Reflex arc worksheet demonstrating the transmission of messages from a stimulus (pin prick) to a response (finger withdrawal), highlighting sensory, association, and motor neurons.

Reflex Arc Worksheet Solution and Explanation

The worksheet focuses on the reflex arc, which is a neural pathway that allows for a rapid, automatic response to a stimulus. Let's go through each question step by step:

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#### 1. This is a picture of the transmission of messages. Messages made by neurons are called _________.
- Answer: sensory
- Explanation: Neurons transmit messages in the form of electrical impulses. These messages are often referred to as "sensory" because they carry information about stimuli from the environment.

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#### 2. What is happening with the pin in figure X?
- Answer: The pin is stabbing the finger.
- Explanation: Pin X is shown piercing the finger, which acts as a stimulus to trigger the reflex arc.

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#### 3. “A” is a _______ neuron. It begins at the finger’s end.
- Answer: sensory
- Explanation: Neuron "A" is a sensory neuron because it detects the stimulus (the pin pricking the finger) and transmits this information to the spinal cord.

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#### 4. It detects stimulus. What is the stimulus it detects?
- Answer: Finger is being poked.
- Explanation: The stimulus here is the physical contact of the pin with the finger, which is detected by the sensory receptors in the skin.

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#### 5. It then produces an _______.
- Answer: impulse
- Explanation: When the sensory neuron detects the stimulus, it generates an electrical impulse to transmit the information to the spinal cord.

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#### 6. What information will the impulse carry?
- Answer: Pain ouch!
- Explanation: The impulse carries the information about the pain caused by the pin pricking the finger.

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#### 7. The sensory neuron carries the impulse to the (C) _______ neuron.
- Answer: association neuron
- Explanation: The impulse travels from the sensory neuron to the association neuron (also known as the interneuron) in the spinal cord. This neuron processes the information.

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#### 8. It is located in the _______.
- Answer: spinal cord
- Explanation: The association neuron is located in the spinal cord, where the processing of the reflex occurs.

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#### 9. The impulse is also sent to the _______ and back to the _______.
- Answer: brain, finger
- Explanation: The impulse is sent to the brain for conscious awareness and back to the finger via motor neurons to initiate a response.

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#### 10. The neurons carrying the impulse back to the finger are called _______ neurons.
- Answer: motor
- Explanation: Motor neurons carry the impulse from the spinal cord back to the muscles in the finger to cause a contraction and pull the finger away from the pin.

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#### 11. The impulse tells the effectors to _______.
- Answer: contract
- Explanation: The motor neurons send the impulse to the muscles (effectors), telling them to contract to move the finger away from the pin.

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#### 12. Muscles connected to the fingers are called _______.
- Answer: effectors
- Explanation: Effectors are the structures (usually muscles or glands) that respond to the neural impulse by producing a specific action.

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#### 13. The impulse sent to an effector is called a _______ impulse.
- Answer: motor
- Explanation: The impulse sent to the muscles (effectors) is called a motor impulse because it causes movement.

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#### 14. This impulse will tell the effectors to pull the finger from the pin. This is called a _______.
- Answer: reflex
- Explanation: The automatic, involuntary response to pull the finger away from the pin is called a reflex.

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#### 15. The impulse is also sent to the brain by a _______ neuron.
- Answer: sensory
- Explanation: A sensory neuron sends the impulse to the brain so that you become consciously aware of the pain.

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#### 16. Once the impulse reaches the brain, you can identify the _______.
- Answer: stimulus
- Explanation: When the impulse reaches the brain, you become aware of the stimulus (the pin pricking your finger).

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#### 17. This whole process is called a _______.
- Answer: reflex arc
- Explanation: The entire sequence of events, from detecting the stimulus to responding automatically, is called a reflex arc.

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Final Answer:

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