6.1.3 The Reflex Arc

• A receptor detects the stimulus and converts it into electrical signals
• What is the function of an effector in a reflex arc?

  Produce involuntary response
• A sensory receptor detects the stimulus and converts it into electrical signals
• A sensory receptor detects stimuli such as pain or heat
• What are the components of a reflex arc?

  Sensory receptor, sensory neuron, interneuron, motor neuron, effector
• The sensory neuron in a reflex arc carries signals to the spinal cord.
• What is the primary function of reflex arcs?

  Protect the body from harm
• The knee-jerk reflex involves the contraction of the quadriceps muscle.


  True
• Arrange the steps of the sneeze reflex in the correct order:

  1️⃣ Irritation detected in nasal cavity

  2️⃣ Sensory neurons transmit signals to brainstem

  3️⃣ Interneurons coordinate response

  4️⃣ Motor neurons signal throat muscles

  5️⃣ Air is expelled in a forceful sneeze
• Steps in a reflex arc pathway

  1️⃣ Stimulus detected by sensory receptor

  2️⃣ Electrical signals carried by sensory neuron

  3️⃣ Signals processed in spinal cord

  4️⃣ Signals relayed to motor neuron

  5️⃣ Effector produces response
• What is the role of the relay neuron in a reflex arc?

  Processes signals in spinal cord
• Which part of the nervous system is primarily involved in involuntary responses?

  Spinal cord
• What is a reflex arc?

  Involuntary response to stimulus
• A relay neuron processes signals in the spinal cord.

  True
• What is an example of a reflex arc in action?

  Touching a hot surface
• A reflex arc provides a fast response without brain involvement.

  True
• What type of action does an effector execute in a reflex arc?

  Muscle contraction
• Match the component of a reflex arc with its description:

  Sensory Receptor ↔️ Detects stimuli and initiates sensory input

  Sensory Neuron ↔️ Carries signals to the spinal cord

  Interneuron ↔️ Connects sensory and motor neurons

  Motor Neuron ↔️ Carries signals to effectors

  Effector ↔️ Executes the response
• What is the role of the interneuron in a reflex arc?

  Processes and relays signals
• What type of response is facilitated by a reflex arc?

  Involuntary
• Involuntary responses occur without conscious thought.


  True
• What happens in the withdrawal reflex when you touch a hot surface?

  Hand withdraws from heat
• What is the role of the iris in the pupillary light reflex?

  Reduces light entering eye
• What type of signals do receptors convert stimuli into?

  Electrical signals
• The receptor detects the stimulus and converts it into electrical signals.
• What is a reflex arc defined as?

  Involuntary response to stimulus
• What type of response does the effector produce in a reflex arc?

  Involuntary
• Match the type of response with its characteristic:

  Voluntary Response ↔️ Under conscious control

  Involuntary Response ↔️ Occurs without conscious thought
• Reflex arcs allow for immediate reactions to stimuli, preventing further damage.


  True
• The withdrawal reflex when touching a hot surface prevents serious burns by quickly pulling the hand away.
• Match the reflex arc with its stimulus and response:

  Withdrawal Reflex ↔️ Touching a hot surface, pulling hand away

  Knee-Jerk Reflex ↔️ Patellar tendon tap, leg jerks outward

  Pupillary Light Reflex ↔️ Bright light, pupil constricts

  Sneeze Reflex ↔️ Irritation in nasal cavity, expelling air
• What does a sensory neuron transmit signals from?

  Receptor to spinal cord
• Order the components of a reflex arc in the correct sequence:

  1️⃣ Receptor

  2️⃣ Sensory Neuron

  3️⃣ Relay Neuron

  4️⃣ Motor Neuron

  5️⃣ Effector
• Where does the sensory neuron transmit electrical signals to?

  Spinal cord
• What does a sensory neuron transmit signals to in the spinal cord?

  Relay neuron
• A reflex arc is a neural pathway that facilitates rapid, involuntary responses to stimuli
• Place the following steps in the correct order to describe the pathway of a reflex arc when touching a hot surface:

  1️⃣ Receptors in the skin detect heat

  2️⃣ Sensory neurons transmit signals to the spinal cord

  3️⃣ Interneurons relay signals to motor neurons

  4️⃣ Motor neurons signal muscles in the arm

  5️⃣ Muscles contract to pull hand away
• The receptor in a reflex arc detects stimuli such as pain or pressure.


  True
• What is the key difference between voluntary and involuntary responses?

  Conscious control
• When touching a hot surface, the reflex arc allows you to pull your hand away quickly, preventing severe burns.