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Cardiovascular System (Heart Anatomy (Chambers and Circulation (Four…

- - - - Separated from other structures by paricardium
        
        Pericardial Cavity
        
        Tough membrane
  - - - Btw junction of 4th&5th ribs
    - - Slight deviation to the left
      - Depression in medial surface of inferior lobe of left lung
  - - - Male: 300-350 grams
      - Female: 250-200 grams
    - - Broad at superior surface
      - Tapering at apex
  - - - Right&Left Atria
        
        Receiving chamber
        
        Contracts to push blood into lower chambers
      - Right& Left Ventricles
        
        Primary pumping chambers
        
        Propel blood to lungs, or to rest of body
    - - Transports blood to/from lungs
        
        Blood picks up O2, delivers CO2 for exhaling
    - - Transport oxygenated blood to most tissues
      - Returns deoxygenated blood & CO2 to heart
        
        Goes back to pulmonary circulation
    - - Leads towards lungs
        
        Bifurcates into left&right Pulmonary Arteries
        
        Branches many times to reach Pulmonary Capillaries
        
        Gas exchange occurs
        
        CO2 exits blood & O2 enters
      - Right ventricle pumps deoxy blood towards PT
    - - Post-natal veins, carry oxy blood
      - Conducts blood in left atrium
        
        Pumps blood into left ventricle
        
        Pumps blood into aorta and onto branches of Systemic Circuit
        
        Eventually leads to systemic capillaries
        
        Exchange w tissue fluid and body cells occurs
    - - Return blood to right atrium
        
        Pumps blood into right ventricle
        
        Continues for a lifetime
      - Major systemic veins
  - - - Sturdy fibrous outer layer
        
        Dense connective tissue
        
        Protects heart
        
        Maintains hearts position in thorax
      - Inner serous layer
        
        Parietal Pericaridum
        
        Fused to fibrous pericard
        
        Inner visceral Pericardium
        
        Epicardium
        
        Fused to heart
        
        Filled w lubricating serous fluid
        
        Reduces friction as heart contracts
        
        Macroscopic
        
        Simple squamous epithelium
        
        Mesothelium
        
        Secretes lubricating fluid
        
        Reinforced w loose, irregular, or areolar conn tissue
    - - 2 auricles, artial leaf-like extension are visible
        
        Relatively thin-walled structures
        
        Can fill w blood & empty into artia
      - Sulci are prominent
        
        fat filled grooves
        
        superior surface
        
        Major coronary blood located here
        
        anterior interventricular sulcus
        
        anterior surface
        
        posterior interventricular sulcus
        
        posterior surface
    - - Epicardium
      - Myocardium
        
        Middle, thickest layer
        
        Built on framework of collagenous fibers
        
        +blood vessels that supply myocard/nerve fibers
        
        regulates the heart
        
        Contracts to pump blood thru heart/major arteries
        
        Muscles swirl/spiral around chambers of heart
        
        Figure 8 pattern
        
        Around artia & bases of great vessels
        
        Allows heart to pump more effectively
        
        Thicker muscle of left ventricle
        
        Generates >pressure
        
        High resistance to pump blood into long systemic circuit
      - Endocardium
        
        Innermost layer
        
        Joined to myocard by thin conn tissue
        
        simple squamous epithelium
        
        Endothelium
        
        Regulates myocardial muscle contraction
        
        Regulates growth of cardiac muscle cells
        
        Secretes endothelins
        
        potent vasoconstrictors
        
        establish homeostatic balance
        
        Regulate ionic concentrations
        
        Regulate states of contractility
  - - - Wall that divides chambers
      - Interatrial Septum
        
        In btw 2 artia
        
        Fossa ovalis
        
        Remnant of fetal foramen ovale
        
        Allowed blood to pass directly from l to r artium
        
        allowed blood to bypass pulmonary circuit
      - Extensions of myocardium
        
        Lined w endocardium
      - Interventricular
        
        Thick bc pressure
        
        Separates ventricle
      - Atrioventricular
        
        Four openings
        
        atria to ventricles to pulmonary trunk&aorta
        
        Each opening has a valve
        
        ensures one-way flow
        
        atrioventricular
        
        Btw right atrium&ventricle: tricuspid
        
        3 flaps, leaflets
        
        2 more items...
        
