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A&P2 > Ch20 > Flashcards

Ch20 Flashcards

1
Q
  • located at the mediastinum- extending form the sternum to the vertberal column, the first rib to the diaphragm and btwn the lungs
  • heart outward appearance
  • apex at tip of left ventricle
  • base is posterior surface
  • anterior surface deep to sternum and ribs
  • infereior surface betwn apex and R border
  • right border faces R lung
  • pulmonary border faces L lung
A

anatomy of the heart

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2
Q
  • Membrane surrounding and protecting the heart
  • Confines while still allowing free movement
  • includes fibrous , serous, and pericardial fluid
A

pericardium

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3
Q
  • Tough, inelastic, dense irregular connective tissue
  • Prevents overstretching, provides protection and anchorage
A

fibrous pericardium

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4
Q
  • Thinner, more delicate membrane
  • Double layer (parietal layer fused to fibrous pericardium, visceral layer also called epicardium)
A

serous pericardium

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5
Q
  • Secreted into pericardial cavity
  • reduces friction
A

pericardial flluid

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6
Q
  • Visceral layer of serous pericardium
  • Smooth, slippery texture to outermost surface
A

epidcardium(external layer)

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7
Q
  • 95% of heart is cardiac muscle
  • middle layer
A

myocardium

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8
Q
  • (inner layer)
  • Smooth lining for chambers of heart, valves and continuous with lining of large blood vessels
A

endocardium

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9
Q
  • ATRIA are Receiving chambers:Right and left
  • Auricles increase capacity
  • VENTRICLES:Right and left
  • Pumping chambers
  • SUCLI:Grooves on the surface of the heart
  • Contain coronary blood vessels
  • Coronary sulcus
  • Anterior interventricular sulcus
A

chambers of the heart

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10
Q
  • Forms right border of the heart
  • _Receives blood from vein_s:Superior vena cava,Inferior vena cava,Coronary sinus
  • Interatrial septum:Separates right and left atrium
  • Has fossa ovalis Remnant of foramen ovale
  • Tricuspid valve:Separates right atrium from right ventricle
A

right atrium

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11
Q
  • forms anterior surface of heart
  • includes trabeculae carneae, tricuspid valve
  • blood leaves thru pulmonary valve into pulmonary trunk and then to R and L pulmonary arteries
A

right ventricle

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12
Q
  • Ridges formed by raised bundles of cardiac muscle fiber
  • Part of conduction system of the heart
  • located on right ventricle
A

trabeculate carneae

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13
Q
  • Connected to chordae tendinae connected to papillary muscles
  • Interventricular septum
  • located on right ventricle
A

tricuspid valve

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14
Q
  • About the same thickness as right atrium
  • Valve
  • Left atrioventricular valve
  • Bicuspid (mitral)
  • Separates left atrium from left ventricle
  • Receives blood from the lungs through pulmonary veins
  • Passes blood through bicuspid valve into left ventricle
A

Left atrium

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15
Q
  • thickest chamber of heart
  • forms apex
  • chordae tendinae attached to paillary muscles
  • blood passes thru aortic valve into ascending aorta
  • some blood flows into coronary arteries
  • during fetal life ductus arteriosus shunts blod from pulmonary trunk to aorta; closes after birth with remnany called ligamentum arteriosum
A

left ventricle

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16
Q

right ventricle pump blood to __ lungs; shorter distance, lower pressure and less resistance while the left ventricle pumps blood to __body bc longer distance, high pressure and more resistance

A

lungs, body

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17
Q

left ventricle works ___to maintain same rate of blood flow as right ventricle

A

harder

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18
Q
  • Dense connective tissue that forms a structural foundation, point of insertion for muscle bundles, and electrical insulator between atria and ventricles
A

fibrous skeleton

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19
Q
  • Tricuspid and bicuspid valves
  • When atria contract and ventricles are relaxed AV valves open, cusps project into ventricles
  • In ventricles, papillary muscles are relaxed and chordae tendinae are slack
  • When atria relax and ventricles contract
  • Pressure drives cusps upward until edges meet and close opening
  • Papillary muscles contract tightening chordae tendinae
  • Prevents regurgitation
A

atrioventricular valves(AV)

