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Heart - Coggle Diagram

- - - - Communication between major coronary arteries and branches
      - May dilate and provide blood supply beyond the obstructed/stenosed epicardial vessel/between side branches of two arteries/ branches
        of same artery or within the same branch.
      - May develop between the terminal extension of two arteries
    - - meet the metabolic demand of the heart.
        
        meet myocardial oxygen
        consumption.
        
        major determinants of myocardial oxygen consumption
        
        heart rate
        
        myocardial wall tension/stress
        
        inotropic state
        
        Myocardial oxygen consumption determines
        
        Vascular resistance
        
        Modulated maily by
        
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        During strenuous exercise
        
        coronary blood flow increases up to 4–6
        times
        
        Impairment on it could be seen in conditions such as
        
        left ventricular
        hypertrophy (LVH),
        
        myocardial ischaemia
        
        epicardial conduit resistance
        
        atherosclerotic stenosis and distal vascular
        bed
        
        maintains satisfactory blood flow by dilating
        
        maximal increase in coronary flow above resting levels
        is defined as coronary flow reserve
        
        CRF
  - - - receives most of
        the venous return from the epicardium and myocardium
      - opens into the right atrium
      - gives rise to tributaries
        
        Great cardiac vein
        
        drain
        
        anterior portion of the interventricular septum
        
        anterior aspects of both ventricles
        
        Middle cardiac vein
        
        Drain
        
        posterior portion
        of the interventricular septum
        
        posterior aspect of both ventricles
        
        Smaller cardiac vein
        
        Drain
        
        Marginal aspect of the right ventricle
        
        Oblique vein
    - - Thebesian
        
        Drain
        
        Endocardium
        
        innermost layers of the myocardium
  - - - junction between anterior and inferior wall of the right ventricle
    - - rounded lateral wall of left ventricle
  - - - Sympathetic
        
        Sympathetic nerves effects
        
        Accelatory
        
        Increase heart rate
        
        Chronotropy
        
        Increase stroke volume
        
        Increase contractility
        
        Ionotropy
        
        Increase speed of conduction
        
        Dromotropy
        
        Mediated by
        
        Adrenergic receptors
        
        β-1
        
        Manily in
        
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        β-2
        
        Mainly in
        
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        Increase cAMP levels through adenylate cyclase
        
        Sympathtetic path ways
        
        Afferent nerves
        
        Via
        
        Cardiac accelerator nerves
        
        Thoracic splanchnic nerves
        
        Reach
        
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        SA node receives most
        of it nerve fibres
        
        right-sided thoracic sympathetic
        ganglia
        
        right vagus
        
        AV nodes
        and ventricles recieve some nerve fibers
        
        leftsided
        thoracic sympathetic ganglia
        
        left vagus
      - Parasympathetic
        
        homeostasis
        
        Main transmitter
        
        acetylcholine
        
        parasympathetic vagal fibres effects
        
        Inhibitory
        
        Reduce heart rate
        
        Reduce stroke volume
        
        Reduce contraction
        
        Reduce conduction velocity
        
        Mediated by
        
        muscaranic
        receptors
        
        act by inhibition of adenylate cyclase
        
        catalyzes the formation of cyclic adenosine monophosphate
        
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        Parasympathetic pathways
        
        Vagi nerves
        
        supply parasympathetic
        fibres
        
        Via cardiax plexuses
        
        To the heart
      - Located close to the arch of the aorta
      - Fibres
        
        Acompany coronary arteries
        
        Reach the heart
        
        Most of them terminate at the nodes
        
        SA
        
        AV
        
        Few of the terminate on atrial and ventricular myocardium
    - - Mainly
        
        vasomotor
        centre of medulla
        
        hypothalamus
      - regulate
        the balance between the level of sympathetic and the parasympathetic output
        
        to the cardiovascular system
        
        normally a tonic
        vagal discharge
        
        overrides the moderate
        tonic discharge in the cardiac sympathetic nerves
      - Receptors
        
        target of numerous drugs
        
        treatment of various cardiovascular disorders
      - Vagi and splanchnic thoracic nerves
        
