Dani - ch 17, 18 Flashcards
each tissue regulates its own local blood flow based on its __ needs
metabolic
tissue needs:
- delivery of ___
- delivery of ____
- removal of ___
- removal of ___
- ___ of ion concentrations
- transport of ____
oxygen nutrients waste carbon dioxide maintenance hormones
50% of blood goes to the ___ and ___
kidneys
liver
blood flow to the tissues is balanced between the tissues ___ need and total volume the ___ can handle
metabolic
heart
tissues meeting their need and workload of the heart are kept to a ___
minimum
acute control of blood flow:
- takes ___ to a few ___
- effect of ___ and ___ ___ changing their vessel diameter
seconds
minutes
metarterioles
precapillary sphincter
long term control of blood flow:
- takes ___ to ___
- result of an increase or decrease in ___ ___ and the number of ___ ___ supplying these tissues
days
months
physical size
blood vessels
acute control of blood flow:
- increase metabolism –> ___ in blood flow
- decrease [O2] –> __ in blood flow
increase
increase
4 reasons for a decrease in oxygen availability
high altitude
pneumonia
CO
cyanide poisoning
vasodilator theory:
- increase in tissue metabolism or decrease in [O2] –> ___ in the rate of formation of vasodilator substances in the tissues
increase
vasodilator theory
- vasodilator substances effect the ___ and ___ ____
metarterioles
precapillary sphincters
___ is a powerful vasodilator for coronary and skeletal muscle blood flow
adenosine
increase tissue metabolism –> ____ release of vasodilators –> ___ arteriole resistance –> ___ blood flow
increase
decrease
increase
6 vasodilators
adenosine ADP compounds CO2 histamines K+ H+
oxygen lack theory
- oxygen is needed for the smooth muscle in the ___ and ___ ____ to contract
arterioles
precapillary sphincter
if oxygen supply is not adequate, the smooth muscle would relax and naturally ___ –> ___ local blood flow
dilate
increase
Increase tissue metabolism or decrease oxygen to the tissues –> ___ tissue [O2] –> ___ arteriole resistance –> ___ blood flow
decrease
decrease
increase
deficiency of glucose, amino acids of FAs in perfusing blood can cause local ____ –> dont have the nutrients to make ___
vasodilation
ATP
vitamin B substances are needed for oxygen-induced phosphorylation of ___
ATP
ATP is needed for smooth muscles of the ___ and ___ ___ to contract
arterioles
precapillary sphincter
___ ___: increase in blood flow after a temporary blockage
reactive hyperemia
hyperemia occurs because of tissue ___ and a build up of ___ metabolites = ___ arterioles and ___ vascular resistance
hypoxia
vasodilator
dilate
decrease
reactive hyperemia
- when the occlusion is release, flow becomes ____ because of the ___ vascular resistance
elevated
reduced
during hyperemia, tissue becomes ___ and vasodilator metabolites are ____
reoxygenated
excreted (from the tissue)
the longer the period of occlusion, the __ the metabolic stimulus for vasodilation leading to ___ in peak reactive hyperemia and ___ of hyperemia
greater
increases
duration
___ ___: increased flow of blood to a tissue and its associated with increased metabolism
active hyperemia
active hyperemia
- blood flow ___ because of increased oxygen consumption during muscular contractions which stimulates the production of ___ substances which then ___ the blood vessels in skeletal muscles
increase
vasodilator
dilate
examples of active hyperemia
exercise
GI tract
active hyperemia can result in up to a __ fold increase in skeletal muscle blood flow with maximal exercise
20
___: process where tissues adjust blood flow over a wide rage of arterial pressure changes
autoregulation
3 organs autoregulation is mostly seen
kidneys
heart
brain
kidney, heart and brain is essential for life, and through autoregulation the body can ___ blood where its needed
divert
increase in arterial pressure –> ___ blood flow
increase
metabolic theory: suggests that as arterial pressure decreases –> oxygen and nutrient delivery ____ resulting in the release of ___ substances
metabolic theory
decrease
vasodilator
metabolic theory: if arterial pressure is too high –> ___ blood flow –> too much oxygen and nutrients that ____ ___ the vasodilator substances –> ___
