the cardiovascular system: blood
DESCRIPTION
The Cardiovascular System: Blood. Chapter 14. Function. Transportation-hormones, gasses, nutrients, ions, heat Regulation- pH, temperature, water balance in cells Protection- clotting, white cells interferons, complement. Composition. Connective tissue-Two parts - PowerPoint PPT PresentationTRANSCRIPT
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The Cardiovascular System: Blood
Chapter 14
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Function
• Transportation-hormones, gasses, nutrients, ions, heat
• Regulation- pH, temperature, water balance in cells
• Protection- clotting, white cells interferons, complement
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Composition
• Connective tissue-Two parts
• Plasma = soluble materials (~55%)
• Formed Elements = cells (~45%)
• Percent occupied by red blood cells (RBC) = hematocrit (Hct)
• White blood cells (WBC) ~1%
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Figure 14.1a
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Figure 14.1b
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Plasma
• ~91% water, 7% proteins, 1.5 % other solutes• Proteins: Albumin (54%)- osmosis and carriers; • Globulins (38%)- antibodies• Fibrinogen (7%)- clotting• Other: Electrolytes , nutrients, gases, hormones,
vitamins & waste products
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Formed ElementsI. Red Blood CellsII. White blood cells
– A. granular Leukocytes1. Neutrophils2. Eosinophils3. Basophils
– B. Agranular leukocytes1. T & B lymphocytes & natural Killer cells2. monocytes
III Platelets
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Formation of Blood Cells
• Called hemopoiesis
• Just before birth and throughout life occurs in red bone marrow
• Contains pluripotent stem cells
• In response to specific hormones these develop through a series of changes to form all of the blood cells
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Figure 14.2a
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Figure 14.2b
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Erythrocytes (RBCs)
• Hemoglobin package- carries oxygen– Also carries some CO2
• Male has ~ 5.4 million cells/µl; Female has ~4.8 million
• membrane, no nucleus, flexible structure• use glucose for ATP production to maintain ionic
composition– No mitochondria
• Wear out fast- live ~120 days
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RBC Cycling
• cleared by macrophages (liver & Spleen)
• Fe- recycled in bone marrow– Carried in blood on transferrin
• Heme bilirubin and excreted (bile)
• Globin A.A. recycled.
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Figure 14.3
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RBC Synthesis
• called erythropoiesis
• From stem cells: hemocytoblasts
• Released as reticulocytes – Mature to erythrocytes in 1-2 days
• Production & destruction is balanced
• Low O2 delivery (hypoxia)
• erythropoietin release (EPO) from kidney• Stimulates erythropoiesis
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Figure 14.4
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White Blood Cells• Defenses: phagocytes, antibody production and
antibacterial action• Phagocytes:
– Neutrophil- first responders– Monocytes macrophages (big eaters)– Eosinophil- phagocitize antibody-antigen complexes Involved in
suppressing allergic responses– Basophil- intensify allergic reactions
• Immune response:– T-cells, B-cells& natural killer (NK) cells
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WBC Life Span
• 5000-10,00 WBC /µl blood
• Limited number of bacteria can be eaten
• Life span is a few days
• During active infection may be hours
• Leukocytosis= increased WBC numbers response to stresses
• Leukopenia = decreased WBC numbers
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Platelets
• Myeloid stem cells megakaryocytes 2000 -3000 fragments = platelets
• Plug damaged blood vessels
• Promote blood clotting
• Life span 5-9 days
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Hemostasis
• Hemostasis = stationary blood• 1. Vascular reactions (spasm)
– Response to damage– Quick reduction of blood loss
• 2. platelet plug formation– Become sticky when contact damaged vessel wall
• 3. blood clotting (coagulation) – Series of chemical reactions involving clotting factors
• Clotting in unbroken vessel= thrombosis
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Coagulation
• Extrinsic pathway common steps– tissue factor(TF) from damaged cells 1
• Intrinsic Pathway common steps– Materials “intrinsic” to blood 1
• 1. prothrombinase which causes
• 2. prothrombin thrombin causes
• 3. fibrinogen fibrin clot
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Clot Retraction & Vessel Repair
• Clot pugs ruptured area
• Gradually contracts (retraction)
• Pulls sides of wound together
• Fibroblasts replace connective tissue
• epithelial cells repair lining
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Control Mechanisms
• Fibrinolysis: dissolving of clot by activated plasmin enclosed in clot
• Clots can be triggered by roughness on vessel wall = thrombosis
• Loose clot = embolus and can block a small vessel = embolism
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Figure 14.5
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Blood Types
• Surface antigens- react with antibodies
• Divided into groups based on antigens– > 24 blood groups and > 100 different antigens
• We will deal with ABO and Rh groups
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ABO Group
• Two antigens = A & B• If have only A –type A• If have only B –type B• If neither then Type O• Blood usually has antibodies that can react with
antigens– e.g. anti-A antibody or anti-B antibody
• You don’t react with your own antigens– Thus: type A has anti-B and vice versa
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Figure 14.6
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Rh Blood Group
• Antigen discovered in rhesus monkey
• If have antigen- Rh+
• Normally don’t have antibodies
• antibodies develop after the first exposure from transfusion
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Transfusions
• If mismatched blood given antibodies bind to it and hemolyze cells
• Type AB has no AB antibodies so can receive any ABO type blood called Universal recipients
• Type O have neither antigen so can donate to any other ABO type called Universal donors
• Misleading because of many other blood groups that must be matched
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The Cardiovascular system: Heart
Chapter 15
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Location
• Thoracic cavity between two lungs– ~2/3 to left of midline
• surrounded by pericardium:• Fibrous pericardium-
– Inelastic and anchors heart in place• Inside is serous pericardium- double layer around
heart– Parietal layer fused to fibrous pericardium– Inner visceral layer adheres tightly to heart– Filled with pericardial fluid- reduces friction during beat.
