Lecture Exam 1- Blood and Respiratory System Flashcards
Three main functions of the circulatory system
transport
protection
regulation
Circulatory System Transport function
blood carries oxygen from lungs to body tissues picking up CO2 from tissues transporting to lungs, nutrients are picked up from digestive transporting to body tissues, metabolic wastes are taken from tissues to the kidney for removal, hormones are taken from endocrine cells to organs, and transports stem cells from bone marrow are moved to tissues where they lodge and mature.
Circulatory System Protection function
blood has roles in inflammation, limiting spread of infection (WBCs destroy microorganism and cancer cells removing tissue debris), and repair (platelets secrete factors to initiate clotting minimizing blood loss, contributing to tissue growth and blood vessel maintenance)
Circulatory System Regulation function
absorbing or giving off fluid under different conditions stabilizes fluid distribution, buffering acids and bases, stabilizing pH of extracellular fluid, cutaneous blood flow is also important in dissipating metabolic heat from body w/ shifts in flow helping to regulate body temperature by routing blood to skin for heat loss or retaining it deeper to conserve heat
Blood plasma and what it consists of
liquid matrix portion of blood (same as serum except serum doesn’t have fibrinogen), yellow fluid making up ½ of blood volume. Suspended in plasma are formed elements- cells and cell fragments ex. RBC, WBC, and platelets.
Function of and three major categories of plasma proteins
clotting, defense against pathogens, transport of other solutes aka iron, copper lipids, and hydrophobic hormones all produced by liver albumin and fibrinogen except globulin.
albumin
smallest most abundant and viscous contributor, responsible for colloid osmotic pressure, transports lipids, hormones, calcium, and other solutes, buffers blood pH. Affecting blood volume, pressure, and flow when changed.
globulin
(antibodies, alpha, beta, and gamma) produced by plasma transport and hemoglobin, copper, blood clotting, lipids, fat-soluble vitamins, and hormones, iron, defense and destroying pathogens, toxins, and microorganism
fibrinogen
forming blood clots by becoming fibrin
Other things found in blood
nitrogenous compounds-breakdown of free amino acids and toxic end product wastes are urea
Nutrients including Glucose, amino acids, vitamins, fats, cholesterol, phospholipids, and minerals
Dissolved O2, CO2, and nitrogen
Electrolytes: sodium makes up most of electrolytes and is most important for osmolarity affecting blood volume and pressure.
Viscosity what is blood’s viscosity and why? plasma?
resistance of a fluid to flow, resulting from the cohesion of its particles. Aka stickiness of a fluid. Blood is 4-5X as viscous as water because of RBCs, plasma is 2X more than water because of protein. If too viscous or not enough strains heart
osmolarity definition, important regulating substances and what happens if too high or too low?
the total molarity of dissolved particles that cannot pass through the blood vessel wall. Substance pass between bloodstream and fluid through capillary walls balancing filtration of fluid from capillarity and reabsorption by osmosis w/ sodium, protein, and erythrocytes playing big part. if too high blood absorbed too electrolytes and water w/ it, high volume and pressure strains heart. if osmolarity drops too low too much water in tissues becoming swollen dropping bp.
hemopoiesis
production of blood, especially its formed elements
hemopoietic tissues
produce blood cells. First RBCs form in yolk sac, then liver and spleen halting at birth. w/ spleen producing lymphocytes and storing blood throughout life
Red bone marrow produces all seven formed elements
Pluripotent stem cells (PPSC)
aka hematopoietic stem cells multiple to maintain small population in bone marrow becoming more specialized cells.
Colony-forming unit
more specialized cells that stem from PPSC destined to produce one of classes of formed elements
Myeloid hemopoiesis-
blood formation in bone marrow
Lymphoid hemopoiesis
blood formation in lymphatic organs (lymphocytes formed in thymus, tonsils, lymph nodes, spleen, and mucous membranes)
Erythrocytes two principal functions and hallmarks of cells
Carry oxygen from lungs to cell tissues. Does not have other organelles utilizes anaerobic fermentation to produce ATP doesnt use oxygen.