increase
wash out
vasoconstriction
myogenic theory - as arterial pressure fall –> arterioles ___ as a result of an intrinsic property that responds to a ___ in blood vessel wall tenstion
vasodilate
decrease
myogenic theory - as a higher arterial pressure stretches the blood vessel wall –> reactive ____ that ___ blood flow nearly back to normal even though the pressure is high
vasoconstrict
reduce
nitric oxide = ____ during stress on the endothelial walls
vasodilator
nitric oxide protects against excessive ____
vasoconstriction
positive feed back loop with hyertension because it causes a damage in the endothelial wall which causes a lack of NO in the vessels –> favoring ___
vasoconstriction
nitroglycerin and other nitrate substances were used to treat ___
angina
___: severe chest pain from ischemia of the heart muscle
angina
___: a powerful vasoconstrictor substance derived from damaged enothelial cells
endothelin
endohelin prevents ___ bleeding because it will ___ blood vessels
excessive
vasoconstrictor
the biggest long term change for local blood flow regulation is an increase in ___
vascularity
metabolism of a tissue is increased over a long period of time, the ___ and ___ of blood vessels to those muscles will ___
size
number
increase
____: growth of new blood vessels
angiogenesis
young person, increase in number of capillaries will begin within a few ___ and be complete within a few ___ and will match almost exactly the new needs of tissue blood flow
days
weeks
elderly person, increase in capillary will happen in ___
months
angiogenesis occurs in response to rapidly___ tissues or tissues with increased ___ rates
growing
metabolic
three angiogenic factors
vascular endothelial growth factor
fibroblast growth factor
angiogen
increase in vascularity is determined by the ____ level of blood flow rather than average blood flow through the tissue
maximum
exercise, vascularity ___ to meet the demands of the level of exercise even though exercise may only last an hour or so per day
increases
____ ____: when an artery or vein is blocked so a new vascular channel develops around the blockage
collateral circulation
collateral vessels are thought to already exist, they become ____ when complete blockage occurs to preserve the tissue with blood flow
vasodilator
collateral circulation is especially evident in ___ circulation where blockage of ____ arteries is common as we age
coronary
coronary
___ ___: hormones or locally produced factors that are absorbed into the body fluids
humoral control
hormones and local factors are designated as ____ agents and ___ agents
vasconstrictor
vasodilator
NE and ACh are secreted from the ___ ____ as a response to SP nerve stimulation during times of stress or exercise
adrenal medulla
___ ___ plays a significant role in regulating arterial pressure by vasoconstriction of small arterioles to increase total peripheral resistance, thereby increasing arterial pressure
angiotensin II
___ plays a similar role as angiotensin II in increasing arterial pressure
vasopressin
___
- polypeptide that is activated because of tissue inflammation or physical stimuli to blood or tissues
- powerful arteriole vasodilation
- increase capillary permeability
bradykinin
____
- released due to tissue damage/inflammation
- powerful arteriole vasodilation
- increases capillary permeability allowing leakage of fluid
histamine
___: vasoconstrictor; stimulates smooth muscle contraction
calcium
___ and ___: vasodilator; inhibit smooth muscle contraaction
potassium and magnesium
increase H+ –> ____
decrease H+ –> ____
vasoconstrictor
vasodilation
CO2 –>
vasodilation
nervous regulation has a more ___ approach than local tissue control
global
nervous regulation _____ blood flow to different areas of the body
redistribution
nervous regulation ___/____ the pumping activity of the heart
increase/decrease
nervous regulation has a very ___ control of systemic arterial pressure
rapid
nervous regulation regulates via the ___ nervous system
autonomic
ANS is comprised of the ___ and ___ nervous systems
sympathetic
