Cardiovascular II Flashcards
Functions of blood
-transport dissolved gases, nutrients, hormones and metabolic wastes
-regulating pH, ion composition of interstitial fluids
-restricting fluid loss at injury sites by clotting
-defending against toxins and pathogens
-stabalizing body temp`
characteritistics of blood
-38 degrees
-high viscosity
-slightly alkaline
whole blood
-plasma + formed elements
plasma
-mostly water
-contains dissolved plasma proteins and other solutes
-similar in composition of interstitial fluid because water and ions
plasma proteins
-albumins
-globulins
-fibrinogen
albumin
-transport of FA, thyroid hormones, some steroid hormones
-major contribtors to plasma osmolarity
globulins
-antibodies
-transport gloobulins incluidng hormone binding proteins, lipoproteins and steroid binding proteins
fibrinogen
-soluble protein that functions in clotting
-fibrin is the insoluble form of fibringogen
formed element
-RBC
-WBC
-cell fragments
hemopoiesis
-process of producing formed elements
red blood cells
-99% of the formed elements
-contain hemoglobin that transport O2 and CO2
-dont have nuceluas, mitochondria or ribosomes
hematocrit
-percentage of blood sample that contains RBC
packed cell volume
-percentage of blood that contains all formed elements
structure of RBC
-small, highly specialized
-biconcave
important effects of RBC structure on function
-large SA:V ratio to quickly absorb and release oxyen
-stacks of RBC called roleux that smooth blood flow through vessels
-can bend and flex when entering small capillaries
hemoglobin
-proteins that transport respiratory gases
-four subunits: each contain 1 heme, 1 iron and each heme can bind to one O2 molecule
oxyhemoglobin
-hemoglobin bind/loaded with oxugen to form oxyhemoglobin
deoxyhemoglobin
-hrmoglobin and oxygen dissociated and unloaded to form deoxyhemoglobin
anemia
-results when hematocrit or Hb content of RBC’s is reduced
-interferes with oxygen delivery to peropheral tissues
erythropoeisis
-RBC formation
-in adults it occurs in myeloid tissue of certain bones
-a reticulocyte is a immature RBC thate scapes from bone marrow into blood
erythropoeitin
-when oxygen in peripheral tissues is low, kidneys secrete Eythropoeitin
-stimulates erythropoeisis
hemoglobin recycling
-macrophaes enguld aged RBC
-remove Hb molecule from ruptured RBC
-breach Hb down into iron and other components
-iron is removed and formed into biliverdin
-biliverdin is converted to bilirubin
-bilirubin is excreted by liver in bile
when iron is removed how is it transported/stored
-is bound and stored in phagocytotic cell or released into bloodstream
-in bloodstream iron is bound to transferrin
transferrin
-in developing RBCs in red bone marrow absorb transferrings and use them to synthesize Hb
-excess transferrins are removed in liver and spleen storing iron in ferritin and hemosiderin
algulttinogens
-surface antigens on RBCs that are markers screened by the immune system
-blood type is determined by presence or absence of surface antigens on RBC’s
alguttinins
-antibodies in the plasma
-through immune response, attack antigens on foreign RBCs causes agglutinations/clumping of foreign cells
Type A blood
-A antigen and anti-B antibodies
Type B blood
-B antigen and anti A antibodies
type O blood
-neither A nor B antigens, both anti A and anti B antibodies
Type AB blood
-both A and B antigens and neither anti A nor anti B antibodies
what happens if donors are not compatible
-RBCs agglutinate and may hemolyze
Rh factor
-presence of Rh surface antigen affects compatibility
-Rh positive can recieve Rh+ or Rh-
-Rh- can only recive Rh- blood
hemolytic disease of the newborn
hemolytic disease of the newborn pt 2
-2nd pregnancy with Rh- mom and Rh+ baby
-mother has anti Rh antibodies already from previous pregnancy
-these antibodies attach fetal RBC leading to hemolytic disease of newborn
-RhoGAM stops development of anti Rh antibodies
WBC functions
-defending body against pathogens
-removing toxins and wastes
-attacking abnormal or damaged cells
where are most WBC located
connective tissue proper and organs of lymphatic system
