Nervous System Structure and Function

Nervous System Structure and Function

• The nervous system is composed of neurons and glial cells
• Neurons are the basic signaling units, transmitting information throughout the system
• Glial cells provide various supportive functions
• Dendrites receive input from other neurons
• Axons transmit signals to axon terminals
• Information is transferred across synapses, either electrically or chemically (via neurotransmitters)
• Neurons can be presynaptic or postsynaptic, or both

Structure of Neurons

• Neurons have a cell body, dendrites, and an axon
• The cell body contains the cellular machinery for protein production
• Dendrites, branching extensions, receive inputs from other neurons
• Axons transmit signals to axon terminals, often with various branches (axon collaterals)
• Many dendrites have specialized spines, knobs that receive inputs from other neurons

Role of Glial Cells

• Astrocytes form the blood-brain barrier, restricting the diffusion of certain substances
• Microglial cells are phagocytes, removing damaged cells
• Oligodendrocytes and Schwann cells produce myelin, acting as electrical insulation

Neuronal Signaling

• Neurons receive, evaluate, and transmit information
• Within neurons, electrical signals flow through the neuron
• Between neurons, information is typically transmitted chemically via neurotransmitters
• Regarding information flow, neurons can be presynaptic, postsynaptic, or both. A neuron becomes presynaptic when its axon connects to another neuron, and postsynaptic when another neuron connects to its dendrites.

The Nervous System: The Bigger Picture

• The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS)
• The CNS includes the brain and spinal cord
• The PNS includes nerves and ganglia (groups of neuronal cell bodies) outside of the CNS
• The nervous system has both sympathetic and parasympathetic branches of the autonomic nervous system
• Sympathetic nerves typically activate fight-or-flight responses
• Parasympathetic nerves typically activate rest-and-digest responses

The Central Nervous System

• The central nervous system is composed of gray matter (neuronal cell bodies) and white matter (axons and glial cells)
• The meninges are protective membranes surrounding the brain and spinal cord
• Cerebrospinal fluid (CSF) fills the subarachnoid space and ventricles
• The spinal cord transmits signals between the brain and the peripheral nervous system

Navigating the Brain

• The brain can be divided into different sections using various orientation planes (rostral, caudal, dorsal, ventral)
• The brain has specific regions, including ventricles, which are fluid-filled cavities within the brain
• These anatomical features provide a way to locate and identify specific structures.

The Cerebral Cortex

• The cerebral cortex has four lobes: frontal, parietal, temporal, and occipital
• The frontal lobe is involved in planning, cognitive control, and movement execution
• The parietal lobe processes sensory information
• The temporal lobe processes auditory, visual, and multimodal information
• The occipital lobe processes visual information
• Functional areas are specialized for different types of processing

Division of the Cortex: Cytoarchitectonics

• Cytoarchitectonics are the cellular structures
• Brodmann created a map of the cortex based on the cytoarchitectural arrangement. This map distinguishes various areas with unique cellular patterns
• The study of cytoarchitecture is important for understanding different functional areas

Functional Division of the Cerebral Cortex

• Sensory, motor, and association cortices are specialized for distinct functions
• The primary somatosensory cortex (S1) receives signals from peripheral receptors via the thalamus
• The primary visual cortex (V1) receives input from the retina

Auditory Cortex

• Associated with the processing of auditory information
• The tonotopic organization of the auditory cortex reflects the relationship between the frequency of sound and its processing location.

This quiz covers the essential components of the nervous system, focusing on neurons and glial cells. Explore the roles of cell body, dendrites, and axons in transmitting signals, as well as the supportive functions of glial cells. Test your knowledge on how information is communicated across synapses.