EXAM 3 Module 5 Flashcards
5 purposes of the cardiovascular system
TRANSPORTATION SYSTEM
1. carries oxygen and nutrients to the cells
2. carries carbon dioxide and metabolites away from the cells
3. transports information (hormones)
4. defense mechanisms
5. carries heat
function of red blood cells/erythrocytes
carry oxygen
function of white blood cells/leukocytes
protect against infection and cancer
function of platelets/thrombocytes
play a role in blood clotting
equation for hematocrit
Hct = RBCV / TBV
equation for red blood cell volume
RBCV = TBV x Hct
equation for plasma volume
PV = TBV - RBCV
as RBC decreases, hematocrit _______
decreases
4 functions of the plasma proteins
- plasma oncotic pressure (prevents loss of fluid from capillaries)
- bind and transport substances
- immunoglobulins (antibodies) for defense
- blood clotting
hemoglobin is found in…
red blood cells
functions of hemoglobin
transport oxygen
transport carbon dioxide and hydrogen ions
nutrients required for erythropoiesis
iron
folic acid
vitamin B12
steps of erythropoietin
- decrease oxygen delivery to kidneys
- increase erythropoietin secretion in kidneys
- increase plasma erythropoietin
- increase production of erythrocytes in bone marrow
- increase blood Hb concentration
- increase blood oxygen-carrying capacity
- restoration of oxygen delivery
in recycling of iron (Fe), iron binds to _______ and is delivered to the _________
transferrin; bone marrow
decrease in the ability of the blood to carry oxygen
anemia
anemia decreases…
number of erythrocytes
hemoglobin content of erythrocytes
or both
too many erythrocytes
polycythemia
main causes of polycythemia
living at high altitude
chronic lung disease
(not getting enough oxygen)
circulation from the left heart, through all the organs and tissues of the body (except the lungs) to the right heart
systemic circulation
circulation from the right heart, through the lungs to the left heart
pulmonary circulation
carry blood away from the heart
arteries
carry blood toward the heart
veins
high levels of oxygen (oxygenated) are found in…
pulmonary veins
aorta
low levels of oxygen (deoxygenated) are found in…
vena cava
arteries
a vascular bed consists of…
arteries
arterioles
capillaries
venues and veins
microcirculation
conduct vessels (blood passes through easily)
arteries
resistance vessels (resistance to blood flow)
arterioles
exchange vessels (diffusion)
capillaries
capacitance vessels (lots of blood volume stored)
venues and veins
consists of arterioles, capillaries, and venues
microcirculation
components flow in one direction, all blood going back to heart will be oxygenated
series
components flow in multiple directions, each organ will be perfused with fully oxygenated blood
parallel
systemic and pulmonary circulations are in… (series/parallel)
series
organs in systemic circulation are in… (series/parallel)
parallel
the volume of blood pumped out by the left heart over a period of time has to ________ the volume of the blood pumped out by the right heart
equal
valves are opened and closed by…
pressure differences
when the left atrium pressure is HIGHER than the vent ventricle pressure, ________ valve opens
mitral
when the left ventricle pressure is HIGHER than the aortic pressure, _______ valve opens
aortic
a cardiac cycle (one heartbeat) is made up of
diastole and systole
ventricle fills, relaxed
diastole
ventricle contracts
systole
in cardiac muscle, adjacent cells are joined end to end with structures called _____________
intercalated discs
functions of intercalated discs
provide strong mechanical connections
contain gap junctions that allow action potentials to spread from one cardiac cell to adjacent cells
contraction of cardiac muscle cells is triggered by…
depolarization of the plasma membrane
(heart MUST depolarize to contract)
parts of the conducting system of the heart
sinoatrial node (SA node)
atrioventricular node (AV node)
bundle of His
left and right bundle branches
Purkinje fibers
the normal pacemaker of the heart is the…
SA node
sequence of excitation
- SA node generates AP spontaneously