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Figure 15.1
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Heart Wall
• Epicardium- outer layer
• Myocardium- cardiac muscle – Two separate networks via gap junctions in
intercalated discs- atrial & ventricular– Networks- contract as a unit
• Endocardium- Squamous epithelium– lines inside of myocardium
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Figure 15.2a
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Figure 15.2b
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Figure 15.2c
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Chambers• 4 chambers
• 2 upper chambers= Atria– Between is interatrial septum– Contains fossa ovalis- remnant of foramen ovalis
• 2 lower chambers = ventricles– Between is interventricular septum
• Wall thickness depends on work load– Atria thinnest– Right ventricle pumps to lungs & thinner than left
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Great Vessels Of Heart- Right
• Superior & inferior Vena Cavae– Delivers deoxygenated blood to R. atrium from
body– Coronary sinus drains heart muscle veins
• R. Atrium R. Ventricle• pumps through Pulmonary TrunkR & L pulmonary arteries• lungs
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Great Vessels Of Heart-Left
• Pulmonary Veins from lungs– oxygenated blood
L. atrium Left ventricleascending aorta body
• Between pulmonary trunk & aortic arch is ligamentum arteriosum
• fetal ductus arteriosum remnant
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Figure 15.3a
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Figure 15.3b
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Figure 15.3c
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Valves
• Designed to prevent back flow in response to pressure changes
• Atrioventricular (AV) valves– Between atria and ventricles
• Right = tricuspid valve (3 cusps)• Left = bicuspid or mitral valve• Semilunar valves near origin of aorta &
pulmonary trunk • Aortic & pulmonary valves respectively
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Figure 15.4ab
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Figure 15.4c
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Figure 15.4d
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Figure 15.5a
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Figure 15.5b
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Blood Supply Of Heart
• Blood flow through vessels in myocardium = coronary circulation
• L. & Right coronary arteries– branch from aorta– branch to carry blood throughout muscle
• Deoxygenated blood collected by Coronary Sinus (posterior)
• Empties into R. Atrium
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Conduction System
• 1% of cardiac muscle generate action potentials= Pacemaker & Conduction system
• Normally begins at sinoatrial (SA) node Atria & atria contractAV node -slowsAV bundle (Bundle of His) bundle branches Purkinje fibers apex and up- then ventricles contract
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Pacemaker
• Depolarize spontaneously
• sinoatrial node ~100times /min
• also AV node ~40-60 times/min
• in ventricle ~20-35 /min
• Fastest one run runs the heart = pacemaker
• Normally the sinoatrial node
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Figure 15.6
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Electrocardiogram
• Recording of currents from cardiac conduction on skin = electrocardiogram (EKG or ECG)
• P wave= atrial depolarization– Contraction begins right after peak– Repolarization is masked in QRS
• QRS complex= Ventricular depolarization– Contraction of ventricle
• T-wave = ventricular repolarization– Just after ventricles relax
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Figure 15.7
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Cardiac Cycle
• after T-wave ventricular diastole– Ventricular pressure drops below atrial & AV valves open
ventricular filling occurs
• After P-wave atrial systole– Finishes filling ventricle (`25%)
• After QRS ventricular systole– Pressure pushes AV valves closed– Pushes semilunar valves open and ejection occurs– Ejection until ventricle relaxes enough for arterial pressure to
close semilunar valves
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Action Potential
• Review muscle
• Heart has addition of External Ca2+
• creates a plateau
• prolonged depolarized period.
• Can not go into tetanus.
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Figure 15.8
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Flow Terms
• Cardiac Output (CO) = liters/min pumped
• Heart Rate (HR) = beats/minute (bpm)
• Stroke volume (SV) = volume/beat
• CO = HR x SV
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Controls- Stroke Volume (S.V.)
