Nervous System From-the-Book Pre-Lab Unit 16 Activity 4 Question 1 Part A Match each of the following components of a reflex arc with its description Drag the terms on the left to the appropriate blanks on the right to complete the sentences. nerve impulse is processed Sensory neuron: receives the stimulus Motor neuron: carries out the motor response Effector > transmits message to the effector Integration center transmits message to the CNS Receptor Submit Request Answer Provide Feedback P Pearson Copyright 2020 Pearson Education Inc. All rights reserved. Terms of Use Privacy Policy Permissions MacBook Pro 19 3 A $ 4 96 5 & 7 2 3 6 0 8 9 W E R. T Y 0 U S D F G H J K
The correct answer and explanation is:
Correct Answer:
- Receptor: Receives the stimulus.
- Sensory Neuron: Transmits the nerve impulse from the receptor to the CNS.
- Integration Center: Processes the nerve impulse.
- Motor Neuron: Transmits the message from the CNS to the effector.
- Effector: Carries out the motor response.
Explanation
The reflex arc is a fundamental neural pathway that enables the body to respond rapidly to a stimulus without conscious thought. At the start of this process, the receptor plays a critical role by detecting changes in the environment such as heat, pressure, or pain. This specialized sensory structure is finely tuned to pick up specific stimuli, initiating the cascade of events that make up the reflex.
Once the receptor is activated, the information is immediately passed along via the sensory neuron. This neuron acts as the messenger, transmitting the nerve impulse from the receptor to the central nervous system (CNS). The speed of this transmission is essential for a swift response, as it ensures that the body can react before any potential harm escalates.
Within the CNS, the integration center (often located in the spinal cord) receives and processes the incoming information. This processing is crucial as it determines the nature of the response. The integration center evaluates the signal and formulates an appropriate reaction without the delay that would occur if the signal had to travel to the brain for interpretation.
Following the processing phase, the motor neuron is activated. Its role is to convey the CNS’s command to the appropriate effector, which is usually a muscle or gland. The effector then executes the motor response – for example, contracting to withdraw a hand from a hot surface or secreting a substance in response to a stimulus.
This streamlined circuit—the reflex arc—allows the body to react in a matter of milliseconds. The design bypasses the slower, more deliberate routes of higher brain processing, thereby providing a rapid, involuntary response that is vital for protecting the body from injury.
Diagram of the Reflex Arc:
graph LR
A[Receptor<br/>(Receives the stimulus)] --> B[Sensory Neuron<br/>(Transmits impulse to CNS)]
B --> C[Integration Center<br/>(Processes impulse)]
C --> D[Motor Neuron<br/>(Transmits message to effector)]
D --> E[Effector<br/>(Carries out response)]