CARDIOVASCULAR PHYSIOLOGY Flashcards
briefly explain compliance?
its the ability of a structure to stretch
what is the equation for compliance?
Delta V/ delta P
what is the maximum arterial pressure reached during peak of ventricular ejection?
systolic pressure
what is the minimum arterial pressure reached during peak of ventricular ejection?
diastolic pressure
what is pulse pressure?
difference in pressure between systolic and diastolic pressure
which process lasts longer; systole or diastole?
diastole lasts around twice as long as systole
what is the main function of the cardiovascular system?
transport
who/what doesn’t require a cardiovascular system and why?
single cell organisms don’t need it since they can transport 02, waste, food, etc through simple diffusion
what is diffusion?
Spontaneous movement of particles caused by random thermal movement
what can be determined using fick’s law?
flow
what is the equation for flow
flow= diffusion coefficent * Delta C * Area
what is flux?
flow/Area
how many vessels do insects have?
1 (dorsal aorta)
do insects have blood?
no, they have haemolyph
what type of circulation do insects have? open or closed?
open circulation, thus the fluid is not contained within the circulation system
how is the haemolyph circulated through the insects body
it enters the heart (each individual pump) and will percolate through the body and will then be taken back up by ostrium (pores)
in piscine circulation, how many chambers are there?
2 (atrium and ventricle)
in piscine circulation, is it open/closed circulation?
closed
in piscine circulation, is it single or double looped?
single
in piscine circulation, how does the blood circulate
atrium –> ventricles –> gills
in piscine circulation, where do 02/CO2 exchanges take place?
at the gills
in amphibian and reptile circulation, how many chambers are there?
3
L/R atrium, single ventricle
in amphibian and reptile circulation, what type pf blood flows in the systemic circulation?
deoxygenated
from RA –> VENTRICLE
in amphibian and reptile circulation, what type pf blood flows in the PULMONARY circulation?
from skin and lung to the LA
in amphibian and reptile circulation, do bloods mix when taken into the single ventricle
no, the oxygenated blood from the pulmonary circuit is brought to the body and the deoxygenated blood from the systemic circuit is brought to the lungs
what reptile circulation differs from the normal reptile circulatory system?
crocodiles
in avian and mammalian circulation, is the system open or closed?
closed
in avian and mammalian circulation, how many chambers are there
4
R/L ATRIUM
R/L VENTRICLE
in avian and mammalian circulation, what type of circulation occurs ont he right side of the heart?
pulmonary circuit
in avian and mammalian circulation, what type of circulation occurs ont he left side of the heart?
systemic
what is haemodynamics?
Branch of physiology which deals with the forces involved in the circulation of
blood
what is volume?
amount of space occupied by blood
generally what is our total blood volume?
~5L
or 7.5% BW
how many L does 1 unit of blood contain?
0.45L
what is stroke volume? what is that volume?
stroke volume is the amount of blood being pushed through by every contraction
it is ~70 mL
what are the proportions of blood in our systems (vessels)
60% venous 10% arteries 10% lungs 10% capillary and arterioles 10% in heart
what term is used to describe the venous system?
capitance
what term is used to describe the arterial system?
resistance system
what is the cardiac output per minute?
5000 mL/ minute
what does blood flow ensure?
that the rate at which blood flow into various body stsems of the blood is adequately recieved
in what state should the blood flow be between the cardiac output of the left/right heart?
in equilibrium
what is the venous return?
flow of blood that enters the heart
when giving blood what is the general blood flow?
45 mL/minute
what is the equation for blood flow?
flow= V/T
or Flow= area * velocitu
what are some factors that can contribute to blood flow?
velocity of the flow
cross sectional area of the blood vessel
in blood circulation, what acts are the exchange vessels?
capillaries
how do vessels change awe advance through the system?
aorta> arteries > arterioles > capillaries < venials< veins< vena cava
what happens to the area due to branching?
the cross sectional area increases
what happens to the flow of blood through every levels of branching?
it stays the same
what must happen in order for blood flow to stay constant when area increases?
the velocity will decrease
what are some advantages of branching in the venous system?
high total area in the capillaries and decreased velocity allows to preserve the capillaries and let enough time pass for the capillaries to unload O2
what happens to resistance if the cross sectional area increases?
the resistance will drop
in what units is pressure usually measured in
mm Hg or cm H20
generally what is our blood pressure (numbers)
120/80 mm Hg
what happens if there is constant pressure everywhere?
no flow
what happens to pressure as we move from inlet to outlet?
the pressure continuously drops
why if flow created?
because Pressure inlet > Pressure outlet
what is needed in order to allow to move in a constant direction?
opposing forces (frictional force)
what explains loss of pressure as we move from inlet to outlet?
frictional forces are converted to heat which dissipates which explains the loss of pressure
what is the average pressure in the aorta?
100 mm Hg
in arteries which pressure is greater pulmonary or systemic?
arterial pressure im the systemic system is greater
how can the pressure be described in arteries versus in vessels?
arteries: cyclic
vessels: oscillation
what is hydrostatic pressure
Pressure exerted by a fluid at
equilibrium at a given point within the fluid, due to the force of gravity
what is the equation for pressure
Force/ Area= F/A= density (rho)* H *g
how many pascales are needed for 1 cm H20?
98 Pa
the blood pressure is greater in veins or arteries?
arteries
in cardiovascular physiology, what is the atmospheric pressure said to be?
O
what was used to measure pressure and give the unit for mm Hg?
mercury sphygmomanometer
what is the perfusion pressure?
pressure inlet - pressure outlet or arterial pressure - venous pressure
what happens if there is no perfusion pressure?
there is no flow
what is needed in order to have flow
delt Pressure not equal to zero
which blood move quicker; central of vessel or wall of vessel?
center of the wall
how can the blood flow be described?
parabolic
what did poiseuille’s law state?
flow= delta P/R
what is the equation for resistance?
R= 8* piL viscosity/r^4
what is resistance proportional to?
length of vessel
viscosity
when is the resistance higher; in active arm or a arm at rest
in resting arm since blood vessels are constricted= smaller area
does the perfusion pressure differ for organs that work in series?
no, perfusion pressure are constant
what happens to the resistance when put in series?
the resistance increases
what happens to the overall resistance in a system in parallel?
it drops
which is stronger/througher between vein and artery?
Artery
what is the equation for compliance?
Delta V/ Delta P
or compliance= 1/slope
which volume is greater; inside veins or inside A?
inside veins
how is the resistance in the great vessels?
low due to big cross sectional area
what are the great vessels
SVC IVC R pulmonary A L pulmonary A Pulmonary trunk L pulmonary Veins R pulmonary veins Aorta
what separates the L and R atrium?
interatrial septum
what separates the Left and righ ventricles?
interventricular septum
the free wall of which ventricle is thicker?
left is thicker than right
what attaches to the papillary muscles and prevents regurgitation of blood into the atrium?
chordae tendinae
what must be done in the case where the papillary muscles die due to heart attack?
valve must be remplaced
what are the atrioventricular valves?
tricuspid and bicusip (mitral)
where are the semilunar valves found?
outlet of the ventricles
what are the semilunar valves?
aortic
pulmonary
what lines the outside of the heart?
epicardium. It’s a though fibrous sac
what is the function of the fluid in the epicardium sac?
lubricate heart and allow for fluid movement
what lines the inside of the heart?
Endocardium composed of endothelial cells
how does the electrical system of the heart function?
through a specialized activation system
how are the Action potentials spread through out the heart?
SA node –> AV node –> bundle of his –> L/R bundle branches –> purkinje ibers
where is the SA node located? be specific!
in RA near opening of SVC
next to what structure are the L/R bundle branches located?
on each side the the interventricular septum
is the activation simultaneous between the L/R ventricles?
yes
where does the purkinje fibers network terminate?
terminates on the epicardial muscle
what are intercalated discs?
microscopic identifying features of cardiac muscle that connect cardiac muscle cells
what does the intercalated disc support?
synchronized cotraction of the cardiac muscle
what is the function of the gap junction?
it connects the cytoplasm of 2 different cells
briefly explain the local circuit currents of the heart
Cell A us activated an contains an action potential, cell b is in a rested state. a cellular current will remove some charges from the resting B charge in order to depolarize it
what are a few important factors to consider about local circuit currents?
all species have ion flow
Negatively charged ions also flow, but in the opposite direction
A Repolarization wave will follow the depolarization wave
what is required in order for propagation of local circuit currents to take place?
intra and extracellular flows of currents
how is an ECG set up?
