Neuron Structure and Reflexes PDF

The Nervous System The Nervous System Function: Coordinates stimulus recognition and response. Components: Neurons: Transmit messages. Glial Cells: Support metabolic functions in neurons. Effectors: Cells/tissues affected by neurons (e.g., muscles). Structure...

The Nervous System The Nervous System Function: Coordinates stimulus recognition and response. Components: Neurons: Transmit messages. Glial Cells: Support metabolic functions in neurons. Effectors: Cells/tissues affected by neurons (e.g., muscles). Structure of a Neuron Dendrites: Receive information. Cell Body: Contains nucleus, organelles, Nissl Bodies (protein synthesis). Axon: Transmits information away from the cell body. This Photo by Unknown Author is licensed under CC BY-SA Nerve: Bundle of neurons and glial cells.  Unipolar Neurons: Have a single process Neuron extending from the cell body, typically found in sensory neurons. Classification (By Bipolar Neurons: Have two processes (one Structure) axon and one dendrite) extending from the cell body, commonly found in the retina of the eye and olfactory system. Multipolar Neurons: Have one axon and multiple dendrites, the most common type in the central nervous system. Pseudounipolar Neurons: Have a single process that splits into two branches, functioning similarly to unipolar neurons, often found in sensory neurons of the peripheral nervous system. This Photo by Unknown Author is licensed under CC BY Neuron Classification (By Function) Sensory Neurons: Connect to sense organs, pick up sensory information. Interneurons: Relay information from sensory neurons, determine response, transmit it. Motor Neurons: Receive response from interneurons, transmit to effector cells. Synapses and Neural Circuits Synapse: Connects neurons to each other and to effector cells to form a Neural Circuit. Neural Circuit: Processes information, coordinates functions like movement. Reflex Arc: Simplest neural circuit (e.g., patellar reflex). Reflexes What is a Reflex? A reflex is an automatic, involuntary response to a stimulus. Reflexes are rapid and occur without conscious thought to protect the body from harm. How Does a 1. Stimulus Detection: Sensory neurons detect a stimulus (e.g., touching a hot surface). Reflex Work? 2. Signal Transmission: The sensory neurons send a signal to the spinal cord. 3. Interneuron Processing: Interneurons in the spinal cord process the information and determine the response. 4. Motor Neuron Activation: Motor neurons receive the response signal from interneurons. 5. Effector Response: Motor neurons transmit the signal to effector cells (e.g., muscles), causing a response (e.g., withdrawing the hand). Example: Patellar Reflex (Knee-Jerk Reflex) Stimulus: Tapping the patellar tendon. Response: The quadriceps muscle contracts, causing the lower leg to kick out.  Reflexes are essential for survival and help maintain homeostasis. They involve a simple neural circuit known as the reflex arc. Reflex actions are faster than voluntary actions because they bypass the brain. This Photo by Unknown Author is licensed under CC BY-SA Homework Read pages 516 – 521 Answer Questions 1, 3, 4, 5,and 7 on page 521 Prep Reflex arc lab