, heart contractibility, and afterload -PRELOAD: refers to length or degree of stretch of sarcomeres in ventricular cells before they contract; degree of preload is largely determined by EDV (amount of blood that has drained into ventricle by end of filling phase) -FRANK-STARLING LAW: relationship between preload and stroke volume is explained by a mechanism known as this, according to this, increased ventricular muscle cells stretch, leads to more forceful contraction, stretching causes a more optimal overlap of actin and myosin filaments in muscle cells; enables a stronger contraction and a higher stroke volume, ensures that volume of blood discharged from heart is equal to volume that enters it; particularly important during exercise, when cardiac output must increase to meet the body's needs

Chapter 17, LO #3, PART 3

-ENDOCARDIUM: this is the lumen of the heart, third and deepest layer of heart wall, contains special simple squamous epithelium called ENDOTHELIUM and layers of CT with elastic and collagen fibers, the endothelial cells of the endocardium are continuous with endothelial cell that line blood vessels and so share many functions

Chapter 18, LO #15, PART 2

-FENESTRATED CAPILLARIES: much leakier than continuous capillaries because their endothelial cells contain fenestrations (pores), pores allow diffusion to take place much more quickly than it does in continuous capillaries, fenestrated capillaries are therefore located in places that require substances to rapidly enter or exit blood -SINUSOIDAL CAPILLARIES: leakiest capillaries; name often simply shortened to sinusoids; have a discontinuous sheet of endothelium, an irregular basal lamina, and very large pores in their endothelial cells, typically 3-4 times larger in diameter to the other capillaries; often have an irregular shape because their boundaries are determined by organ in which they reside, located in organs and tissues like the liver, facilitate transfer of large substances such as blood cells and large proteins between interstitial fluid and blood

Chapter 17, LO #17, PART 2

-FILLING: ventricles fill with blood and are in diastole, AV valves are open, atrial systole occurs, semilunar valves are closed -CONTRACTION: ventricle systole begins, AV and semilunar (aortic and pulmonary) valves close when enough pressure builds in the ventricles, atrial diastole begins... END DIASTOLIC VOLUME occurs during this step, which is is the volume of blood in the right and/or left ventricle at end load or filling in, 120mL -EJECTION: ventricular systole continues, AV valves are still closed, atrial diastole continues, pressure open SL valves, and blood is ejected into the pulmonary artery and aorta, STROKE VOLUME occurs during this step which is, is the volume of blood pumped from the left ventricle per beat, 70 mL -RELAXATION: ventricular diastole begins, AV valves are still closed, atrial diastole continues, SL valves close, END-SYSTOLIC VOLUME occurs in this which is, is the volume of blood in a ventricle at the end of the contraction, 50 mL

Chapter 17, LO #5, Describe the structure and function of the great vessels that enter and leave the chambers of the heart

-GREAT VESSELS: bring blood to and away from heart; largest in body -SUPERIOR AND INFERIOR VENAE CAVAE: 2 veins that drain majority of systemic circuit, both vessels have large openings into posterior aspect of right atrium -PULMONARY TRUNK: largest vessel in pulmonary circuit; receives deoxygenated blood pumped from right ventricle, located on anterior aspect of heart, nearly along midline, where trunk originates from right ventricle, trunk splits into right and left PULMONARY ARTERIES: bring deoxygenated blood to right and left lungs, respectively; pulmonary arteries branch extensively inside lungs to become tiny PULMONARY CAPILLARIES where gases are exchanged

Chapter 17, LO #18, Define cardiac output and stroke volume. Describe how stroke volume and cardiac output is calculated

-HEART RATE (HR): heart undergoes an average of 60-80 cardiac cycles or beats per minute, a value known as this, it is one determinant of CARDAIC OUTPUT (CO): amount of blood pumped into pulmonary and systemic circuits in 1 minute, also determined by STROKE VOLUME: amount of blood pumped in 1 heartbeat, SV can be calculated by subtracting amount of blood in ventricle at end of a contraction (ESV) from amount of blood in ventricle after it has filled during diastole (EDV), usually about 70 mL, CO: heart rate by stroke volume usually about 5040 mL/min or 5 liters/minute -resting cardiac output averages about 5 liter/minute; right ventricle pumps about 5 liters into pulmonary circuit and left ventricle pumps same amount into systemic circuit in 1 minute, normal adult blood volume is about 5 liters, so entire supply of blood pressure passes through heart every minute

Chapter 19, LO #6, Define hematopoiesis. Explain the basic process of erythropoiesis and its regulation through erythropoietin. Briefly outline what happens to erythrocytes as they age and wear out.

-HEMATOPOIESIS: the process that takes place in the red bone marrow where formed elements in blood are produced by HEMATOPOIETIC STEM CELLS (HSCs) -ERYTHROPOIESIS: is a specific hematopoietic process that produces erythrocytes from HSCs, takes about 5-7 days, begins when HSCs differentiate into progenitor cells called erythrocyte colony-forming units (CFUs); committed to forming only 1 cell type, erythrocyte CFUs differentiate into proerythroblasts when hormone ERYTHROPOIETIN (EPO) (secreted by kidneys) is present, proerythroblasts develop into erythroblasts; rapidly synthesize Hb and other proteins, the nucleus in erythroblast shrinks as it matures; eventually ejected resulting in a reticulocyte, reticulocytes enter the bloodstream (after ejecting remaining organelles) by exiting through pores in sinusoidal capillaries of bone marrow

Chapter 18, LO #6, Define hemodynamics and blood flow. List 2 factors that determine blood flow

-HEMODYNAMICS: physiology of blood flow in cardiovascular system; basic concepts, gradients drive most processes in body whether concentration gradients, pressure gradients, or electrical gradient, heart provides force that drives blood through blood vessels by creating a pressure gradient, pressure is highest near heart and decreases as blood moves further away, blood flow down this pressure gradient from area of higher pressure near heart to area of lower pressure in peripheral vasculature -BLOOD FLOW: volume of blood that flows per minute, generally, blood flow matches cardiac output; averages about 5-6 liters/minute and has 2 factors: 1. flow in directly proportional to pressure gradient, meaning that blood flow increases when pressure gradient increases and vice versa 2. flow is inversely proportional to resistance; that is, as resistance increases, blood flow decreases

