part 6 Flashcards
What is the resistance like in the venous compartment?
it is very small.
What is pulse pressure like in the capillaries?
No pulse pressure.
What is arteriosclerosis?
hardening of arteries that leads to a loss of normal elastic dampening, and this leads to passing on the pulse of the waves downstream where it can do damage.
What is the average pressure in veins?
zero mm Hg
Systemic venous blood pressure is aka?
Central venous pressure.
What is the average central venous blood pressure?
zero mm Hg
What makes the central venous blood pressure rise above zero?
The collective venous pump system.
What makes up the venous pump?
Valves and skeletal muscle.
What are the 2 pumps in the systemic circulatory system?
- The left ventricle. 2. The collective venous pump.
What is hydrostatic forces?
the affect of gravity on blood pressure.
With hydrostatic forces what part or level of the body while standing will blood pressure be at 100 mm Hg?
At the level of the heart.
When standing what will the venous blood pressure in the feet rise to?
about 90 mm Hg
When walking what will the venous blood pressure in the feet rise to?
about 25 mm Hg.
What is venous pressure like in the head while standing?
negative (well not actually negative, but air can enter here with an accident because there is no pressure).
How was blood pressure taken in the old world?
By palpating for a pulse and then looking at tissues.
What is the modern world name used for how we meausre blood pressure?
Sphygmomanometry.
What is a formula for blood pressure?
cardiac output multiplied by peripheral resistance.
What are 3 causes of peripheral resistance?
- Blood volume. 2. viscosity of blood. 3. size of vasculature container (r^4).
What can affect blood pressure?
almost anything.
What do we need to do to determine the anti-hypertensive therapies we can use?
Determine what is causing the hypertension.
What is mean arterial blood pressure?
it is cardiac output multiplied by peripheral resistance usually 100mm Hg.
Since we said delta-P is stable we took it out of the equation for flow, but what makes delta-P stable or constant?
a dozen or more control systems.
What would a control that is high gain and low gain mean?
High gain would be high power to correct something. Low gain would be low power to correct something.
What are the 2 main controls of blood pressure?
- Baroreceptors. 2. Renal-blood pressure control.
Short term and long term blood pressure controls are best done with what system?
Short term- ANS affecting the heart and vessels. Long term- controlling blood in vascular compartments.
What receptors will function as a baroreceptor for controlling blood pressure? Where are they found at?
aortic and carotid baroreceptors. Aortic found on aortic arch. Carotid found in carotid bifurcation
What type of sensors are baroreceptors?
Pressure
What cranial nerves make up these baroreceptors that help control blood pressure?
aortic- X, Carotid-IX.
Where are signals from the baroreceptors sent?
To the cardiovascular center in the brain medulla.
How will baroreceptor reflex alter blood pressure?
Through efferent innervation to heart and vasculature.
If blood pressure is low how will the baroreceptor reflex help?
The receptors send signals to the brain and then the brain will send an increased sympathetic respons to the heart and increase cardiac output. It will send an increased sypmathetic respons to blood vessels to vasoconstrict.
If blood pressure is high how will the baroreceptor reflex help?
The receptors send signals to the brain and then the brain will lessen the sympathetic respons to the heart and decrease cardiac output. It will lessen the sypmathetic respons to blood vessels and will slow vasoconstriction.
How sensitive are baroreceptors?
very responsive at normal blood pressures.
How fast acting, and effective are baroreceptors at stabalizing blood pressure?
Rapid-acting and high gain.
How long will baroreceptor reflex work at stabalizing blood pressure?
about 2-4 days and then it falls off.
After 2-4 days when barorecpetors stop working what are they doing?
They are re-adjusting the level at which they will help correct blood pressure levels.
What is the suggested usage for the baroreceptor refelx?
For sudden changes in Blood pressure.
What is the baroreceptor reflex used for?
Postural changes.
What will the mean blood pressure be if the baroreceptor refelx is gone?
It will remain at 100 mm Hg, but it will vary a lot more.
What will the arterial chemoreceptor reflex use?
Chemical sensors for oxygen.