Central regulation of autonomic body functions

Author ass.prof. N.M. Volkova

Autonomic control areas in the brain stem and hypothalamus

Influence of Higher Parts of the Brain on Autonomic Functions

Structures of the limbic system

Autonomic Nervous System• 2 divisions:

– Sympathetic • “Fight or flight”• “E” division

– Exercise, excitement, emergency, and embarrassment

– Parasympathetic • “Rest and digest”• “D” division

– Digestion, defecation, and diuresis

Suprachiasmatic Nucleus (SCN)

The Biological Clock • A tiny sliver of brain tissue, less than the size of a

pinhead, regulates the timing of our bodies. Within this sliver lies a biological clock that keeps track of the time of day, and seasons of the year, and marches our bodies and brains in step.

• The small cluster of nerve cells that forms the biological clock is called the suprachiasmatic nucleus (SCN). Its name derives from the location of the SCN, just above where the broad optic nerve trunks cross over each other (a site known as the "optic chiasm") on their way back from the eyes to the visual center of the brain.

• The SCN also receives information about light and dark from the eyes, but it has its own dedicated pathway of nerves, the retino-hypothalamic tract (RHT), which is separate from the main nerve bundles carrying visual information to the brain.

Biological feedback for coping stress

Autonomic reaction to ideferent information

Autonomic reaction to important information

Structures of the limbic system

THE STRESS REACTION• When stress occurs, the

sympathetic nervous system is triggered. Norepinephrine is released by nerves, and epinephrine is secreted by the adrenal glands. By activating receptors in blood vessels and other structures, these substances ready the heart and working muscles for action.