Cardiac output at rest: where is the main flow going?
digestive system, kidneys, muscle, brain
BFlow changes based on metabolism
Blood Flow + Pressure relationship (gradients)
High to Low (^ change in P = ^ flow)
inversely proportional to vascular resistance (^ resistance = less flow)
\
Left Ventricle creates pressure and flow
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Cardiac output at rest: where is the main flow going?
digestive system, kidneys, muscle, brain
BFlow changes based on metabolism
Blood Flow + Pressure relationship (gradients)
High to Low (^ change in P = ^ flow)
inversely proportional to vascular resistance (^ resistance = less flow)
\
Left Ventricle creates pressure and flow
Blood Pressure moving through vessels (high to low)
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
Vena Cava
Resistance to BFlow
resistance factor (it -- resistance --)
viscosity ^^
vessel length ^^
radius v^
@@Radius impact on blood flow + by what factor?@@
smaller radius→ ^ resistance = less flow
@@radius decrease by factor of 2: r@@
@@flow decrease by factor of 16: r^4@@
What controls BFlow
vasoconstriction + dilation
effect of viscosity on blood flow
^ viscosity (thick) = less blood flow
blood doping
example of effect of viscosity: excessive RBC’s will increase viscosity (thick) = decrease blood flow = decrease O2 delivery
Order of size of vessels
arteries →arterioles → capillaries → venules (dont need to know) → veins
Layers of Vasculature (blood + lymph vessels)
tunica intima = endothelium (+ areolar connective tissue)
tunica media = muscle + elastin
tunica externa = connective tissue - collagen, elastin
What layer of vasculature arterioles have the most of
smooth muscle -- tunica media
what layer of vasculature capillaries are
single endothelium
what layer of vasculature arteries mainly have
collagen + elastin -- tunica externa
when there is a large section between arterioles and capillaries… what happens to diffusion?
larger section = more diffusion time/ time for exchange = less speed thru capillaries
**pulse through arterioles to capillaries is non existent for smooth movement
ARTERIES - fibres? what do they do?
high flow rate + high pressure (pressure reservoir when heart relax)
large radius = low resistance
collagen →strength for tension
elastin →stretch/recoil
pulsate flow
systolic (contract) pressure = 120 mmHg
diastolic (relax) pressure = 80 mmHg
atherosclerosis
cholesterol build up within arteries
Atherosclerosis - atheroma
fatty plaques within vessel WALLS
harden into plaques
restrict blood flow… clot
Causes:
Risk factor for:
Pulse Pressure
dif btwn systolic + diastolic pressures
increase as age
ARTERIOLES - main function? applications?
change blood flow + resistance + control flow
smooth out pulsatile flow (from arteries to capill.)
RADIUS:
vasoconstrict + vasodilate (triggered by local + central factors)
vasoconstriction - what is it? what causes it?
narrow vessels
^ resistance = reduce flow
smooth muscle contraction
\
causes:
vasodilation - what is it? what causes it?
enlargement of vessel
less resistance = ^ flow
smooth muscle relaxation
\
causes:
Vascular tone - what is it? what @@influences@@ it?
contractile activity
Arterioles →extrinsic control
maintain Mean Arterial Pressure + redistribute blood
SNS input (vasoCONSTRICT)
Hormones
\
CAPILLARIES --
gas exchange
thin wall = %%less diffusion distance%%
small radius = slow velocity of BFlow = large cross-sectional area = ^ gas exchange time
^ SA
Pre-capillary Sphincters
constrict sphincter = close capill. bed (@rest are often closed)
relax sphincter = open capill. bed
metarteriole - btw arteriole + venule
Types of Capillaries
Continuous
Fenestrated
Sinusoids
Capillary Bulk Flow - Causes
GIST: hydrostatic pressure (cap) + osmotic pressure (tissue) regulate bulk flow
\
Starling Forces (physical forces) determine fluid flow btwn capillaries + tissues: PRESSURE GRADIENTS
\
pressure of capillary end close to arteries
high BP inside
lower osmotic pressure outside
more want to move out
pressure of capillary end close to veins
low BP inside
higher osmotic pressure outside
more want to move in
what is the lymphatic system? functions?
