Identify the principle parts of the nervous system Describe the cells that make up the nervous system Describe what starts and stops a nerve impulse.

The Nervous System

Identify the principle parts of the nervous system

Describe the cells that make up the nervous system

Describe what starts and stops a nerve impulse (action potential)

The role of neurotransmitters Compare the functions of the CNS & PNS Identify the principle parts of the brain

Objectives

Principle Parts of Nervous System

Central nervous system (CNS): “command central”◦ Components: brain and spinal cord◦ Functions: receives, processes, and transfers

information

Peripheral nervous system (PNS): “messengers”◦ Components: nerves outside CNS◦ Sensory neurons: carry information toward the CNS◦ Motor neurons: carry information away from CNS

Components of the Nervous System

1. Somatic - under conscious control (movement of skeletal muscles)

2. Autonomic – unconscious control (smooth muscle, cardiac, glands)

Motor Division: 2 parts

Sympathetic – flight or fight Parasympathetic – conserves energy,

promotes nonemergency functions

Autonomic divisions: 2 parts

Cells of the Nervous System Communicators/messengers

Neurons: specialized cells for communication:◦ Cell adaptations: cell body, axon, dendrites◦ Types: sensory, interneurons, motor neurons

Types of Neurons in the Nervous System

Of PNS transmit impulses to the CNS Specialized to respond to specific stimuli

like light or pressure Impulses are electrical –as they travel they

cause depolarization and repolarization of membrane potential = measurable difference in voltage across a cell membrane

Sensory neurons - INPUT

Of CNS transmit impulses between components of CNS

Receives information from sensory neurons, Integrates/interprets information and Influences the functioning of other neurons

Interneurons - INTERGRATION

Of PNS transmit electrical impulses away from the CNS to muscles and glands

Motor neurons - OUTPUT

Cell body – BATTERY - nucleus, DNA, mitochondria, etc

Dendrites – SENSORS - extension of cell body (soma) = info receivers/receptors

Axon – WIRING – long, slender tube of cell membrane specialized to conduct electric impulses

Axon terminals & axon bulbs (plugs & lights) – connections to tissues or other neurons

Neuron Structure

Sensory neural axons originate from a dendrite

Interneurons and motor neurons axons originate from axon hillock (cone shaped area of soma)

Neuron adaptations

Types of Neurons in the Nervous System