-small fraction in the blood
characteristics of circulating RBCs
-all can migrate out of bloodstream
-all capabale of amoebic movement
-all are atttracked to specific chemical stimuli (positive chemotaxis)
-some are phagocytotic
types of WBC
-nuetrophils
leukocytes
monocytes
eosinophils
basophils
nuetrophils
-AKA polymorphonuclear lukeocytes
-50-70% of circulating WBCs
-attack and digest bacteria
-pale cytoplasmic granules conataining lysosomal enzymes, bactericidal compounds
-release prostaglandins and histamines
-degranulation occirs when vesicle contaiining pathogen fuses with lysosomes
-contribute to pus
eosinophils
-engulf bacteria, protozoa, and cellular debris
-attack large parasites by releasing toxic compounds like Nitric oxide and cytotoxic enzymes
-sensitive to allergens
-release enzyme that reduce inglammation caused by mast cells and nuetrophils
basophil
-cross capillary endothelium and accumulate in damaged tissues
-release histamine and heaprin
-histamine - dilates blood vessels
-heparin prevents clotting
monocyte
-large spherical
-remain in bloodstream 24 hours
-enter peripheral tissue to become macrophages
-macorphages are agressive, engulf large pahtogens
-release chemicals that attract other phagocytotic cells adn fibroblasts to injured area
lymphocytes
-continuously migrate in and out of bloodstram
-mostly in organs or lymphati csystem and connective tissues other than blood
-part of bodys dpecific defence system
three classes of lymphocytes
-T cells
-B cells
-NK cells
T cells
-cell mediated
-attack foreign cells or control other lymphocytes
B cells
humoral immunity
-differentiate into plasma cells which synthesize antibodies
Natural Killer cells
-detect and destroy abnormal cells
summary of the WBC function
Production of cells of the blood photo
platelets
-cell fragments for clotting
-removed by phagocyts mainly in the spleen
-1/3 of platelets stored in spleen and movilized during circulatory crisis
functions of platelets
-release important clotting chemicals
-temporarily pathc damaged vessel walls
-reduce size of break in vessel wall
thrombocytopoiesis
-plately produciton
-occurs in red bone marrow
megakaryocytes
-giant cells in red bone marrow
-produce platelets by shedding membrane enclosed packets of cytoplasm
thrombopoietin
-hormone control of platelet production
-kidneys produce thrombopoetin
-increases number of egakaryocytes in bone marrow
-each megakaryocyte stimulated to produce more platelets
-IL-6 and multi CSF also are involved in platelet production
hemostasis
-stop loss of blood from broken blood vessel
-three phases: vasciular, platelet and coagulation
vasicular phase of hemostatsis
-endothelial cells contract and expose basement membrane to bloodstream
-endothelial cells release chemical factors and local hormones such as ADP, endothelins and cause smooth muscle contraction and cell division
-endothelial plasma membrane become sticky so platelets can adhere
platelet phase
-platelet adhesion - platelets attach to exposed surfaces
-platelet aggregation - platelet stick to each other and from platelet plug
-activated platelets release clotting compounds such as ADP and thromboxane A2, clotting factors, PDGF, and calcium ions
factors that limit growth of platelet plug
-prostacyclin inhibits platelet aggregation
-inhibitory compounds from WBC
-circulating enzymes break down ADP
-negative feedback from serotonin
-blood clots isolate area from general circulation
coagulation phase of hemostasis
-transform blood from liquid to solid gel so it cant flow
-depends on clotting factors/procoagulants (Ca and 11 different proteins)
-proenzymes converted to active enzymes that direct clotting
three pathways of coagulation phase
-extrinsic, intrinsic and common
-step involving 12 plasma clotting factors to form fibrin mesh
clot retraction
-pulls torn edges of vessel closer together
-reduced bleeding
-with the clot, platelts contract to shrink fibrin mesh
-dluid and serum pulled from the clot
-stabalizes injury site
-reduced size of damaged area so repairs can happen
clot destruction
