Reflex arcs Practice Questions
20 free Reflex arcs practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
A reflex arc consists of all of the following components EXCEPT:
- A Receptor that detects the stimulus
- B Effector that produces the response
- C Afferent sensory neuron
- D Cerebral cortex
Correct answer: Cerebral cortex
A reflex arc operates without conscious cortical involvement, so the cerebral cortex is not a required component. The basic parts are a receptor, sensory neuron, integration centre, motor neuron, and effector.
The simplest type of reflex arc that contains only one synapse is called:
- A Polysynaptic reflex
- B Autonomic reflex
- C Monosynaptic reflex
- D Visceral reflex
Correct answer: Monosynaptic reflex
A monosynaptic reflex involves a single synapse between sensory and motor neurons. The stretch reflex is a classic example.
Which reflex is an example of a monosynaptic reflex?
- A Withdrawal reflex
- B Crossed extensor reflex
- C Stretch reflex
- D Golgi tendon reflex
Correct answer: Stretch reflex
The stretch reflex involves direct synaptic transmission between sensory and motor neurons. This allows for a rapid response.
The receptor involved in the stretch reflex is the:
- A Golgi tendon organ
- B Muscle spindle
- C Free nerve ending
- D Pacinian corpuscle
Correct answer: Muscle spindle
Muscle spindles detect changes in muscle length. They initiate the stretch reflex to maintain muscle tone.
In a reflex arc, the integration center is located in the:
- A Cerebrum and its association areas
- B Cerebellum and its deep nuclei
- C Spinal cord or brainstem
- D A peripheral nerve trunk
Correct answer: Spinal cord or brainstem
Reflex integration commonly occurs in the spinal cord or brainstem, allowing rapid responses without cortical processing.
The withdrawal reflex is classified as:
- A Monosynaptic and ipsilateral
- B Polysynaptic and ipsilateral
- C Monosynaptic and contralateral
- D Autonomic and visceral
Correct answer: Polysynaptic and ipsilateral
The withdrawal reflex involves multiple interneurons and occurs on the same side as the stimulus. It protects the body from harmful stimuli.
Which neuron carries impulses from the receptor to the central nervous system in a reflex arc?
- A Motor neuron
- B Interneuron
- C Sensory neuron
- D Postganglionic neuron
Correct answer: Sensory neuron
Sensory neurons transmit impulses from receptors to the CNS. They form the afferent limb of the reflex arc.
The effector in a somatic reflex arc is usually a:
- A A secretory gland
- B Smooth muscle of a viscus
- C Cardiac muscle of the heart
- D Skeletal muscle
Correct answer: Skeletal muscle
Somatic reflexes act on skeletal muscle, producing rapid movements without conscious control.
Which reflex helps maintain posture and muscle tone?
- A Withdrawal reflex
- B Stretch reflex
- C Flexor reflex
- D Visceral reflex
Correct answer: Stretch reflex
The stretch reflex continuously adjusts muscle length. It plays a major role in posture and muscle tone.
The crossed extensor reflex is functionally important because it:
- A Enhances perception of the painful stimulus
- B Maintains balance during withdrawal
- C Inhibits antagonist muscles on the same side only
- D Prevents fatigue of the withdrawing limb
Correct answer: Maintains balance during withdrawal
The crossed extensor reflex activates extensor muscles on the opposite side to support body weight, maintaining balance when one limb withdraws from a stimulus.
Which component of the reflex arc determines the speed of the reflex response?
- A Type of receptor
- B Number of synapses
- C Type of effector
- D Strength of stimulus
Correct answer: Number of synapses
The number of synapses directly affects synaptic delay. Fewer synapses result in faster reflexes.
The afferent limb of a reflex arc ends in the:
- A Effector organ of the reflex
- B Anterior horn of the spinal cord
- C Posterior horn of the spinal cord
- D Peripheral nerve ganglion
Correct answer: Posterior horn of the spinal cord
Sensory neurons enter the spinal cord through the posterior horn. This is where reflex integration begins.
Which reflex involves inhibition of the muscle that is being stretched?
- A Stretch reflex
- B Golgi tendon reflex
- C Withdrawal reflex
- D Crossed extensor reflex
Correct answer: Golgi tendon reflex
The Golgi tendon reflex causes relaxation of the muscle under excessive tension. This prevents muscle damage.
Reciprocal inhibition in reflex action refers to:
- A Activation of both agonist and antagonist
- B Inhibition of sensory neurons
- C Inhibition of antagonist muscles
- D Suppression of reflex response
Correct answer: Inhibition of antagonist muscles
Reciprocal inhibition relaxes antagonist muscles while agonists contract. This allows smooth and coordinated movement.
Which reflex is mediated entirely at the spinal level without brain involvement?
- A Pupillary light reflex
- B Stretch reflex
- C Salivary reflex
- D Accommodation reflex
Correct answer: Stretch reflex
The stretch reflex is integrated within the spinal cord. It does not require higher brain centers.
Damage to the sensory limb of a reflex arc will result in:
- A Exaggerated reflex
- B Loss of reflex
- C Increased muscle tone
- D Spastic paralysis
Correct answer: Loss of reflex
If sensory input cannot reach the CNS, the reflex cannot be initiated. This leads to loss of the reflex.
Which reflex is an example of a protective reflex?
- A Stretch reflex
- B Withdrawal reflex
- C Deep tendon jerk reflex
- D Postural balancing reflex
Correct answer: Withdrawal reflex
The withdrawal reflex rapidly removes the body from painful stimuli. It serves a protective function.
The motor neuron of a spinal reflex exits the spinal cord through the:
- A Posterior root
- B Posterior horn
- C Anterior root
- D Dorsal root ganglion
Correct answer: Anterior root
Motor neurons leave the spinal cord via the anterior root. They carry impulses to the effector muscle.
Which factor increases the strength of a reflex response?
- A Reduced stimulus intensity
- B Fewer activated receptors
- C Temporal summation
- D Decreased synaptic transmission
Correct answer: Temporal summation
Temporal summation increases the frequency of impulses reaching the CNS. This enhances reflex response strength.
A reflex that involves internal organs and smooth muscle is classified as:
- A Somatic reflex
- B Spinal reflex
- C Visceral reflex
- D Monosynaptic reflex
Correct answer: Visceral reflex
Visceral reflexes regulate the activity of internal organs. They commonly involve smooth muscle or glands.