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Physiology Unit 4
Cardiac
190
Physiology
Undergraduate 2
03/08/2011

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Term
fx of membranes surrounding heart
Definition
confines while still allowing free mvmt
Term
tough, elastic connective tissue around heart that prevents overstretching, provides protection, and anchorage
Definition
fibrous pericardium
Term
thinner more delicate membrane (also called epicardium)
-double layer - parietal and visceral
Definition
serous pericardium
Term
what reduces friction in pericardial cavity
Definition
pericardial fluid
Term
rt. atrium rec blood from where? (3)
Definition
superior and inferior vena cava, coronary sinus
Term
what muscles help heart contractions, rhythm and prevent overflow into atria?
Definition
pectinate muscles
Term
separates R and L atrium, has fossa ovalis and ductus arteriosis
Definition
Interatrial septum
Term
separates rt atrium from rt ventricle
Definition
tricuspid valve
Term
forms anterior surface of heart
Definition
rt ventricle
Term
ridges formed by raised bundles of cardiac muscle fiber, part of conduction system of heart, Located in RV
Definition
trabeculae carneae
Term
what assists tricuspid valve with mvmt, preventing backflow, etc
Definition
chordae tendinae and papillary muscles
Term
what increases capacity of atria?
Definition
auricles
Term
grooves on surface of heart, contain coronary bl vsls and coronary sulcus
Definition
Sulci
Term
visceral layer of serous pericardium, smooth and slippery texture
Definition
epicardium
Term
95% of heart is ____ muscle
Definition
cardiac muscle on myocardium
Term
smooth lining for chambers of heart, valves; continuous with lining of large bl vsls
Definition
endocardium
Term
forms base of the heart; has pectinate muscles in auricle, contains bicuspid valve
Definition
Left atrium
Term
bicuspid valve also called
Definition
mitral
Term
Forms apex, thickest chamber of heart

- also has trab carn and chordae tend, pap muscles
Definition
Left ventricle
Term
dense connective tissue that forms

-structural foundation
- point of insertion for muscle bundles
- electrical insulator between A and V
- allows for lag time to allow V to get full
- muscles anchor to this
Definition
Fibrous skeleton
Term
LV has to work harder to maintain same rate of blood flow as RV - T or F
Definition
TRUE
Term
how do aortic and pulm valves open?
Definition
pressure in V exceeds pressure in arteries
Term
Left side of heart, rec blood from lungs - which circulation?
Definition
systemic
Term
right side of heart, rec bl from body
Definition
pulmonary circ
Term
cardiovascular system includes
Definition
blood, heart, bl vsls
Term
how many times does heart BEAT per
minute
day
yr
lifetime
Definition
60
100,000
35 million
2.5 billion
Term
how many Liters does heart PUMP per
minute
day
yr
Definition
5 L
14,000 L
10 million L
Term
how many times does heart PUMP per
minute
day
yr
Definition
5 L
14,000 L
10 million L
Term
2007, Japanese researchers discovered that what step is unnecessary when performing CPR?
Definition
artificial breathing
Term
provides alternate routes or COLLATERAL circuits; in coronary arteries, allows for heart muscle to rec sufficient O2 even if artery partially blocked.
Definition
anastomoses
Term
collect in coronary sinus and empty into RA
Definition
coronary veins
Term
coronary arteries branch from ___
Definition
ascending aorta
Term
fx of ductus arteriosus in fetal dev; turns into what at birth?
Definition
bypasses lungs, becomes ligamentum arteriosum
Term
what holds fibers together in intercalated disks?
Definition
desmosomes
Term
allow Action potential conduction from one fiber to the next in intercalated disks
Definition
gap junction
Term
striated, one nucleus, lots of mitochondria, stair-step appearance, connected by intercalated disks
Definition
cardiac muscle
Term
act as pacemaker, FORM conduction system
- self-excitable, generates AP that trigger heart contraction, specialized cardiac muscle fibers
Definition
autorhythmic fibers
Term
located in RA wall, begins conduction system, beats 100 bpm
Definition
SinoAtrial Node
Term
pathway for conduction system of heart
Definition
SA node - AV node - AV bundle (Bundle of His) - bundle branches - Purkinje fibers (muscles contract)
Term
only site where AP can conduct from atria to ventricles due to fibrous skeleton
Definition
AV bundle (Bundle of His)
Term
AV node located in
Definition
interatrial septum
Term
lag time in conduction system of heart is where? FX of lag time?
