The Nervous System

What is it and how does it work?

Central Nervous System

Peripheral Nervous System

The Nervous System

•Our body’s speedy electrochemical communication network

•Brain & Spinal Cord form the CENTRAL NERVOUS SYSTEM which communicates with the body’s sensory receptors, muscles, and glands via the PERIPHERAL NERVOUS SYSTEM

•CNS is in charge of the executive functioning while the PNS serves as the delivery function

The Peripheral Nervous SystemAutonomic Nervous Autonomic Nervous

SystemSystem Controls the body’s Controls the body’s

automatic actions automatic actions (breathing, heartbeat, etc) (breathing, heartbeat, etc)

controls our glands & controls our glands & muscles of our internal muscles of our internal organs, influencing things organs, influencing things like glandular activity & like glandular activity & digestiondigestion

may be consciously may be consciously overridden overridden

divides into sympathetic divides into sympathetic & parasympathetic systems & parasympathetic systems

Somatic Nervous Somatic Nervous SystemSystem

• Enables voluntary control Enables voluntary control of our skeletal muscles of our skeletal muscles

• Responsible for Responsible for processing sensory processing sensory information that arrives via information that arrives via external stimuli including external stimuli including seeing, hearing, and seeing, hearing, and touchingtouching

• Consists of sensory Consists of sensory (afferent) neurons that (afferent) neurons that carry info to CNS & motor carry info to CNS & motor (efferent) neurons that (efferent) neurons that carry info from CNS to carry info from CNS to musclesmuscles

The Autonomic Nervous System

Sympathetic Nervous Sympathetic Nervous SystemSystem

• Arouses and expends Arouses and expends energy energy

• Activated when body is Activated when body is excited, enraged, or excited, enraged, or challenged challenged

• When stimulated: When stimulated: • pupils dilatepupils dilate• heartbeat acceleratesheartbeat accelerates• digestion is inhibiteddigestion is inhibited• stimulates secretion of stimulates secretion of epinephrine & epinephrine & norepinephrinenorepinephrine• relaxes bladderrelaxes bladder• stimulates ejaculation in stimulates ejaculation in malesmales

Parasympathetic Parasympathetic Nervous SystemNervous System

Conserves energy as it Conserves energy as it calms the body when stress calms the body when stress subsides subsides • When stimulated: When stimulated: • pupils contractpupils contract• heartbeat slowsheartbeat slows• digestion is stimulateddigestion is stimulated• gallbladder is stimulated gallbladder is stimulated • contracts bladdercontracts bladder• allows blood to flow to allows blood to flow to sex organs sex organs