Chapter 19, LO #5, Discuss the structure and function of hemoglobin

-HEMOGLOBIN: large protein that consists of 4 polypeptide subunits: 2 alpha chain, 2 beta chains, each polypeptide is bound to an iron- containing compound called a HEME GROUP, an iron ion in each heme group is oxidized when it binds to oxygen in regions of high oxygen concentration (such as lungs); forms a red molecule called OXYHEMOGLOBIN HbO2, releases oxygen into regions (tissues surrounding systemic capillary beds) where oxygen concentration is low, also binds to CARBON DIOXIDE (CO2) forming CARBAMINOHEMOGLOBIN where oxygen levels are low; accounts for about 23% of CO2 transported in blood

Chapter 19, LO #11, Distinguish between the terms hemostasis and coagulation

-HEMOSTASIS: "blood stoppage", refers to the maintenance of healthy blood volume, prevents significant blood loss -COAGULATION: "bring together", formation of a blood clot- solid mass to prevent further blood loss, series of reactions that occur at the surface of the platelets and/or damaged endothelial cells

Chapter 19, LO #12, List and describe the 5 stages involved in hemostasis

-HEMOSTASIS: involves a series of 5 distinct events; form a gelatinous blood clot that plugs broken vessel; primary function is to limit significant blood loss -1. VASCULAR SPASM: begins immediately when a blood vessel is injured and blood leaks into ECF with 2 responses, vasoconstriction and increased tissue pressure both act to decrease blood vessel diameter, blood loss is minimized as both BP and blood flow are educed locally by these responses -2. PLATELET PLUG FORMATION: a patch, consisting mostly of platelets, adheres only to injury site, further reducing blood loss, following factors are involved in plug formation when collagen fibers are exposed and chemicals are released from damaged cells, injured endothelial cells release VON WILLEBRAND FACTOR (vWF) glycoprotein that binds to receptors on surface of platelets plasma membranes

Chapter 18, LO #19, Describe hydrostatic pressure and define filtration

-HYDROSTATIC PRESSURE: force that a fluid exerts on wall of its container -movement of water across a capillary is driven by a process called filtration; movement of a fluid by a force such as pressure or gravity -PRESSURE AT WORK IN A CAPILLARY: 2 basic pressures that drive water movement work within a capillary: hydrostatic and osmotic pressure: promote movement in opposite directions- hydrostatic pressure drives water out of the capillaries and osmotic pressure generally draws fluid into capillary -blood is fluid in a vessel that is creating hydrostatic pressure; therefore BP is equal to hydrostatic pressure, hydrostatic pressure in a capillary changes from its arteriolar end, where it measures about 35 mm Hg, to its venular end, where it measures about 15 mm Hg; hydrostatic pressure of interstitial fluid is so low that it is functionally 0 mm Hg... thus there are steep hydrostatic pressure gradients on both ends of capillary that drive water out of capillary and into interstitial fluid

Chapter 17, LO #9, Define autorhythmicity. Differentiate between a cardiac pacemaker and contractile cells

-Heart does not require conscious intervention to elicit cardiac muscle to contract -AUTORHYTHMICITY: cardiac muscle exhibits this meaning it sets its own rhythm without aide from NS -cardiac muscle cells contract in response to electrical excitation in form of action potential -PACEMAKER CELLS: cardiac electrical activity is coordinated by a very small, unique population of cardiac muscle cells called this -CONTRACTILE CELLS: these cells rhythmically and spontaneously generate action potentials that spread to other type of cardiac muscle cells called this

Chapter 19, LO #7, Compare and contrast the relative prevalence and morphological features of the 5 types of leukocytes; as well as the function of each

-LEUKOCYTES: WBC's- larger than erythrocytes with a prominent nucleus; use blood-stream as transportation; generally do not perform their function within blood, adhere to walls of blood vessels then squeeze between endothelial cells to enter surrounding tissue... 2 basic categories: GRANULOCYTES: contain cytoplasmic granules that are released when activated and AGRANULOCYTES: lack visible granules -1. GRANULOCYTES: readily distinguished by their unusual nuclei: single nucleus composed of multiple connective lobes, all cells in this group contain general LYSOSOMAL GRANULES as well as granules unique to each granulocyte, divided into 3 categories based on color that granules appear, either light lilac, dark purples, or red, when stained with methylene blue or acidic (cosin) dye

Chapter 18, LO #13, Briefly describe the endocrine and renal long-term control of BP

-LONG TERM CONTROL: is mediated by urinary system and certain hormones of endocrine system, long-term effects achieved by increasing or decreasing water lost as urine which affects blood volume, certain hormones increase and decrease blood volume

Chapter 18, LO #3, Define lumen and tunics. Describe the 3 tunic layers

-LUMEN: all blood vessels are tubular organs that contain a central space (hole) -TUNICS: the layers that surround the lumen and there are 3 -TUNICA INTIMA: innermost layer, composed of ENDOTHELIUM: continuous with inner lining of the heart (ENDOCARDIUM); endothelial cells provide a smooth surface over which blood can flow with a minimum of friction and turbulence... internal elastic lamina fibers give vessel properties of distensibility (ability to stretch) when subjected to increased pressure, and elasticity (ability to recoil back to original size) when stretching force is removed

Chapter 18, LO #18, PART 2

-METABOLIC CONTROLS: mediated by chemicals present in interstitial fluid surrounding capillaries; chemicals are result of cellular metabolic (ATP-generating) activities, in cells that are producing ATP rapidly, low concentrations of oxygen and high concentrations of carbon-dioxide and hydrogen ions cause smooth muscle cells of local arterioles to relax; increases prefusion and ensures adequate oxygen and nutrients, in cells that are producing ATP slowly, high concentrations of oxygen and low concentration of carbon dioxide cause constriction of local arterioles and a decrease in perfusion

Chapter 18, LO #17, Define microcirculation and identify the 2 types of vessels in which it occurs. Describe the use of the thoroughfare channel.