Pick up Co2 from tissues and bring to lungs. Resilient and durable can stretch, bend and fold squeezing through capillary
Hemoglobin what it consists of
gives RBC its red pigment carries oxygen and aids in transporting CO2 and buffering pH
Each Hb molecule consists of:
Four protein chains—globins alpha and beta chains bind to CO2
Four heme groups- binds oxygen to an iron atom w/ each carrying one molecule of O2
Heme groups
Nonprotein moiety that binds O2 to ferrous ion (Fe) at its center
Quantities of Erythrocytes and Hemoglobin determined by
RBC count and hemoglobin concentration indicate amount of O2 blood can carry
Hematocrit (packed cell volume): percentage of whole blood volume composed of RBCs
Men 42% to 52% cells; women 37% to 48% cells
Hemoglobin concentration of whole blood
Men 13 to 18 g/dL; women 12 to 16 g/dL
RBC count
Men 4.6 to 6.2 million/mL; women 4.2 to 5.4 million/mL. Lower in women than men because androgens stimulate RBC production w/ men have higher than woman, women have menstrual losses, hematocrit inversely proportional to body fat percentages higher in women than men woman blood vessels closer to surface
What is erythropoiesis production? How many are produced, how long do they last and how long does the process take?
RBC production
1 million RBCs are produced per second, Average lifespan of about 120 days
Development takes 3-5 days.
What are the three steps in erythrocyte production
Reduction in cell size, increase in cell number, synthesis of hemoglobin, and loss of nucleus and other organelles
Describe erythrocyte production?
Hemopoietic becomes erythrocyte colony-forming unit (ECFU) w/ receptors for EPO (erythropoietin from kidneys) stimulating ECFU to become erythroblasts, which build to synthesize hemoglobin. Once hemoglobin is completed nucleus shrivels and is discharged becoming reticulocytes. Reticulocytes leave bone marrow and enter blood ribosomes disintegrate becoming erythrocytes.
Iron metabolism
Fe2+ more absorbable converted from Fe3+ from stomach. Gastroferritin binds Fe2+ transporting to small intestine absorbed by blood transferred to transferrin traveling to bone marrow, liver, and other tissues. Bone marrow uses iron for hemoglobin synthesis, muscles use for myoglobin, and all cells make cytochromes in mitochondria. Liver binds surplus iron to apoferritin forming ferritin w/ iron to release when needed.
Erythrocyte Homeostasis
negative feedback control, kidney’s detecting low count increasing EPO output.
Hypoxemia caused by:
low RBC count
hemorrhage, high altitude, and exercise.
Erythrocyte death and disposal. What happen as they age? What are each of the components converted to and how are they disposed of?
as RBCs age membrane proteins (spectrin) deteriorate and become fragile, and cannot repair w/out cellular components. Narrow channels of spleen test ability of old, fragile RBCs to squeeze through where they become trapped, broken up, and destroyed. When rupture releases hemoglobin, macrophage separate heme from globin otherwise causes renal failure, leaving plasma membrane, digested by liver & spleen. iron released to blood, rest of heme turned into biliverdin>bilirubin by macrophage in spleen binds to albumin, liver separates and put bilirubin (green) in bile where it travels to to gallbladder then to small intestine converting to urobilinogen brown color of feces or urochrome yellow of pee.
Jaundice
yellowish cast of skin and whites of eyes as sign of rapid hemolysis, liver disease, or bile duct obstruction interfering w/ bilirubin disposal.
Enlarged and tender spleen indicates what?
diseases where RBCs rapidly breakdown
What is Polycythemia?
an excess of RBCs. Primary- cancer of erythropoietic line of red bone marrow, secondary- all other causes including: dehydration (less plasma more RBC concentration), smoking, air pollution, emphysema (lung tissue not available to oxygenate blood so RBC increase until polycythemia w/ blood still not being properly oxygenated), high altitude, excessive aerobic exercise.
What are the dangers of polycythemia?
Increased blood volume, pressure, viscosity
What can polycythemia lead to?
embolism, stroke, or heart failure
Anemia what are the three causes and what are the signs and symptoms of it in an individual
:lack of iron in blood 1) inadequate erythropoiesis or hemoglobin synthesis commonly because of kidney failure, 2) hemorrhagic anemia from bleeding, 3) hemolytic anemia from RBC destruction. Symptoms include: hypoxia of tisssues, blood osmolarity & viscosity reduced w/ lethargy, shortness of breath, pale skin, edema, faster heart beat, pressure drops, necrosis of brain, heart, and kidney tissues or cardiac failure
What is sickle cell disease?
hereditary hemoglobin defects because of recessive allele causing sickle cell shaped RBCs because of regular misbinding of hemoglobin to O2
what happens at low O2 w/ sickle cell disease?
