GROSS ANATOMY

Detailed explanation-1: -Your brainstem also contains your reticular activating system (RAS). The RAS is a network of neurons (cells that carry electrical signals and chemicals through your brain). Your RAS controls your sleep and wake cycles. It also helps you stay alert and attentive to your surroundings.

Detailed explanation-2: -The brain stem, at the base of the brain, communicates with the hypothalamus to control the transitions between wake and sleep. (The brain stem includes structures called the pons, medulla, and midbrain.)

Detailed explanation-3: -The brain stem connects the cerebrum with the spinal cord. It contains a system of nerve cells and fibers (called the reticular activating system) located deep within the upper part of the brain stem. This system controls levels of consciousness and alertness.

Detailed explanation-4: -The reticular activating system’s fundamental role is regulating arousal and sleep−wake transitions. The ascending reticular activating system projects to the intralaminar nuclei of the thalami, which projects diffusely to the cerebral cortex.

Detailed explanation-5: -The brainstem reticular formation (RF) represents the archaic core of those pathways connecting the spinal cord and the encephalon. It subserves autonomic, motor, sensory, behavioral, cognitive, and mood-related functions.