Functions, Divisions, & Neurons The Nervous System Functions, Divisions, & Neurons

Functions Sensory Input Integration Motor functions

Divisions of Nervous System Central nervous system (CNS) Peripheral nervous system (PNS)

Central Nervous System Brain Spinal cord

Peripheral Nervous System Consists of nerves and ganglia Further divided: Afferent division (sensory) Efferent division (motor)

Efferent Division of PNS Further divided: Somatic nervous system (voluntary) Autonomic nervous system (involuntary)

Autonomic nervous system Further divided: Sympathetic Parasympathetic

Nerve Tissue Neuron Neuroglia (glial cell)

Neuron

Types of Neurons Afferent (sensory) Efferent (motor) Inter-neurons (association neurons)

Neuroglia Do not conduct nerve impulses Serve as protection and nourishment for neurons

Nerve Impulses Resting membrane Stimulation of neuron

Resting membrane Non-conducting neuron Lots of Na+ outside neuron Lots of K+ inside neuron, but even more negative ions found inside Membrane is polarized

Stimulation of Neuron A stimulus changes the membrane to allow passive movement of ions. Stimulus must be strong enough to make membrane highly permeable (threshold).

Action Potential – Nerve Impulse Depolarization Reverse polarization Repolarization

Action Potential Animation Nerve Impulse

Conduction of Impulse Action potential must continue the length of a neuron Neurotransmitters carry impulse across the synaptic cleft to new neuron

Continuous vs Saltatory Action Potentials

Reflex Arcs Functional unit of nervous system Allows for rapid response to stimulus Components: Receptor Sensory neuron Integration center Motor neuron Effector