- AP spreads over the atria by cell-to-cell transmission (gap junctions)
- AP gets to the ventricles ONLY THROUGH the AV node
- AP goes through the AV node VERY SLOW, allows for atria to complete ventricular filling
- AP is conducted rapidly through bundle of His, right and left bundle branches, and the Purkinje fibers
- AP is conducted cell-to-cell in the ventricular wall
the AV node makes it so that the electrical signal can only go in ___________ from the atria to the ventricle
one direction
if an AP originates in a ventricle, it _______ (will/will not) disturb the SA nodal rhythm
will not
if no impulse is conducted through the AV node, the _________ will act as a pacemaker (keeps the ventricles beating if the AV nodal conduction is completely blocked
His bundle
the AP in cardiac muscle cells is _________ (shorter/longer) because of the ___________
longer; plateau phase
cardiac action potentials
1. _________ (upstroke) of the AP due to opening of Na+ channels, more positive
2. plateau phase due to opening of _____ channels
3. __________ of the AP, due to K+ (more negative)
depolarization;
Ca2+;
repolarization
in the plateau phase, cardiac muscle cannot be tetanized meaning…
another AP cannot be elicited
(heart has to relax between contractions so it can fill)
Ca2+ ions entering the cell during the plateau phase regulate cardiac __________
contractility
steps of cardiac contractility
- heart must depolarize
- calcium enters plateau phase
- calcium triggers contraction
the AP in SA nodal cells has a ____________
pacemaker potential
pacemaker potential is due to…
funny channels
SA-nodal action potentials
1. pacemaker potential due to __________, ___ enters
2. __________ is reached
3. depolarization upstroke ________ produced, ___ enters
4. __________, __ exits
funny channels, Na+;
threshold;
action potential, Ca2+;
repolarization, K+
differences between SA nodal and cardiac muscle cell action potentials
- cardiac muscle cell AP has plateau phase and true RMP
- SA-nodal cell AP has pacemaker potentials (funny channels)
- cardiac muscle cell AP has Na+ upstroke, SA-nodal cell has Ca2+ upstroke
- SA-nodal cells spontaneously depolarize because of funny channels
SA node is innervated by…
both sympathetic and parasympathetic nervous system
increased sympathetic stimulation to the
SA node results in…
more norepinephrine release to beta receptors (atria and ventricles)
more funny channels open (increased Na+)
faster depolarization
increased heart rate
reaches AP threshold faster
generates more APs
increased sympathetic stimulation to the SA node results in…
more acetylcholine release to muscarinic receptors (atria)
funny channels close (decreased Na+)
slower depolarization
decreased heart rate
muscarinic receptors are found on the _______
atria
beta receptors are found on the ________
atria and ventricles
parasympathetic -> acetylcholine -> muscarinic receptors -> _______ HR
decreased
sympathetic -> norepinephrine -> beta receptors -> ________ HR
increased
if you block the vagus to the SA node (parasympathetic), HR goes from 70 b/m to 110 b/m and results in…
large resting vagal (parasympathetic) tone to the SA node (large change)
if you block the sympathetic nerves to the SA node, HR goes from 70 b/m to 60 b/m and results in…
small resting sympathetic tone to the SA node (small change)
difference between SA node AP and His bundle AP
His bundle acts as pacemaker for the ventricles only when no AP is conducted through AV node
difference: SA node has more funny channels, His bundle has less funny channels
p-wave
atrial depolarization
QRS-complex
ventricular depolarization
T-wave
ventricular repolarization
ventricle has greater tissue mass, so ventricular depolarization __________ atrial repolarization
obliterates
QRS missing after P wave, AV nodal tissue is refractory for a long time
2nd degree AV block
long distance between P wave and QRS, complete heart block
3rd degree AV block
______________ plays a major role in cardiac but not skeletal muscle excitation-contraction coupling
extracellular Ca2+
4 phases of the cardiac cycle
- ventricular filling