-MICROCIRCULATION: flow of blood that takes place within body's capillary beds is called this involves true capillaries: where materials are exchanged, and a small central vessel, true capillaries from interweaving networks with multiple anastomoses; fed by proximal end of central vessel, which is formed by either a small terminal arteriole or a metarteriole, each capillary- metarteriole contains a precapillary sphincter, controls amount of blood flowing into capillaries, at rest, only about 25% of body's capillary beds are fully open -THOROUGHFARE CHANNEL: true capillaries are drained at distal end of capillary bed by a portion of central canal called this, they lack precapillary sphincters, which reflects fact that this is drainage end of capillary bed, when precapillary sphincter close, blood flows straight from metarteriole to thoroughfare channal and into a venule without passing through capillaries, blood does not flow backward into true capillaries from thoroughfare channels because pressure gradient favors movement of blood in 1 direction only

Chapter 19, LO #7, PART 4

-MONOCYTES: largest leukocytes; have large U-shaped nuclei surrounded by light blue or purple cytoplasm, only circulate in blood briefly before exiting capillaries to enter tissues where some mature into macrophages, -MARCOPHAGES: phagocytic cells that ingest dead and dying cells, bacteria, antigens, and other cellular debris, activate other components of immune system by displaying phagocytosed antigens to other leukocytes

Chapter 19, LO #7, PART 2

-NEUTROPHILS: most common leukocyte; have cytoplasmic granules that absorb both dyes; stains a light lilac color, active phagocytes that ingest and destroy bacterial cells, also called POLYMORPHONUCLEOCYTES (poly or PMNs); uniquely shaped nucleus composed of 3-5 lobes, injured cells release chemicals that attract neutrophils; process called CHEMOTAXIS, in which neutrophils exit blood stream and releases granules in damaged tissue, granule contents directly kill bacterial cells, attract more neutrophils and leukocytes to region, and enhance inflammation -EOSINOPHILS: have bilobed nucleus and appear red due to the uptake of eosin dye, phagocytes that ingest foreign molecules, respond to infections with parasitic worms and allergic reactions, granules contain enzymes and toxins specific to PARASITES; also chemicals that mediate inflammation

Chapter 17, LO #14, PART 2

-P WAVE: small, initial of these represents depolarization of all cells within atria except SA node; P wave nearly always registers as an upward deflection on ECG -QRS COMPEX: large these, represents ventricular depolarization; actually 3 separate waves; Q wave is first downward deflection, R is large upward deflection, S is following downward deflection -T WAVE: small these, occurs after S wave of QRS complex; represents ventricular repolarization; T wave is an upward deflection under normal conditions

Chapter 17, LO #12, Outline the 4 phases of a pacemaker cell action potential

-PACEMAKER CELLS: make up about 1% of cardiac muscle cells, CARDIAC CONDUCTION SYSTEM: there 3 populations of these cells called this, in the heart that are capable of spontaneously generating action potentials, thereby setting the pace of the heart, depolarization in a pacemaker cell occurs much more slowly; due in part to lack of voltage-gated sodium ion channels in pacemaker sarcolemma... pacemaker cell action potentials lack plateau phase and membrane potential oscillates-that is, it never remains at a resting level and instead occurs in a cycle, with last event triggering first, occurs because of nonspecific cation channels that are unique to pacemaker cells 1. SLOW INITIAL DEPOLARIZATION PHASE: pacemaker potential starts with the plasma membrane in a hyperpolarized state-at its minimum membrane potential; opens nonspecific cation channels in the membrane; allow sodium ions to leak into the cell and potassium ions to leak out; results in an overall slow depolarization to threshold

Chapter 19, LO #3, Describe the overall composition of plasma, including the major types of plasma proteins, their functions, and where in the body they are produced

-PLASMA: pale yellow liquid whose volume is 90% water; factor is determining viscosity, or thickness, of blood... less water=greater viscosity and sluggish blood flow -PLASMA PROTEINS form a COLLOID; makes up about 9% of plasma volume -ALBUMIN: large protein synthesized in liver; responsible for blood's colloid osmotic pressure; draws water into blood by osmosis -IMMUNE PROTEINS: or gammaglobbulins; also known as ANTIBODIES; made by leukocytes, components of immune system

Chapter 19, LO #9, Explain how platelets differ structurally from the other formed elements of the blood

-PLATELETS (aka thrombocyte): are small cell fragments surrounded by a plasma membrane with the following characteristics, smallest formed elements; involved in hemostasis, s process that stops blood loss from an injured blood vessels, platelets do not have nuclei or organelles found in most whole cells, platelets contain several types of granules; contain clotting factors, enzymes, some mitochondria, and glycogen deposits; enable them to carry out oxidative catabolism, also contain cytoskeletal elements; include microtubules associated with actin and myosin filaments

Chapter 17, LO #5, PART 2

-PULMONARY VIENS: once blood is oxygenated in pulmonary capillaries, it returns to heart by a set of PULMONARY VEINS; most people have 4 pulmonary veins that drain oxygenated blood into posterior part of left atrium -AORTA: supplies entire systemic circuit with oxygenated blood, largest and thickest artery in systemic circuit and in entire body, stems from left ventricle as ascending aorta, after which it curves to left and makes U-turn as aortic arch

Chapter 18, LO #8, Define resistance. Discuss the 3 variables that affect peripheral resistance. State which variable has the most immediate and dramatic effect. Define laminar flow.

-RESISTANCE: any impendence to blood flow, vessels near the heart contribute little to overall resistance while resistance is greatest further away from heart, in body's periphery, as peripheral resistance increases, blood pressure also increases... resistance is mainly determined by the following 3 variables: -1.BLOOD VESSEL RADIUS: resistance varies inversely with the vessel's radius; as a radius increases (dilates) resistance to blood flow decreases and vice versa; the quickest variable to change -2. BLOOD VISCOSITY: viscosity is defined as inherent resistance that all liquids have to flow; the more viscous a liquid the more is molecules resist being put into motion and staying in motion; blood has a relatively high viscosity due to number of proteins and cells it contains

Chapter 17, LO #4, PART 2

-RIGHT CORONARY ARTERY: travels inferiorly and laterally along the right atrioventricular sulcus, where it gives off several branches that supply right atrium and -MARGINAL ARTERY: largest branch and is names because it typically arises near inferior margin or border of the heart -POSTERIOR INTERVENTRICULAR ARTERY: after marginal artery branches off, right coronary artery curls around to posterior heart and travels in posterior interventricular sulcus as appropriately named POSTERIOR INTERVENTRICULAR ARTERY -LEFT CORONARY ARTERY: shortly after the rt. coronary artery, ascending from ascending aorta, it generally branches into 2 parts -ANTERIOR INTERVENTRICULAR ARTERY: left anterior descending artery, LAD, travels along anterior interventricular sulcus; at apex of heart, it generally curls around and travels a short distance along posterior interventricular sulcus -CIRCUMFLEX ARTERY: curves along left atrioventricular sulcus and flexes around heart; supplies left atrium and parts of left ventricle; in some people, replaces right coronary artery in supplying branch that becomes posterior interventricular artery

