Nervous System Overview

Overview of the Nervous System

• Central Nervous System (CNS): Brain and spinal cord
• Peripheral Nervous System (PNS): Nerves beyond the brain and spinal cord

Functional Organization

• CNS processes sensory (afferent) inputs and generates motor (efferent) outputs
• Functions in integration and reflexes

Neurons

• Main cell type in the nervous system that conducts electrical signals
• Differences between neurons (individual cells) and nerves (bundles of neurons)

Supporting Cells

• Oligodendrocytes (CNS) and Schwann cells (PNS): Produce myelin sheaths
• Astrocytes: Support and protect neurons; important for integrity of the CNS
• Microglial cells: Immune function in the CNS
• Ependymal cells: Produce cerebrospinal fluid (CSF)

Brain Structure

• Divided into four main parts: Cerebrum, Diencephalon, Cerebellum, Brain Stem
• Cerebrum: Largest part; processes sensory information, voluntary movement
• Diencephalon: Thalamus (relay station) and Hypothalamus (regulates autonomic functions)
• Cerebellum: Coordinates fine motor movements
• Brain Stem: Controls basic life functions (breathing, heart rate)

Spinal Cord and Nerves

• Divided into cervical, thoracic, lumbar, sacral, and coccygeal regions
• Spinal Nerves: 32 pairs, each connected to specific areas of the body
• Dorsal (afferrent sensory signals) and Ventral (efferent motor signals) pathways

Reflexes

• Involuntary responses processed at spinal cord level with fast reaction times
• Involves sensory input, integration, and motor output in a reflex arc

Functional Divisions of Peripheral Nervous System

• Afferent (sensory) division: Carries signals into CNS
• Efferent (motor) division: Divided into Somatic (voluntary muscle) and Autonomic (involuntary organs)

Key Terminology

• Afferent: Sensory signals entering the CNS
• Efferent: Motor signals exiting the CNS
• Cervical, Thoracic, Lumbar, Sacral, Coccygeal: Classifications of spinal nerves
• Somatic system: Skeletal muscle control
• Autonomic system: Organ function control

Neuron Types and Pathways

• Neurons are categorized based on location and function (sensory, motor, interneurons)
• Sensory neurons connect to CNS from sensory receptors, motor neurons connect from CNS to muscles

Summary of Brain Functions

• Cerebrum: Thought, emotion, sensory perception
• Diencephalon: Sensory relay and hormonal control
• Cerebellum: Motor coordination and timing
• Brain Stem: Vital functions control and reflexes

Web Resources: Recommendations for further study and review notes for upcoming tests.

Additional materials and questions to prepare for the upcoming learning assessments.