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38 Cards in this Set
- Front
- Back
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What does sympathetic stim do to the veins? Do they constrict them?
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No, they just make them stiffer and less stretchy.
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What does increased pressure to the baroreceptors do to their nerve signaling?
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it increases firing rate.
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What nerve does the carotid sinus barocreceptor feed into?
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CN 9
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What nerve does the aortic arch barocreceptor feed into?
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CN10
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Where do these cranial nerves pass the signal onto?
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the nucleus tractus solitarius
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What does the nucleus tractus solitarius do when it is stimulated?
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It goes to another area in the medulla and stimulates the cardiac deceleators (PS) and inhibit the cardiac accelerator/vasoconstrictors (S)
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Where is the nucleus tractus solitarius and the cardiac acc/declelerators loacted?
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In the medulla
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What will the cardiac accelerators do?
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increase the SA node firing and contractility
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Is the sympathetic chain to the left or right of the spine?
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The right
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What happens when yu inhibit sympathetic stimulation to the heart to HR and SV? Why?
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they will both decrease. Even though you have a larger filling volume, the contractility will decrease and venous return will decrease even more.
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What happens to the veins when you inhibit sympathetic tone? WHat does this do to CO?
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It increases venous compliance so it decreases venous return and thus CO.
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What is the main reason why someone has HTN?
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They have fluid management problems with the kidneys that readjust the set point of the baroreceptors.
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What are the baroreceptors good for?
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preventing acute changes in BP.
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What receptor does Epi vs NE bind to at the endothelial cell?
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Epi- B2
NE- a1 |
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When is endothelin released from endothelial cells?
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when they are damaged.
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When may the Cushing Reflex be advantageous?
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if you have fluid in the brai that is compresing brain blood vessels and the increased peripheral constriction raises the brain BP enough to prevent ischemia.
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When may the Cushing Reflex be disadvantageous?
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when you are bleeding in your head that is causing the pressure and the reflex will make you bleed more
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What will interstitial edema do to the veins?
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It would compress them.
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What is mean circulatory filling pressure?
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BP when there is no flow which is around 7-8mmHg.
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What is normal stressed volume?
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the volume of blood that you take out to make the mean pressure go down to 0. About 25mL/kg
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What is unstressed volume?
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The volume/kg that can bbe left in the body when the pressure is 0mmHg. Usually 15mL/kg.
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What can you do without moving to enhance venous return?
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Inspire deeply to expand the VC.
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How much will intrapleural pressure be when you inspire?
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About -5-6 mmH2O
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When you let go in the third phase of the valsalva maneuver, why does BP increase to more than normal?
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You overshoot BP because the previous sympathetic stimulation is still going with the high HR and vasoconstriction, then baroreceptors get stimulated and modulate.
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When is the venous blood pressure in your legs the highest?
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When you are standing still with none of the skeletal muscle pumps pushing blood through the valves.
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What will high right atrial pressure do to ventricular filling and venous return?
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it will increase ventricular filling, but inhibit venous return.
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What is your central venous pressure?
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The same as your right atrial pressure
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What happens to central venous pressure as you increase CO? WHy?
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It would decrease because you are moving blood quickl out of the venous system and also you want a lower VC pressure to increase the gradient for venous return.
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Do you need to give the double labels on the axis of the cardiac and venous function curve?
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NO! They are the same friggin thing!
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What happens in our central nervous system when we trigger mechano and chemo receptors for exercise?
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We stimulate S signals to the heart and blood vessels and decrease PS to the heart
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What are the 2 ways in which venous return is increased in exercise?
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Contraction of skeletal muscle and decreased compliance of veins
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What does decreased compliance of veins do to the overall unstressed volume?
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decreases it since there is less container volume
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T/F: in exercise, the S NS constricts all blood vessels except skeletal and kidney.
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FALSE! It is the local metabolic effects ar these organs that open them up.
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Do non exercising skeletal muscle have increased blood flow during exercise?
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Not really, they are constricted by the NS and aren't producing metabolites to override that.
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Which areas does the NS not constrict during exercise?
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The heart and the brain
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How does the heart get more circulation?
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as needed from it's oxygen consumption
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Which electrolyte increases during exercise?
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K
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What will K do to vessels?
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It will signal them to vasodilate
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