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20
Q
  • Aortic and pulmonary valves
  • Valves open when pressure in ventricle exceeds pressure in arteries
  • As ventricles relax, some backflow permitted but blood fills valve cusps closing them tightly
  • No valves guarding entrance to atria
  • As atria contract, they compress and nearly collapse the venous entry points
A

semilunar valves

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21
Q
  • Left side of heart
  • Receives blood from lungs
  • Ejects blood into aorta
  • Systemic arteries, arterioles
  • Gas and nutrient exchange in systemic capillaries
  • Systemic venules and veins lead back to right atrium
A

systemic circuit

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22
Q
  • Right side of heart
  • Receives blood from systemic circulation
  • Ejects blood into pulmonary trunk then pulmonary arteries
  • Gas exchange in pulmonary capillaries
  • Pulmonary veins takes blood to left atrium
A

pulmonary circuit

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23
Q
  1. right atrium(deoxygenated blood)
  2. tricuspid valve to right centricle
  3. pulmonary valve to pulmonary trunk and pulm arteries
  4. in pulm capillaries, blood loses CO2 and gains O2
  5. pulm veins(oxygenated blood)
  6. left atrium
  7. bicupsid valve to left ventricle
  8. aortic valve to aorta and systemic artieries
  9. in systemic capillaries blood loses O2 and gains CO2
  10. superior vena cava, inferior vena cava and coronary sinus lead back to the right atrium
A

blood flow diagram

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24
Q
  • Myocardium has its own network of blood vessels
  • Coronary arteries branch from ascending aorta
  • [Anastomoses provide alternate routes or collateral circuits/Allows heart muscle to receive sufficient oxygen even if an artery is partially blocked]
  • Coronary capillaries
  • Coronary veins[Collect in coronary sinus,Empty into right atrium]
A

coronary circulation

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25
Q
  • Shorter and less circular than skeletal muscle fibers
  • Branching gives “stair-step” appearance
  • Usually one centrally located nucleus
  • Ends of fibers connected by intercalated discs containing desmosomes (hold fibers together) and gap junctions (allow action potential conduction from one fiber to the next)
  • Mitochondria are larger and more numerous than in skeletal muscle
  • Same arrangement of actin and myosin
A

histology of cardiac muscle tissue

26
Q
  • specialized cardiac muscle fibers that are self excitable
  • repeatedly generate action potentials that trigger heart contractions
  • pacemaker /form conduction system
A

autorhythmic fibers

27
Q
  1. SA node in right atrial wall propagates thru atria(via gap junctions) to contrac atria
  2. reaches AV node in interatrial septum
  3. enters AV bundle of his where action potentials can conduct from atria to ventricles due to fibrous skelton
  4. enters R and L bundle branches which extend thru interventricular septum toward apex
  5. largediameter purkinje fibers conduct action potential to remainder of ventricular myocardium where ventricles contract
A

conduction system

28
Q
  1. SA node
  2. AV node
  3. AV bundle(bundle of his)
  4. right and left bundle branches
  5. purkinje fibers
A

conduction system

29
Q
  • initiates 100x per sec
  • nerve impules form ANS and hormones modify timing and strength of each heartbeat but doesnt est fundamental rhythm
A

(in the conduction system)SA node

30
Q

initiated by SA node spreads out to excite “working” fibers called contractile fibers
Stages :

  1. Depolarization
  2. Plateau
  3. Repolarization
A

action potential

31
Q
  • contractile fibers have stable resting membrane potential
  • Voltage-gated fast Na+ channels open
  • Na+ flows in
  • Then deactivate and Na+ inflow decreases
A

depolarization in action potential

32
Q

– period of maintained depolarization

  • Due in part to opening of voltage-gated slow Ca2+ channels
  • Ca2+ moves from interstitial fluid into cytosol
  • Ultimately triggers contraction
  • Depolarization sustained due to voltage-gated K+ channels balancing Ca inflow with K outlflow
A

plateua (2nd stage of action potential)

33
Q

recovery of resting membrane potential

  • Resembles that in other excitable cells
  • Additional voltage-gated K+ channels open
  • Outflow of K+ restores negative resting membrane potential
  • Calcium channels close
A

repolarization- last stage of action potential

34
Q
  • time interval during which second contraction cannot be triggered
  • Lasts longer than contraction itself
  • Tetanus (maintained contraction) cannot occur
A

refractory period of action potentials

35
Q
  • Composite record of action potentials produced by all the heart muscle fibers
  • Compare tracings from different leads with one another and with normal records
  • 3 waves: P, QRS, and T
A

ECG or EKG(electrocardiogram)

36
Q
  • systole=contraction
  • diastole=__
A

relaxation

37
Q

wave in which: cardiac action potential arises in SA node

A

P wave

38
Q
  • Atrial contraction (atrial systole)
  • Action potential enters AV bundle and out over ventricles
  • Masks atrial repolarization
A

QRS complex wave

39
Q

contraction of ventricles(ventricular systole) begins shortly after QRS complex appears and continues during ____ segement

A

S-T

40
Q

wave of repolarization of ventricular fibers and then ventricular relaxation (diastole)