        Btw left atrium&ventricle: mitral; bicuspid
        
        2 cusps, anterior&posterior medials
        
        1 more item...
        
        semilunar valves
        
        pulmonary semilunar; right; pulmonic
        
        3 small flaps
        
        2 more items...
        
        aortic semilunar;aortic valve
        
        prevents backflow from aorta
        
        3 flaps
        
        1 more item...
        
        Dense connective tissue
        
        cardiac skeleton
        
        four rings surround openings btw artia&ventricles,PT&aorta
        
        Point of attachment for heart valves
        
        Provides boundary for electrical conduction system
    - - Receiving chamber for blood
        
        From systemic circulation, coronary sinus
      - Bulk of internal surface is smooth
      - Pectinate Muscles
        
        Anterior surface
      - Tricuspid valve
        
        Guards opening btw atrium&venticles
    - - Receives blood from right atrium
        
        Thru tricuspid valve
        
        Each flap of valve attached to chordae tendineae
        
        Strong strands of conn tissue
        
        tendinous cords
        
        heart strings
        
        80% collagenous fiber
        
        also elastic fiber, endothelium
        
        Connect each flap to papillary muscle
        
        Anterior, posterior, septal
        
        contractions generate tension on CT
      - Trabeculae Carneae
        
        Ridges of cardiac muscle
        
        covered by endocardium
        
        moderator band
        
        lines walls of ventricle
        
        crucial role in cardiac conduction
    - - Oxygenated blood returns here
        
        Via 1/4 pulmonary veins
      - Auricle contains pectinate ridges
      - artial contraction is 20% of ventricular filling
      - opening btw left atrium & ventricle guarded by mitral valve
    - - Thick muscular layer
      - Trabecualae Carneae
      - Mitral Valve
        
        Connected to papillary muscles via chordae tendineae
        
        Two papillary on left, three on right
      - Major pumping chamber for systemic circuit
        
        Ejects blood into aorta via aortic semilunar valve
  - - - requires reliable source of O2&nurtients
      - requires way to remove waste
      - needs dedicated/complex circulatory system
    - - Supply blood to myocardium
      - rise from left posterior aortic sinus & anterior aortic sinus
        
        to make left&right coronary arteries
      - Left CA
        
        distributes blood to left side of heart
        
        also left atrium&ventricle, &interventricular septum
        
        gives rise to circumflex artery
        
        eventually fuses w right CA
        
        gives rise to anterior interventricular artery
        
        Anatomosis
        
        vessels unite to form interconnectiions
        
        allows blood to circulate to region
        
        even if they're blocked
        
        very small
      - Right CA
        
        distributes blood to right atrium`
        
        also both ventricles&the heart conduction system
        
        gives rise to marginal arteries
        
        supply blood to superficial right ventricle
        
        gives rise to posterior interventricular artery
        
        supplies interventricular septum&both ventricles
    - - drain the heart
      - Great cardiac vein
        
        surface of heart following interventricular sulcus
        
        eventually flows along coronary sulcus
        
        into coronary sinus
        
        on the posterior surface
        
        receives posterior cardiac vein
        
        drains areas supplied by marginal artery branch
        
        of circumflex artery
        
        receives middle cardiac vein
        
        drains areas supplied by posterior interventricular artery
        
        receives small cardiac vein
        
        drains anterior surface of right ventricle
        
        bypasses coronary sinus
        
        drains directly into right atrium
- - - - In one minute
  - - - per beat
    - - venous return alters stretch of heart
      - inotropic agents influence crossbridge form
    - - relevant in elderly
  - - - results in optimal filament overlap
    - - heart contracts +forcefully when filled w +blood
  - - - women&children
    - - change heart rate
      - alter act of nodal cells
        
        SA and/or AV node
      - work via ANS or hormones
      - Positive CAs +heart rate
        
        sympathetic nerve stimulation
        
        causes norepinephren release on heart
        
        causes adrenal to release EPI&NE
        
        bind to nodal cells
        
        increase NC firing rate
        
        receptors=beta1 adrenergic
        
        G-protein, adenylate cyclase, cAMP, pkc
        
        phosphorylated CA2+ channels enhance CA2+ influx
        
        1 more item...
        
