Physiology Flashcards: Baroreceptors & Chemoreceptors
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Questions and Answers

What is important about the elastic recoil in the arterioles?

During systole, the volume and pressure are transported onto arteries, thus expanding them. During diastole, there is recoil which maintains the pressure and continues to move blood downstream.

Why is low blood pressure bad?

It causes inadequate blood flow through various organs, leading to malnutrition and inability to remove waste products.

What is the fast response to a change in blood pressure?

For an increase in BP, parasympathetic response is stimulated and sympathetic response inhibited, leading to vasodilation and decreased cardiac output.

What is the slow response to a change in blood pressure?

<p>The kidney increases urine volume and fluid loss, inhibiting the secretion of ADH.</p> Signup and view all the answers

Where are baroreceptors located and what do they respond to?

<p>Baroreceptors are located in the aorta and carotid sinus, responding to changes in blood pressure.</p> Signup and view all the answers

Describe the baroreceptor reflex mechanism.

<p>The change in BP is detected by baroreceptors, sending signals to the cardiovascular center. Increased pressure triggers parasympathetic response; decreased pressure triggers sympathetic response.</p> Signup and view all the answers

What is orthostatic hypotension?

<p>It is a condition where blood tends to fall away from the brain when standing up too quickly.</p> Signup and view all the answers

What is syncope?

<p>Fainting due to standing too quickly.</p> Signup and view all the answers

What happens to baroreceptors during orthostatic hypotension?

<p>Upon standing, mean pressure drops, decreasing the firing rate of carotid and aortic baroreceptors, activating sympathetic input and decreasing parasympathetic input.</p> Signup and view all the answers

What is an alpha-1 blocker medication?

<p>A medication for high blood pressure that can cause problems with orthostatic hypotension by preventing proper vasoconstriction.</p> Signup and view all the answers

What effect does increasing blood volume have on blood pressure?

<p>Increasing blood volume generally raises blood pressure.</p> Signup and view all the answers

How is the effectiveness of the heart as a pump measured?

<p>By heart rate and stroke volume.</p> Signup and view all the answers

What regulates the resistance of a system?

<p>The diameter of the vessels.</p> Signup and view all the answers

How are changes in blood flow accomplished?

<p>By changing resistance to flow in the arteries or arterioles through vasoconstriction or vasodilation.</p> Signup and view all the answers

What is a precapillary sphincter?

<p>A ring of smooth muscle that can block entry to capillaries.</p> Signup and view all the answers

What problems do veins face?

<p>Veins have low mean pressure and must work against gravity to pump blood back to the heart.</p> Signup and view all the answers

What is a venous valve?

<p>Infoldings of endothelium in veins that prevent backflow of blood.</p> Signup and view all the answers

Study Notes

Elastic Recoil in Arterioles

  • During systole, arteries expand due to increased volume and pressure.
  • In diastole, arterial recoil maintains pressure, facilitating blood flow downstream.

Impact of Low Blood Pressure

  • Low blood pressure disrupts blood flow from arteries to capillaries, compromising organ function.
  • Insufficient blood circulation can result in malnutrition and hinder waste removal.

Fast Response to Blood Pressure Changes

  • In response to increased blood pressure, parasympathetic activity is stimulated while sympathetic activity is inhibited.
  • This leads to vasodilation and decreased cardiac output, functioning as a negative feedback mechanism to lower blood pressure.

Slow Response to Blood Pressure Changes

  • Increased blood volume or pressure triggers kidney responses, increasing urine output.
  • The secretion of ADH is inhibited, reducing the reabsorption of water and lowering blood pressure.

Baroreceptors and Chemoreceptors

  • Baroreceptors are located in the aorta and carotid sinus; they respond to blood pressure fluctuations.
  • Chemoreceptors, adjacent to baroreceptors, monitor changes in pH and CO2 levels.

Mechanism of Baroreceptor Reflex

  • Baroreceptors detect blood pressure changes and transmit signals to the medulla's cardiovascular center.
  • A rise in blood pressure activates parasympathetic responses, while a decrease triggers sympathetic responses to stabilize heart rate and contraction force.

Orthostatic Hypotension

  • Orthostatic hypotension occurs when standing up quickly causes blood to shift away from the brain due to gravity.

Syncope

  • Fainting, or syncope, can result from sudden changes in posture, such as standing too quickly.

Baroreceptor Reflex and Orthostatic Hypotension

  • Transitioning to a standing position decreases mean arterial pressure, reducing baroreceptor firing.
  • This activates sympathetic responses, causing vasoconstriction, increased cardiac contractility, and a rise in blood pressure.

Alpha-1 Blocker Medication

  • Alpha-1 blockers for hypertension can exacerbate orthostatic hypotension by impairing arterial constriction during sympathetic stimulation.

Blood Volume and Blood Pressure Effects

  • Increasing blood volume generally leads to lower blood pressure; conversely, decreasing blood volume raises blood pressure.

Measuring Heart Pump Effectiveness

  • The heart's pumping efficiency is assessed through its rate and stroke volume.

Regulation of Systemic Resistance

  • Vessel diameter is the primary factor regulating systemic resistance in the circulation.

Blood Flow Regulation

  • Blood flow adjustments occur through changes in resistance in arteries and arterioles via vasoconstriction or vasodilation.

Precapillary Sphincters

  • Precapillary sphincters are muscular rings that control blood flow into capillaries.

Challenges Faced by Veins

  • Veins operate under low mean pressure, requiring mechanisms to ensure efficient blood return to the heart, especially against gravity in lower extremities.

Venous Valves

  • Infoldings in vein endothelium prevent backflow, maintaining unidirectional blood flow toward the heart and ensuring effective circulation.

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Description

Explore essential concepts about baroreceptors and chemoreceptors in this flashcard quiz. Understand the importance of elastic recoil in arterioles and the implications of low blood pressure on circulation. Perfect for students in physiology and cardiovascular studies.

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