Reflex | MCQs

Explanation

A reflex action is a rapid, automatic response to a stimulus.

The simplest reflex arc involves only two neurons:

1. Sensory neuron (afferent): carries information from the receptor to the spinal cord
2. Motor neuron (efferent): carries the response from the spinal cord to the effector (muscle or gland)

Key Point:

The longest reflex pathway involves multiple neurons.

It is called a "long reflex" or " polysynaptic reflex".

Explanation

When an action is produced with the involvement of thoughts, they are called voluntary action.

It involves actions like walking, eating, jumping and running.

Explanation

The central nervous system consists of the brain and spinal cord. 

Explanation

Free movements responding to external stimuli are called tactic movements (or taxis).

Tactic movements are directional responses

Where an organism moves toward or away from a stimulus, such as light (phototaxis) or chemicals (chemotaxis)

Explanation

 In a vertebrate, a reflex action is induced by a sensory nerve. 

A sensory nerve detects the stimulus, which triggers the signal to the spinal cord, leading to the motor neuron response in a reflex action. 

Explanation

• Reflex actions are rapid, automatic responses to stimuli that occur without the involvement of the brain.
• Instead, they are mediated by the spinal cord or peripheral nerves.

Explanation

The Medulla oblongata is the part of the brainstem that controls involuntary reflex actions, such as:

• Blood pressure
• Heartbeat
• Peristalsis (movement of food through the digestive system)
• Rate of respiratory movements
• Contraction and dilation of blood vessels

Explanation

A reflex action does not typically involve the brain;

it is usually mediated by the spinal cord, along with sensory and motor neurons.

Explanation

Words like myself, yourself, himself, herself, itself, ourselves, yourselves and themselves called: Reflexive Pronouns