        Thyroid hormone, caffeine, nicotine, cocaine
      - Negative CAs -heart rate
        
        Parasympathetic activity
        
        PS axons release ACh on nodal cells
        
        ACh binds M2 muscarinic receps (K channels)
        
        Channels open
        
        K+ exits, cell becomes more negative
        
        longer time for nodal cells to reach threshold
        
        makes heart rate slower
        
        Beta-blocker drugs
        
        interfere with EPI and NE beta binding
        
        used to treat high BP
    - - baroreceptors&chemoreceptors
        
        send signals to cardiac center
        
        influences symp and parasymp to alter cardiac output
    - - protects heart from overfilling
      - Baroreceptors in artial walls
        
        stimulated by +venous return
      - +nerve signals to cardioacceleratory center
      - +excitation of symp axons
        
        to heart
      - heart rate+ to move blood thru quick
        
        less atrial stretch
    - - low RHR
        
        <60BPM
      - normal in athletes
      - hypothyroidism, electrolyte imbalance, congestive heart failure
    - - high RHR
        
        100 BPM
      - heart disease, fever, anxiety
    - - rapid, irregular heart rate
  - - - or amt of blood in vent. b4 systole
  - - - after contraction finished
  - - - prior to contraction
      - EDV
    - - or increase time to fill
        
        +w slower heart rate
      - +during exercise
  - - - at end of diastole
  - - - to ejection of blood by ventricles
      - pressure must be > b4 blood ejected
    - - plaque in vessel lining
      - increases afterload
      - seen w aging
      - results in -SV
- - - - have narrower lumen than veins
    - - More than veins
      - More resistant to BP changes
    - - extending from the heart
      - decrease in lumen diameter
      - decrease in elastic fibers
      - increase in smooth muscle
    - - Elastic
        
        Largest, diamter 2.5 to 1 cm
        
        conduct blood from heart to M.A.
        
        have large amt of elastic fibers
        
        allows for stretch/recoil
        
        helps propel blood thru arteries
        
        during diastole
        
        conducting
      - Muscular
        
        distributing
        
        Medium arteries, diameter from 1 to 3 cm
        
        distribute blood to specific regions
        
        muscle allows vasoconstriciton
        
        and dilation
        
        Elastic tissue in two layers
        
        internal elastic lamina
        
        btw tunic intima & tunic media
        
        External elastic lamina
        
        btw tunic media & tunic externa
      - Arterioles
        
        Smallest, diameter 3 to 10 mm
        
        largest have 3 tunics
        
        smaller have only thin endothelium
        
        plus single layer smooth muscle
        
        smooth muscle somewhat constricted
        
        vasomotor tone
        
        regulated by vasomotor center in brain
  - - - no subendothelial layer
      - composed of endothelium, basement membrane
    - - Allows for rapid gas/nutrient exchange
    - - 8 to 10 mm in diameter
    - - Continuous
        
        endothelial cells form a continuous linign
        
        tight junctions connect cells
        
        do not form complete seal
        
        intercellular clefts
        
        large particles cannot pass
        
        cells, proteins
        
        smaller molecule can pass thru
        
        glucose
        
        Common
        
        muscle, skin, lungs, CNS
      - Fenestrated
        
        Continuous, but with pores
        
        allows mvmt of smaller plasma proteins
        
        found where much fluid transport happens
        
        intestine capillaries
        
        absorbing nurtients
        
        kidney capillaries
        
        filtering blood to form urine
      - Sinusoid
        
        discontinuous capillaries
        
        endothelial cells form incomplete lining
        
        has large gaps
        
        incomplete/absent basement membrane
        
        openings allow transport of large substances
        
        formed elements, large proteins
        
        found in bone marrow, spleen, some endo glands
    - - groups of capillaries functioning together
      - fed by metarteiole
      - precapillary sphincter
        
        smooth muscle ring
        
        at true cap origin
        
        relaxation permits blood to flow
        
        contraction causes blood to bypass
      - perfusion
        
        amt entering capillaries
        
        mL/min/g
  - - - Have narrower lumen than arteries
    - - less than arteries
      - wall collapses if no blood in vessel
    - - smallest, diameter 8 to 100 mm
      - companion vessels w arterioles
      - smallest are post cap venules
      - largest have all 3 tunics
      - merge to form veins
    - - most larger veins have lot of valves
        
        prevent blood from pooling in limbs
        
        ensure flow towards heart
        
        valves: tunica intima&elastic&collagen fibers
        
        similar to semilunar valves
    - - how blood moves from veins into circ
    - - blood shifted back into reservoirs
- - - - ensure proper timing of contraction
    - - have action potentials, do not contract
    - - initiates heartbeat
        