At low O2 sickle cells are deoxygenated, and they polymerize to pointy shape at end causing it to become rigid, sticky, and clump together causing pain. Blockages can lead to kidney or heart failure, stroke, severe joint pain or paralysis.
why are the body’s attempt to counteract sickle cell blockages futile?
W/ breakdown of these causing anemia. Chronic hypoxemia causes fatigue, weakness, slow mental development, deterioration of heart and other organs, w/ overactive hemopoietic tissues (spleen become enlarged and fibrous) misshaping and block blood vessels, kidney, heart, stroke, joint pain, paralysis.
why is sickle cell anemia still prevalent?
Protective against malaria as if heterozygous as they have normal phenotype
Antigens
Complex molecules on surface of cell membrane such as proteins, glycoproteins, and glycolipids unique to each individual occur on all cells body to distinguish cells from foreign matter. When detects foreign that activate an immune response genetically unique to everybody used to distinguish cell from foreign matter.
Antibodies
Proteins (gamma globulins) secreted by plasma cells. Immune response to foreign matter binding to them, marking them for destruction.
Agglutination
Antibody molecule binding to antigens
Causes clumping of red blood cells can bind up to 10
agglutinogens
RBC antigens
Called antigen A and B and O (no antigens)
Determined by glycolipids on RBC surface
agglutinins
Antibodies. Found in plasma
Anti-A and anti-B
ABO blood type group is determined by? what is the most common type? least common?
presence or absence of antigens (agglutinogens) on RBCs Blood type A person has A antigens Blood type B person has B antigens Blood type AB has both A and B antigens Blood type O person has neither antigen Most common: type O Rarest: type AB
What are the ABO group antibodies?
(agglutinins); anti-A (found in B or O blood type) and anti-B (found in A or O blood type)
Appear 2 to 8 months after birth; maximum concentration by 10 years of age. Produced in response to bacteria in intestines.
Antibody-A or antibody-B (or both or neither) are found in plasma
You do not form antibodies against your antigens
Agglutination of Erythrocytes ABO Group and the response if the transfusion is mismatched
Agglutination
Each antibody can attach to several foreign antigens on several different RBCs at the same time
Responsible for mismatched transfusion reaction
Agglutinated RBCs block small blood vessels, hemolyze, and release their hemoglobin over the next few hours or days
Hb blocks kidney tubules and causes acute renal failure
Universal donor blood type?
Type O: most common blood type
Lacks RBC antigens
Donor’s plasma may have both antibodies against recipient’s RBCs (anti-A and anti-B)
universal recipient blood type?
Type AB: rarest blood type
Lacks plasma antibodies; no anti-A or anti-B
How can you minimize transfusion reaction?
May give packed cells (minimal plasma), which reduces risk of transfusion reaction
What are Granulocytes?
granules containing azurophilic absorbing blue or violet dyes of blood stains and lysosomes visible w/ defense against specific pathogens neutrophils, eosinophils, basophils
What are leukocytes?
white blood cells, protect against infectious microorganism, other invaders, and diseases. Spend only few hours in bloodstream then migrate into connective tissue living there.
Agranulocytes
WBC w/out granules
lymphocytes, monocytes
Neutrophils
most abundant clearly visible but random shaped nucleus w/ 3-5 lobes Barely visible fine reddish to violet granules in cytoplasm containing lysosome and other antimicrobial; aggressively anti-bacteria, neutrophilia rise in # because of infection. Creamy color of pus disposed of by rupture of blister.
Eosinophils
found in mucous membranes of the respiratory, digestive, and lower urinary tracts. Two large lobes w/ coarse rosy to orange colored granules. Secrete chemicals that weaken or destroy parasites aka hookworms, tapeworms, disposing inflammatory chemicals, antigen-antibody complexes, and allergens. With allergies, parasites, and collagen, spleen and CNS diseases account for increases in their #s.
basophils
arest, have large abundant, blue-dark violet specific granules, nucleus is sometimes obscured but w/ a S or U shape. Secrete two chemicals: histamine and heparin. Release chemical signals attracting eosinophils and neutrophils to infection site.
histamine
vasodilator widens blood vessels, speeds flow of blood to injured tissue, makes blood vessels more permeable allowing blood components to enter quickly
heparin
anticoagulant inhibits blood clotting promoting mobility of WBCs to area
Lymphocytes
-second most common. Various types and sizes found in fibrous connective tissue (medium and large), and circulating blood (small). Uniform nucleus that look similar to basophils, clear cytoplasm w/ round, ovoid, slightly dimpled on side w/ dark violet staining nucleus. Variable amounts of bluish cytoplasm (scanty to abundant); Diverse infections and immune response, including destroy cancer, viral infection, foreign cells, secrete antibodies to coordinate actions of other immune cells and provide immune memory.
