Nervous System Overview

Nervous System Overview

• The nervous system is responsible for information processing and communication between different parts of the body.
• It is more than just the brain, and is a system that helps us sense, interpret, and respond to the world around us.

Structure of the Nervous System

• The central nervous system (CNS) consists of the brain and spinal cord, and is responsible for processing and integrating information.
• The peripheral nervous system (PNS) connects the CNS to the outside world and the body, and is divided into sensory and motor portions.
• The sensory portion senses the external world, while the motor portion controls muscles and organs.

Divisions of the Peripheral Nervous System

• The somatic nervous system (SNS) controls voluntary movements and sensory perception.
• The autonomic nervous system (ANS) regulates involuntary actions such as heartbeat, digestion, and breathing.
• The ANS is further divided into the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS).
• The SNS is responsible for the "fight or flight" response, while the PNS controls the "rest and digest" response.

Cells of the Nervous System

• There are two main types of cells in the nervous system: neurons and glia.
• Neurons transmit information across the nervous system and are essentially the "wires" of the nervous system.
• Glial cells, also known as glia, provide support and maintenance functions for neurons.

Neuron Function

• Neurons receive and transmit signals through dendrites and axons.
• The axon carries the nerve impulse from the cell body to the next cell.
• Neurons can transmit signals over long distances, with the sciatic nerve being the longest nerve in the body.

Glial Cells

• Oligodendrocytes provide insulation to neurons in the CNS, allowing neurons to pass electrical signals rapidly.
• Schwann cells provide insulation to neurons in the PNS.
• Astrocytes perform various functions to support neuron function, while microglia act as the brain's immune system.

Neural Circuits

• The nervous system works by transmitting signals from one neuron to another, forming a neural circuit.
• Neurons can be classified as afferent, efferent, or interneurons based on their function in the circuit.
• Afferent neurons receive information and pass it towards the CNS, while efferent neurons receive information from the CNS and pass it to the periphery.

Reflex Circuit

• A classic example of a neural circuit is the reflex circuit, which involves three neurons: afferent sensory neuron, interneuron, and efferent neuron.
• This circuit allows for rapid responses to stimuli, such as pulling your hand away from something hot.

Nervous System Overview

• The nervous system processes information and facilitates communication between different body parts.
• It involves more than just the brain, enabling us to sense, interpret, and respond to the world around us.

Structure of the Nervous System

• The central nervous system (CNS) consists of the brain and spinal cord, responsible for processing and integrating information.
• The peripheral nervous system (PNS) connects the CNS to the outside world and the body, divided into sensory and motor portions.

Divisions of the Peripheral Nervous System

• The somatic nervous system (SNS) controls voluntary movements and sensory perception.
• The autonomic nervous system (ANS) regulates involuntary actions like heartbeat, digestion, and breathing.
• The ANS is further divided into the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS).
• The SNS is responsible for the "fight or flight" response, while the PNS controls the "rest and digest" response.

Cells of the Nervous System

• There are two main types of cells: neurons and glia.
• Neurons transmit information across the nervous system, serving as the "wires" of the nervous system.
• Glial cells (glia) provide support and maintenance functions for neurons.

Neuron Function

• Neurons receive and transmit signals through dendrites and axons.
• The axon carries the nerve impulse from the cell body to the next cell.
• Neurons can transmit signals over long distances, with the sciatic nerve being the longest nerve in the body.

Glial Cells

• Oligodendrocytes provide insulation to neurons in the CNS, enabling rapid electrical signal transmission.
• Schwann cells provide insulation to neurons in the PNS.
• Astrocytes perform various functions to support neuron function.
• Microglia act as the brain's immune system.

Neural Circuits

• The nervous system works by transmitting signals from one neuron to another, forming a neural circuit.
• Neurons can be classified as afferent, efferent, or interneurons based on their function in the circuit.
• Afferent neurons receive information and pass it towards the CNS, while efferent neurons receive information from the CNS and pass it to the periphery.

Reflex Circuit

• A reflex circuit involves three neurons: afferent sensory neuron, interneuron, and efferent neuron.
• This circuit allows for rapid responses to stimuli, such as pulling your hand away from something hot.