Reflex Action

Q.

Define the reflex arc and state its components.

Q.

What is an example of polysynaptic reflex?

Q.

In a reflex action, the reflex arc is formed by

Q.

Draw a well labelled diagram of a neuron showing the following parts- Perikaryon, dendrites, axon, node of Ranvier, and myelin sheath.

Q. Any change in the environment that results in a change in activity of the body is known as _______.

1. stimulus
2. response
3. impulse
4. Effector

Q. Moving the hand back immediately on touching a hot object is an example of reflex action.

1. True
2. False

Q.

Reflex actions are under the control of

1. brain

2. spinal cord

3. medulla

4. spinal cord and medulla

Q.

Question 1
What is the difference between a reflex action and walking?

Q. How are involuntary actions and reflex actions different from each other?

Q.

______________ detect environmental signals and convey this information to the central nervous system, _____________ convey signals from one neuron to another, and ___________ convey signals from the central nervous system to effector organs.

1. Afferent neurons; efferent neurons; interneurons

2. Interneurons; sensory neurons; efferent neurons

3. Efferent neurons; interneurons; afferent neurons

4. Afferent neurons; interneurons; efferent neurons

Q.

The order of sequence of tissues involved in producing of a reflex action when a bright light is focused on the eye would be

1. effector, sensory neuron, relay neuron, motor neuron, receptor

2. receptor, sensory neuron, relay neuron, motor neuron, effector

3. effector, motor neuron, relay neuron, sensory neuron, receptor

4. receptor, motor neuron, relay neuron, sensory neuron, effector

Q. Playing harmonium by striking a particular key on seeing a music note is an example of

1. All of the above.
2. Conditioned reflexes
3. Simple reflexes
4. Basic reflexes

Q. _______________ neurons carry impulses from the CNS to the effectors. ________________ neurons are also known as sensory neurons.​

1. Afferent; Efferent​
2. Motor; Afferent​

Q. Consider the following statements.
(a) Sudden action in response to something in the environment is called reflex action.
(b) Sensory neurons carry signals from the spinal cord to muscles.
(c) Motor neurons carry signals from receptors to the spinal cord.
(d) The path through which signals are transmitted from a receptor to a muscle or a gland is called a reflex arc.
Which of the above statements are correct?

1. (a) and (b)
2. (a) and (c)
3. (a) and (d)
4. (a), (b) and (c)

Q. The growth of a plant in response to gravity is called ______ .

1. geotropism
2. chemotropism
3. phototropism
4. hydrotropism

Q.

When you touch a hot pan accidently, you pull your hand back immediately. Identify the stimulus in the above statement.

1. Touching the hot pan

2. Pulling the hand back

3. Touching the pan and pulling your hand back

4. Statement is not an example of reflex

Q. Taking hands off a sharp object is an example of a response.

1. True
2. False

Q. Which of the following is a type of a reflex reaction?

1. Hunger
2. Sneezing
3. Moving your hand from a hot object
4. Both B and C

Q. Which of the following is not a natural reflex action?

1. Knee-jerk
2. Blinking of eyes due to strong light
3. Salivation at the sight of food
4. Sneezing when any irritant enters the nose

Q.

How is the pain message sent to your brain when your finger gets accidently caught at the door?

Q.

An automatic response that does not involve the control of brain is called ____________ action.

1. reflex

2. voluntary

3. sensitivity

4. systemic

Q. Choose the correct sequence of the reflex action.

1. Receptor$\to$ Sensory neuron $\to$ Relay neuron$\to$ Motor neuron $\to$ Effector
2. Sensory neuron $\to$ Relay neuron$\to$ Receptor $\to$ Motor neuron $\to$ Effector
3. Effector $\to$ Sensory neuron $\to$ Relay neuron$\to$ Motor neuron $\to$ Receptor
4. Receptor$\to$ Relay neuron$\to$ Sensory neuron $\to$ Motor neuron $\to$ Effector

Q. Any detectable change which generates a response in an organism is called stimulus.

1. True
2. False

Q. Statement 1: Afferent neurons bring messages to the CNS.​
Statement 2: Efferent neurons carries messages from CNS.

1. Statement 2 is correct but statement 1 is incorrect
2. Both the statements are correct
3. Statement 1 is correct but statement 2 is incorrect
4. Both the statements are incorrect

Q.

The neuron which carries nerve impulse from receptors to spinal cord is called afferent neuron.

1. afferent neuron

2. efferent neuron

Q. Which one is the spinal nerve?

1. Trigeminal
2. Hypoglossal
3. Olfactory
4. None of the above

Q. How are involuntary actions and reflex actions different from each other?

Q. Give an example for conditioned reflexes.

Q. Name the neurons which carry impulses from receptor to brain.

Q. The number of spinal nerves in a human being are

1. 10 pairs
2. 31 pairs
3. 21 pairs
4. 30 pairs