Structure & Function of the Withdrawal Reflex, a Polysynaptic Reflex

The video tutorial explains the withdrawal reflex, a phasic reflex that occurs in response to a noxious stimulus. It contrasts this with a tonic reflex, which indicates potential neurological damage. Using a scene from 'Raiders of the Lost Ark', the video illustrates an abnormal physiological response to a hot object. The tutorial then details the mechanism of the withdrawal reflex, involving sensory neurons, interneurons, and motor neurons, leading to muscle contractions that remove the body part from the stimulus. Practical examples, such as stepping on a tack, are used to demonstrate the reflex in action.

What distinguishes a phasic reflex from a tonic reflex?

• A tonic reflex is faster than a phasic reflex.

• A tonic reflex is only present while the stimulus is present.

• A phasic reflex is only present while the stimulus is present.

• A phasic reflex continues after the stimulus is removed.

Which of the following is an example of a noxious stimulus that can trigger the withdrawal reflex?

• Hearing a loud noise

• Smelling a strong odor

• Seeing a bright light

• Touching a hot pan

What is the role of nociceptors in the withdrawal reflex?

• They process visual stimuli.

• They control muscle contraction.

• They sense pain and relay information to the spinal cord.

• They detect changes in temperature.

Which type of neuron is responsible for transmitting the pain signal to the spinal cord in the withdrawal reflex?

• Motor neuron

• Interneuron

• Sensory neuron

• Peripheral neuron

What is the primary function of the interneuron in the withdrawal reflex pathway?

• To excite the motor neuron for muscle contraction

• To relay the signal to the brain

• To inhibit the sensory neuron

• To detect the noxious stimulus

In the context of the withdrawal reflex, what is the expected response when a person touches a hot object?

• The person slowly moves their hand away.

• The person immediately withdraws their hand.

• The person holds onto the object for a few seconds.

• The person does not react at all.

What physiological response should occur when stepping on a tack?

• The foot does not react.

• The foot remains on the ground.

• The foot is quickly withdrawn.

• The foot slowly moves away.