Regulation of Heart Rate by Autonomic Nervous System
Rahul's Noteblog
Notes on Neurology
Regulation of Heart Rate by Autonomic Nervous System
Heart Regulation by Chemoreceptors:
Heart Regulation by Baroreceptors:
Regulation of Heart Rate by Autonomic Nervous System
• Cardiac Output = Stroke Volume X Heart Rate.
• Heart Rate is varied to produce change in CO and BP.
• CO rises during exercise.
• HR is best regulated by the autonomic NS and hormones from the adrenal medullae (epinephrine and norepinephrine).
• Sensory receptors > cardiovascular center in medulla oblongata > increase or decrease in frequency of nerve impulses in both sympathetic and parasympathetic branches of ANS.
• Sensory receptors: proprioceptors, chemoreceptors, and baroreceptors.
• Sympathetic neurons go from medulla oblongata > spinal cord (thoracic region) > SA (cardiac accelerator), AV, portions of myocardium.
This is how HR increases (Sympathetic Stimulation):
• Impulses from cardiac accelerator > norepinephrine released & binds to beta-1 on cardiac muscle > rate of depolarization increases > HR increases.
• Impulses from cardiac accelerator > norepinephrine released & enhances Ca2+ entry through the voltage-gated slow Ca2+ channels, increasing contractility.
This is how HR decreases (Parasympathetic Stimulation):
• Impulses > stimulate r. & l. vagus (CN X) n. to release ACh > heart (SA, AV, atrial myocardium) > HR decreases.
Additional Reading:
Basic Neurology
1. Peripheral Nervous System
2. Central Nervous System
3. The Ventricular System
4. The Spinal Cord
5. The Brain Stem
6. The Cerebellum
7. Visual Pathways
8. Diencephalon
9. Basal Ganglia
10. Cerebral Cortex
11. The Limbic System
12. Sleep Disorders
13. Autonomic Nervous System
14. Cranial Nerves and Parasympathetic Ganglia
15. Cells of the Nervous System
16. Cerebrospinal fluid
17. Additional short notes on Cerebrum
18. Functions and Diseases of Cerebrum
19. Subcortical Grey Matter
20. Notes on The Spinal Cord
21. Regulation of Heart Rate by Autonomic Nervous System
22. Action Potentials, Axon Conduction, and Neuromuscular Junction
Related Topics
1. Nervous System Disorders
2. Histology of Nervous Tissue
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Page accessed on: July 29, 2010, 11:22 am.