        Regulate cardiovascular function
        
        Afferent input
        
        Baroreceptors
        
        Regulate arterial pressure
        
        Regulate heart rate
        
        Chemoreceptors
        
        Regulate breathing
        
        O2 levels
        
        CO2 levels
        
        Efferent output
        
        Control bodies response to changes on the heart
        
        Sympathetic and parasympathetic
  - - - Sinus node
        
        Sinoatrial
        
        Location
        
        Right atrium
        
        Near the superior vena cava
        
        Cista terminalis
        
        Inervation
        
        principally by the parasympathetic
        nervous system
      - Node of Tawara
        
        Location
        
        Right atrium
        
        part
        of the inter-atrial septum
        
        gives rise to the AV bundle
      - AV Bundle of His
        
        closely related to the annuli of aortic, mitral and tricuspid valves
        
        Supply
        
        AV nodal
        artery
        
        first septal perforator of LAD
        
        Divides
        
        Right bundle branch
        
        Along right side of the inter-ventricular septum to the
        tips of the two ventricles
        
        Left bundle branch
        
        Along the left side of the inter-ventricular septum to the
        tips of the two ventricles
- - - - Tissues
    - - Eliminated by
        
        Liver
        
        Kidneys
        
        Lungs
    - - When the pressure of the upper chamber is higher than the pressure of the lower chamber the valve opens
        
        Aurioventricular valves
        
        Blood increases pressure
        
        When the lower chamber{s pressure increase the pulmonary or aortic valve opens
    - - unique ability of automatic
        impulse generation
        
        automatic rhythmicity.
    - - Determined by K+ conductance
      - Action potential
        
        sudden, rapid, transient, and propagating change in the resting membrane potential.
        
        initiated by increased membrane conductance of sodium ions
        
        upstroke
        
        Phase 0
        
        After an increased membran conductance of potasium ions
        
        Initial repolarisation phase
        
        Decreaed sodium ion conductance
        
        Phase 1
        
        transient increase in inward Ca++ ion and outwrad K+ ion conductance
        
        Phase 2
        
        plateau phase
        
        declining inward Ca++ ion conductance
        and an increase in the outward K+ ion conductance
        
        3 more items...
        
        long duration about 300 ms
  - - - Hormonal
      - Intrinsic
      - Neural
    - - stimulation of one
        cardiac cell initiates stimulation of adjacent cells
      - Types
        
        Electrical
        
        specialised myocardial cells
        
        lost the
        ability to contract
        
        conduction and formation of cardiac impulses
        
        Properties
        
        conductivity
        
        ability to transmit electrical impulse from one
        cell to another
        
        excitability - ability of the cell to respond
        to electrical impulses
        
        automaticity
        
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        positively charged ions across the cardiac cell
        
        membranes results in the formation of these electrical
        
        impulses
        
        The movement of the primary
        
        intracellular ion (potassium) and primary extracellular
        
        ion (sodium) mediates the regulation of electrical
        
        charges.
        
        The cyclical shift of ions changes the electrical
        
        field inside the cell leading to depolarisation and repolarisation
        
        [
        
        1 more item...
        
        In the resting state of the cell, the electrical activity is
        
        more positive outside the cell and more negative inside
        
        the cell and no electrical activity occurs
        
        When
        
        the cell is stimulated, the permeability of the membrane
        
        changes allowing sodium to enter the cell
        
        1 more item...
        
        Myocardial
        
        Two properties
        
        contractility
        
        contraction mechanism
        
        excitation–contraction coupling
        
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        extensibility
      - The depolarisation (electrical
        
        activation), contraction and repolarisation (Fig.
        
        1.10) of cardiac cells is due to the ability of the electrical
        
        cells to generate and conduct electrical impulses
  - - - contractility
        
        ionotropy
      - speed of conduction
        
        dromotropy
      - increasing
        the heart rate
        
        chronotropy