What points towards the right shoulder?
The left hip?
Base
Apex
Location of the heart(cavities)?
Ventral
Thoracic
Mediastinum
Pericardial cavity
What are the three layers of the pericardium?
Superficial fibrous pericardium
Outer
Two layer. Serous pericardium
What is the function of the outer pericardium layer?
Protects anchors and prevents overfill
Epicardium contents and function?
Blood lymph and nerve supply
Produces serous fluid and protects
Myocardium function
Cardiac muscle Collagen and elastin Anchors cardiac muscle fibers Supports vesss and valves Limit spread of ap Arousal of heart
Endocardium?
Continuous with bv lining
What do surface grooves on heart do?
Three grooves?
Carry coronary bv to heart wall
Atrioventricular
Anterior/posterior interventricular sulcus
Characteristics of atria ?
Separated by interstitial septum
Thin walls
What do auricles do?
Increase atrial volume
What vessels feed the right atrium?
Vena cava
Coronary sinus
What vessels feed left atrium?
Pulmonary veins
What separates ventricles
Interventricular septum
What marks the position of the septum externally?
Ant/post interventriucular sulci
What does left ventricle recieve blood from and pump blood through?
Pulmonary veins
Aorta to systematic arteries
What does the right ventricle receive blood from and pump blood through?
Atrium
Pulmonary trunk–> arteries
Pulmonary circuit?
Carries blood to and from lungs
Systemic circuit?
To and from body tissues and coronary circuit
Pulmonary root of blood?
R ventricle–> pulmonary semilunar valve –> trunk–> arteries–> lung capillaries –> veins –> left atrium–> left av valve and then ventricle
Systemic circuit?
L ventricle–> aortic semilunar valve–> aorta –> systemic arteries –> tissue capillary beds–> systemic veins –> vena cavae –> r atrium -> right av valve –> right ventricle
Coronary circulation?
Blood supply to heart, has high ago demand many anastomoses
Arteries = coronary, marginal, circumflex, anterior interventriucular arteries
Vein = cardiac (small/ anterior/great)
Angina?
Temporary blockage to myocardium of blood
Lack of o2 weakens cells
Myocardial infarction
Heart attach
Coronary blockage -> lack of o2 -> cells die -> non contractile scar tissue replaces
Extent and location of Damage depends
Atrioventricular valves types and characteristics?
Right av= tricuspid prevent back flow in right atrium when r ventricle contracts
Left av = bicuspid prevents backflow in left atrium when ventricle contracts
What do chordate tendineae do?
Anchor av valve cusps to papillary muscles and prevent flaps from being inverted during ventricular contraction
What are papillary muscles for?
Contract before ventricles to take up slack of CT and prevent valves from being pushed open backwards into atria
Semilunar valves?
Right - (pulmonary) prevents backflow into r ventricle when relaxed
Left - aortic prevents bf into l ventricle when relaxed
Sounds you hear of a heart?
1= closing av valves contraction 2= closing SL valves relaxation
Heart murmurs?
Valve problem
Leaky valves
Murmurs , turbulence in blood flow
Stenosis
Narrows valves and impedes flow
Cardiac muscle cell characteristics?
Short, far, branched, uni nucleus , intercalated discs
T tubules in muscle cells
Mitochondria?
Wide but less numerous
Large and numerous
What do intercalated discs include?
Desisomes - contraction
Gap junctions - ion passage
How does the heart contract?
As a single unit
What kind of contraction does cardiac muscle have?
All or nothing, with long refractory period
What are pacemaker cells?
Initiate & distribute impulse , ensuring depolarization, auto rhythmic, unstable resting potential -60mv, that continuously depolarizes
What is the insintric conduction system?
Coordinated and synchronized heart, faster beat,
What is the order of autorhythmic cardiac cells?
SA Intermidal pw AV AV bundle R & L bundle branches Purkinje fibers
What does a sinoatrial node?
Generates impulse About 75/min
Depolarizes fastest
Atrioventricular node?
Smaller diameter fibers has fewer gap junctions
Delays jmpulses .1 second
Depolarizes 60 times/min in absense of SA node
Atrioventricular bundle?
Connection between atria and ventricles
Right and left bundle branches?
Two pw in interventriucular septum that carry impulses towards apex of heart
Purkinje fibers?
Complete pw into apex and ventricular walls
AV bundle and them depolarize 30/min in absence of av node input
Sequence of stimulation and contraction?
SA node develops pacemaker potential
Transmitted to walls of atria
atria contracts
Impulse delayed at av node atria completes contraction
Impulse transmitted from av node to walls of ventricles
Ventricles contract
Produces normal sinus rhythm
Arrhythmias?
Irregular heart rhythms
Uncoordinated atrial and ventricular contractions
Fibrillation ?
Rapid, irreg contractions
Defective SA node?
If av node takes over there will be a junctional rhythm (40-60bpm)
Defective av node results in?
Partial or total heart block
Few or no pulses from SA node reach the ventricles which best at different rate from atria
Too much coffee or nicotine?
PVC, extra systole premature ventriculAr contraction
Contraction of contractile cells?
Membrane starts of polarized
Stimulus from pacemaker cells cause na to rush in which causes depolarization and then ca enters which triggers opening of ca gates in sr.. Na gates shut, ca binds to tropinin, contraction, ca gates stay open causing depolarization plateau. Then k replolarizes, then ca causes an absolute refractory period
What does heart depend on?
Aerobic respiration, 02& fuel and adequate blood supply
Ischemia?
Blockage of coronary artery leads to o2 deficit myocardium
The 3 waves of ECG?
P - atria depolarization
Qrs - ventricle depolarization
T- ventricle repolarization
Four phases of a cardiac cycle?
Ventricular filling
Sty stole
Isovolumetric relaxtion
Quiescent period
What does rising ventricular pressure cause?
Av valves to close
Isovolumetric contraction phase?
All valves closed
Ejection phase of ventricle systole?
V pressure exceeds pressure in large arteries opening SL valves
Isovolumetric relaxation?
Docrotic notch (ride in aortic pressure) Ventricles relax
Quiescent period?
Everything relaxed (.4 secs)
Co?
Heart rate x stroke volume
5.25 avg
CO def?
Volume of blood pumped by each ventricle in one min
Cardiac reserve?
Max co - resting co
Three factors that affect sv?
Preload
Contractility
After load
Preload?
degree of stretch in cardiac muscle before they can contract
Frank starling law of heart?
Greater edv the greater the contraction force
What is edv increased by?
Slow heart beat and exercise
What is edv decreased by ?
Rapid heart rate and decreased bv
What is contrractility?
Increase force of contraction independent of muscle stretch and edv
What is contractility caused by?
Calcium ions
After load?
Pressure that must be overcome for ventricles to eject blood
Caused by htn
What makes it harder for ventricles to contract?
Back pressure in ventricular system