parasympathetic
___ NS - important in the control of blood flow
sympathetic
____ NS - important in regulating heart rate and heart function
parasympathetic
sympathetic nerves leave the spine on each side of the spinal cord to form a ___ ___
sympathetic chain
2 routes to regulate the blood flow
- nerves that innervate the ___
- nerves that innervate the ___ ____ ___
heart
peripheral blood vessels
all blood vessels except the capillaries are innervated by the ___ nerves
sympathetic
innervation of small arteries and arterioles ___ vascular resistance
increase
innervations of the veins __ the volume in the small arteries and arterioles to return more blood to the heart
decreases
distribution of SP vasoconstrictor system is greater in the __, __, ___ and ___
kidneys
gut
spleen
skin
less SP vasocontrictor system to ___ ___, ___ and __
skeletal muscle
brain
heart
the continual firing of sympathetic vasoconstrictor nerve fibers = ___ ____ tone
sympathetic vasoconstrictor tone
the constant impulses maintain a partial state of contraction of the blood vessels = ____ ____
vasomotor tone
neurotransmitter for the vasoconstrictor is ___ which acts on the ___ ___ receptors of vascular smooth muscle to cause vasoconstriction
NE
alpha andrenergic
SP nerves carry SP vasodilator fibers so ___ causes dilation in skeletal muscle blood vessels by acting on ____ __ receptors
epinephrine
beta 2
___ ___ is located bilaterally in the reticular substance of the medulla and lower third of the pons
vasomotor center
vasomotor center is composed of a ____ and ___ areas
vasoconstrictor
vasodilator
vasomotor center has the capacity to increase arterial pressure:
- ____ most of the arterials
- ___ total peripheral resistance
constrict
increase
vasomotor center has the capacity to increase arterial pressure:
- strongly ___ large vessels to increase venous return and cardiac output
- increase in venous return, heart muscles are stretched so to ___ contractility
constricts
increase
vasomotor center has the capacity to increase arterial pressure:
- the ANS directly stimulates the heart and ___ HR and heart muscle contractile force thus ___ CO
increase
increase
baroreceptor reflex: initiated by ___ recepetors in the walls of large systemic arteries
stretch
baroreceptor reflex:
- increase pressure stretches the baroreceptors –> send signal to ___ ___ –> feedback signal sent via the ___ nervous system –> circulation –> ___ arterial pressure back to normal
vasomotor center
autonomic
reduce
baroreceptor reflex:
- ___ term regulation
short
baroreceptor:
- ___ type nerve endings
- wall of each ___ ___ artery just above carotid bifurcation
- in the walls of ___ ___
spray
internal carotid
aortic arch
baroreceptors:
- signals from the aortic arch are transmitted through the __ nerve to the NTS of the medulla
vagus
carotid sinus baroreceptors respond to pressures between ___ and ___mmHg
60
180
aortic baroreceptors respond to pressure levels about __ mmHg higher
30
baroreceptors respond more to ____ in pressure than to stationary pressure
changes
if MAP is __mmHg and rising, the rate of impulse transmission from the baroreceptor is twice that of a stationary 150mmHg
150
as MAP increases, the number of baroreceptor signals ___ from the carotid sinus –> inhibit the ___ center –> ___ vagal PS center –> ___ of veins and ___ HR
increase vasoconstriction excite vasodilation increase
baroreceptors referred to as the __ __
pressure buffers
baroreceptor are not effective for ___ term control because they ___ if pressure remains the same
long
adapt
chemoreceptors reflexes sense __ receptors
chemical
chemoreceptors sense a
- ___ in O2
- ___ in CO2
- ___ in H+
decrease
increase
increase
There are __ carotid bodies and __ aortic bodies
2
3
both the atria and the pulmonary artery have stretch receptors in their walls called __ ___ receptors
low-pressure
CNS ___ response = one of the most powerful of all activators of the SP vasoconstrictor system
ischemic
CNS ischemic response is called the ___ ___ stance to control arterial BP
last ditch
Cushing’s response: responds to increased pressure of the CSF around the ___
brain