Definition
AV node; allows ventricle to fill more completely
Term
our natural pacemaker is the ___; what system slows it down?
Definition
SA node; parasympathetic system constantly slowing it down
Term
our natural pacemaker is the ___; what system slows it down?
Definition
SA node; parasympathetic system constantly slowing it down
Term
what is bpm at AV node? at Purkinje fibers?
Definition
40-60bpm
20-35 bpm
Term
stages of A.P. in heart
Definition
depolarization
plateau
repolarization
Term
fx of plateau period in cardiac A.P.; due to what partly?
Definition
maintained depolariz, allows ventricles to fill...due in part to V.G. Ca+ slow channels opening (Ca+ moves into cell)
Term
where is refractory period in cardiac A.P.? what is it? how long last?
Definition
in depolar and plateau state; time during which 2nd contraction can't be triggered...lasts longer than contraction itself
Term
what does plateau period ultimately trigger?
Definition
contraction
Term
depolarization sustained due to what?
Definition
VG K+ channels balancing Ca+ inflow with K+ outflow
Term
all events associated with one heartbeat
Definition
cardiac cycle
Term
faster the heart beats, the ___ the relaxation period
Definition
shorter
Term
volume of blood ejected from left or right V into aorta or pulm trunk each minute
Definition
cardiac output
Term
stroke volume x heart rate =
Definition
cardiac output
Term
difference between max CO and CO at rest
Definition
cardiac reserve
Term
CO for typical resting male
Definition
5.25 mL = 70mL/beat x 75 bpm
Term
avg cardiac reserve is ___ times the resting value
Definition
4-5x
Term
what measures the fitness of the heart?
Definition
Cardiac output
Term
composite record of A.P's produced by all heart muscle fibers; can compare tracings with each other and with normal records; has 3 recognizable waves
Definition
ECG or EKG
Term
P wave appears when; during ___ contraction
Definition
cardiac A.P. arises in SA node; during atrial contraction
Term
action potential enters AV bundle and out over Ventricles in this wave; masks atrial repolarization
Definition
QRS wave
Term
begins shortly after QRS complex appears and continues into S-T segment of wave
Definition
ventricular systole
Term
T wave represents; followed by
Definition
repolarization of V fibers; ventricular diastole
Term
factors that ensure LV and RV pump = volumes of blood
Definition
preload, contractility and afterload
Term
degree of stretch on heart b4 it contracts; when increased, incr force of contraction
Definition
preload
Term
more heart fills with blood during diastole, greater force of contraction during systole
Definition
Frank-Starling law of the heart
Term
preload is proportional to the ___
Definition
EDV (end-diastolic volume)
Term
volume of blood returning to RV
Definition
venous return
Term
2 factors that determine EDV
Definition
duration of V diastole, venous return
Term
2 factors that determine EDV
Definition
duration of V diastole, venous return
Term
strength of contraction at any given preload
Definition
contractility
Term
positive inotropic agents ___ contractility and often promote Ca+ inflow during cardiac A.P.
Definition
increase
Term
Positive inotropic agents include ___, and also increase stroke volume
Definition
Epi, NEpi, digitalis
Term
Negative inotropic agents ___ contractility; ex of agents include
Definition
decrease; beta-blocker, Ca channel blocker, hypoxia, acidosis, some anesthetics, increased K+ in interstitial fluid
Term
resistance heart meets after lag time; pressure to overcome before semilunar valve can open
Definition
afterload
Term
increase afterload, ___ Stroke volume; why
Definition
decrease; blood remains in ventricle at end of systole
Term
hypertension and atherosclerosis increase ___
Definition
afterload
Term
-90mV to +20mV (change of 110mV) - what stage of A.P?
Definition
depolarization
Term
working atrial and ventricular muscle fibers are ____ fibers
Definition
contractile
Term
where does contractile fiber receive an A.P? where does it go?