• Degree of stretch = Frank-Starling law– Increase diastolic Volume increases strength of
contraction increased S.V.– Increased venous return increased S.V.
• increased sympathetic activity
• High back pressure in artery decreased S.V.– Slows semilunar valve opening
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Controls- Heart Rate
• Pacemaker adjusted by nerves– Cardiovascular center in Medulla
• parasympathetic- ACh slows– Via vagus nerve
• Sympathetic - norepinephrine speeds
• Sensory input for control:– baroreceptors (aortic arch & carotid sinus)- B.P.
– Chemoreceptors- O2, CO2, pH
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Other Controls• Hormones:
– Epinephrine & norepinephrine increase H.R.– Thyroid hormones stimulate H.R.– Called tachycardia
• Ions– Increased Na+ or K+ decrease H.R. & contraction force– Increased Ca2+ increases H.R. & contraction force
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Figure 15.9
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Exercise
• Aerobic exercise (longer than 20 min) strengthens cardiovascular system
• Well trained athlete doubles maximum C.O.
• Resting C.O. about the same but resting H.R. decreased
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Figure 15.10
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The Cardiovascular System: Blood Vessels and Circulation
Chapter 16
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Blood Vessels
• Arteries- from heart1. Elastic => large
2. Muscular => distribution to organs
3. Arterioles => distribution to capillaries- mostly muscle
• Capillaries- thin walled for diffusion
• Veins- to heart1. Venules => from capillaries
2. Veins from tissue to vena cavae to heart
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Figure 16.1ab
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Figure 16.1c
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Blood Vessel Structure
• Three layers
• Arteries-> thicker tunica media– Elastic tissue and/or muscle– As they get smaller-> more muscle– Arterioles-> very muscular- control
• Veins- bigger lumen and thinner walls
• Veins-> valves to prevent backflow– Venules very thin, no valves
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Vessel Functions
• Muscular arteries & arterioles regulate flow• Sympathetic activity to smooth muscle
vasoconstriction (narrowing)• Decreased sympathetic activity or NO causes
relaxation or dilation• Arterioles adjust flow into capillaries• Systemic veins & venules serve as blood
reservoirs (~64% total blood volume)
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Capillary Details
• Capillaries only have endothelium– Very thin cells & cell nuclei protrude into
lumen- easy diffusion
• Connected from arterioles to venules in networks– Sometimes direct route from arteriole to venule
• Filling controlled by small arterioles & precapillary sphincters
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Figure 16.2a
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Figure 16.2b
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Capillary Exchange
• Slow flow through capillaries– Allows time for exchange through wall
• Blood pressure – filtration of fluid out of capillary– Mostly in first ½ of vessel length
• Osmosis (protein concentration) – Reabsorption of fluid from outside to inside– Mostly in last ½ of vessel length
• Balance determines fluid in circulation– Excess fluid returned via lymphatic system– Local signals can adjust capillary flow
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Figure 16.3
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Venous Return
• Blood enters veins at very low pressure.
• Needs more pumping to get back to heart
• = action of heart; muscle pumps; respiratory pump
• Some pressure from heart action
• Not enough to overcome gravity
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Muscle & Respiratory Pumps
• Contracting skeletal muscles squeeze veins emptying them
• Because of venous valves flow is toward heart• Respiratory pump has similar action• Inhalation decreased thoracic pressure &
increased abdominal pressure Blood flows toward heart
• Exhalation allows refilling of abdominal veins
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Figure 16.4
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Blood Flow
• from high pressure area to lower pressure area, i.e. down pressure gradient
– Greater gradient greater flow
• Ventricular contraction blood pressure (BP)– Highest in aorta and declines as flows through vessels– 110-70 mmHg in aorta ~16 mmHg at venules 0 at R. Atrium
• Resistance= opposition to flow• depends on lumen diameter & length & blood viscosity
– Smaller lumen greater resistance– Higher viscosity greater resistance– viscosity of blood depends on Hct
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Resistance
• Depends on vessel lumen diameter– Smaller lumen greater resistance
• And blood viscosity – Higher viscosity greater resistance
– viscosity of blood depends on Hct
• And total vessel length– Longer the length of flow the more friction with wall
– Total body resistance increases with growth and addition of tissue
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Anatomical Design
• Length and pressure
• Design and local flow control- central pressure
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Pressure Gradients
• Adult anatomy gives constant length
• If central blood pressure is controlled it is constant
• Only variable is radius of the arterioles
• Each tissue can do it separately
• Review design in picture below– All tissues have the same pressure gradient
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Pressure Gradients (Cont.)
• Note pulse in aorta & large arteries
– MAP• pressure fall related to resistance
– Note role of arterioles
• Note low venous pressures– can’t get back to the heart!
