B3W3 Flashcards
Regulation of MAP (intrinsic v extrinsic types)
Intrinsic:
Autoregulation
Metabolic
Myogenic
Endothelial
Extrinsic:
Baroreceptor reflex
Lung Reflex
Chemoreceptors
Muscle metaboreceptors
What are the 4 types of intrinsic MAP regulation and what do they do
- Endothelial (NO/endothelian)
- Myogenic (stretch leading to vasoconstriction)
- Autoregulation (maintaining local flow)
- Metabolic (K, O2, CO2, ADP, ATP, H, Adenosine levels)
What are the types of extrinsic regulation (short term vs long term)
- short term (baroreceptors/chemoreceptors)
- long term through renal stimulation
Vascular smooth muscle in systemic circulation ONLY react to ….?
sympathetic innervation from a1 receptors for vasoconstriction
Vascular smooth muscle in pulmonary circulation ONLY reacts to …..?
sympathetic innervation from B2 receptors for vasoconstriction
Cardiac muscle short term innervation is innervated by ……
both parasympathetic and sympathetic. HR is innervated by parasympathetic, contractility innervated by sympathetic
Are baroreceptors high or low pressure sensors?
HIGH. THEY SENSE HIGH PRESSURE
Where are the baroreceptors located
aortic arch, carotid
Difference between the carotid and aortic arch pressure sensors
carotid = lower threshold, more sensitive
Stimulus, Pathway, Response, Effect and Goal of Baroreceptors
stimulus: high pressure from increase stretch
pathway: increases in BP increases stretch, TRPC1 stretch sensitive non selective cation channels open, depolarization, increased firing of sensory nerves to the NTS
Response: increases PNS output and decreases SNS
effect: bradycardia, vasodilation, decreased contractility
Goal: restore MAP
How does increasing and decreasing stimulation to baroreceptors work
they are tonically active (always active) but by increasing frequency of firing, different response
How do baroreceptors decrease MAP
stretch receptors no longer have stimulus, decreased firing rate to NTS, parasympathetic decreases to increase HR, sympathetic increases to increase HR, contractility vasoconstriction and venous return
How do the kidneys increase MAP
stimulation of renin release, catalyzes the RAAS cascade to increase ADH, aldosterone, increase water and salt retention to maintain blood volume
What does the cardiopulmonary reflex arch respond to ?
low pressure/high volume of blood
Location, stimulus, activation/response, effect, goal of the cardiopulmonary reflex
location: veins, arteries, pulmonary arteries on the venous time
stimulus: increasing blood volume, increasing preload, increasing cardiac filling pressure (LVEDP)
Activation/response: decreases in sympathetic output to increase ANP (antinaturetic peptide which will increase excretion) and decrease ADH (antidiuretic hormone which produces high urine output)
Effect: Vasodilation of renal circulation, decreases in SV (which increases more Na H2O excretion time) increases HR
goal - maintain volume by excreting urine
Peripheral chemoreceptor Circuit
Hypoxic conditions
location: carotid body/aortic body
stimulus- decreased O2, increased CO2 and decreased pH
activation: increases sympathetic and decreases sympathetic
effect: leads to vasoconstriction, bradycardia, hyperventilation
central chemoreceptor control
hypercarbic drive
location: brain and medulla
stimulus: increases in CO2, decreases in pH of the interstitial fluid of the brain
activation: sympathetic
effect: peripheral vasoconstriction with hyperventilation
Exercise reflex circut
Location: muscle afferents of skeletal muscles
Stimulus: metabolites (K, H, Adenosine)
Response: increases in sympathetic responses, decrease in parasympathetic responses
effect: tachycardia, vasodilation of active muscles, vasoconstriction of inactive muscles
Lung Reflex
Location: lung
Stimulus: lung inflation
response: decreases sympathetic innervation leading to vasodilation of muscles, decreases parasympathetic responses (increases HR)
Effect: vasodilation of vessels and tachycardia
What are the two values and which way are they pointing on the cardio vascular curve?
Line going down is vascular function
line going up is cardiac function
The y axis = CO
x axis = (R) atrial pressure
What does the intersection of the vascular and cardiac curve mean?
It is the steady state that is maintained by the body to maintain vascular and cardiac function
What are the three values that can change the cardiac vascular curve
increase/decrease in ionotrophy
change in blood volume
change in TPR
If there are changes in ionotropic effects, which line of the graph changes and how does it move?
Changes the cardiac function by:
increasing ionotropy = moving it up
decreasing ionotrophy = moving it down
If there are changes in blood volume, which line of the graph changes and how does it move?
The vascular function curve moves and it will:
increasing blood volume: move it up
decreasing blood volume: move it down
If there are changes in TPR, which line of the graph changes and how does it move?
Both the cardiac and vascular function will move:
increasing TPR: moving down
decreasing TPR: moving up
What are the systems that are involved in special circulation?
brain, shplanic, skeletal muscle, skin, heart
When is there the most blood flow to the heart?
