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Anatomy and Physiology Ch.19 The Heart Test 2

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What are the 2 major divisions of the cardiovascular system?
Pulmonary and systemic circuit
Pulmonary circuit
primarily the right side of the heart; pumps blood to the lungs
Systemic circuit
primarily the left side of the heart; pumps blood to the rest of the body
Mediastinum
centrally located between the lungs; contains the heart and great vessels (aorta, vena cava); contains the thymus and trachea
the base of the heart
on top of the heart; where main vessels located
apex
the bottom of the heart
pericardium
the parietal and visceral layers. has pericardial fluid between these.
pericarditis
inflammation of the pericardium
parietal pericardium
outside layer of the pericardium and is tough for protection
visceral pericardium or epicardium
inside layer of the pericardium and is very thin; it goes by different names with respect to different areas
myocardium
the involuntary muscles that pump the heart is thick and has spiral fibers which force more blood out of the heart
endocardium
the layer that lines the interior of the heart chambers and is very thin
atria
the chambers of the heart that receive blood from the vessels and are the top chambers
ventricles
the cambers of the heart that are on the bottom and receive blood from the atria; left wall is always thicker than the right
vena cavas
the major vein that brings all blood from the body to the right side of the heart
branches of the right pulmonary artery
the artery that is responsible for bringing blood to the lungs
pulmonary veins
the veins that bring blood in from the lungs
left atrium
the pulmonary veins bring blood into here
interatrial septum
the wall the is between the atria
interventricular septum
the wall that is between the ventricles
atrioventricular valves
tricuspid valves and bicuspid valves
tendon chords
anchor heart valve to the papillary muscles
semilunar valves
pulmonary valve and aortic valve
coronary arteries
supply blood to the inner tissue of the heart; these arteries are found through the valves
why the blood flows
the heart creates pressure gradients; blood always travels from high pressure to low pressure
how the blood flows
atria contracts and av valves open, blood flows into ventricles and atria relax as ventricles contract,av valves close, but semilunar valves open
coronary vessels
vessels that supply blood to the tissue of the heart
left coronary arteries
left circumflex branch>left marginal branch, anterior interventricular branch comes back by way of great cardiac vein
right coronary arteries
right marginal branch(supplies blood to the right atrium and ventricle), posterior interventricular branch, comes back by way of the middle cardiac vein
angina pectoris
partial blockage of blood vessel; causes chest pain; ischemia; part of the heart tissue dies
ischemia
oxygen not getting to the heart
myogenic
the fact that the signal for a heart beat originates in the heart itself
cardiomyocytes
the cells of the heart
intercalated discs
where the cardiocytes join end to end; has 3 features which are interdigitating folds, mechanical junctions, and electrical junctions
cardiac muscle
the cells have presence of sarcoplasmic reticulum where Ca is stored, Ca is required by the heart to contract; the have large t tubules, which allow propagation of signals deep into the tissues (this allow more Ca to flow in)
interdigitating folds
the plasma membrane of intercalated discs; interlock with eachother and increase the surface area of intercelluar contact
mechanical junctions
2 types: fascia adherens and desmosomes- these anchor the plasma membrane of the intercalated discs
electrical junctions
called gap junctions and allow ions to flow into a cardiocyte and allow the cells to electrically stimulate the others
sinoatrial node
pacemaker; initiates heart beat; determines heart rate
atrioventricular node
fires and sends signal to the right and left bundle of His
cardiac conduction system
the SA node fires, which makes the AV node fire, signal travels through bundle of His into the Purkinje fibers, which distribute the signal through the ventricles
vagus nerve
gives inhibitory signals to the heart
systole
contraction of the heart
diastole
relaxation of the heart
sinus rhythm
the normal heartbeat triggered by SA node
nodal rhythm
slower heartbeat that is triggered by the AV node; usually happens when the SA node has problems
ectopic foci
when the SA and AV node goes out this fires signals; in this case a pacemaker is artificially installed
arrhythmia
premature ventricular contractions; caused by stress and heart block
bundle branch block
a block due to damage to one or both bundle branches
total heart block
a block in which signals fail to reach the ventricles and ventricle beat at their own rhythm
pacemaker potential
sodium slowly leaks in channels, at threshold (-40) Ca channels open, then Ca and Na both rush in, this depolarization which causes K channels to open and the K leaves causing repolarization
action potential of a ventricular cardiocyte
stimulation from the SA node opens Na channels, Na flows in and depolarizes the cell to threshold and then opens more Na channels, when the potential peaks to +30 mV and the cell is depolarized the Na channels close. slow Ca channels open and prologue the depolarization and K leaks out and they go against eachother creating a plateau, Ca closes and K open all the way and repolarizes the cell
electrocardiogram
purley electrical measurements, consist of P wave QRS complex and T wave
P wave
firing of SA node and atrial depolarization
QRS complex
ventricular depolarization, atrial repolarization
T wave
ventricular repolarization
cardiac cycle
consist of one complete contraction and relaxation of all 4 heart chambers
pressure and flow
need pressure gradient to have flow, as pressure increases volume decreases; the higher the BP the more resistance the blood encounters
S1
the heart sound that comes from closure of AV valves "lubb"
S2
the heart sound that comes from the closure of semilunar valves "dubb"
quiescent phase
total relaxation of atria and ventricles; Av valves fully opened and blood flows through passively
ventricular filling
active filling of the ventricles;atrial systole and the ventricles fill with blood and have an end diastolic volume (EDV) of about 130 mL in them
Isovolumetric contraction
when the ventricles contract but do not eject blood because the pressure is greater in the aorta and pulmonary trunk than the ventricles
ejection
when the ventricular pressure exceeds the arterial pressure, it sends spurts of blood out rapidly then slows down when pressure lessens; ejects about 54% of the EDV- the SV
stroke volume
the amount of blood ejected during ventricular ejection; about 70 mL
end systolic volume
the amount of blood that was left behind in the ventricles after the ejection; about 60 ml
isovolumetric relaxation
when the semilunar valves close to prevent backflow and the ventricles diastole
cardiac output
the amount ejected by each ventricle in 1 mintue
CO
HR(beats per minute)xSV=
tachycardia
when the resting HR is greater than 100 beat per minute
bradycardia
when the resting HR is lower than 60 bpm
positive chronotropic agents
increase resting HR; epinephrine
negative chronotropic agents
lower resting HR; ACTH
preload
in terms of SV is the amount of tension found just before ventricles contract
Frank-starling law of the heart
SV is proportional to the EDV- the ventricles always pump out what they receive
contractility
refers to how hard the myocardium contracts for a given preload; factors that increase this are positive inotropic agents and those that reduse it are negative know table 19.2
afterload
the sum of all forces a ventricle must overcome before it can eject blood; significant contribution is the aorta and pulmonary trunk pressure ; it opposes the semilunar valve and limits SV
cor pulmonale
right ventricular failure due to obstructed pulmonary circuation