Tuesday, May 08, 2007

The Human Nervous System - PART ONE

Divisions of the Nervous System

The human nervous system has two major divisions:

1) The Central Nervous System (CNS) which is made up of the brain and spinal cord.

2) The Peripheral Nervous System (PNS) division that contains nerves that transmit information to and from the CNS.

From there the PNS is divided into the autonomic nervous system (ANS) which controls involuntary information and it conducts impulses from the CNS to cardiac muscle, smooth muscles (ie. digestive system), and glands. The ANS then gets divided into the sympathetic and parasympathetic nervous system which will be discussed later.

The other partition of the PNS is the somatic nervous system which conducts impulses from the CNS to skeletal muscle.

Both of these divisions play an important role to bodybuilders. It allows us to lift heavy ass weights and digest much needed food.

Breakdown of the Nervous System

The Central Nervous System - The Brain

As previously mentioned the CNS is made up of the brain and spinal cord. The CNS is responsible for integrating, processing, and co-ordination sensory input and motor output. It also plays a role of higher functions, such as intelligence, memory, learning and emotion.

The brain is divided into numerous regions which include the brainstem, cerebellum, diencephalon, telencephalon and the limbic system.

The Brainstem

The brainstem is made up of the medulla oblongata (medulla for short), pons and midbrain. The medulla oblongata is important for relaying sensory information to the thalamus and to other brainstem centers. Also, it contains major centers concerned with the regulation of autonomic function, such as heart rate, blood pressure and the digestive activity. Which all play an important role in the world of gym, the medulla can increase our heart rate so much needed oxygen gets delivered to the muscle and adjusting of blood pressure so we don't faint.

The pons relays sensory information to the cerebellum and thalamus. Also, it is contains subconscious somatic and autonomic motor center. Any motor movements that we don't think about will be sent here.


The cerebellum functions by complex feedback circuits that monitors and coordinates other areas of the brain and spinal cord that are involved in motor control.. The cerebellum receives motor output signals from the central command in the cortex. This cerebellum, also obtains sensory information from peripheral receptors in muscles, tendons, joins and skin and from visual, auditory, and vestibular end organs. The cerebellum serves as the major comparing, evaluating, and integrating center for postural adjustments, locomotion, maintenance of equilibrium, perceptions of speed of body movement and other diverse reflex functions related to movement. Movements that are first learned by trail and error, like riding a bicycle or proper form of deadlifts or squats, remain coded as coordinated patterns in the cerebellar memory banks. Essentially, this motor control center ?fine tunes? all forms of muscular activity


The diencephalon is made up of the thalamus and hypothalamus. The thalamus provides the switching and relay centers for both sensory and motor pathways. Ascending sensory information from the spinal cord and cranial nerves (other than olfactory nerves) is processed in the thalamus before the information is relayed to the cerebrum or brain stem. The thalamus also plays an important role in regulating a sleep and wakefulness states and also has a role in controlling arousal, the level of awareness and activity.

The hypothalamus which lies inferior to the thalamus in the cerebrum, controls metabolic and body temperature. It also influences activity of the ANS; it receives regulatory input from the thalamus and responds to the effects of diverse hormones.


The telencephalon contains the two hemispheres of the cerebral cortex which makes up approximately 40% of the total brain weight. It is divided into four lobes; front, temporal; parietal and occipital. Neurons in the cortex provide specialized sensory motor functions. Deep to each cerebral hemisphere and in close association with the thalamus lie the basal ganglia, which play an important role in control of motor movements.


Kurt Kuhn - www.FUSIONBodybuilding.com

1 comment:

Anonymous said...

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