Definition
from neighboring fibers; brings it to threshold
Term
Depolarization opens the FAST VG Na+ channels...how long does it take for these channels to inactivate and close
Definition
few milliseconds
Term
Plateau is at __ mV
Definition
0mV
Term
In plateau, sarcolemma is activated by voltage change...which opens VG Ca SLOW chnls, allows for influx of Ca+ ...what else is triggered?
Definition
Ca comes out of S.R. too
Term
what disorder (that causes contractions, and doesn't allow relaxation) CANNOT happen in heart
Definition
tetanus
Term
what also happens when VG K+ chnls open on sarcolemma and K+ leaves cell?
Definition
Ca coming out of S.R. and interstitial, slow Ca channels opening
Term
ANS and Epi/NEpi most important factors in this fx
Definition
regulation of heartbt
Term
what hormones increase heart rate and contractility
Definition
Epi, NEpi, T3 and T4
Term
concentration of K, Ca and Na important for regulation of ___; ionic imbalance can compromise ___
Definition
heart rate

pumping effectiveness
Term
bl vsl layer made up of endothelial tissue (like lining of heart)
Definition
Tunica Interna
Term
bl vsl layer made up of smooth muscle, regulates diameter of lumen
Definition
tunica media
Term
bl vsl layer made up of smooth muscle, regulates diameter of lumen
Definition
tunica media
Term
bl vsl layer made up of smooth muscle, regulates diameter of lumen
Definition
tunica media
Term
bl vsl layer made up of elastic and collagen fibers, helps anchor vsl to surrounding tissue
Definition
tunica externa
Term
what supplies bl to tissues of vsls?
Definition
capillaries
Term
arteries able to stretch and expand in response to pressure without tearing
Definition
T
Term
alternate routes for circulation, all body regions supplied by 2 or more arteries
Definition
collateral circulation or anastomoses
Term
alternate routes for circulation, all body regions supplied by 2 or more arteries
Definition
collateral circulation or anastomoses
Term
vasoconstriction happens in these bl vsls, resulting in raised BP
Definition
arterioles
Term
flow from metarteriole thru capillaries and into postcapillary venule
Definition
microcirculation
Term
what causes capillaries to contract if blood not needed in FFF
Definition
precapillary sphincters
Term
primary fx is to exchange between bl and interstitial fluid
Definition
capillaries
Term
primary fx is to exchange between bl and interstitial fluid
Definition
capillaries
Term
some microcirculatory exchange happens in venules - T or F
Definition
TRUE
Term
not designed to withstand high pressure, generally thinner walls than arteries, has valves that aid in venous return
Definition
veins
Term
blood reservoir in body, largest amt of bl at rest is here
Definition
systemic veins and venules
Term
reduces vol of bl in reservoirs, allows greater bl vol to flow where needed
Definition
venoconstriction
Term
mvmt of substances betw bl and interstitial fluid through 3 methods - what are they
Definition
capillary exchange through
Diffusion
Transcytosis
Bulk Flow
Term
most important method of capillary exchange, crosses capillary wall thru intracellular clefts, or endothelial cells or fenestrations
Definition
diffusion
Term
most plasma proteins can't cross thru capillaries, except in sinusoids
Definition
TRUE
Term
protein in urine usually means what?
Definition
kidney disease or infection
Term
tight junctions in this limit diffusion
Definition
BBB
Term
transcytosis important for what molecules?
Definition
large, lipid-insoluble molecules that can't cross cap walls any other way
Term
substances in bl plasma become enclosed in pinocytotic vessicles
Definition
transcytosis
Term
passive process where large #s ions, molec, or particles in fluid move together in same direction - based on PRESSURE GRADIENT
Definition
bulk flow
Term
what's most important cap exch method for regulation of relative vol of bl and interstitial fluid
Definition
bulk flow
Term
flow from cap to interstitial, OUT of bl
Definition
filtration
Term
flow from intersti fluid to cap; INTO blood
Definition
reabsorption
Term
balance of two pressures that regulate filtration and reabsorption
Definition
net filtration pressure
Term
flow from intersti fluid to cap; INTO blood
Definition
reabsorption
Term
balance of 2 pressures that regulate filtration and reabsorption
Definition
net filtration pressure
Term
pressure on vsl as bl flowing thru; generated by pumping action of heart
-moves from 35mmHg to 16mmHg as moves across capillary
Definition
BHP - Blood hydrostatic pressure
Term
more water in vsls than outside of vsls causes this pressure - about 1mmHg
Definition
Interstitial fluid osmotic pressure (IFOP)
Term
which side of heart failure causes systemic congestion
Definition
R-HF
Term
which side of HF leads to pulmonary edema?
