Principles of Animal Physiology

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Components of circulatory systems
• Fluid - contains transport molecules and cells
  (blood or hemolymph)
• Pump - to move the fluid around
• Conduits (vessels) - to carry the fluid between
  pump and body tissues

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Types of circulatory systems

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Open and Closed systems
• Open circulation
• Contains Hemolymph
• Hemolymph moves from vessels to extracellular
  spaces among tissues
• Hemocoel - extracellular spaces containing
  hemolymph
• Hemolymph may be moved by body movements, cilia
  or flagella, or by hearts

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Circulation in an open system

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Open and Closed systems
• Colsed circulation
• Contains Blood
• Blood moves through vessels but not among tissues
• Capillaries - exchange of materials occur
• Blood moved about the body by the heart or by
  body movements

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Ciruclation in a closed system

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Principles of Animal Physiology
Circulatory Systems
Circulatory Fluids

• Two components to circulatory fluids
• Plasma
• Watery, containing dissolved and dispersed
  molecules
• Cellular elements
• In hemolymph
• Hemocytes - various cell types
• Responsible for immune functions, clotting,
  oxygen transport
• Blood
• Erythrocytes - red blood cells for transporting
  oxygen
• Leukocytes - white blood cells for immune
  response
• Thrombocytes for platelets - for clotting

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Principles of Animal Physiology
Circulatory Systems
Circulatory Fluids

• The Hematocrit
• Percent of packed cell volume in whole blood
• Human - 45 in males 42 in females
• White whale - 53 in females 52 in males
• Pekin duck - 45 at seal level 56 at high
  altitude
• Sriped bass - 39 at 5C 53 at 25C

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Principles of Animal Physiology
Circulatory Systems
Introduction

• Plasma and Hematocrit volumes

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Principles of Animal Physiology
Circulatory Systems
Circulatory Fluids

• Plasma in Circulatory Fluids
• Contains 90 or more water
• A medium for carrying organic and inorganic
  substances
• Plasma proteins - 6-8 of plasma weight -osmotic
  pressure and buffering
• Most abundant electrolytes - Na, Cl-, HCO3-, K,
  and Ca
• Nutrients - glucose, amino acids, lipids, and
  vitamins
• Waste - creatinine, bilirubin, urea
• Dissolved gases
• Hormones

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Principles of Animal Physiology
Circulatory Systems
Circulatory Fluids

• Erythrocytes
• Transport oxygen
• Transport carbon dioxide
• Oblong oval or biconcaved flattened discs
• Flexible
• Contain no nucleus, orgennelles, or ribosomes
• Contain plasma and hemoglobin
• Does not use the oxygen that they carry
• Lifespan - 100 to 120 days

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Principles of Animal Physiology
Circulatory Systems
Circulatory Fluids

• Erythrocytes

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Principles of Animal Physiology
Circulatory Systems
Circulatory Fluids

• Blood Cell Production (Hemopoiesis)

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Pumps
• Flagella
• Fluid moved by beating epithelial cells
• Extrinsic muscle or skeletal pumps
• Fluid moved by motion of skeletal muscles
• May occur during locomotion
• Peristaltic muscle pumps
• Occurs during contraction of vessel muscle walls
• Chamber muscle pumps
• Hearts
• Most have at least two chambers

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Types of pumps in animals

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Two chambered heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Dual Pumps in Avian and Mammalian Hearts
• 4 chambers - 2 atria and 2 ventricles
• Atria receive and store blood
• Ventricles pump blood away from the heart
• Veins return blood to the heart
• Arteries take blood away from the heart
• Septum is muscular tissue that separates the two
  sides of the heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Dual Pumps

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Principles of Animal Physiology
Circulatory Systems

• Atria - holding chambers
• Ventricles - produce pressure to drive blood
  through system
• Arteries - low-resistance, little pressure loss,
  pressure resevoirs
• Arterioles - high resistance, regulate blood
  pressure, distribute blood to various organs
• Capillaries - site for nutrient and waste product
  exchange
• Venules - nutrient and waste product exchange,
  regulates capillary blood pressure
• Veins - low resistance conduits, facilitates flow
  back to the heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Heart Valves Ensure Unidirectional Blood Flow

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• The Mammalian Heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Blood flow through mammalian heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• The Mammalian Ventricles
• Myocardium
• Epicardium
• Epicardium

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Mechanism of Valve Action

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Organization of Mammalian Cardiac Muscle Fibers
• Intercalated discs
• Desmosomes
• Gap junctions
• Functional syncytium
• Myoglobin

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Conducting Pathway in Mammalian Heart
• SA node
• Internodal pathway
• AV node
• Bundle of His
• Left Right bundle branches
• Purkinje fibers

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Conducting Pathway in Mammalian Heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Pacemaker Activity in Cardiac Autorhythmic Cells
• Pacemaker cells
• SA node
• AV node
• Bundle of His
• Purkinje fibers
• Pacemaker potential
• Decrease in outward K current
• Constant inward Na current
• Increase in inward Ca current
• Depolarization
• Continued inward Na current
• Influx of Ca

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Pacemaker Activity of Cardiac Autorhythmic Cells

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Action Potential of Contractile Cardiac Muscle
  Cells
• RMP about -90 mV
• Rising phase - influx of Na
• Initial repolarization - ?PNA ?PCa2 ?PK
• Plateau - slow inward Ca2 current decreased K
  efflux
• Repolarization - inactivation of Ca2 channels
  increase outward K current

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Action Potential and Tension Development in
  Cardiac Contractile Muscle Cell
• Refractory period
• Tetanus

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Action Potential of Contractile Cardiac Muscle
  Cells

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Comparison of action potential in different
  regions of the heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• The Electrocardiogram

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Mechanical Events of Mammalian Cardiac Cycle

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Mechanical Events of Mammalian Cardiac Cycle
• Early Ventriclular Diastole
• Late Ventricular Diastole
• End of Ventricular Diastole - end-diastolic
  volume
• Onset of Ventricular Systole
• Isovolumetirc Venticular Contraction
• Ventricular Ejection
• End of Ventricular Systole - end systolic volume
• Onset of Ventricular Diastole
• Dicrotic notch
• Isovolumetric Ventricular Relaxation
• Ventricular Filling

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• The Cardiac Output
• Cardiac out (CO) volume of blood pumped by each
  ventricle per minute
• CO HR x SV, HR heart rate, SV stroke volume
• Starlings law of the heart
• Increased filling pressure (volume) leads to
  increased cardiac output
• If HR 72 beats/min, SV 0.07L/beat, then
• CO 72 beats/min X 0.07L/min
• 5.0 L/min

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• Autonomic innervation of the heart

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Principles of Animal Physiology
Circulatory Systems
Circulatory Pumps

• ACh
• ?APs interval of pacemaker cells ?? HR
• Negative chronotropic effect
• ?Velocity of conduction, may lead to AV
• block ? ectopic pacemaker
• Nor(epinephrine)
• ? heart rate via pacemaker cells
• Positive chronotropic effect
• ? strength of contraction (myocardial cells)
• Positive inotropic effect

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Principles of Animal Physiology
Circulatory Systems

• Autonomic control of SA node activity and heart
  rate

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Principles of Animal Physiology
Circulatory Systems

• Control of cardiac output

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Principles of Animal Physiology
Circulatory Systems

• Summary of factors influencing cardiac output

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Principles of Animal Physiology
Circulatory Systems

• Blood pressure in various blood vessels of the
  systemic circulation

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Principles of Animal Physiology
Circulatory Systems

• Relation btw. Velocity of blood flow and
  Xsectional area of vascular tree