chpt 9: heart tings Flashcards
what type of Ca2+ is found in the heart tings
cytosolic Ca2+
what is a prolapsed valve
- backward valve
function of chordea tendinae
prevent everted valves
when do valves open
when the pressure is greater behind the valve
what happens when the pressure is greater in front of the valve
valve closed
what is the inflammation of the pericardial sac
pericarditis
what happens when one has pericarditis
- painful friction rub b/w pericardial layers
- viral or bacterial infection
what is the innermost and thinnest wall of the heart that comes in contact with blood
endocardium/ endothelium
what is endocarditis
infection in the endocardium
what happens when one has endocarditis
- sudden heart attack and then death
which heart wall layer has cardiac muscle
myocardium
which layer has intercalated discs
myocardium
desmosomes and gap junctions make up
intercalated discs
function of gap junctions
- signals pass through fast
what type of junction is an adhering junction
desmosomes
function of desmosomes
- hold cells together
- handle mechanical stress
- transfer signals fast without heart rupturing
epicardium is the
thin outer layer of the heart
- surrounded by pericardal sac
function of secretory lining of pericardial sac
lubricates heart
what allows the heart to remain properly positioned
tough, fibrous covering of pericardial sac
name of heart contracting itself
autorythmicity
which cells are 99% of cardiac muscle cells
contractile cells
do contractile cells initiate ap
no
function contractile cells
- mechanical work/ pumping
which cardiac cells make up less than 1% of the cells and set the electrical activity/ pace of heart
autorythmic cells
do autorythmic cells contract
no
location of sinoatrial node
r.a, near superior vena cava
which node is the pacemaker of the heart than triggers contractile cells
SA node
SA node beats/ min is
70-80
which node is located at the base of R.A near septum
AV node
slient / latent pacemakers are
AV nodes and bundles of his and Purkinje fibers
what node sets the beat for 40-60 beats / min
AV node
Bundles of His location
originate from AV node and enter interventricular spetum
beats / min of Bundles of His and purkinje fibers
2-40
where does the 100 msec delay occur in the internodal pathway of excitation and why
AV node, to allow ventricles to fill in
function of interatrial spread of excitation
- ensures both atria become depolarized simultaneously
when does a 30-sec delay occur
- sa node to av node (internodal)
- sa node to sa node (interatrail)
- av node to bundle of his (internodal)
complete heart block is
when conducting tissue b/w atria and ventricle is damaged
what is dysfunctioning in complete heart block
SA node
50b/ min occur during
complete heart bock
how does one feel during complete heart block
long-lasting fatigue
when does AV node take over
complete heart block
abnormally excited area, initiates a premature ap that spreads through the heart occurs when
all nodes except of pf are working
what are the beats/ min of Pf during ectopic focus
140b/ min
when does the ventricle contract before the atria
ectopic focus
what is the resting membrane potential for pacemaker cells
- 60 mV
slow depolarization =
pacemaker potential
when does slow depolarization b/f depolarize
pacemaker activity
what channel is activated during slight hyperpolarization
If (current, funny)
function of If
- increases Na and K permeability
why is If also considered HCN (Hyperpolirzation- activated Cyclic Nucleotide)
- cuz it is activated upon hyperpolarization
what causes slow depolarization
Ca2+ transient channels, Na and K influx, and slow closing K channels
what is the Ca2+ transient channels are also known as
t- type ca2+ channels
when do t- type ca2+ channels open
- open at lower membrane potential
-
what helps cause more depolarization and helps it reach the threshold
Ca2+
- 40mV is ___ for pacemaker activity
threshold
what is peak for pacemaker activity
0mV
function of L-type Ca2+
- causes the rising phase in pacemaker activity
- bring in more Ca2+
what channel is slower than Na+ channeled cells
L-type Ca2+
function of K+ in pacemaker activity
causes repolarization
when is there a prolonged refractory period like ap
- electrical activity in contractile cells
is there summation in contractile cells
no
-80 mV is the resting potential for
contractile cells
what causes the rising phase in contractile cells
I Na, current Na
+30 mV is ___ for contractile cells
peak
what causes peak/ rising phase in contractile cells
Na increase
I Ca 2+ L function in contractile cells
plateau, long lasting
- balance of ions in and out
what is the delayed rectifier
its the current K increase
what does the current K/ delayed rectifier do
falling phase / increase K+ efflux
how long is the plateau/ refractory period + function
250 sec, allows blood to fill in
Electrocargiogram function
- see how the heart is behaving
- shows entire cardiac cycle
- record of electric activity that reaches the surface of body cuz of depolarization and repolarization
where are leads of ECG placed
- R arm, L Arm, L leg
P wave is responsible for
atrial depolarization
what does p wave determine
rthym, rate, block
what refers to the AV nodal delay of 100 msec
PR segment
significance of QRS complex
ventricle depolarization (pump blood out) - mask atrial repolarization
what is it called when the ventricles are contracting and relaxing?