network of open-ended vessels
drains fluid from tissues
\
return of excess filtered fluid
defense against disease
transport absorbed fat
return filtered protein
\
@@lymph@@ @@vessels@@
@@similar structure to veins@@
lower pressure
have valves
edema
swelling of tissues
too much interstitial fluid
\
Causes:
venules
capill. beds uniting
porous + allow fluids and WBC into tissues
larger ones have 1+ smooth muscle cell layers
VEINS - main purpose? characteristics?
return to heart
low pressure
larger radius
low resistance to BFlow
slow flow
blood reservoir
Venous Return: Increased and Decreased by…?
Decrease:
Increase:
\
\
increase venous return = ^ EDiastolicV = ^ SV = ^ CO
venous valves + skeletal pump - functions?
VV: prevent backflow
SP: pushes blood upward
Skeletal muscle contract + relax - top + bottom valves what?
SP relax - bottom valve open, top closed
SP contract - bottom closed, top open
Embolism
blockage of a blood vessel, sometimes sudden
ex. scuba diving + nitrogen
locations: pulmonary, cerebral, cardiac
… i dont think we have to know this one
STROKE:
less blood supply to brain
TIA’s: Transient Ischemic Attacks
CVA: Cerebrovascular accidents
Stroke symptoms
depend on area of brain
\
controllable and non controllable risk factors of stroke
80% strokes are preventable
controllable:
non controllable:
Ways to asses stroke
EEG + CT + MRI
Angiogram (measure blood vessel)
doppler flow (flow thru blood vessels)
Ways to treat a stroke
anticoagulants →less clotting
hypertensive meds →lower BP
carotid endarterectomy →scrape fat
\
change diet + exercise
BP - main causes
CO
total peripheral resistance (all vessels together… force against flow)
\
mean arterial pressure = CO x total peripheral resistance
Short + Long Term control for BP
short: seconds
long: mins-hrs
Things contributing to MAP (flow chart)
\
Baroreceptors
fast + cardiovascular
pressure receptors (exp. in blood)
\
^ BP = stimulated
low BP = inhibited
HIGH BP response
everything decrease EXCEPT PNS + baroreceptors firing
\
less SNS:
→vasodilation →less TPR →less BP
→less contractility →less SV →less CO →less BP
→ venodilation →less VR →less SV →less CO →less BP
LOW BP response
everything increase EXCEPT PNS + baroreceptors firing
\
^ SNS:
→vasoconstriction →^ TPR →^ BP
→^ contractility →^ SV →^ CO →^ BP
→ venoconstriction →^ VR →^ SV →^ CO →^ BP
^HR
TPR: total peripheral resistance
Renal Regulation
long term BP control by altering BVolume
kidneys
Direct Renal Mechanism in Renal Regulation
change BV indep. of hormone
Indirect Renal Mechanism in Renal Regulation
Renin-angiotensin
Renin-Angiotensin System with less BP
less arterial BP →
release renin →
trigger production of angiotensin II → (vasoconstrictor)
aldosterone + ADH secretion →
conserve fluid→
\
**BP decreases, everything else increases
Renin-Angiotensin System with ^ BP
**BP increases, everything else decreases
Hypotension
LOW BP
Below 100/60 (systolic/diastolic)
*not a condition in the list we need to know*
Hypertension
HIGH BP
Above 140/90 (systolic/diastolic)
\
KNOW: (on other cards)
Primary Hypertension Causes
salt
hormones
arterioles abnormalities
poor kidney function (renin-angiotensin system)
age + genetics
smoking / diet / obesity
stress
Secondary Hypertension Examples
10% of cases
happens secondary to other primary problems
EX.
Complications of Hypertension
congestive heart failure (muscle doesn’t pump as good)
stroke / heart attack
spontaneous hemorrhage
renal failure
retinal damage (blood vessels in eyes)
Treatments of Hypertension
ACE inhibitors (ANG I to II) (prevents blood vessel narrowing)
beta blockers
Ca blockers
Diet + exercise (salt)