Chapter 18, LO #12, Briefly describe the endocrine and neural short-term control of BP. Include descriptions of the baroreceptor and chemoreceptor reflex mechanisms

-SHORT-TERM CONTROL: is primarily accomplished by NS and certain hormones of the endocrine system, such short-term effects are generally achieved by adjustment of resistance and cardiac output -BARORECEPTORS: a negative feedback loop that responds to an increase in blood pressure received by specialized mechanoreceptors called baroreceptors -CHEMORECEPTORS: a feedback loop that results in vasoconstriction and a rise in BP due to signals received by chemoreceptors, PERIPHERAL CHEMORECEPTORS: primarily play a role in the regulation of breathing, but they also affect BP; receptors respond mostly to the level of oxygen in the blood, CENTRAL CHEMORECEPTORS: respond to decreases in pH of interstitial fluid in the brain; triggers another feedback loop that indirectly increases the activity of sympathetic neurons; results in vasoconstriction and a rise in BP

Chapter 17, LO #13, List and describe the parts of the cardiac conduction system

-SINOATRIAL NODE (SA NODE): under normal conditions, SA node has fastest intrinsic rate of depolarization- about 60 or more times per minute, a rate that is subject to influence from sympathetic and parasympathetic nervous system (ANS) -ATRIOVENTRICULAR NODE (AV NODE): slower than SA node, with an intrinsic rate of only about 40 action potentials per minute -PURKINJE FIBER SYSTEM: cells depolarize only about 20 times per minute; sometimes called atypical pacemakers because their action potentials rely on different ion channels and they function in a slightly different way -ATRIOVENTRICULAR BUNDLE (AV BUNDLE): penetrates heart's fibrous skeleton in inferior interatrial septum and superior interventricular septum -RIGHT AND LEFT BUNDLE BRANCHES: course along right and left sides of interventricular septum, respectively -TERMINAL BRANCHES: penetrate ventricles and finally come into contact with contractile cardiac muscle cells

Chapter 17, LO #13, PART 2

-SINUS RHYTHMS: SA node is normal pacemaker of entire heart; electrical rhythms generated and maintained by SA node are known as this, under normal conditions SA node generates an action potential; spreads rapidly by gap junctions to surrounding atrial cells, AV node and Purkinje fiber system normally only conduct action potentials generated by SA node; if SA node ceases to function, AV node can successfully pace heart, albeit somewhat slow

Chapter 17, LO #2, PART 2

-SYSTEMIC PUMP: left side of the heart, receive oxygen-rich blood from pulmonary veins, gas exchange occurs between tissues and blood in SYSTEMIC CAPILLARIES and picks up waste and distributes hormones, and oxygen-poor blood is returned to right side of heart to become oxygen-rich again (SYSTEMIC CIRCUIT) -SECONDARY FUNCTIONS: helps maintain homeostasis of pressure that exerts on blood vessels-rate and force play a big role in this (blood pressure) Acts as an endocrine organ (produces ATRIAL NATRIURETIC PEPTIDE ANP: which lowers BP by decreasing sodium ion retention in kidneys, reducing osmic water reabsorption and volume and pressure of blood in blood vessels

Chapter 19, LO #10, Define thrombopoiesis. Discuss the roll of the megakaryocyte in the formation of platelets

-THROMBOPOIESIS: platelet formation, begins at HSCs differentiate into committed precursor cells called megakaryoblasts from myeloid cell line -MEGAKARYOCYTE: megakaryoblasts develop into this; go through repeated cycles of mitosis without cytokinesis; cell itself never divides; results in a massive cell with multiple copies of DNA within a single nucleus, mature of these when stimulated by hormones (thrombopoietin), send cytoplasmic extensions through cleft in bone marrow sinusoids into bloodstream; break off into thousands of platelets, platelets have a limited lifespan of about 7-10 days after which they are removed from circulation by liver and spleen

Chapter 19, LO #3, PART 2

-TRANSPORT PROTEINS: bind to lipid-based molecules that otherwise are incompatible with mostly water-based plasma; allows transportation of these molecules in blood CLOTTING PROTEINS: stop bleeding from injured blood vessels by forming a blood close with assistance from platelets -last 1% of plasma volume consists of several small molecules mostly dissolved in water portion of plasma, forming a solution. These molecules can be readily exchanged between blood and interstitial fluid in most capillary beds

Chapter 18, LO #3, PART 2

-TUNICA MEDIA: middle layer of blood vessel wall is this, composed of 2 layers with the following features, a layer of smooth muscle cells arranged in a circular manner around lumen, and another layer of elastic fibers called external elastic lamina, smooth muscle cells of tunica media control diameter of blood vessel and therefore amount of blood that flows to organs, sympathetic nerves stimulate smooth muscle cells of tunica media to contract (vasoconstriction); narrows diameter of vessels, when sympathetic stimulation of smooth muscle cells decreases, these cells relax and vessel's diameter increases (vasodilation)/ thickest layer of arteries -TUNICA EXTERNA: outermost layer, aka tunica adventitia, is composed of dense irregular collagenous CT; supports blood vessel and prevents it from overstretching, VASO VASORA: tiny vessels supplying tunica media and tunica externa, supply oxygen and nutrients to outer layers of larger blood vessels, whose cells are too far away from lumen to receive oxygen and nutrients by diffusion along

Chapter 19, LO #16, Explain why blood type O- is the universal donor and type AB+ is the universal recipient

-UNIVERSAL DONOR: type-O-, erythrocytes do not have A, B, or Rh surface antigens, can be given to any other blood type in an emergency when blood matching is not an option -UNIVERSAL RECIPIENT: type AB+, these individuals do not make antibodies for any antigens, individuals with AB+ blood type can generally receive blood from any blood type, matching is still the safest

Chapter 18, LO #11, Explain why pressure is so low in veins and describe the 4 mechanisms that assist in the return of venous blood to the heart.