ST segment
what is a section called when contractile cells are in plateau and ventricles have completely depolarized
ST segment
T wave is
ventricle repolarization
when are ventricles relaxing and filling with blood
during the TP interval
analyzing rate is
determined from distance b/w 2 consquetives ORS
tachycardia is
high heart rate of more than 100 beats/ min
which segment is looked at to determine tachycardia
P to P
top of QRS to the next R determines
bradycardia
what is it called when the heart rate is less than 60b/ min
bradycardia
what node determines the heart rate
SA node, cuz it has a fast rate of depolarization to threshold
rhythm is the
regulating or spacing of ECG waves
variation for normal rhythm and sequence of excitation of the heart is known as
arrhythmia
heart rate for atrial flutter
200-380b/ min
atrial flutter is
the rapid but regular sequence of atrial depolarization
when is there no distinct P wave and ORS occurs sporadically
atrial fib
what is a rapid, controlled and irregular beating/ depolarization of atria known as
atrial fib
what happens to the ventricles and atrial fib
irregular rhythms
why is contraction weaker in atrial fib
less filling occurs so contraction is weaker
when does pulse deficit occur/ what is it
the difference in heart rate + pulse rate in atrial fib
what does the ECG look like during ventricular fib
saw-edged
what arrhythmia is more serious
Ventricular fib
what triggers the SA node to restart and multiple impulses all over the place
Ventricular fib
what happens to vital organs in ventricular fib
possible failure
a block is
defects in cardiac conducting system where the ventricle sometimes fail
what sequences of P: QRS does block occur in
2:1 or 3:1
what does the number in P mean in heart block
how often impulses pass to ventricles
what is complete heart block
- complete disassociation b/w atrial and ventricular activity
when do ventricles govern own rate at lower rate
complete heart block
cardiac myopathies is
damage of heart muscles
what is it called when there is an inadequate delivery of O2 blood to heart tissue
myocardial ischemia
necrosis is
death of heart muscle cells
what happens when a bv supplying the heart is blocked or ruptured
acute myocardial infraction aka heart attack
TP is interval is ___ event of the cardiac cycle
diastole
when are AV valves open and SL valves closed
diastole
how much blood enters the ventricles during diastole
80%
what marks the end of diastole
end diastole volume
what happens to the SA node during late ventricular diastole
- sa node reaches threshold and fires (P wave)
when does 20% enter the ventricle
late ventricular diastole
end of diastole / end diastolic volume does ___ to ventricle
- increase pressure
what marks the closure of AV valves
end of diastole / end diastolic volume
what is end diastolic volume
135ml of blood in the ventricle at the end of diastole
what is the max amount of blood that the ventricle can contain during a cycle
~135mL
when does isovolumetric contraction occurs
after end of diastole
when are all valves closed but the pressure in ventricles continues to increase
isovolumetric contraction
how long before atrial contraction occur before ventricular contraction
160 msec
at which event of the cardiac cycle is the QRS formed
ventricle systole
what happens during ventricle systole
- ejection of blood begins
- ventricles empty
- SL valves are open, AV valves are closed
how much blood is left behind during isovolumetric ventricular relaxation
65mL
when does the heart go back to normal
isovolumetric ventricular relaxation
ESV/ end systolic volume is
65mL of blood left in the heart
how is heart health measured
by cardiac output
what is cardiac output
volume of blood pumped by each ventricle / min / whats happening in the heart
how do you calculate cardiac output
(EVD-ESV) x heart rate
what does it mean when 5L/ min of blood is pumped
normal cardiac output
amount of blood pumped out per contraction is referred to as
stroke volume
what determines stroke volume
- venous system
- sympathetic activty
what is the first heart sound thats heard at the closure of AV vlaves
Lub
lub marks the
begning to ventricular systole
what does lub sound like
longer, soft, dull
dup is the
- second heart sound
- marks ventricular diastole
- heart is filling w blood
closing of ___ valves determines shart, short sound of dup
SL valves
valve disfunction causes/ is known as
heart murmurs
types of murmurs
- stenotic
- infufficent
- diastolic (timing)
- systolic (timing)
when does a stenotic murmur occur
- stiff narrowed valve due to disease
what type of murmur creates a whistling sound
stenotic
what happens to the AV valves when in stenotic murmur
- blood doesnt flow forward
- valve doesnt open properly
lub-dup- whistle is an example of
diastolic, stenotic flow
when is the valve leaky, incomplete, and doesnt close properly
- insufficient murmur
what kind of sound is made during an insufficient murmur
swish
lub-swish-dup is an example of
- insufficient, leaky AV
when do systolic murmurs occur
- lub- murmur- dup
lub-dup-whistle happens during
stenotic, av, diastolic murmurs
an insuffienct, leaking SL valve with a diastolic murmur sounds like
lub-dub- swish