Definition
L-HF
Term
which side heart failure causes pulmonary edema
Definition
L-HF
Term
condition where heart pumping becomes less efficient, caused by CAD, MI, longterm hi BP, PRELOAD increases, less efficient
Definition
congestive heart failure
Term
pressures that promote filtration
Definition
Interstitial fluid osmotic pressure and Blood hydrostatic pressure
Term
pressures that promote reabsorption
Definition
blood colloid osmotic pressure (BCOP)
Term
pressure incurred bc of bl plasma proteins automatically pull water in. Avg 36mmHg
Definition
blood colloid osmotic pressure (BCOP)
Term
nearly as much is reabsorbed as is filtered - whose law is this?
20 L filtered, 17 reabsorbed, where does other 3L go?
Definition
Starling's Law; into lymphatic vsls and eventually back to blood thru subclavian veins
Term
arterial end, Net outward pressure is ___; at venous end fluid reabsorption pressure is ___
Definition
10mmHg; -9mmHg
Term
blood pressure depends on total vol of
Definition
blood
Term
what generates bl pressure?
Definition
contraction of ventricles
Term
opposition to bl flow due to friction betw bl and walls of bl vsls; depends on 3 things
Definition
vascular resistance;
size of lumen, blood viscosity, total bl vsl length
Term
ratio of RBC's to plasma and protein concentration...higher means higher vascular resistance
Definition
bl viscosity
Term
what 3 things bring bl back to heart
Definition
pumping of LV
skeletal muscle mvmt
diaphragm
Term
vol of bl flowing back to heart thru systemic veins
Definition
venous return
Term
monitor pressure changes and stretch in bl vsl walls, located in carotid artery and aorta
Definition
baroreceptor / reflexes
Term
carotid sinus reflex help regulate BP where?
Definition
in brain
Term
aortic reflex regulates BP where?
Definition
systemically
Term
when baroreceptors are stretched, more ___ happen, tells body to get rid of water, event lowers BP
Definition
action potentials
Term
when BP falls, baroreceptors stretched less, there is slower rate of impulses to cardiovascular center and how do PSNS and SNS respond?
Definition
decrease parasym, increase symp
Term
what can you do if HR soars, and need to get it back down
Definition
carotid sinus massage, dump face in cold water
Term
monitor concentration of various chem in bl
Definition
chemoreceptors
Term
monitor mvmt of joints and muscles to provide input during physical activity
Definition
proprioceptors
Term
neural reflexes (baro, chemo and proprioceptors) influenced by what NS?
Definition
ANS
Term
detect hypoxia (Lo O2), hypercapnia (Hi CO2) and acidosis (high H) -- send signals to cardiovascular center - which incr SNS to arterioles and veins, they vasoconstrict and incr BP
Definition
chemoreceptors
Term
chemoreceptors also give input to ___ center to adjust ____ rate
Definition
respiratory to adjust breathing rate
Term
where are chemoreceptors located?
Definition
close to baroreceptors in carotid sinus and aortic arch
Term
what 3 hormones raise BP?
Definition
RAA, Epi and NEpi, and ADH
Term
what hormone lowers BP - only one
Definition
ANP- atrial natriuretic peptide
Term
what hormone lowers BP - only one
Definition
ANP- atrial natriuretic peptide
Term
hormones help regulate ___ and ___ by
- altering Cardiac output
- changing systemic vascular resistance
- adjusting total bl vol
Definition
regulate BP and blood flow
Term
autoregulation of BP by tissues - what does this mean?
Definition
tissues can use precap sphincters to shut down bl supply if they know they have too much O2
Term
going back to -90mV means what has happened?
Definition
repolarization
Term
determined by substances that alter mvmt of Ca+ thru slow Ca+ channels
Definition
strength of heartbeat
Term
how does Epi increase heart contraction?