![Page 83: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/83.jpg)
Figure 16.5
![Page 84: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/84.jpg)
Regulation of Blood Pressure & Flow
• Fast responses: e.g. standing up
• Slower responses: e.g. blood volume
• Distribution: e.g. to working muscles
• Balance of CO with flow to body
• Interacts with many other control systems
• Cardiovascular (CV) Center major regulator
![Page 85: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/85.jpg)
Inputs
• Higher centers: – cerebral cortex, – limbic system,– hypothalamus– HR increases before race; – flow adjusted for body temperature
• Sensory receptor input:– proprioceptors, – baroreceptors – chemoreceptors
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Inputs (Cont.)
• Proprioceptors:– Start HR change as activity starts
• Baroreceptors: in aorta & carotid pressure parasympathetic & sympathetic stimulation CO
• Chemoreceptors: in aorta & carotid– Low O2, high H+, CO2 vasoconstriction
BP
![Page 87: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/87.jpg)
Figure 16.6
![Page 88: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/88.jpg)
Output
• ANS to heart Sympathetic HR & force of contraction Parasympathetic HR
• Vasomotor – to arterioles vasomotor tone– To veins move blood to heart BP
![Page 89: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/89.jpg)
Hormone regulation
• Renin-Angiotensin system– Angiotensin II vasoconstriction+ thirst aldosterone Na+ & water loss in urine on
• Epinephrine & Norepinephrine CO
• ADH = Vasopressin constriction BP Thirst & water retention in kidney BP
• ANP- from cells in atria– Vasodilation & loss of salt & water in urine BP
![Page 90: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/90.jpg)
Figure 16.7
![Page 91: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/91.jpg)
Checking Circulation- Pulse
• Pulse in arteries = HR– Use radial artery at wrist, – carotid artery, – brachial artery
• Tachycardia = rapid rest rate (>100 bpm)
• Bradycardia= slow rest rate (<50 bpm)
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Blood Pressure
• Use sphygmomanometer – Usually on brachial artery
• Raise pressure above systolic- – stop flow
• Lower pressure in cuff until flow just starts– first sound Systolic Pressure
• Lower until sound suddenly gets faint Diastolic pressure
• Normal values <120 mmHg for systolic & < 80 mmHg for diastolic
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Circulatory Routes
• Two parts: Systemic & Pulmonary• Systemic circulation- throughout body
– Oxygenated blood deoxygenated as it goes
• All systemic arteries branch from aorta• All systemic veins empty into Superior
Vena Cava, Inferior Vena Cava or the Coronary Sinus– Carry deoxygenated blood to heart
![Page 94: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/94.jpg)
Figure 16.8
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Figure 16.9
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Figure 16.10a
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Figure 16.10b
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Figure 16.10c
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Figure 16.11
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Figure 16.12
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Figure 16.13
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Figure 16.14a
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Figure 16.14b
![Page 104: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/104.jpg)
Figure 16.14c
![Page 105: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/105.jpg)
Figure 16.15
![Page 106: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/106.jpg)
Pulmonary Circulation
• From right ventricle pulmonary trunkR. & L. pulmonary arteries
– Carry deoxygenated blood R. & L. lungs
– Gas exchange occurs 2 R. & 2 L. pulmonary veins
– Carry oxygenated blood L. atrium
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Hepatic Petal Circulation
• Portal vein transports blood from one capillary bed to another
• GI organs Splenic & superior mesenteric veins hepatic portal veinsinusoids in liver
– Mixes with oxygenated blood hepatic vein inferior Vena Cava
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Figure 16.16a
![Page 109: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/109.jpg)
Figure 16.16b
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Fetal Circulation
• Specialized for exchange of materials with maternal blood and bypass of lungs
• Exchange in placenta umbilical vein liver ductus venosus inferior vena cava R. atrium
– Mixes with deoxygenated blood from lower body foramen ovale L. Atrium• Or R. Ventricle Pulmonary trunk ductus
arteriosus aorta internal iliacs umbilical arteries Placenta
![Page 111: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/111.jpg)
Figure 16.17
![Page 112: The Cardiovascular System: Blood](https://reader035.vdocuments.mx/reader035/viewer/2022070402/568138fa550346895da0af65/html5/thumbnails/112.jpg)
At Birth
• Umbilical arteries medial umbilical ligaments
• Umbilical vein ligamentum teres• Ductus venosus ligamentum venosum• Placenta expelled• Foramen ovalis closes fossa ovale• Ductus arteriosus ligamentum arteriosum
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Aging
• Stiffening of aortae
• Loss of cardiac muscle strength– Reduced CO & increased systolic pressure
• Coronary artery disease
• Congestive heart failure
• atherosclerosis
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