-enzyme plasmin trapped in clot and breaks down fibrin
-phagocytic lukeocytes remove products of clots
why is pressure generated by the heart
-to overcome resistance
blood flow through the vessel is impacted by
-pressure gradient (increase pressure=increased flow, size gradient from one vessel to another)
-flow and resistance are inversely related
types of pressure
-blood pressure (arterial pressure)
-capillary hydrostatic pressure (within capillary beds)
-venous pressure (in venous system)
circulatory pressure must overcome
-total peripheral resistance
total peripheral resistance
-total resistance of all systemic vessels together
-affected by: vascular resistance, blood viscosity, turbulence
vascular resistance
-due to friction between blood and vessel walls
-dependent on vessel length and diameter
-resistance increases as vessel diameter decreases
blood viscosity
-resistance cause by moleculed suspended in liquid
-whole blood is 4x as viscous as water
turbulence
-sirling action that distubs smooth flow of liquid
-occurs in heart chambers and great vessels
-atherosclerotic plauqes cause abnormal turbulence
collagen and elastin fibers function of arteries
-collagen fibers for strength against pressure of blood during systole
-elastin fibers for elasticity to arterial walls to absorb pressure waves that come with each heartbeat
contractility of arteries
-arteries change diameter
arterial smooth muscle adrenergic receptors
what vessels are the pressure reservoir
-arteies bevaise of elasticity
arterioles
-very little elastin but have large smooth muscl elayer innervated by SNS
-able adjust circumference
-all arteioles have vascular tone
systolic pressire
-peak arterila pressure during ventricular systole
pulse pressure
-difference between systolic and diastolic pressure
diastolic pressure
-minimum arterial pressire at end of ventricular diastole
mean arterial pressure
-average pressure driving blood forward during cardiac cycle
-diastolic pressure + one third pulse pressure
-average of blood pressure
elastic rebound
-arterial walls
-stretch during systole
-rebound during diastole
-keep blood moving furing diastole
pressures in muscular arteries and arterioles
-MAP declines as arterial pressure decreases with distance from heart
-MAP declines when arterial bancehs become smaller and more numerous
-pulse pressure decreases due to elastic rebound in arteries
What vessels act as a blood reservoir
-veins
venous pressure
-determines the amount of blood arriving at the right atrium
-low effective pressure and low resistance in veins
return of the blood to the heart is assisted by
-skeletal muscular compression of veins
-when leg muscles are immovilized, blood supply to the brain is reduced and fanting may result
-the respiratory pump- thoracic cavity expands during inhalation, decreasing venous pressure in the chest
short and long term factors to facilitate venous return
capillaries
-thin walled, small radius, extensively branched
-maximize surface area to minimize diffusion distance
-slow blood flow for exchange
-narrow, water filled gaps between cells for passage of water soluble substances, lipid soluble substances dissolve in lipid bilayerw
how do materials move across capillary walls
-diffusion
-filtration
-reabsorbtion
water ion and small molecules diffusion across capillaries
-dbiffuse between endothelial cells or through pores
ions dissue across capillaries
-through channels in plasma membranes
large water soluble compounds diffusion across capillaries
-pass through fenestrated capillaries
lipids and lipid soluble materials such as steroid hormones diffusion across capillaries
-diffuse through endothelial plasma membrane
capillary sphincter
-controls blood flow to capillary from arteriole
-ring of smooth muscle around entrance to capillary but capillary has no smooth muscle
vasomotion
-contraction and relazation of precapillary sphicters
-causes blood flow in capillary beds to constantly change routes
capacitance of a blood vessel
-ability to stretch
-relationship between volume and pressure