Leads are put onto two point (red and black +/-) and voltmeter will measure the voltage by calculating the difference between two given points in the body
what type of recording is provided by an ECG?
extracellular recording
what is voltage?
the difference in potential?
what lead is put to zero and serves as a reference point?
right lead
what is the wave complex of an ECG?
p wave
QRS complex
T wave
what wave corresponds to the AP fired from the SA node?
None, there is no way to know from an ECG if the SA node is fine
what is denoted by the P wave
1st half: activation of the RA
2nd half: activation of the LA
why is the AV node essential to the heart?
the heart muscle is not excitble, hence without it i the atriums and ventricles would not be activated
is activity denoted at the AV node, bundle of his, bundle branches or purkinje fibers?
no
what evidence shows that the purkinje fibers exist thrrough the activation of the septum?
the presence of the Q wave
what gives rise to the R wave?
simultaneous activation of L/R ventricles
what causes the S wave?
the delayed activation of 3-4 areas of the ventricles are activated
what wave is created by the repolarization of the ventricles?
T wave
how can a lead be described?
- Used to describe the electron itself
- o Combination of electrodes taken to the voltmeter
what can be constructued with a 12 lead ECG?
entire 3D electrocardiogram since ECG is obtained in two different plane
from a 12 lead ECG what are some information that can be obtained?
- aVR :T wave can be inverted and is totally fine along with only Q wave
- V3: no Q wave: RS complex only
- V2: lack P wave
how is the resting potential in ventricles compared to in neurons?
more hyperpolarized
how does the difference in AP differ between ventricles and nerves/skeletal cells
much longer in the ventricles (o.3 vs 0.1 ms)
how many different species of ion channels are there in cardiac cells?
~ 20 different
what ions are the channels in the cardiac cells specific for?
Na and Ca2+
what happens to the permeability of Na and Ca as AP increases?
the permeability also increases
what state are the channels in at rest?
closed state
at rest what is the cardiac cell membrane highly permeable to?
K+
what happens when the K+ channels close?
allows for Ca2+ to move in
which channel between sodium and calcium closes more rapidly when activated
sodium
What generatees the sinus node AP?
influx of Ca2+ into the cell is what generates the upstroke
is their a resting potential in the SA node?
no, these act as the pacemaker cells of the heat
what is the SA and AV node AP considered to be in terms of speed?
slow AP
What is the speed of propagation in the SA nodes when firing an AP?
0.01-0.05 m/sec
are their sodium channels present in the sinus?
no
what parts of the heart have fast ap?
- Ventricular muscles
- Atrial muscles
- Bundle of his
- Bundle branches
- Purkinje fibers
What is a fast AP?
0.5-5m/s
what is a cardiac arythmia?
disturbance of heart rate
what is regulated in coronary autoregulation?
the coronary flow adjusts to maintain adequate flow in the heart when the pressures decrease
the pulmonary vascular resistance is measure based on which part of the heart?
left heart
what is the pulmonary perfusion pressure?
10 mm Hg
what is the atrial perfusion pressure?
100 mm Hg
is the cardiac output the same or different between the aortic and pulmonary circuits?
same
what is the resistance in the pulmonary circuit as opposed to the systemic?
resistance is decreased by ~10X
how can the mean arterial pressure be changed?
must change one or more of the following variables
heart rate
total peripheral resistance
stroke volume
why is arterial BP important?
