LESSON 16 - heart and circulation : peripheral Flashcards
when you have an increase work of muscle what does that mean for critical power and oxygen uptake ?
increase critical power and oxygen power
what does central delivery of oxygenated blood look like in regards for O2 delivery and O2 utilization ?
increase O2 utilization and delivery
what are the 5 parts of the cardiovascular system we talk about ?
- arteries
- arterioles
- capillaries
- venules
- veins
what do arteries do ?
carry blood away from heart
what do arterioles do ?
control blood flow, feed capillaries
what do capillaries do ?
provide site for nutrient and waste exchange
what do venules do ?
collect blood from capillaries
what do veins do ?
carry blood from venules back to heart
what part of the cardiovascular system takes deoxygenated blood and brings it to be deoxygenated ?
capillaries
which part of the cardiovascular system has the highest pressure/ highest resistance ?
arteries
between arteries and veins which are “thick and hard to collapse” ?
arteries
describe arteries :
- high pressure
- conducts O2 rich blood t tissues
- connect left ventricle to tissue
what do arteries and arteries connect ?
left ventricle to tissue
what do arteries and arterioles walls contain ?
circular layers of smooth muscle that constrict or relax to regulate peripheral blood flow
what are arteries and arterioles innervated by ?
sympathetic nervous system efferents
within arteries and arterioles does gas exchange occur ?
no gas exchange takes place between arterial blood and surrounding tissues
what does efferents mean ?
exitting heart
what does afferent mean ?
back to the heart
why cant gas exchange occur in arteries and arterioles ?
walls too thick
what is the only location of gas exchange ?
capillaries
describe capillaries :
network of microscopic blood vessels so thin they provide room for single red blood cells to squeeze through in single file
what products rapidly transfer across thin, porous capillary walls ?
gas, nutrients, and waste products
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velocity progressively ________ as blood moves toward and into capillaries
decreases
what do porous help with ?
allowing stiff slip through
what is the normal cardiac output of arterial blood in litres ?
4-6 liters
describe blood flow response to 1-leg exercise in severe intensity vs moderate intensity :
- higher PO
- greater VO2
- not reaching study state
- increases in proportion with oxygen uptake / utilization requirements
what is hemodynamics ?
is how your blood flows through your blood vessels
what is the term used to describe how your blood flows through your blood vessels ?
hemodynamics
blood flow is required by all tissues and is dependent on what two factors :
pressure and resistance
describe pressure :
- force that drives flow
- provided by heart contraction
- blood flow from region of high pressure to region of low pressure
if there is no gradient what does this mean for flow ?
no flow
describe pressure :
- force that opposes flow
- provided by physical properties of vessels = cause pressure differential from arterial to venous circulation
what does vasoconstriction do for radius ?
decreases radius
what is the most important determinant of resistance ?
modification of vessel radius
what are the two modifications of vessel radius ?
vasoconstriction and vasodilation
what locations of the heart is blood flow from region of high pressure to region of low pressure
region of high pressure = LV & arteries
region of low pressure = RA & veins
how do we calculate blood flow (Q) ?
Q = MAP / TPR
what does Q stand for ?
local blood flow
what does MAP stand for ?
mean arterial pressure
what does TPR stand for ?
total peripheral resistance
what term is “taking systolic/diastolic blood pressure and finding the average”
MAP
what is arterial pressure ?
driving pressure from the hear
what takes longer to fill up the heart ?
DSP (diastolic)
between thirds how much is diastolic vs systolic ?
2/3 DBP and 1/3 systolic
what are the three things in arterial blood pressure ?
- systolic pressure (SBP)
- diastolic pressure (DBP)
- mean arterial pressure (MAP)
describe systolic pressure :
- highest pressure in artery (during systole)
describe diastolic pressure :
- lowest pressure in artery (during diastole)
what is the bottom number for diastolic pressure ?
around 70 to 80 mmHg
what is the top number for systolic pressure ?
around 110 to 120 mmHg (rest)
how do we calculate MAP ?
around 2/3 DBP + 1/3 SBP
what does DBP stand for ?
diastolic blood pressure
what does CVP stand for ?
central venous pressure
what is central venous pressure ?
blood pressure taken in the vena cava or right atrium pressure
what reflects the amount of blood returning to the heart and the ability of the right heart to pump blood into pulmonary circulation ?
central venous pressure
what is the normal rages of venous blood pressure ; central venous pressure ?
0 - 8 mmHg
why does systolic blood pressure go up during exercise ?
to direct more flow during exercise
what does η =
viscosity of blood
what does L =
length of vessel
what does r^4 =
vessel radius
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“resistance to cardiac output offered by ALL of the systemic vasculature, excluding pulmonary ___________ “
vasculature
what determines resistance to cardiac output ?
poiseuille’s law
how many factors are there for poiselle’s law ?
3
what are the three factors of poiselle’s law ?
- viscosity
- length of conducting tube
- radius of blood vessel
what does vasoconstriction do for TPR ?
increase it
what does a longer vessel mean for resistance ?
more resistance
between the three factors of poiseuille’s law, which can only acutely change ?
number 3 ; radius of blood vessel
what are known as “resistance vessels” ?
arterioles
what is vasoconstriction (VC) ?
narrowing of blood vessels
what is vasodilation (VD) ?
widening of blood vessels
what does vasodilation mean for TPR ?
decrease TPR
what does vasoconstriction mean for TPR ?
increase TPR
what is responsible for the following ? :
- control total peripheral resistance
- site of most potent VC and VD
- diversion of blood to regions most in need
arterioles (resistance vessels)
an increase in MAP means what for TPR ?
decrease in TPR
TRUE OR FALSE ?
blood flows to sites where its most needed
true
TRUE OR FALSE ?
regions of increased metabolism = increase blood flow
true
with blood flow (at rest = 5L/min) how much % is distributed ?
liver, kidneys, receive = 50% of.
skeletal muscle receives = 20% of.
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with blood flow (heavy exercise = 25 L/min) exercising muscles receive ___ of via VD.
- flow to liver, kidneys decrease via VC.
80 %
what are resting cardiac output and leg blood flow ?
cardiac output = 10 L/min
leg blood flow = 4 L/min
what are exercise cardiac output and leg blood flow ?
cardiac output = 25 L/min
leg blood flow = 20 L/min
what is leg blood flow ?
80% of cardiac output
what type of wall of smooth muscle do arterioles have ?
strong muscular wall
what do smooth muscle use between actin and myosin to develop force tension and Ca+ serve to initiate contraction ?
crossbridge
an increase intramuscular Ca+ = contraction or relaxation
contraction
a decrease intramuscular Ca+ = contraction or relaxation
relation
what is smooth muscle innervated by ?
sympathetic nerve efferents
what is resistance through arterioles mostly determined by ?
the diameter of the vessel
what’s the term for narrowing of blood vessel ?
vasoconstriction
what’s the term for widening of blood vessel ?
vasodilation
what causes vasoconstriction ?
caused by smooth muscle cell contraction
what happens to lumen during vasoconstriction ?
becomes smaller (decreased radius)
what causes vasodilation ?
caused by smooth muscle relaxing
what happens to lumen during vasodilation ?
becomes larger (increase radius)