-VALVES: venous of these prevent the backflow in some veins, smooth muscle in vein walls can contract under sympathetic NS stimulation to increase rate of venous return -SKELETAL MUSCLE PUMPS: skeletal muscles surrounding deeper veins of upper and lower limbs squeeze blood in veins and propel it upward (toward heart) as they contract and relax -RESPIRATORY PUMP: helps propel blood through thoracic and abdominal cavity veins, driven by rhythmic changes in pressure in thoracic and abdominopelvic cavities that occur with ventilation, during inspiration, high pressure in abdominopelvic cavity creates a pressure gradient that pushes blood in abdominal veins upward, and low pressure in thoracic cavity allows thoracic veins to expand, during expiration- abdominal veins expand and fill with blood while thoracic veins are squeezed

Chapter 18, LO #5, Define vascular anastomoses and describe the types of anastomoses

-VASCULAR ANATOMOSES: locations where vessels connect by pathways called collateral vessels -ARTERIAL ANATOMOSES: exist in many organs such as heart and brain, as well as around joints; new arterial anastomoses can be formed when blood flow through an artery is insufficient to meet tissue's metabolic needs -VENOUS ANASTOMOSIS: most common type of anastomosis; neighboring veins are connected by small collaterals; smaller veins are often so interconnected that they form complex, web-like patterns -ARTEROVENOUS ANASTOMOSIS: artery empties directly into a vein without passing through a capillary bed

Chapter 18, LO #4, PART 3

-VEINS: typically outnumber arteries and their lumens have a larger average diameter; veins have the following characteristics, 70% of total blood in body is located in the veins; allows them to function as blood reservoirs because blood can be diverted from veins to other parts of system, typically have thinner walls, fewer elastic fibers, less smooth muscle, and larger lumens than arteries -VENULE: smallest veins; drain blood from capillary beds, tiny postcapillary venules consist of little more than endothelium and some surrounding CT; structure enables them to exchange material with surrounding interstitial fluid, 3 tunics become more distinct a venules merge to become larger venules and then veins -most veins have a thin tunica media with few smooth muscle cells, and their diameter changes only slightly with vasodilation and vasoconstriction, many veins continue VENOUS VALVES; extensions of tunica intima that overlap and prevent blood from flowing backward in venous circuit; especially numerous in veins of legs, where blood flow toward heart is strongly opposed by gravity

Chapter 17, LO #3, PART 2

-VISCERAL PERICARDIUM: innermost layer of the pericardium, also known as the EPICARDIUM of the heart wall, the most superficial layer of the heart wall, rests on top of a thin layer of areolar CT that contains large fat deposits -MYOCARDIUM: deep to CT of the epicardium, the second and thickest layer of the heart wall, contains cardiac muscle tissue and fibrous skeleton -CARDIAC MUSCLE CELLS: cardiac muscle tissue consists of this aka MYOCYTES and the ECM, this is attached to and woven through FIBROUS SKELETON; composed of dense irregular collagenous CT, gives cardiac cells something to pull against, provides support and acts as an insulator for electrical activity

Chapter 19, LO #1, Describe the major components of blood. Define buffy coat and hematocrit

-about 5 liters of BLOOD: a fluid CT that makes up about 8% of total body weight, circulates through blood vessels at all times.. 2 major components of blood: PLASMA: liquid ECM of blood, FORMED ELEMENTS: include cells and cell fragments found suspended in plasma... 3 types of formed elements: ERYTHROCYTES (RED BLOOD CELLS), LEUKOCYTES (WHITE BLOOD CELLS), AND PLATELETS (SMALL CELLULAR FRAGMENTS) -three distinct layers are formed when blood sample is centrifuged: -PLASMA: top layer, about 55% of total volume -BUFFY COAT: middle layer, leukocytes and platelets called this make up about 1% of total -ERYTHROCYTES: bottom layer, remaining 44%, percentage of blood (by volume) composed of erythrocytes called HEMATOCRIT

Chapter 19, LO #13, Briefly discuss the roles of prostacyclin, nitric oxide, and anticoagulant in the regulation of clotting

-blood clotting is produced y a positive feedback mechanism; must be tightly regulated to prevent mishaps, endothelial cells produce and secrete 2 chemicals that regulate 1st and second stages of clot formation -PROSTACYCLIN; prostaglandin; inhibits platelet aggregation -NIRTIC OXIDE: causes vasodilation -endothelial cells and hepatocytes produce ANTICOAGULANTS: inhibit coagulation; antithrombin III, heparin sulfate, Protein C

Chapter 19, LO #15, Explain the differences between the development of the anti-Rh antibodies and the development of anti-A AND ANTI-B antibodies. Define transfusion reaction

-blood sample is treated with 3 different antibodies; agglutination indicates that antigen is present on erythrocytes; no agglutination indicates that specific antigen is absent; antibodies used: ANTI-A ANTIBODIES: bind and agglutinate A antigens -ANTI-B ANTIBODIES: bind and agglutinate B antigens -ANTI-Rh ANTIBODIES: bind and agglutinate Rh antigens -your immune system recognizes antigens on your erythrocytes as "self" antigens; does not produce antibodies to self antigens, because if it did, your antibodies would bind your own antigens, immune system does produce antibodies to foreign antigens; means that antibodies are present in your plasma only if antigens are absent from your erythrocytes

Chapter 18, LO #14, Define tissue perfusion and state which tissues are not perfused by capillaries. Describe the basic structure of a capillary. Define pericyte.

-capillaries are the smallest blood vessels that wind through the cells of most tissues to supply metabolic needs, tissues without capillary beds include epithelial tissue, cartilage, the sclera and the cornea -TISSUE PERFUSION: blood flow in a tissue through a capillary bed is known as this -capillaries are extremely thin vessels, with walls that are only about 0.2 um thick, each capillary consists only of an endothelium rolled into a tube and a small amount of basal lamina secreted by endothelial cells -PERICYTES: cells found around some capillaries; have contractile filaments and appear to control blood flow through capillary, walls of most capillaries consist of 1-3 endothelial cells joined by tight junctions; curl around capillary's entire circumference

Chapter 17, LO #15, Define cardiac cycle. Relate the opening and closing of specific heart valves to pressure changes in the heart chambers