stenotic, SL valve doesnt open with a systolic murumur sounds like
lub-whistle-dup
what disease can causes murmurs
rheumatic fever
what causes rheumatic fever
- strep throat bacteria
how does one fix a dysfunctional valve
- valve replacement or death
what happens when strep throat goes untreated
rheumatic fever = valves disfunction = heart attack or heart failure
what does the para sym system secerte / vagus nerve
ACh
what do muscarinic receptors receive/ respond to
ACh
funcation of parasym innervation in heart
- slow heart down
- decrease rhythm of SA node
what CN supplies the para sym function of the heart
Vagus (CN 10)
location of vagus nerve in parasym
atria and AV node
what allows heart rate to vary activity of cAMP
parasym and sym
what secretes NE or E which binds with B receptors
sympathetic sys
atria and ventricles are innervated by
nerves from the sympathetic sys
function of sympathetic sys in heart
increase:
- stroke volume
- heart rate
- rythm of SA node
- contraction of heart
- EDV
what brings NE or E into the heart to do work
increased EDV
extrinsic factors that influence the heart are
- sympathetic sys stimulation
- increased E that contracts heart
intrinsic factors that influence the heart are
increase Sv by increasing contraction of heart
- increased EDV which bring in NE or E
what does the frank starling law of heart state
- increasing diastolic filling = increasing EDV and the heart is then more stretched = increased SV
heart failure is
inability of CO to keep pace with bodys demand of supplies and waste removal
what does the frank straking curve look like in a prime defect
shift right and downwards
decreased cardiac contractility and less SV being pumped occurs during
prime defect
how does one compensate for heart failure
- sympathetic system increases activity for a limited time
- kidneys retain extra salt and water
why do kidneys retain extra salt and water to compensate for heart failure
- expand bv
- increase EDV to stretch cardiac muscles
- to increase SV
what is forward failure
heart fails to pump an adequate amount of blood forward
why does forward failure occur
cuz SV is small
what is it called when blood and enters and is pumped out and the venous sys dams up
backward/ congestive heart failure
which side of the heart will it worse to get any kind of heart problems
left side
how much O2 does the heart use at rest
65% available
when is most of the O2 received
during diastole
why is most of the blood received during diastole
- the heart is compressed during systole
- aortic valve partially blocks entrance of coronary valve
function of adenosine in the heart
helps move blood, causes vasodilation of vv
what kinda of chemical messanger system does adenosine use
paracrine signals
what causes coronary artery disease
changes within the ca that prevent blood from getting through coronary vessels
myocardial ischemia and heart attacks are the results of
coronary artery disease
how does coronary artery disease occur
- profound vascular spasm of ca
- formation of atherosclerotic plaque
- thromboemolidm
how does one fix cornonary artery disease
- digitalis
- verampil
- nitroglycerin
how common are heart attacks in canada
32p of pop die fromthem
function verapamil
- Ca2+ channel blocking agent
function of digitalis
increase cardiac contractility by inducing accumulation of cytosolic ca
function of nitroglycerin
- allows coronary dilation
- relaxes vascular smooth muscles
what is the first indicator of coronary artery disease
profound vascular spasm of ca
how is profound vascular spasm of ca reversible
- diet and exercise
what causes when one has profound vascular spasm of ca
decreased O2 which leads to platelet activary factor (spasms)
what is the first stage of the formation of atherosclerotic plaque
- inflammatory response and oxidized LDL
waht is formation of atherosclerotic plaque
plaque forming in chain rxns
what else causes plaque forming in chain rxns
- BP
- free radical bacteria and virsues
what does oxidized LDL attract
phagocyte and monoctyes
what becomes large macrophages that consume oxidized LDL
monocytes
whats triggers the inflammatory response and what does it set up
- injury to bv that sets up formation of plaque
-
eating of LDL forms
foam cells and fatty strands that smooth muscles gather around
smooth muscles gathering around form
Benin tumor or atheromas which forms plaque
how does plaque block blood flow
unit with Ca+ and it hardens
what is Angina Pectoris
chest pain felt on the left side (arm and shoulder)
what cuases Angina Pectoris
reduced blood flow and O2
drugs (glycerin) and rest can reverse
Angina Pectoris
what happens when plaque breaks away
it forms a clot (thrombosis) which moves around and blocks vessels (embolism)
why is it so dangerous for an embolism to be a bit above the left coronary artery
85p of blood comes there from the heart
what is immediate death
- acute cardiac failure
what causes immediate death
the heart is too weak to pump effectively to support body tissues
- fatal rupture of death caused by degenerating area of heart is known as
- slowly progressive
delayed death from complications
fatal ventricular fibrillation brought by oxygen deprived heart causes
immediate death