Monocytes
Usually largest WBC; large and clearly visible nucleus light violet ovoid, kidney or horseshoe shaped. Abundant cytoplasm w/ sparse fine granules angular and spiky shapes. Rise in inflammation and infections become macrophages. Become macrophages, phagocytize pathogens, dead neutrophils, and debris of dead cells, coordinate immune system by being antigen-presenting cells.
Leukopoiesis and the general differentiation groups
formation of leukocytes and its life cycle. Production of white blood cells and dead by macrophages. Hemopoietic stem cells, differentiate into 1) myeloblasts>neutrophils, eosinophils, and basophils, or 2)monoblasts > monocyte, or 3 )lymphoblasts> lymphocytes.
how do colony forming units for leukocytes determine what is needed?
Colony forming units each have receptors for colony-stimulating factors w/ several types to distinguish which cells needed infection vs. allergies.
Where does leukopoiesis occur?
These are all stored in red bone marrow, sometimes start in thymus too, release granulocytes and leukocytes when needed, lymphocytes start there but develop spleen, lymph nodes etc.
How long do these cells live for?
Granulocytes 8-9 hours in blood live 5 days, monocytes 10-20 hours then turn into macrophages living for several years. lymphocytes few weeks to decades leave bloodstream for tissues lymphatic back to blood stream.
leukopenia
low WBC count (lead, arsenic, and mercury poisoning, radiation sickness, measles, mumps, chicken pox, polio, influenza, typhoid fever, and AIDS or drugs) w/ elevated risk of infection.
leukocytosis
high white blood cell count. Indicates infection, allergy, or other diseases. Dehydration or emotional disturbances.
Complete Blood Count
Includes several values
Hematocrit
Hemoglobin concentration
Total count for RBCs, reticulocytes, WBCs, and platelets
Differential WBC count
RBC size and hemoglobin concentration per RBC
Differential white blood cell count and specifically which type
we have can help identify what kind of disease you have. Can specifically find: anemia by low RBC counts, size, shape, or HB content. Platelet deficiency- adverse drug reaction. High neutrophil- bacterial infection, eosiniophil- allergy or parasitic. WBC types- leukemia,
What is Leukemia? what kinds are there? What can happen if untreated? How do you treat?
- cancer of hemopoietic tissue producing high number of circulating leukocytes and their precursors. Myeloid (uncontrolled granulocyte production), lymphoid (uncontrolled lymphocyte or monocyte production), acute(suddenly, rapidly, death w/in months) or chronic (slow over months, survival 3 years). Treat w/ chemo transplants control of anemia, hemorrhaging, and infection. Leukemic proliferate replacing normal marrow w/ deficiency of elements w/ high leukocytes w/ opportunistic infection or organisms that usually dont affect healthy people causing them to become anemic fatigued causing hemorrhaging and impaired blood clotting, bone and joint pain as cancer moves.
platelets what are they and what are their structure
play an important role in all three hemostatic mechanisms
small fragments of marrow cells (megakaryocytes) second most abundant formed element. W/ complex internal structure including lysosomes, mitochondria, microtubules, and microfilaments; granules w/ secretions and open canalicular system no nucleus w/ pseudopods and ameboid movement.
Platelet function
secrete vasoconstrictors (chemicals that stimulate constriction of broken vessels), stick together to form plugs sealing small breaks, secrete procoagulants (clotting factors), formation of clot-dissolving enzyme (dissolved blood clots once done), secrete chemicals attracting neutrophils and monocytes to inflammation, internalize and destroy bacteria, secrete growth factors stimulating mitosis in fibroblasts and smooth muscle.
Hemostasis
—the cessation of bleeding
Stopping potentially fatal leaks
Hemorrhage: excessive bleeding
Thrombopoiesis-
megakaryoblasts w/ receptors stimulated by thrombopoietin (liver and kidneys) that replicate DNA w/out dividing forming big cells (megakaryocytes)
Platelets circulate freely for 5-6 days. 40% of blood in spleen are the megakaryocytes.