Diastole
How would tachycardia affect the blood flow to the heart?
increasing HR decreases diastole which would lead to a decrease in blood flow to the heart
In general, O2 extraction levels in the heart are ….. compared to the rest of the body
MUCH HIGHER (about 70-80% of O2 extracted at basal conditions
When there is an increase in exercise and metabolism of the heart, how is there O2 maintenance ?
Blood flow increases to heart to meet O2 requirements
What is a vasoactive chemical which causes vasodilation of coronary arteries
adenosine
What happens when O2 supply does not meet demand?
If O2 demand increases, O2 supply must increase or risk myocardial infarction
How do you increase O2 supply
increase blood flow
how do you decrease O2 demand
decrease HR or decrease contractility
Describe coronary steal
when there are two paths of blood flow and one has a plaque, this vessel is already dilated. When there is a vasodilator or exercise introduced, the normal vessel will undergo vascular innervation to dilate and will have an increase in blood flow. The ischemic vessel is already dilated and therefore will remain the same and still have the reduced blood flow
Skeletal muscle cicrulation has an …… range of blood flow values
increased (it can go from low levels to high levels of blood flow at times of rest to times of exercise
what is a microvascular unit in skeletal muscle circulation
it is a group of capillaries supplied by a single terminal arteriole
How is vasodilation of skeletal muscles regulated by VSMC
Potassium mediated VSCM hyperpolarization leads to dilation and increase in blood flow
Which are the metabolites which can activate skeletal vasodilation
K, adenosine, H, lactate, CO2
…% of our cells are skeletal muscle cells
50
…% of our mass is skeletal muscle
90
…% of at rest CO goes to skeletal muscle
20
Skeletal muscle innervation by neuro system
very limited
Celiac artery innervates…
the stomach, spleen, and pancreas
superior and inferior mesenteric arteries innervate….
stomach, pancreas, intestines
Describe the parasympathetic and sympathetic innervation of enteric circulation
sympathetic: vasoconstriction to decrease flow
parasympathetic: increases gut motility, glandular secretions, metabolism, increases flow
How does blood flow volume change in post prandial hyperemia
goes from 30 mL to 250 mL of blood
What are the vasodilators in postprandial hyperemia
cholecystokinin and bradykinin
How are villi so good at being nutrient absorption spots?
have fenestrations and high surface areas
Name the blood reservoirs of the body and how much they hold
Spleen (50-100)
Abdominal (300)
Liver (100-300)
What are lacteals
Where lipophilic nutrients are taken up and dumped into the lymphatic system
countercurrent exchange of the villi predisposes villi to …..
ischemia
Blood flow to villi. What happens when there are long term decreases in flow
leads to necrosis of a villi
How much resting CO does the liver receive
25%
how much blood does the hepatic artery supply and how much O2
25% blood, 75% O2
How much blood does the portal vein provide and how much O2
portal vein - 75% of blood supply
25% of O2 needs
What are sinuous capillaries
having lots of fenestrations, but larger to allow for protein transfer in liver
What adrenergic receptor is responsible for innervation of the liver
a1
what is the top level of skin that has capillaries
dermis
difference between apical vs non apical
apical = lips, hands, feet, ears, nose
apical skin generally has more flow through anastomoses
Innervation of apical vs non apical
apical = NE, sympathetic innervation, constriction
(dilation is passively completed by lower sympathetic firing)
non apical = Ach, sympathetic innervation leading to bradykinin dilation
NE for constriction
When there is a decrease in body temperature in apical skin….
increase in sympathetic response, leading to vasoconstriction to decrease flow and decrease heat loss
When there is an increase in body temperature in apical skin….
decrease in sympathetic response, leading to vasodilation, leading to flow and increasing heat loss
Apical skin is different from non apical skin as there are ……
glomus bodies
Homeotherm are the most ….
efficient organisms at generating their own body heat
endoderm v ectoderm
endoderm make their own body heat, ectoderm rely on environment
Give resting body temp
37 C (98.6)
<34 C body temp causes….
slowed metabolism and arrythmia
> 45 C body temp…..
destroys proteins and enzymes leading to death
Core temperature relies on …
age, menstrual stage, physical activity, time of day
Which part of the hypothalamus corresponds to hot and cold regulation
Anterior hypothalamus aids in response to hot temperatures to increase skin blood flow
posterior hypothalamus aids in response to cold temp. This leads to shivering, decreased skin flow and non shivering thermogenesis
What are the modes of heat transfer
radiation (sun), conduction (skin to skin) , convection (heat carried from cardiovascular system) , evaporation (sweat)
Go through the temperature chart in your head saying the temperatures and corresponding physiological change
27-29: arrythmias
30-34: impairment to temp regulation
34-36: hypothermia
36-38: normal
38-40: hyperthermia
40-44: heat stroke with organ failure and brain lesions