- isovolumetric ventricular contraction
- ventricular ejection
- isovolumetric ventricular relaxation
valves during ventricular filling
AV valve opened
aortic valve closed
valves during isovolumetric ventricular contraction
AV valve closed
aortic valve closed
valves during ventricular ejection
AV valve closed
aortic valve opened
valves during isovolumetric ventricular relaxation
AV valve closed
aortic valve closed
when left ventricle ejects blood, walls of the aorta and large arteries stretch open
systolic pressure
walls slowly recoil and pressure in aorta slowly falls
diastolic pressure
relationship between heart rate, cycle length, and systole and diastole equations
HR = 60 / T (cycle length)
T = 60 / HR
T = T syst + T diast
as HR increases, T (cycle length) will…
decrease
as HR increases, T syst and T diast will…
decrease
the volume of blood in the ventricle at the end of diastole, just prior to systole
end-diastolic volume
EDV determines __________
stroke volume
the volume of blood remaining in the ventricle at the end of ejection
end-systolic volume
the blood volume ejected by a ventricle during one heart beat
stroke volume
stroke volume equation
SV = EDV - ESV
the ratio of stroke volume to end-diastolic volume
ejection fraction
ejection fraction equation
EF = SV/EDV
the blood volume pumped out by a ventricle in one minute
cardiac output
equation for cardiac output
CO = SV x HR
cardiac output, heart rate, and stroke volume of the right heart compared to the left heart are…
the same
1st heart sound
tricuspid and mitral valves closed
2nd heart sound
pulmonary and aortic valves closed
increased sympathetic activity ________ HR
increases
increased parasympathetic activity ________ HR
decreases
stroke volume is regulated by…
end-diastolic volume
cardiac contractility
Frank-Starling mechanism
larger EDV produces stronger contraction and larger SV
length-tension relationship
larger EDV leads to larger initial fiber length
(more muscle length, more force)
importance of Frank-Starling mechanism
matches CO to the venous return
matches outputs of the two ventricles
blood volume builds up in pulmonary circulation, causes more filling of the left ventricle and EDV increases
left ventricle SV increases until it matches the right ventricle SV
sympathetic stimulation of the ventricle
activates beta receptors on ventricle
increases calcium
increases contractility
increases stroke volume
to increase SV, increase __________ or preload
sympathetic
parasympathetic -> acetylcholine -> __________ receptors
muscarinic
sympathetic -> norepinephrine -> __________ receptors
beta
3 ways blood flow to organs is regulated
autonomic nervous system
hormones
local control
2 ways to keep pressure in aorta constant
baroreceptor reflex
long-term mechanisms
if pressure of fluid within a vessel is increased…
walls stretch out
diameter increases
if pressure inside vessel is higher than pressure on the outside…
fluid will leak out
counteracts leaking out of plasma
plasma oncotic pressure
if pressure inside a tube is higher at point A than point B…
fluid flows from point A to point B
(downhill)
flow is determined by…
pressure difference and resistance
flow equation
F = change in P / R
(change in P = P a - P b)
higher resistance, ________ flow
lower
resistance is determined by…
radius
viscosity
radius of the blood vessel contracts, increases resistance
vasoconstriction
radius of the blood vessel increases, decreases resistance
vasodilation
total peripheral resistance (CO) equation
CO = (MAP - RAP) / TPR
mean arterial pressure (MAP) equation
MAP = CO x TPR
MAP determines…
blood flow
if MAP falls below set point, control systems bring it back up by increasing ______ and ______
CO; TPR
increased metabolic activity that results in vasodilation
active hyperemia
vasoconstriction and vasodilation can be produced by…
sympathetic
in response to increased sympathetic stimulation of a-receptors…
vasoconstriction
exchange occurs between
capillaries and interstitial fluid
direction: from higher to lower concentration
diffusion
bulk flow filtration
net movement from ISF to capillaries
bulk flow absorption
