The Nervous System

1. Central Nervous System (Brain and Spinal Cord)

1.1. The spinal cord is an extension of the brain and neural pathway running down the back ending at the waist. It transmits info between the brain and peripheral nervous system by: receiving info from sense organs; carrying commands from the brain to muscles, glands, organs throughout the body.

1.1.1. Protected by a bony column called the spine

1.1.2. Spinal reflexes allow for quick response to stimuli

1.1.2.1. A reflex is an automatic reaction to stimulus, while a spinal reflex actually bypasses the brain

2. Peripheral Nervous System-connects CNS to other parts of the body

2.1. Somatic nervous system communicates messages between the CNS and sensory organs and muscles.

2.1.1. Composed of sensory and motor neurons

2.1.1.1. Sensory neurons send messages to the brain

2.1.1.2. The CNS processes info from the sensory neurons and sends them to motor neurons which control body movement

2.2. Autonomic nervous system controls involuntary processes such as: heartbeat, respiration, digestion, and dilation of pupils

2.2.1. Sympathetic nervous system speeds up bodily processes and draws from stored reserves (arousal state)

2.2.2. Parasympathetic nervous system slows down bodily processes and provides energy through aiding with digestion (relaxed state)