-systemic veins constrict in response to blood loss to increase amount of blood in arterial system and capillaries
tissue perfusion
-blood flow through tissues
-O2 to tissues
-CO2 away
-affected by: cardiac output, peripheral resistance, blood pressure
cardiovascular regulation
-when certain cells become active circulation to that region must increase
cardiovascular regulation ensures that blood flow changes occur
-at appropriate time
-in the right area
-without changing blood pressure and blood flow to vital organs
controlling cardiac output and blood pressure (regulation)
-autoregulation causing immediate localized homeostatic adjustment
-nueral mechanism respond quickly to changes at specific sites
-endocrine mechanisms direct long term changes
autoregulation diagram
autoregulation of blood flow within tissues
-adjusted by periperhal resistance while cardiac output stays the same
-precapillary sphincters are stimulated to constric or dilate
-local vasoconstricters reduce blood flow by constricting sphicters
vasodilators and autoregulations
-vasodilators factors that promote dilation of precapillary sphincters increasing blood flow
-vasodilators include: low O2 or high Co2, lactate, NO, high K or H. chemicals of inflammation, elevated local temp
nueral mechanmisms of cardiovasicular regulation
-cardiovascular center of medulla oblongata
-cardioacceletory center, and cardioinhibitory center
-vasomotor center control vasoconstriction (NE and adrenergic nerves), vasodilartion (cholinergic nerves and NO)
-vasomotor tone produced by constant action of sympthatetic vasoconstrictor nerves
Baroreceptor reflexes
-stretch receptors in the wall of carotid sinuses, aortic sinuses, right atrium
aortic reflex
-changes in blood pressure in ascending aorta triggering the aortic reflex that adjusts blood pressure and flow in systemic circuit
when BP rises CV centers
-decrease CO
-cause peripheral vasodilation
when BP falls CV centers
-increase CO
-cause peripheral vasoconstriction
atrial baroreceptors
monitor blood pressure at the end of the systemic circuit
bainbridge reflex
responds to stretching og the wall of the right atrium
increasing blood pressure diagram
decreasing blood pressure diagram
the baroreceptor refelx
-influence CO and TPR to increase or decrease BP when needed
chemoreceptor reflexes
-peripheral chemoreceptors in carotid bodies and aortid bodies that monitor blood
-respond to changes in pH, O2 and CO2
-coordinate Cv and respiratory activities
increasing CO2 level diagram
how do emotional states alter BP
-by cardiac stimulation and vasoconstriction
endocrine mechanisms affecting CV regulation
-NE and E
angiotensin II
-response to decrease renal BP
-stimulates: aldosterone, ADH secretion, Thirst, CO and peripheral vasoconstriction
ADh
-released by poertior pit
-elevates BP
-reduced water loss at kidneys
-ADH responds to low blood volume, high plasma osmotic concentration, circulating angiotensin II
erythropoitin
-released by kidney
-responds to low BP or low O2 content in blood
naturietic peptides
-ANP produced by right atrium
-BNP produced by ventricular muscle cells
-respond to excessive diastolic stretching
-reduced blood volume and blood pressure by seeveral means
top priority of blood flow
-brain
-high oxugen demnad
-when peripheral vessels constrict, cerebral vessels dilte normalizing blood flow
lactic acid and low O2 levels
-dilate coronary vessels
-increase coronary blood flow
benefit of regular moderate excersize
-moves LDLP from blood to liver
-slows formation of plauqes
-reduced the risk of MI by almost half
-speeds recovery after heart attach
-reduces symptoms of CAD such as angina
short term elevation of BP
-carotid and aortic reflexes increase CO and cause peripheral vasocnstriction
-sympathetic nervous sytsem constricts arteriols and venconstriction improves venous return
-hormonal effects increase CO, increase peripheral vasoconstriction
long term restoration of blood volume
-recall fluid from interstitial space
-aldosterone and ADH promote fluid retention and reabsorbtion
-thirst increeases
-erythropoeitin stimulated RBC production
