CHAPTER 7
Control and Co-ordination
Objective Questions
Multiple Choice Questions
- The seat of intelligence and voluntary actions in the brain is
(a) Cerebellum
(b) Cerebrum
(c) Medulla
(d) Hypothalamus.
- Gustatory receptors are specialized in detecting
(a) Taste
(b) Light
(c) Smell
(d) Touch.
- The gap between two neurons is called a/an
(a) Dendrite
(b) Synapse
(c) Axon
(d) Impulse.
- The brain is responsible for
(a) thinking
(b) regulating the heart beat
(c) balancing the body
(d) All of these.
- Junction between two neurons is called
(a) cell junction
(b) neuro muscular junction
(c) neural joint
(d) synapse.
- Spinal chord originate from
(a) Cerebrum
(b) Medulla
(c) Pons
(d) Cerebellum.
- Posture and balance of body is controlled by
(a) Cerebrum
(b) Medulla
(c) Pons.
(d) Cerebellum
- In a neron, conversion of electrical signal to a chemical signal occurs at/in
(a) Cell body (b) Axonal end (c) Dendrite end (d) Axon. Ans. 1. (b), 2. (a), 3. (b), 4. (d), 5. (d), 6. (b), 7. (b), 8. (b).
Fill in the Blanks
- Part of the brain that controls muscular co-ordination is……………
- Heart beat is controlled by……
3………… is the structural and functional unit of the nervous system.
Ans. 1. Cerebellum, 2. Medulla Oblongata, 3. Neuron.
True/False
- The hind-brain is the main thinking part of the brain.
- Nerves from all over meet in a bundle in the spinal cord on their way to the brain.
- Gustatory receptors detect smell while olfactory receptors detect taste.
- The communication between the central nervous system and the other parts of the body is facilitated by peripheral nervous system.
Ans. 1. False, 2. True, 3. False, 4. True.
Match the Columns
Column ‘A’ Column ‘B’
- Gustato receptors. (a) Ears
- Thermo receptors (b) Nose
- Auditory receptors. (c) Toungue
- Olfactory receptors. (d) Skin
- Optic receptors. (e) Neuron
- Unit of nervous system. (f) Eyes
Ans. 1. (c), 2. (d), 3. → (a), 4. (b), 5.→ (f), 6. → (e).
Answer in one Word/Sentence
- Name the three parts of the brain.
Ans. Fore-brain, mid brain and hind-brain.
- Which part of the brain controlls posture and balance of the body?
Ans. Cerebellum in hind brain.
- Which part of nervous system controls the reflex action ?
Ans. Spinal cord.
Very Short Answer Type Questions
- 1. What is a nervous system?
Ans. The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body.
- 2. What is a reflex action ? Ans. A reflex action is an involuntary and instantaneous movement in response to astimulus. A reflex is caused by neural pathways called reflex arcs which can t on an before that impulse reaches the brain.
- 3. What is the difference between a reflex action and walking ?
Ans. A reflex action is a rapid, automatic response to a stimulus. It does not involve any thinking eg. closing of eyes in response to bright light. Walking, however, is an involuntary action. It is under our conscious control. The response to the reflex action is generated at the spinal cord, whereas walking is under the control of the brain.
- 4. Which signals will get disrupted in case of a spinal cord injury?
Ans. Reflex actions are involuntary actions and they are controlled by the spinal They will thus get disrupted in case of a spinal cord injury.
Short Answer Type Questions
- 1. Draw a labelled diagram of the structure of neuron (nerve cell).
Ans.
- 2. How are involuntary actions and reflex actions different from each other?
Ans. Involuntary actions cannot be consciously controlled. For example, we cannot consciously control the movement of food in the alimentary canal. These actions are directly under the control of brain. Reflex actions, like closing of eyes when bright light is focussed show sudden response and do not involve any thinking. This means, brain is not involved in this. Reflex actions are controlled by spinal cord. Stimulus is not required in case of involuntary actions while it is required in case of reflex actions. All involuntary actions are reflex, but all reflex actions are not involuntary.
- 3. Draw a labelled diagram of Human Brain.
Ans. Labelled diagram of Human Brain
Long Answer Type / Analytical Questions
- 1. What is a synapse ? What happens at the synapse between two neurons ?
Ans. The synpase is the tiny gap between two adjacent neurons. The information acquired (like touching a hot object) at the end of a dendritic tip of a nerve cell sets off a chemical reaction that creates an electrical impulse. This impulse travels from the dendrite to the cell body and then along the axon to its end. At the end of axon, the electrical impulse sets off the release of some chemicals.
These chemicals cross the gap, or synapse and start an similar electrical impulse in a dendrite of the next neuron. This is the process how nervous impulses travel in the body. A similar synapse finally allows delivery of such impulses from neurons to other cells, such as muscle cells or gland.
- 2. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise ?
Ans. All information from our environment is detected by the specialised tips of some nerve cells. These receptors are usually located in our sense organs such as the inner ear, the nose, the tongue and so on. So, gustatory receptors will detect taste, while olfactory receptors will detect smell. We detect that we are touching a hot object by the action of receptors present on various organs or tissues. If olfactory receptors do not work properly then we are not able to smell things like incense stiks, perfumes, aroma of food, etc.
- 3. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Ans. Comparison between nervous and hormonal mechanism
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