Class 10 Science CONTROL AND COORDINATION Practicec Problems

Question 1
What is a synapse?
Answer
The junction between the axon and the dendrites of the next neuron is called the synapse.
Question 2
What are nerve fibres?
Answer
The long axons of neurons along with the associated structures are called the nerve fibres.
Question 3
What are nodes of Ranvier?
Answer
The nerve fibres may be enclosed within sheaths called ad myelin sheath. Along the fibres there are regions where the myelin sheath is absent. These regions are called the nodes of anvier.
Question 4
What are the three types of nerves?
Answer
The three types of nerves are:

Sensory nerves or the receptor nerves	Motor nerves or the effector nerves	Mixed nerves
They are made up of only sensory neurons. For example, the cranial nerves that conduct impulses from the organs to the central nervous system.	They are made up of only motor neurons. For example, the cranial nerves that conduct impulses from the organs to the central nervous system	The nerves that are made up of both sensory and motor neurons. For example, all spinal nerves.

Question 5
What are receptors?
Answer
Receptors are structures at the ends of the nerve fibres that collect the information to be conducted by the nerves.
Question 6
What are effectors?
Answer
Effectors are muscles or glands which work in response to the stimulus received from the motor nerves.
Question 7
What are the three divisions of the human nervous system?
Answer
Human Nervous system can be divided into:

i)	Central nervous system
ii)	Peripheral nervous system
iii)	Autonormic nervous system

Question 8
What is the central nervous system composed of?
Answer
The central nervous system is made up of the brain and the spinal cord.
Question 9
How are organs of the central nervous system protected?
Answer
The organs of the central nervous system are protected by three membranes called the meanings and a fluid within these membranes called the cerebrospinal fluid. The latter acts like a shock absorber of the brain. The brain is protected by the hard skull and the spinal cord is enclosed inside the bony vertebral column.
Question 10
What is meningitis?
Answer
The brain and the spinal cord are protected by membranes called the meninges. An infection of the meninges is called meningitis.
Question 11
Name the different region of the brain and their parts?
Answer
There are three main regions of the brain.

Fore brain	- It is made up of cerebrum, hypothalamus and thalamus
Mid brain	It is relay center
Hind brain	It consists of cerebellum, pons and medulla oblongata

Question 12
What is cerebrum? What are its functions?
Answer
Cerebrum is the largest part of the brain and is a part of the fore brain. It is made up of two hemispheres called the cerebral hemispheres. Cerebrum is responsible for the intelligence, thinking, memory, consciousness and will power.
Question 13
What is the importance of hypothalamus?
Answer
Hypothalamus, a small region situated below the thalamus, is an important region of the brain. It carries out the following important functions:

i)	It receives the taste and smell impulses
ii)	It coordinates messages from the autonomous nervous system
iii)	Controls the heart rate, blood pressure, body temperature and peristalsis
iv)	It also forms an axis with the pituitary which is the main link between the nervous and the endocrine systems
v)	It also has centers that control mood and emotions

Question 14
What are the functions of mid brain?
Answer
The functions of the mid brain are:

i)	It serves as a relay centre for sensory information from the ears to the cerebrum
ii)	It controls the reflex movements of the head, neck and eye muscles
iii)	It provides a passage for the different neurons going in and coming out of the cerebrum.

Question 15
What is cerebellum? Where is it present? What are its functions?
Answer
Cerebellum is a part of the hind brain.

i)	It is responsible for maintaining the balance while walking, swimming, riding, etc.
ii)	It is also responsible for precision and fine control of the voluntary movements. For example, actions like eating are possible while talking or listening.

Question 16
What is the importance of medulla oblongata?
Answer
edulla oblongata has the following functions:

i)	It has the cardiovascular center- It controls the rate and force of heart beat, blood pressure, constriction and dilation of blood vessels
ii)	It has the breathing center- It controls the involuntary breathing mechanism
iii)	It also controls activities such as sneezing, coughing, swallowing, salivation and vomiting

Question 17
What are the functions of spinal cord?
Answer
The functions of the spinal cord are:

i)	Coordinating simple spinal reflexes
ii)	Coordinating autonomic reflexes like the contraction of the bladder
iii)	Conducting messages from muscles and skin to the brain
iv)	Conducting messages from brain to the trunk and limbs

Question 18
What are ganglia? Give an example.
Answer
Ganglia are centers of collection of nerve cell bodies. For example: dorsal root ganglion of the spinal cord.
Question 19
What is a reflex?
Answer
When the stimulation of a receptor results in a spontaneous, involuntary reaction, it is called reflex action or simply reflex.
Question 20
What are the two main types of reflexes? Give one example for each.
Answer
The two main types of reflexes are:

i)	Unconditioned reflex for example: moving away the hand on touching a hot object
ii)	Conditioned reflex for example: salivation at the sight of favorite food.

Question 21
What are exocrine and endocrine glands?
Answer
Exocrine glands are those which pour their secretions into a duct. For example, sweat glands, tear glands, etc. endocrine glands are those which are richly supplied with blood vessels and pour their secretions into the latter. The secretions reach their target through blood. These glands are called the ductless glands as they do not have ducts. For example, thyroid, adrenal, etc.
Question 22
What are hormones?
Answer
Hormones can be defined as secretions that are poured into blood in order to reach a specific target organ.
Question 23
What are the characteristics of hormones?
Answer
Hormones have the following characteristics:

i)	They may be proteinaceous or non- proteinaceous (amino acids or steroids)
ii)	They are secreted as per need and not stored, only excreted
iii)	Their secretion may be regulated by nerves or by feedback effect
iv)	They are transported by blood
v)	They mostly cause long-term effects like growth, change in behavior, etc
vi)	They do not catalyze any reactions
vii)	They function by simulating or inhibiting the target organs.

Question 24
Name the various endocrine glands?
Answer
The various endocrine glands are pituitary, pineal, thyroid, parathyroid, thymus, pancreas, adrenal and the gonads (ovaries and tastes).
Question 45
What is TSH? Where is it produced?
Answer
TSH is thyroid stimulating hormone that stimulates thyroid to produce thyroxine. It is produced by the anterior lobe of the pituitary.

 

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