-cardiac muscle cells contract as a unit to produce one coordinated contraction, called a heartbeat; muscle cells are arranged in a spiral pattern, producing a "wringing" action in heart when it contracts -CARDIAC CYCLE: pressure changes caused by contractions drive blood flow through the heart, with valves preventing backflow; sequence of events that take place within heart from 1 heartbeat to the next is known as this -blood flow in response to pressure gradients; as ventricles contract and relax, pressure in chambers changes, causing blood to push on valves and either open or close them: when ventricles contract their pressures rise above those in right and left atria and in pulmonary trunk and aorta; causes blood to flow from ventricles vessels and produces 2 changes in valves, both AV valves are forced shut by blood pushing against them, both are semilunar valves are forced open by outgoing blood

Chapter 19, LO #2, List the basic functions of the blood

-exchanging gases: both oxygen and carbon dioxide are transported by the blood -distributing solutes: plasma transports ions, nutrients, hormones, and water, and plays a role in regulating ion concentration in tissues -preforming immune functions: both leukocytes and immune system proteins are transported throughout the body in the blood -maintaining body temperature: blood carries away heat generated as a byproduct of many chemical reactions in the body -functioning in blood clotting: platelets and certain proteins form blood clot; seals damaged blood vessels to prevent blood loss -preserving acid-base homeostasis: pH of blood is maintained between 7.35-7.45; remains relatively constant as blood contains as blood contains several important buffering systems -stabilizing BP: blood volume is a major factor in determining BP

Chapter 19, LO #5, PART TWO

-hemoglobin also binds to carbon monoxide (CO) to form CARBOXYHEMOGLOBIN; binds more strongly to iron ion than oxygen, changes shape of Hb making it unable to unload oxygen into oxygen-deprived tissues; can lead to death -life span of erythrocyte is relatively short, ranging from 100-120 days, due to damage incurred by harsh environment in which they exist, lack means for repair; lost majority of organelles by replacing them with hemoglobin during maturation, body must continuously make new erythrocytes

Chapter 19, LO #15, PART 2

-note that anti-A and anti-B antibodies are pre-formed; they are present in plasma even if individual has never been exposed to those antigens, anti-Rh antibodies, however, are produced only if a person has been exposed to blood containing Rh antigens, therefore, an Rh- individual generally has no anti-Rh antibodies unless he or she has been exposed to Rh+ erythrocytes - antigens and antibodies are basis for blood matching; blood taken from a donor is screened for compatibility prior to its administration to a recipient, a match occurs if donor blood type if compatible with recipient blood type -TRANSFUSION REACTION: recipient antibodies bind to donor antigens; causes agglutination that destroys donor erythrocytes, possibly leading to kidney failure and death

Chapter 19, Lo #6, PART 2

-regulation of erythropoiesis: erythropoietin triggers negative feedback loop; maintains hematocrit within normal range -stimulus: blood levels of oxygen fall below normal -receptor: kidney cells detect falling oxygen levels -control center: kidneys produce more erythropoietin and release hormone into bloodstream -Effector/response: production of erythrocytes increases -homeostasis: blood levels of oxygen rise to normal

Chapter 19, LO #4, Describe the structure and function of erythrocytes

-shapes and components of erythrocytes facilitate their transport of oxygen and carbon dioxide through blood, typical erythrocyte is a biconcave disc: flattened, donut-shaped cell that is concave on both sides, RBC shape increases surface area of cell; vital role in gas exchange; mature RBC's are anucleate, having lost their nucleus during maturation; also lack most other cellular organelles, creates room in cytosol for enzymes and nearly 1 billion oxygen-binding hemoglobin proteins

Chapter 17, LO #2, Explain how the heart functions as a double dump and why this is significant. Also list the 2 secondary functions of the heart.

-the heart has two separate circuits and is divided into a right and left -PULMONARY PUMP: this is the right side of the heart, it leads into the lungs, collectively called the PULMONARY CIRCUIT -PULMONARY ARTERIES: these of the pulmonary circuit deliver oxygen-poor blood to the lungs, gas exchange happens between tiny air sacs in lungs (ALVEOLI) and the smallest vessels of pulmonary circuit (CAPILLARIES), veins of pulmonary circuit then deliver this oxygen-rich blood to the left side of the heart

Chapter 17, LO #6, Describe the structure and function of the chambers and internal anatomy of the heart

-the heart has: 2 of the following ATRIA: receives blood from veins and pumps blood into ventricles through structures called VALVES (these have flaps that close when the ventricles contract, keeping blood from going backward, are not symmetrical, rt atrium is larger, thinner-walled, and more anterior than left atrium: thicker-walled, smaller, posterior of heart, makes up most of the heart's base -AURICLE: externally, each atrium has a muscular pouch that is named because it resembles the ear, expands to give atria more space in which to hold blood, auricle of right is a lot larger than left PECTINATE MUSCLES: muscular ridges on the anterior side of the internal surface of the right atrium the left atrium is formed by pulmonary veins and internal walls are smooth -INTERATRIAL SEPTUM: a thin wall that separates 2 atria -FOSSA OVALIS: small indentation in septum; remnant of a hole known as foramen ovale present in interatrial septum of fetal heart

Chapter 17, LO #1, Describe the location and basic anatomy of the heart in the thoracic cavity

-the heart pumps blood into blood vessels: a system of tubules hat distribute through the cardiovascular system -HEARTS: cone-shaped, slightly to the left side in thoracic cavity, posterior to the sternum in mediastinum and rests on the diaphragm, about 1 pound and the size of a fist... APEX: point of cone and points toward the left hip... BASE: flattened and posterior side facing posterior rib cage...