A

T wave

41
Q
  1. depolarization of atrial contractile fibers in SA node (P)
  2. atrial systole (contraction)
  3. depolarization of ventricular contractile fibers (QRS)
  4. ventricular systole
  5. repolarization of ventricular contractile fibers (T)
  6. ventricular diastole [relaxation]
A

action potential and contraction on ECG

42
Q
  • All events associated with one heartbeat
  • Systole and diastole of atria and ventricles
  • Forces blood from higher pressure to lower pressure
  • During relaxation period, both atria and ventricles are relaxed
    • The faster the heart beats, the shorter the relaxation period
    • Systole and diastole lengths shorten slightly
A

cardiac cycle

43
Q
  • During atrial systole, ventricles are relaxed
  • During ventricle systole, atria are relaxed
A

In each cardiac cycle, atria and ventricles alternately contract and relax

44
Q
  • Auscultation
  • Sound of heartbeat comes primarily from blood turbulence caused by closing of heart valves
  • 4 heart sounds in each cardiac cycle – only 2 loud enough to be heard
    • Lubb – AV valves close
    • Dupp – SL valves close
A

heart sounds

45
Q

the amount of blood pumped by each ventricle in one minute

A

cardiac output

46
Q

Cardiac output (ml/min)= heart rate (beats/min) x stroke volume (ml/beat)

A

cardiac output equation

47
Q
  • = volume of blood ejected from left (or right) ventricle into aorta (or pulmonary trunk) each minute
  • Entire blood volume flows through pulmonary and systemic circuits each minute
A

CO

48
Q
  • __ ___- difference between maximum CO and CO at rest
  • Average ___ ___is 4-5 times resting value
A

cardiac reserve

49
Q
  1. Preload – effect of stretching
  2. Contractility
  3. Afterload – force to be overcome

all are factors that ensure left and right ventricles pump equal volumes of blood

A

regulation of stroke volume

50
Q
  • Degree of stretch on the heart before it contracts
  • Greater preload increases the force of contraction
  • Frank-Starling law of the heart – the more the heart fills with blood during diastole, the greater the force of contraction during systole
  • Preload proportional to end-diastolic volume (EDV)
  • Factors that determine EDV
  • Duration of ventricular diastole
  • Venous return – volume of blood returning to right ventricle
A

preoad

51
Q
  • Strength of contraction at any given preload
  • Positive inotropic agents increase contractility
  • Often promote Ca2+ inflow during cardiac action potential
  • Increase stroke volume
  • Epinephrine, norepinephrine, digitalis
  • Negative inotropic agents decrease contractility
  • Anoxia, acidosis, some anesthetics, and increased K+ in interstitial fluid
A

contractility

52
Q
  • Pressure that must be overcome before a semilunar valve can open
  • Increase in afterload causes stroke volume to decrease
  • Blood remains in ventricle at the end of systole
  • Hypertension and atherosclerosis increase afterload
A

afterload

53
Q
  • Cardiac output depends on heart rate and stroke volume
  • Adjustments in heart rate important in short-term control of cardiac output and blood pressure
  • Autonomic nervous system and epinephrine/ norepinephrine most important
A

regulation of heart beat

54
Q
  • Originates in cardiovascular center of medulla oblongata
  • Increases or decreases frequency of nerve impulses in both sympathetic and parasympathetic branches of ANS
  • Noreprinephrine has two separate effects
  • In SA and AV node speeds rate of spontaneous depolarization
  • In contractile fibers enhances Ca2+ entry increasing contractility
  • Parasympathetic nerves release acetylcholine which decreases heart rate by slowing rate of spontaneous depolarization
A

autonomic regulation

55
Q
  1. input to cardiovascular center:
  • higher brain centers like cerebral cortex, limbic sys, and hypothalamus
  • sensory receptors like proprioceptors,chemoreceptors, and baroreceptors
  1. output to heart:
  • cardiac accerlerator nerves(sympathetic)increased rate of spontaneous depolarization in SA node increases heart rate
  • increased contractility of atria and ventricles increase stroke volume
  • VAGUS nerves(parasympathetic)->descreased rate of spontaneous depolarization in SA node decreases heart rate
A

nervous system control of the heart

56
Q
  • Epinephrine and norepinephrine increase heart rate and contractility
  • Thyroid hormones also increase heart rate and contractility
A

hormones

57
Q
  • Ionic imbalance can compromise pumping effectiveness
  • Relative concentration of K+, Ca2+ and Na+ important
A

cations

58
Q

superior part of the interventricular septum fails to form; blood mixes betwn 2 ventricles but bc the left is stronger, more blood shunted form left to righ [1 in every 500 births]

A

ventricular septal defect

59
Q

part of the aorta is narrowed, increasing hte workload on the left ventricle[1 in ever 1500 births]

A

coartation of the aorta

60
Q

multiple defects; pulmonary trunk too narrow and pulmonary valve stenosed resulting in a hypertrophied right ventricle; ventricular septal defect; aorta opens form both ventricles; wall of right ventricle thickened form over work(1 in every 2000 births]

A

tetralogy of fallot

61
Q
A

A&P2 (17 decks)

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