The Nervous SystemChapter 2

The Nervous System

Central Nervous System (CNS) Brain and Spinal Cord (all nerves

within our bones) p. 61 Peripheral Nervous System

(PNS) All other nerves in the body that

are not part of the Brain and Spinal Cord

Links the Central Nervous System to the rest of the body

The Peripheral Nervous System

2 parts of the Peripheral Nervous System Somatic – Controls voluntary movement

through the body’s skeletal muscles Autonomic – Controls the automatic

functions of our body (ex. heart). Mnemonic is autonomic and automatic.

Somatic Nervous System

Autonomic Nervous System

The Autonomic Nervous System Sympathetic

Mobilizes our body to respond to stress

Fight or Flight Response – state of increased physiological arousal, helps the body cope with and survive threatening situations

Parasympathetic Slows our body down after

responding to stress

How does the Parasympathetic and Sympathetic affect our bodies?

Sympathetic vs. Parasympathetic

Sympathetic - Arousal Pupil: Dilates Heart: Accelerates Stomach: Digestion Inhibited Perspiration: Increases

Sympathetic vs. Parasympathetic

Parasympathetic – Calming Pupil: Contracts Heart: Slows down Stomach: Digestion is stimulated Perspiration: Decreases

Types of Neurons

Sensory Neurons – aka Afferent Neurons

Interneurons- connect sensory/motor neurons.

Motor Neurons – aka Efferent Neurons

Sensory Neurons

Sensory Neurons – aka Afferent Neurons Take info from the senses to

the brain Ex. You touch a hot light bulb,

receptors in your skin carry information to your spinal cord. When pain information enters the spinal cord it is sent to the interneuron

Interneurons

Interneuron Neurons of the central nervous system Communicate between sensory inputs

and motor outputs Ex. Information taken to the spinal cord

is sent to motor neuron by the interneuron

Motor Neurons

Motor Neurons – aka Efferent Neurons Take info from the brain to the senses

(think exits the brain) Ex. Information is sent from the spinal

cord to the muscles in the hand, causing the hand to withdraw quickly▪ At this same time, the interneuron may also

send information to other parts of the brain, which in turn sends out other motor neurons causing you to move your facial muscles (look of pain) or vocal muscles (yell)

Reflex

Reflex – an unlearned or involuntary reaction to some stimulus. These are processed through the spinal chord

Neural Network

Neural Network – interconnectedness of the body’s neurons, works together in groups.

(Ex. – student neural network) VIDEO- Crash course- nervous

system