Megakaryocytes
live in bone marrow adjacent to blood sinusoids multiple lobe nucleus large collections of blood. Sprouting long tendrils proplatelets protruding through endothelium into sinusoid blood. Flow shears off proplatelets becoming platelets in small vessels of lungs.
Three hemostatic mechanisms
vascular spas, platelet plug formation, and blood clotting
Vascular spasm
prompt constriction of broken vessel. Injury stimulates pain receptors which innervate blood vessels causing short-term constriction, injury to smooth muscle of blood vessel causes long vasoconstriction w/ platelet releasing serotonin
Platelet plug formation
when vessel broken collagen fibers exposed to blood when platelets contact collagen/rough surfaces they grow long spiny pseudopods (Spider-man webs) adhering to vessel & platelets, which contract and draw walls of vessel together forming platelet plug loose and delicate (blot not wipe). w/ platelet aggregation degranulation/exocytosis of granules occurs releasing serotonin, ADP (attracts more platelets stimulating degranulation), thromboxane (promotes platelet aggregation, degranulation, and vasoconstriction)
Blood clotting
(coagulation)
process is to: convert plasma protein fibrinogen into fibrin (sticky protein adheres to walls of vessel). Blood cells and platelets stick to fibrin sealing break in vessel.
Use combination of both extrinsic and intrinsic for inside and outside. Use various procoagulants (clotting factors produced by liver) to help seal the break. Once factor X activated combines w/ others to form prothrombin activator, which acts on prothrombin converting to thrombin, which converts fibrinogen into fibrin, which covalently bond to each other. Platelet and endothelial cell them secrete platelet-derived-growth factor (PDGF) stimulating fibroblasts (invade clot producing fibrous connective tissue strengthening and sealing vessel) and smooth muscle cells to multiple and repair vessel
Extrinsic mechanism-
initiated by clotting factors released by damaged blood vessel and perivascular tissues from outside blood each activate part of pathway w/ a shortcut to coagulation. Pathway to activate factor X
Intrinsic mechanism-
platelets adhere to fatty plaque of atherosclerosis clotting factors in blood itself that each activate part of pathway. Pathway to activate factor X
Blood Clot Dissolution-
fibrinolysis. Factor 12 catalyzes formation of kallikrein converts plasminogen to plasmin, fibrin-dissolving enzyme which breaks up clot
Platelet repulsion
do not adhere to smooth prostacyclin-coated endothelium of healthy blood vessels
Dilution-
small amounts of thrombin form spontaneously in plasma w/ less flow can accumulate to cause clotting in circulatory shock
Antithrombin
-secreted by liver deactivated thrombin before acting on fibrinogens, heparin, interferes w/ formation of prothrombin activator blocking action of thrombin and fibrinogen, and promoting action of antithrombin.
What are clotting disorders causes by?
Deficiency of any clotting factor can shut down the coagulation cascade
hemophilia
Hemophilia—family of hereditary diseases characterized by deficiencies of one factor or another different types missing different factors w/ certain parts of cascade not properly clotting given specific factors. Physical exertion can cause bleeding into muscles and joints causing excruciating pain and joint immobility from hematomas (masses of clotted blood)
kinds of hemophilia
Sex-linked recessive (on X chromosome)
Hemophilia A missing factor VIII (83% of cases)
Hemophilia B missing factor IX (15% of cases)
Hemophilia C missing factor XI (autosomal)
Thrombosis
abnormal clotting in unbroken vessel often commonly found in older people’s leg veins and vessels because they don’t work as well and the people don’t move around as much and are inactive.
Thrombus
is a clot. Can grow large enough to obstruct small vessel or piece may break loose and travel in bloodstream as embolus (can lodge in small artery blocking blood flow) can cause infraction of downstream tissues.
