Divisions of the Nervous System The Nervous System

Divisions of the Nervous System

The Nervous System �Nervous System – The entire network of neurons in the body. �Includes: � Central Nervous System � Peripheral Nervous System � Their subdivisions

The Central Nervous System �Central Nervous System – The brain and spinal cord. �“Command Central”

The Central Nervous System �The Brain �Makes complex decisions �Coordinates body functions �Initiates our behaviors �Responsible for voluntary movements

The Central Nervous System �The Spinal Cord �Serves as a sort of neural cable, connecting the brain with parts of the peripheral nervous system extending into the trunk and limbs. �Does not connect the brain to internal organs. �Responsible for simple reflexes.

The Peripheral Nervous System �The Peripheral Nervous System – Plays a supportive role, connecting the central nervous system with the rest of the body through bundles of sensory and motor axons, called nerves.

The Peripheral Nervous System �Carries messages between the brain and: �Sense Organs (eyes, ears, etc. ) �Internal Organs �Muscles

The Peripheral Nervous System �The “Pick-up and Delivery Service” for the Central Nervous System.

Divisions of the PNS �Somatic Nervous System �Carries sensory information to the central nervous system. �Sends voluntary messages to the body’s skeletal muscles.

Divisions of the PNS �Autonomic Nervous System �Sends communication between the central nervous system and the internal organs and glands. � Regulate digestion � Respiration � Heart Rate � Arousal

Divisions of the PNS �Sympathetic Division �Part of the Autonomic nervous system �Sends messages to internal organs and glands that help us respond to stressful and emergency situations.

Divisions of the PNS �Parasympathetic Division �Part of the autonomic nervous system �Monitors the routine operations of the internal organs. �Returns the body to calmer functioning after arousal by the sympathetic division.

The Nervous System and Drugs �Agonist – Drug or other chemical that enhances or mimics the effects of neurotransmitters. �Antagonist – Drug or other chemical that inhibits the effects of neurotransmitters.