Circulation: Regulation Flashcards
For acute control of tissue metabolism, what is being compared?
Blood flow to rate of metabolism
For acute control of tissue metabolism, an increase in metabolism by 8x increases the blood flow by how much?
4x
The availability of oxygen to the tissues decrease when…?
- High altitude
- Pneumonia
- CO poisoning
- Cyanide poisoning
For acute control of oxygen availability, what is being compared?
Blood flow to arterial oxygen saturation
For acute control of oxygen availability, if arterial pressure drops to 25% of normal value, what happens to blood flow?
Increases 3x
(Increase/decrease) of oxygen availability and (increase/decrease) metabolism can induce the formation of vasodilator substances
Decrease oxygen
Increase metabolism
Acute vs long-term control, which provides even better control of flow in proportion to the needs of the tissues?
Long-term control
How does nitroglycerin work?
Forms free radical nitric oxide (which relaxes). Increase cGMP, dephosphorylation of myosin chain and results in vasodilation
Endothelin is a vaso-(dilator/constrictor)
vasoconstrictor
When does endothelin increase in someone’s body?
When vessels are injured
Norepi Histamine Angiotensin II Epinephrine Bradykinin Vasopressin
Which are vasoconstrictors and vasodilators
Vasoconstrictors
Norepi, Epi, Angiotensin II, and Vasopressin
Vasodilators
Bradykinin + Histamine
Where is renin produced?
Kidney
Where is angitensinogen produced?
Liver
Angiotensin I is physiologically (active/inert)
inert
What allows angiotensinogen to form angiotensin I?
Renin
What allows angiotensin I to form angiotensin II?
ACE (angiotensin converting enzyme)
What routes can angiotensin II take?
- Inactivated
- Aldosterone
- Angiotensin receptor
What enzyme would inactivate angiotensin II?
Angiotensinase
With aldosterone, what happens?
Increase reabsorption of Na+ and water, increase blood volume and increase BP
With angiotensin receptors activated, what happens?
Vasoconstriction, then increase BP
Ca2+ causes (vasoconstriction/vasodilation)
vasoconstriction
K+ causes (vasoconstriction/vasodilation)
vasodilation
Mg2+ causes (vasoconstriction/vasodilation)
vasodilation
CO2 causes (vasoconstriction/vasodilation)
vasodilation in most tissues, but dilates especially in the brain
Innervation of (small/large) vessels increase resistance to blood flow
small
Innervation of (small/large) vessels push blood to heart thus increasing blood volume in chambers
large
What nerve carries parasympathetic signals to the heart?
Vagus nerve
When blood pressure drops, baroreceptors are (stimulated/inhibited)
inhibited
When blood pressure increases, baroreceptors are (stimulated/inhibited)
stimulated
When blood pressure goes down, what is the short term solution?
Baroreceptor reflex
When blood pressure goes down, what is the long-term regulation?
Using renin
What is the primary purpose of arterial baroreceptor system?
Reduce minute-by-minute variation in arterial pressure
When is the chemoreceptor reflex important?
When arterial pressure falls below 80mm Hg