        pacemaker
      - location
        
        posterior wall of right atrium
      - Internodal pathways (SECOND)
    - - location
        
        floor of right atrium
        
        near right AV valve
    - - Bundle of His
      - Extends from AV node
        
        Through interventricular septum
      - divides into left and right bundles (FIFTH)
    - - Course thru walls of ventricles
      - extend from left and right bundles
        
        at heart's apex
  - - - rapid influx of Ca2+, outflux of K+
- - - - QRS Complex
    - - P Wave
    - - T Wave
  - - - Contraction of atria follows depolarization
      - contract from superior portion to atrioventricular septum
        
        pressure rises, blood pumped into ventricles thru valves
      - Start of atrial systole: ventricles filled 75% of cap.
        
        due to inflow during diastole
        
        atrial contraction contributes to remaining space
        
        atrial kick
      - Atrial systole last 100ms
        
        ends prior to ventricular systole
    - - follows depolarization of ventricles
      - lasts 270 ms
      - at end of atrial systole, prior to atrial contrac
        
        ventricles contain 130mL blood
        
        known as End Diastolic Volume, preload
      - Initial ventricle contraction
        
        chamber blood pressure rises
        
        blood flows back towards atria
        
        volume remains constant
        
        AKA isovolumic contraction
      - Ventricular ejection phase
        
        2nd phase
        
        pressure is > than PT & aorta
        
        blood pumped thru semilunar valves
        
        both ventricles pump same amt of blood
        
        pressure in aorta will be higher
      - End systolic volume will be 50-60mL
        
        blood remaining in ventricle
    - - Ventricular relaxtion
      - follows repolarization of ventricles
      - Lasts 430 ms
      - Early phase
        
        pressure within ventricle begins to fall
        
        when lower than PT&Aorta, blood flows back to heart
        
        produces dicrotic notch
        
        semilunar valves close
        
        no change in volume
        
        isovolumic ventricular relaxation phase
      - Late ventricular diastole
        
        ventricular muscle relaxes, BP drops further
        
        drops below atrial pressure
        
        blood flows from major veins into atria
        
        blood flows from atria into ventricles
        
        both chambers are in diastole, semilunar valves remain closed
        
        1 more item...
  - - - diastole
      - blood flows from veins into atria
        
        pressure rises
        
        blood moves passively into ventricles
    - - atrial systole
      - atrial pressure rises, more blood pumped in ventricles
    - - pressure rises in ventricles
        
        blood pumps into PT & aorta
- - - - Response to exercise
        
        Hypertrophy
        
        Athlete hearts pump blood more effectively
        
        Results in +protein myofilaments that >size w/o >#
      - Striations
        
        alternating A and I bands
      - Can have >1 nucleus
    - - Cardiomyocytes are short, small diameters
      - cardio T-tubules found only at Z-discs
        
        cardio has 1/2 as many t-tubules
      - slower cardio contraction
      - cardio is involuntary
      - cardio has long refractory period
  - - - myocardial contractile cells
        
        99% of cells in atria, ventricles
        
        conduct impulses
        
        responsible for contractions
        
        propel the blood
        
        AP w extended plateau phase
        
        results in extended refractory period
        
        allows completion of heart contraction
        
        necessary for effective blood pumping
      - myocardial conducting cells
        
        1% of cells
        
        form conduction system
        
        generally smaller than contractile cells
        
        except purkinje
        
        similar functions to neurons
        
        initiate/propagate AP
        
        travels throughout heart
        
        triggers contractions that propel blood
        
        Establish heart rate
        
        transmit it thru myocardium
      - T-tubules penetrate from sarcolemma to interior of cell
        
        allows electric impulse to reach interior
        
        found only at Z-discs
        
        Sarcoplasmic reticulum store few calcium ions
        
        most Ca+ comes from outside cell
        
        results in slower onset of contraction
      - Branch freely, junctioned by intercalated discs
        
        synchronized contraction of muscle
        
        sacrolemmas bind here
        
        consist of desmosomes
        
        have tight junctions
        
        large # of gap junctions
        
        allows passage of ions btw cells
        
        help sync contraction
  - - - spreads rapidly from cell to cell
        
        triggers contractile mechanism
    - - endocrine, nervous systems