IB Biology Topic C3.1.14 Feedback Control of Heart Rate Revision Notes (SL/HL)

IB Biology Topic C3.1.14 Feedback Control of Heart Rate Revision Notes (SL/HL) | RevisionDojo

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Baroreceptors, Chemoreceptors, and the Medulla Adjust Heart Rate by Feedback

Heart rate is regulated to keep homeostasis, using baroreceptors, chemoreceptors, and the medulla oblongata.
These receptors monitor blood pressure, blood pH, and the levels of oxygen and carbon dioxide.

Analogy

Think of the heart as a car engine.
Baroreceptors and chemoreceptors are sensors reading speed and fuel; the medulla is the driver adjusting the throttle for a smooth ride.

Two Sensor Types Track Pressure and Blood Chemistry

Baroreceptors Monitor Blood Pressure

Baroreceptors are pressure-sensitive nerve endings in the walls of major arteries, such as the aorta and carotid arteries.
They detect pressure changes by sensing the stretch of the arterial walls.
1. High blood pressure: baroreceptors increase their firing rate.
2. Low blood pressure: baroreceptors decrease their firing rate.

Example

When you stand up quickly, blood pressure drops for a moment.
Baroreceptors detect this and trigger a rise in heart rate to restore normal pressure.

Chemoreceptors Monitor Blood Chemistry

Chemoreceptors detect changes in blood pH and in oxygen and carbon dioxide levels.
They sit in the aortic bodies and carotid bodies.
1. Low oxygen or high carbon dioxide: chemoreceptors increase their firing rate.
2. High oxygen or low carbon dioxide: chemoreceptors decrease their firing rate.

Note

Chemoreceptors are especially sensitive to carbon dioxide, because rising CO2 lowers blood pH and causes acidosis.

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Baroreceptors, Chemoreceptors, and the Medulla Adjust Heart Rate by Feedback

Heart rate is regulated to keep homeostasis, using baroreceptors, chemoreceptors, and the medulla oblongata.
These receptors monitor blood pressure, blood pH, and the levels of oxygen and carbon dioxide.

Analogy

Think of the heart as a car engine.
Baroreceptors and chemoreceptors are sensors reading speed and fuel; the medulla is the driver adjusting the throttle for a smooth ride.

Two Sensor Types Track Pressure and Blood Chemistry

Baroreceptors Monitor Blood Pressure

Baroreceptors are pressure-sensitive nerve endings in the walls of major arteries, such as the aorta and carotid arteries.
They detect pressure changes by sensing the stretch of the arterial walls.
1. High blood pressure: baroreceptors increase their firing rate.
2. Low blood pressure: baroreceptors decrease their firing rate.

Example

When you stand up quickly, blood pressure drops for a moment.
Baroreceptors detect this and trigger a rise in heart rate to restore normal pressure.

Chemoreceptors Monitor Blood Chemistry

Chemoreceptors detect changes in blood pH and in oxygen and carbon dioxide levels.
They sit in the aortic bodies and carotid bodies.
1. Low oxygen or high carbon dioxide: chemoreceptors increase their firing rate.
2. High oxygen or low carbon dioxide: chemoreceptors decrease their firing rate.

Note

Chemoreceptors are especially sensitive to carbon dioxide, because rising CO2 lowers blood pH and causes acidosis.

Definition

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Duis aute irure dolor in reprehenderit

Note

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Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C3.1.14: Feedback Control of Heart Rate Notes

Baroreceptors, Chemoreceptors, and the Medulla Adjust Heart Rate by Feedback

Two Sensor Types Track Pressure and Blood Chemistry

Baroreceptors Monitor Blood Pressure

Chemoreceptors Monitor Blood Chemistry

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Baroreceptors, Chemoreceptors, and the Medulla Adjust Heart Rate by Feedback

Two Sensor Types Track Pressure and Blood Chemistry

Baroreceptors Monitor Blood Pressure

Chemoreceptors Monitor Blood Chemistry

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics