BRAINCAKEChemoreceptors
During exercise the heart rate increases to increase the supply of oxygen to respiring cells and to remove CO2. Heart muscle is myogenic. The SAN determines the rate at which the heart contracts. But the SAN can be stimulated by the nervous system.
The medulla oblongata has two centres in the cardiovascular centre of the brain which can modify the heart rate
The cardiac accelerator centre sends impulses to the SAN via the accelerator nerve which is part of the sympathetic nervous system. This increases the heart rate in response to a decrease in the pH of blood.
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Key terms in this lesson
- sino-atrial node
- A small group of cells in the wall of the right atrium that acts as the heart's pacemaker, generating regular electrical impulses that initiate each heartbeat.
- myogenic
- Describes muscle, such as cardiac muscle, that can initiate its own contraction without needing stimulation by a nerve impulse.
- chemoreceptor
- A sensory receptor that responds to changes in the concentration of chemicals, such as pH-sensitive receptors in the carotid artery and aorta.
- medulla oblongata
- The region of the brain containing the cardiovascular centre, which regulates heart rate via the sympathetic and parasympathetic nervous systems.
More in Neuronal Communication
- Receptors in the Eye - Cone Cells
- Sino-Atrial Node
- Contraction of the Heart
- Autonomic Control of the Heart Rate
- Pressure Receptors
- Reflex Arc
- Taxes
- Kinesis
All 38 lessons in Neuronal Communication · All AQA A-level Biology topics