Chapter 17, LO #16, Relate the heart sounds to events of the cardiac cycle

-under normal conditions, blood flow through open AV and semilunar valves is relatively quiet; sounds occur only when valves close, sounds are not due to actual valve "slamming shut" likely result from vibrations of ventricular and blood vessels walls -there are 2 heart sounds: S1 or lub is heard when AV valves close, typically longer and louder then S2 -S2: dub, heard when semilunar valves close

Chapter 17, LO #11, Describe the 4 phases of a cardiac muscle (contractile cell) action potential, including the ion movements that occur in each phase, and explain the importance of the plateau phase

1. RAPID DEPOLARIZATION PHASE: in response to pacemaker cell action potentials that cause voltage changes in adjacent cells, voltage-gated sodium ion channels in sarcolemma are activated; causes a rapid and massive influx of sodium ions; leads to rapid membrane depolarization 2. INITIAL REPOLARIZATION PHASE: there is a small, initial repolarization immediately after depolarization spike; due to abrupt inactivation of sodium ion channels and to a very small outflow of potassium ions through selected potassium ion channels that are open only briefly

Chapter 17, LO #8, Trace the pathway of blood flow through the heart, the pulmonary circuit, and the systemic circuit. Describe the lever of oxygenation at each location

1.start oxygen poor blood at earlobe, down jugular veins 2.superior vena cava 3. right atrium 4. AV valves 5. right ventricle 6. pulmonary trunk-through semilunar valves 7. pulmonary arteries- right and left 8. lungs 9. pulmonary capillary beds-oxygen-rich 10. pulmonary veins 11. left atrium 12. bicuspid or mitral valve 13. left ventricle 14. aorta- through aortic semilunar arc 15. arteries- carotid 16. systemic capillaries- gas exchange in tissue

Chapter 17, LO #12, PART 2

2. FULL DEPOLARIZATION PHASE: when membrane reaches threshold, voltage-gated calcium ion channels open, allowing calcium ions to enter cell and thereby causing membrane to fully depolarize 3. REPOLARIZATION PHASE: recall that calcium ion channels are time-gated for closing, so after a certain time (100-150msec), they close; at the same time, voltage-gated potassium ion channels begin to open; allows potassium ions to exit cell, and membrane begins to repolarize 4. MINIMUM POTENTIAL PHASE: potassium ion channels remain open until membrane reaches its minimum potential; when this happens, membrane is hyperpolarized, which opens nonspecific cation channels, and cycle begins again

Chapter 18, LO #15, Describe the different types of capillaries, and explain how their structure relates to their function

3 types of capillaries- capillaries in different parts of body have slightly different functions and, accordingly, slightly different structures; 3 types are continuous, fenestrated, and sinusoidal -CONTINUOUS CAPILLARIES: majority of the body's capillaries are these, located in muscles, skin, and most nervous and CT, are the least leaky- they permit fewest substances to enter or exit blood by paracellular route because their endothelial cells are joined together by tight junctions

Chapter 17, LO #11, PART 2

3. PLATEAU PHASE: depolarization is sustained at about 0 mV; known as this, it is critically important phase is mostly due to the slow opening of calcium ion channels and the resulting influx of calcium ions, if this step did not happen cardiac action potential would last for only 1-5msec, like skeletal muscles and resting heart is would be 15 times faster, this lengthens cardiac action potential to about 200-300 msec; slows heart rate, providing the time required for the heart to fill with blood, also increases the strength of heart's contractions and prevents TETANY (sustained contractions) in the heart by lengthening REFRACTORY PERIOD (time during which an excitable cell cannot be stimulated to contract again); allows the heart to relax and ventricles to refill with blood before cardiac muscle cells are stimulated to contract again 4. REPOLARIZATION PHASE: the final phase of action potential occurs when both sodium and calcium ions channels return to their resting states and most of the potassium ion channels open; allows positively charged potassium ions to exit cardiac muscle cell; membrane potential returns to its resting value of about -85mV

Chapter 18, LO #4, Compare and contrast arteries and veins. Describe the structure and function of the specific types of arteries and veins

ARTERIES: have thicker tunicae mediae, reflects arteries' role in controlling blood pressure and blood flow to organs, internal and external elastic laminae are much more extensive in arteries then in veins, arteries in higher pressure than veins... 3 different types of arteries: -1. ELASTIC ARTERIES (conducting arteries): largest in diameter; include aorta and its immediate branches; nearest heart and therefore under highest pressure of any vessels in cardiovascular system -2. MUSCULAR ARTERIES (distributing arteries): generally intermediate in diameter; contain a well-developed tunica media composed primarily of smooth muscle cells; most smaller branches off aorta are considered muscular arteries, including most that are supply arteries

Chapter 17, LO #10, Describe the histology of cardiac tissue

CARDIAC MUSCLE CELLS: have striations, typically branched with single nucleus; shorter and wider then skeletal muscle fibers, contains much MYOGLOBIN: protein that carries oxygen; nearly half of their cytoplasmic volume is composed of mitochondria; reflect their high energy demands; also abundant glycogen storage around each nuclei -INTERCLATED DISCS: join adjacent cardiac muscle cells; join pacemaker cells to contractile cells, and contractile cells to one another, contain desmosomes that hold cardiac muscle cells together and gap junctions that allow ions to rapidly pass from 1 cell to another, permitting communication among cardiac muscle cells

Chapter 17, LO #14, Identify the waveforms in a normal electrocardiogram (ECG) and relate the ECG waveforms to atrial and ventricular depolarization and repolarization and to the activity of the conduction system

ECG: important clinical tool for examining health of the heart; graphic depiction of electrical activity occurring in all cardiac muscle cells over a period of time, recorded by placing electrodes on surface of a patient's skin: six on chest and 2 on each extremity, electrical changes are shown on ECG as deflections or waves that show changes in electrical activity- if there is no net difference, there is no deflection shown, one of the most obvious changes in the heart revealed by an ECG is a disturbance in electrical rhythm known as dysrhythmia or arrhythmia, ECG recording generally consists of 5 waves, each of which represents active depolarization or repolarization of different parts of heart

Chapter 19, LO #8, Define leukopoiesis. Briefly describe the formation of the 5 leukocytes

LEUKOPOIESIS: process in bone marrow in which HEMATOPOIETIC STEM CELLS (HSCs) form new leukocytes; HSCs divide and produce 2 cell line -MYELOID CELL LINE: produces most formed elements, including erythrocytes and platelets -LYMPHOID CELL LINE: produces lymphoblasts, committed to becoming B and T lymphocytes, which then develop into prolymphocyte precursor cells -B and T LYMPHOCYTES mature in different locations: B: remain in bone marrow during maturation, T: migrate from bone marrow to thymus gland in mediastinum to complete maturation

Chapter 18, LO #20, Define osmotic pressure. Describe colloid osmotic pressure. Explain how hydrostatic pressure and colloid osmotic pressure drive the movement of water across the capillary wall. Define net filtration pressure.

OSMOTIC PRESSURE: osmosis involves movement of water from a solution with a lower solute concentration to one with a higher solute concentration; number of solute particles in a solution determines its osmolarity (osmotic concentration), solute particles in a solution exert a force, or "pull" on water molecules called osmotic pressure (OP), osmotic pressure is determined almost exclusively by number of particles not their size, osmotic pressure of capillary blood is about 25 mm Hg; created almost exclusively by large proteins in blood, especially protein albumin, proteins are too large to leave capillary, so osmotic pressure remains consistent throughout capillary's length and osmotic pressure is very low in interstitial fluid, this difference is osmotic pressure creates an osmotic pressure gradient known as COLLOID OSMOTIC PRESSURE(COP), or oncotic pressure -CAPILLARY NET FILTRATION PRESSURE: colloid osmotic pressure and hydrostatic pressure gradient drive water in opposite directions, hydrostatic pressure pushes water out of capillary and colloid osmotic pressure pulls water into capillary, difference between these gradients is NET FILTRATION PRESSURE (NFP)

Chapter 17, LO #3, Describe the layers of the pericardium and heart wall. Discuss the important function of the fibrous skeleton

PERICARDIUM: membranous structure surround the heart and composed of different layer -FIBROUS PERICARDIUM: thin inner serous membrane that produces serous fluid -PARIETAL PERICARDIUM: fused to inner surface of fibrous pericardium, encases the heart like a sac, but when it reaches great vessels, it folds under itself and forms another layer that adheres directly to the heart -PERICARDIAL CAVITY: between parietal and visceral layer, contains very thin layer of serous fluid (PERICARDIAL FLUID) acts as a lubricant, decreasing friction

Chapter 17, LO #7, PART 2

SEMILUNAR VALVES: blood is stopped from flowing back into ventricles by 2 valves, back flow can also be a problem in pulmonary artery and aorta, because blood begins to flow backward when ventricles relax as a result of higher pressure in arteries and gravity, refers to half-moon of their 3 cusps; also composed of endocardium and a central collagenous core -PULMONARY VALVE: names according to artery in which they reside, it is located between right ventricle and pulmonary trunk; AORTIC VALVE; is posterior to is between left ventricle and aorta

Chapter 17, LO #7, Describe the structure and function of the valves of the heart

VALVES: ensure backflow of blood, there are 2... not really a need for valves between atria and veins because of gravity and pressure -ATRIOVENTRICULAR VALVES (AV): backflow of blood from ventricles into atria is prevented by these valves between atria and ventricles, they consists of flaps called CUSPS; composed of endocardium overlying a core of collagenous CT...each valve is names for the number of cups it has: -TIRCUSPID VALVES: between the right atrium and ventricle contains 3 cusps -BICUSPID VALVES or MITRAL: between left atrium and ventricle has 2 cusps -CHORDAE TENDINEAE: fibrous, tendon-like structures attached to inferior end of each cusp; attach to papillary muscles that contract just before ventricles begin ejecting blood; creates tension on chordae tendineae keeping valves closed

Chapter 17, LO #6, PART 2

VENTRICLES: larger then atria and have thicker walls, much stronger pumps which is needed to get blood all the way through the body, contracting ventricles then eject blood into arteries; carrying to the systemic or pulmonary circuit, they are asymmetrical... right: wider and thinner walls because of pressure difference in pulmonary and systemic circuits, right has little resistance to pump left have much, left has to work harder and has a greater muscle mass; walls of the left ventricle are 3 times thicker than these of right ventricle -TRABECULAE CARNEAE: both ventricles have internal ridged surfaces created by irregular protrusions of cardiac muscle tissue called this -PAILLARY MUSCLES: each one contains finger-like projections of muscle called this, attach by tendon-like cords called CHORDAE TENINEAE to valves located between atria and ventricles -INTERVENTRIUCLAR SEPTUM: a thick, muscular wall, separates right and left ventricles; contracts with the rest of the ventricular muscle; helps to expel blood into pulmonary trunk and aorta

Chapter 19, LO #14, PART 2

antigens on erythrocytes (genetically determined carbohydrate chains) give rise to different blood groups, 2 groups of the 30 different antigens found on erythrocytes are particularly useful for clinical use ABO GROUPS AND Rh BLOOD GROUP, ABO group gives rise to A and B ANTIGENS so 4 types: -TYPE A- only A antigens is present on erythrocytes -TYPE B- only B antigen -TYPE AB-both A and B antigen -TYPE 0- neither A or B antigen are present on erythrocytes; there is no 0 antigen -Rh BLOOD GROUP: feature Rh antigen 1st discovered in rhesus monkeys; individuals with Rh antigen (D antigen), on their erythrocytes are Rh- positive and without Rh negative, so with these groups combined we can have 8 different groups.. O+ is most common in US and AB- is least common - blood typing in laboratory uses antibodies that bind to individual antigens on erythrocytes, antibodies (called agglutinins) bind to surface-bound antigens; cause them to clump together or agglutinate, ultimately agglutination promotes erythrocyte destruction; called HEMOLYSIS

Chapter 17, LO #10, PART 2

cardiac muscle cells contain selective gated ion channels in its sarcolemma, opening and closing of this action is responsible for both pacemaker and contractile cardiac potentials -CARDIAC CONDUCTION SYSTEM: pacemaker cells undergo rhythmic, spontaneous depolarization that lead to action potentials; spread quickly through heart by this group of interconnected pacemaker cells -action potential are transmitted from pacemaker cells to contractile cells through intercalated discs that unite them, GAP JUNCTIONS in these discs allow electrical activity generated by pacemaker cells to rapidly spread to all cardiac muscle cells by electrical synapse, permits heart to contract as a unit and produce a coordinated heartbeat

Chapter 19, LO #6, PART 3

destruction of erythrocytes: become trapped in the sinusoids of spleen, spleen macrophages digest erythrocyte, hemoglobin is broken down into amino acid, iron ions, and heme, HEME ia 1st converted to waste product BILLIVERDIN (greenish pigment); can then be converted further to a yellowish waste product called bilirubin; bilirubin is sent to liver for excretion, iron ions and amino acids are recycled; used to make new hemoglobin in red bone marrow; transported back to red bone marrow in bloodstream by a protein called TRANSFERRIN

Chapter 17, LO #15, PART 2

when ventricles relax, opposite occurs; pressures in ventricles fall below those in atria and in pulmonary trunk and aorta, higher pressure in atria forces AV valves open, allowing blood to drain from atria into relaxed ventricles, higher pressures in pulmonary trunk and aorta push cusps of semilunar valves closed