Definition
enhances Ca flow,
Term
how do cardiac muscle mitochondria produce ATP
Definition
aerobic respiration
Term
after MI, patient will have this in their blood; it's released when cells are damaged or dead into bloodstream
Definition
creatin kinase (CK)
Term
two most important factors in reg of heart rate
Definition
ANS (PSNS and SNS)
Epi and NEpi from Adrenal medulla
Term
Maximum heart rate (MHR) figured out how?
Definition
220-age
Term
what centers receive signals from neural ceptors
Definition
cardiovascular center of medulla oblongata, limbic system, cerebral cortex
Term
SNS pathway to speed up WHOLE heart
Definition
med oblong - spinal cord - thoracic region - cardiac accelerated nerves - SA node - AV node -- myocardium
Term
effect of NEpi on SA and AV node
Definition
speeds up rate of sponataneous depolarization
Term
effect of NEpi on contractile fibers on cardiac muscle
Definition
enhances Ca+ entry thru VG slow Ca+ chnls
Term
PSNS affects heart thru which nerve? What's pathway?
Definition
L and R Vagus nerve;
medulla oblongata - SA node - AV node and atrial fibers
Term
why does PSNS have slower effect on heart than SNS?
Definition
bc PSNS doesn't get to myocardium, only goes to top part of heart, takes longer for PSNS to affect whole heart
Term
decr heart rate by promoting K+ leakage into interstitial tissues from inside nodal cells...causes hyperpolar of cells and takes longer for cells to reach threshold -- effect of what neurotransmitter?
Definition
ACh
Term
reestablishment of bl flow after blockage of coronary artery deprives heart of O2, can damage tissue further
Definition
reperfusion
Term
complete obstruction to bl flow in coronary artery, causes death to tissue bc of interrupted bl supply
Definition
MI
Term
heart cells can regenerate - how find out?
Definition
yes - found out thru transplant across gender, found that DNA was changing over time
Term
accumulation of atherosclerotic plaques in coronary arteries, leads to reduced bl flow to myocardium
Definition
coronary artery disease (CAD)
Term
failure of myocardium to contract
Definition
asystole
Term
cessation of effective heartbeat, may be completely stopped or in v-fib
Definition
cardiac arrest
Term
fraction of EDV that is ejected during avg heartbt, equals SV/EDV
Definition
ejection fraction
Term
how does aerobic exercise help heart?
Definition
decr BP
incr CO
weight control
incr fibrinolytic activity
Term
how long does atrial contraction/systole last? what waves does it encompass?
Definition
0.1 sec
P wave to Q wave
Term
what valves open during atrial systole?
Definition
AV open, SL closed
Term
130 mL ends up in ventricle, as atria contract, it adds 25 mL of that to ventricle...130mL is the ___
Definition
End-diastolic volume
Term
atrial systole happens after
Definition
SA node impulse
Term
ALL valves closed, keeping bl vol constant in ventricle
- begins R wave (begin ventric depolar)
Definition
Isovolumetric ventricular contraction
Term
S wave to T wave (after-effect of atrial depolar)
AV closed, SL open
LASTS 0.25 sec
Definition
ventricular ejection
Term
ea ventricle overcomes pressure in aorta or pulm trunk, ejection fraction is ___
Definition
70mL
Term
end-systolic volume or residual vol is how much?
Definition
about 60mL
Term
how much pressure is in pulm trunk?
how much in RV?
Definition
20mmHg
25-30mmHg
Term
how much pressure in aorta?
how much in LV?
Definition
80mmHg
120mmHg
Term
begins at end of T wave; all valves closed, ventricular pressure decr rapidly
-beings ventricul repolar
Definition
isovolumetric ventricular relaxation
Term
after T wave to next P wave
AV valves open, SL closed
as pressure in V drop, opens AV valves and bl begins to fill ventricles
Definition
ventricular relaxation
Term
esp significant in malignant tumors that secrete protein TAF to create more arteries to dominate bl flow to itself
Definition
angiogenesis
Term
calcium channel blockers do what?
Definition
decr strength of heart contraction, and thus workload of heart
dilate arteries to reduce pressure and resistance
prevents angina bc dilated vsls bring more O2 to heart
slows heart rate and can help control abnormal heart rhythms
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