Arterial BP drives the flow of blood throughout the entire system
what is kept constant by organs despite fluctuations of pressure and how?
blood flow is kept constant by autoregulating the resistance to flow
how do organs minimize fluctuation in arterial pressure?
through neurohormonal control
what is the benefit of using the oscillimetric method to calculate BP?
indirect thus no harm, also easily to understand and read; no need to be knowledgable about BP to understand how to use it
what is calculated during oscillimetric method of BP measurement?
the slope is used to calculate both the systolic and diastolic BP
what is listened to during auscultation method of measuring BP?
the korotkoff sounds
when can sounds be heard in the auscultations method?
sound is only produced when arteries are partially occluded.
how are the korotkoff sounds produced?
the sounds are produced by the passage from a small cross sectional area to a large cross sectional area causing for flow to become turbulent
can sounds be heard if arteries are fully occluded or fully opened?
no sounds can be heard
what instrument is used to listen to the sounds when measuring BP?
stethoscope
when is the pulse first felt during the palpitation method?
when the arterial pressure > pressure in the Cuff
what A is used to feel the pulse in the palpation method?
radial a.
using the palpation method, the pressure peak is a good approximation of what pressure?
of the systolic pressure
what instrument is used to measure blood pressure in palpation?
aneroid sphygmomanometer
what inspired the function of the aneroid sphygmomanometer?
the mercury sphygmomanometer
is their fluid in the aneroid gauge?
no fluid
what are the indirect methods to measure blood pressure?
palpation
ausultation
oscillation method
what is a direct method of measuing BP?
puncture of A. based on the Hydrostatic pressures
what happens to arteries over time?
the arteries become stiffer, thus less complient
what is th windkessel effect?
it implies the elastic mechanism of the major blood vessels which lessen the flucuating effects of BP during diastole ejection
what is accounted for in the wind kessel effect?
-shape of arterial wave form in terms of the interactions of the stroke volume and compliance of the aorta
when talking about blood pressure what what are we actually measuing?
the systemic blood low in the big arteries
what happens to BP in the diastolic phase?
it decreases
what is pumped by the lV for the first 1/3 of cardiac contractions?
70 mL of blood into the aorta gets pumped from the LV
what is the max pressure?
systolic pressure
what is the min pressure?
diastolic pressure
what is pulse pressure?
systolic pressure - diastolic pressure
what is the value for mean pressure?
100mm Hg
what does the sarling’s law of the heart state?
if the volume in the ventricle increases, the the stroke volume will be greater; thus greater extension of heart fibers= greater squeeze of the heat
how is the pressure in the right ventricle compared to the left ventricle?
smaller
how is the pressure in the great arteries on the right side of the heart compared to the left side?
smaller
what is stroke volume?
the output of blood ejected through each pump of the heart (70 mL)
what is end diastolic volume a good index of?
preload
what is preload?
Preload is the amount of blood the veins return to the heart before contraction
what is the ejection fraction?
Ejection fraction= stroke volume/ end diastolic volume = 0.6 ~ 60%
what is the cardiac output’?
Cardiac output= heart rate x stoke volume = 5 L/min
what is the heart rate in sinus bradycardia?
<60 bpm
how would the waves look on the grid sheet during sinus bradycardia?
the wave would take > 1 second to be completed
in what type of people is sinus bradycardia common?
athletic people
when does our heart beat naturally drop below 60 BPM?
when we are sleeping
what is sinus tachycardia?
when BPM > 100
What may cause sinus tachycardia?
can be of physiological or pathological reasons (such as fever)
what is a sinus arrhythmia?
a heart beat that is either too fast or too slow
what happens in a 2:1 AV block?
every 2nd P wave is not followed by a QRS wave
what causes AV block?
SA node has been depolarized hence it means that the conduction is either stopped in the AV node, bundle of his or L/R bundle branches
what is used to ensure proper contraction an avoid AV block?
electronic pace maker
what happens in complete AV block
nerve impulse generated in the sinoatrial node (SA node) in the atrium of the heart does not propagate to the ventricles.
what waves can be observed in compelte av block?
atrial repolarization waves
how many pacemakers are required in complete AV block?
2
subsidiary pacemaker and electronic pace maker
what demonstrates a complete AV block?
lack of relation between P and QRS waves
what is a subsidary pacemaker?
second source of rythmic control of the heart which is availible for controlling cardiac activity if the SA pacemaker fails
what is the rate of the subsidary pace maker compared to the SA node?
smaller
what happens to the heart beat due to presence of 2 different pacemakers?
2 different beats can be detected