Pulmonary embolism:
clot may break free, travel from veins to lungs can die of hypoxia
Embolus
—anything that can travel in the blood and block blood vessels
Infarction
(tissue death) may occur if clot blocks blood supply to an organ (MI or stroke)
650,000 Americans die annually of thromboembolism (traveling blood clots)
Clinical Management of Blood Clotting Goal
prevent formation of clots or dissolve existing clots
Preventing clots
Vitamin K is required for formation of clotting factors
Coumarin, warfarin (Coumadin)—vitamin K antagonists- making clot less readily
Aspirin suppresses thromboxane A2, factor in platelet aggregation
Other anticoagulants discovered in animal research
Medicinal leeches used since 1884 (hirudin)- secrete local anesthetic so bites painless ihbitting thrombin
Snake venom from vipers (arvin)- breaks down fibrinogen
Dissolving clots that have already formed
Streptokinase:enzyme made by streptococci bacteria
Used to dissolve clots in coronary vessels
Digests almost any protein
Tissue plasminogen activator (TPA): works faster, is more specific, and now made by transgenic bacteria. Converts plasminogen into clot-dissolving enzyme plasmin
Hementin:produced by giant Amazon leech. anticoagulatnt dissolving blood clots
Cardiovascular system-
heart (muscular pump keeps blood flowing through vessels) and blood vessels (deliver blood to all body’s organs and return it to the heart.)
Circulatory system-
consists of heart, blood vessels, blood, and lymphatic system
describe the pulmonary circuit
begins at the right side of the heart, which carries deoxygenated blood w/ CO2 and other waste to lungs for gas exchange receiving from circulated body (superior and inferior vena cava) that is pumped into the pulmonary trunk, which divides into right and left pulmonary arteries. This blood is carried to alveoli of lungs, where CO2 is unloaded and O2 is picked up where it then flows through pulmonary veins to left side of the heart
describe the pathway of the systemic circuit
Fully oxygenated blood arrives from lungs via pulmonary veins to left side of heart carrying blood through Aortic arch, U shaped, passes downward posterior to heart splitting off to the arteries that supply head, neck, and upper limbs, and splits and travels through thoracic and abdominal cavities into smaller arteries of organs to lower limbs. After circulation, systemic blood that is now deoxygenated returns to the right side of heart by superior vena cava (draining upper body) and inferior vena cava (draining everything below diaphragm) w/ major arteries and veins entering and leaving at great vessels.
Position, Size, and Shape of the Heart
size of fist. Heart lies w/in the thick partition mediastinum extending from broad base at the uppermost end, where major vessels attach, to bluntly pointed apex at lower end above diaphragm, tilting towards left. Right side has three lobes, left side two lobes.
Pericardium what is it? Where does it connect? What is it made of? What are its layers? what is its function?
double-walled cavity area or sac containing heart. Outer wall, pericardial sac (parietal pericardium) anchored by ligaments to diaphragm below and sternum above, w/ loosely anchored fibrous connective tissue connecting to mediastinal on posterior of heart. Made of tough superficial fibrous tissue of dense irregular connective tissue and a thin, deep serous layer. Serous layer turns inward at base of heart forming visceral pericardium, equivalent to epicardium w/ fluid exuded by serous layer lubricating membrane allowing heart to beat w/ minimal friction so it slides easier. Function: to isolate heart from other organs allow room to expand, but resisting excessive expansion.
What is the structure and significance of the framework of collagenous and elastic fibers in myocardium and what are its functions?
make up fibrous skeleton concentrating in walls between heart chambers in rings around the valves and sheets of tissue interconnecting rings. Functions: provides structural support for heart around valves and openings of great vessels holding oepn and preventing excessive stretch during blood surge 2) anchors cardiomyocytes giving them something to pull against 3) nonconductor of electricity serves as insulation between atria and ventricles not passing stimulation between the two 4) elastic recoil of fibrous skeleton may aid in refilling heart w/ blood after each beat.
Myocardial infarction and how are coronary ratios special in trying to prevent this? what symptoms present?
caused because of lack of blood supply such as a fatty deposit, not always cause by anastomoses, or blood clot in coronary artery. Coronary arteries protect against this by converging at various points combining blood flow to farther downstream (arterial anastomoses) alternative routes of blood flow supplying heart tissue w/ blood if primary is obstructed. Signs of heart attack- heavy pressure or squeezing pain into left arm, chest pressure, angina pectorosis- pain because of lost blood flow.
Compare the blood flow peak in systemic arteries versus coronary arteries
Organs other than heart, blood flow peaks when heart contracts and ejects blood into systemic arteries, diminishing when ventricles relax and refill.
In coronary arteries- Flow peaks when heart relaxes in coronary arteries 1) contraction of myocardium squeezes coronary arteries and obstructs blood flow 2) when ventricles contract, aortic valve is forced open and cusps covering openings to coronary arteries, blocking blood from flowing into them 3) when they relax, blood in aorta briefly surges back toward heart fills aortic valve cusps and flows into coronary arteries