NIOS Class 12 Biology Chapter 17 Solution – Coordination and Control : The Nervous and Endocrine Systems
NIOS Class 12 Biology Solution Chapter 17 Coordination and Control : The Nervous and Endocrine Systems . NIOS Class 12 Biology Chapter 17 Question Answers Download PDF. NIOS Class 12 Biology Notes.
Board |
NIOS |
Class |
12th (Higher Secondary) |
Subject |
Biology |
Topic |
Question Answer, Solution, Notes |
1.) With the help of a flow chart write down the basic components of the nervous system in the space given below.
2.) Name the ganglia which
(a) forms the brain – supraoesophageal ganglion
(b) lies below the oesophagus and is joined to brain.- sub oesophageal ganglion
3.) Which part of nervous system of cockroach can be compared to our spinal cord though our spinal cord is dorsal and this part of nervous system of cockroach is ventral?
Ans: Ventral nerve cord is of nervous system of cockroach can be compared to our spinal cord.
4.) Name the main parts of the brain.
Ans: Cerebrum, cerebellum, medulla oblongata, thalamus and hypothalamus are the main parts of the brain
5.) Mention the one functions each of :
(i) Cerebrum.- – is responsible for intelligence ,thinking , reasoning and memory
(ii) Cerebellum-. Responsible for balance and muscular coordination in body.
(iii) Medulla oblongata – provides involuntary actions
(iv) Hypothalamus.- maintain homeostasis in the body
6.) What are the
(i) gray matter, and. Is the outer region of cerebrum that contains cell bodies of the nerve cells and being grayish in colour it is called gray matter
(ii) white matter made of? White matter is the inner region composed of whitish axon fibres 7.) Name the fluid in the cavities of the brain
INTEXT 17.2
1.) What are the two subdivisions of the autonomic nervous system?
.Ans: ANS innervates the involuntary muscles and the glands .They are subdivided into Sympathetic nervous system and parasympathetic nervous system .
2.) Name the specific subdivisions of the autonomic nervous system concerned with
the following:
(i) Slowing down heart beat – parasympathetic nervous system
(ii) Increasing salivary secretion- parasympathetic nervous system
(iii) Dilatation of the pupil – sympathetic nervous system
(iv) Increasing intestinal peristalsis – parasympathetic nervous system
(v) Muscle contraction of the urinary bladder giving the feeling the need for urination. – parasympathetic nervous system
3.) Why is the peripheral nervous system called so?
Ans: The peripheral nervous system consists of all nerves arising from the brain and the spinal cord.It is called peripheral nervous system because it connects the periphery (surface) of the body
4.) State the alternative terms for sensory and motor nerves.
Ans: The alternative term for sensory nerves is afferent nerves and for motor nerves it is efferent nerve .
INTEXT 17.3
1.) Given below are a few examples of reflexes. Write against each, the category of reflex, whether simple or conditioned.
(i) Knee jerk -Simple
(ii) Salivation on seeing a favorite dish.- conditioned
(iii) Tying of shoe laces while talking – conditioned
(iv) Closing of eyelids if a strong beam of light is flashed across – Simple
(vi) Mistaking a coiled rope as snake if you happen to step on it in darkness- conditioned
INTEXT 17.4
1.) State the function of the following parts of the eye:
(i) Iris – It contains two kinds of muscles : circular muscles for narrowing the pupil, and radiating muscles for dilating it.
(ii) Ciliary muscles- helps in near vision.
(iii) Pupil – It controls amount of light entering the eye
(iv) Vitreous humour – It maintains shape of the eye ball and protects retina
(v) Retina – Retina is the innermost sensitive layer.It produces nerve impulses into the optic nerve
2.) Name the following:
(i) Area of sharp vision in the eye .- yellow spot
(ii) The kind of lens used for correcting near-sightedness – Concave lens.
(iii) The condition in which the lens of the eye turns opaque – cataract
(iv) The capacity of eye to focus objects at different distances – accommodation
INTEXT 17.5
1.) Which part of the ear is involved when:
(i) a gymnast performs various balancing feats. – vestibule
(ii)you hear a song with help of cochlea
2.) Name the following :
(i) The part into which the sound waves are directed by the ear pinna.
Ans: Auditory meateus
(ii) The kind of balance with which the semi-circular canals are concerned.
Ans: static balance
(iii)Any two sensations felt through free nerve endings in the skin.
Ans: touch, pressure, warmth etc.
INTEXT 17.6
1.) Name the following
(i) The organ in the neck on the trachea close to which thyroid is located
Ans: larynx,
(ii) The condition caused due to oversecretion of thyroxin
Ans: cretinism
iv) The condition of passing much glucose in the urine
Ans: diabetes mellitus
(v) The source gland of ADH
Ans: posterior pituitary
2.) What are pheromones?
Ans: Pheromones are the secretions that a person releases into the environment and which cause other members of the same species to react in a particular way. The following list includes several pheromone example.
Common ants leave a trail on the ground or walls as they move along an unseen path created by a body secretion. It facilitates their sequential arrival at the destination as well as their safe return to their own nest.
TERMINAL EXERCISE
1.) Name the two divisions of the nervous system?
Ans: (i) Central nervous system (ii) Peripheral nervous system
2.) What is gray matter?
Ans: gray matter, and. Is the outer region of cerebrum that contains cell bodies of the nerve cells and being grayish in colour it is called gray matter.
3.) Name the chemical involved in the transmission of nerve impulse across a synapse.
Ans: Acetylcholine is the chemical involved in the transmission of nerve impulse across a synapse.
4). Give two examples of sensory nerves
Ans: Cranial nerve and mixed cranial nerve are the examples of sensory nerves.
5.) Name the respective areas of the retina concerned with best vision and no vision.
Ans: Yellow spot lying at the visual axis is the place of best vision in the normal and no vision at the black spot s no sensory cells are present.
6.) What is the role of the eustachian tube in the ear?
Ans: The eustachian tube joins the pharynx and tympanic cavity. It balances the pressure on the eardrum’s or the tympanum’s two sides.
7.) Name the hormone and its source glands, whose deficiency leads to diabetes insipidus.
Ans: The hormone is insulin and it is secreted by pancreas in human body
8.) What are pheromones?
Ans: Pheromones are the secretions that a person releases into the environment and which cause other members of the same species to react in a certain way.
9.) Name and explain the event that happens immediately when a nerve fibre gets stimulated?
Ans: immediately when a nerve fibre gets stimulated, depolarization is caused
10.) Are the endocrine glands and the ductless glands one and the same thing? Give one example
Ans: Instead of passing through ducts, the secretions are injected directly into the circulation. Other organs or glands, such as the stomach and the duodenum, also manufacture certain hormones.
. 11.) Describe any one example of condition reflex in the humans.
Ans: conversing with someone while tying shoe laces, not knowing whether to place the left lace over the right or the other way around.
12.) List the functions of medulla oblongata.
Ans: (i) It is the centre for breathing, coughing, swallowing, etc.
(ii) It regulates numerous other involuntary activities, including the movement of the alimentary canal and the heartbeat.
13.) Differentiate between sympathetic and parasympathetic nervous systems.
Ans:
sympathetic nervous systems. |
parasympathetic nervous systems. |
The sympathetic nervous system prepares the body to deal with them. |
The parasympathetic nervous system restores normal conditions when an emergency has passed. |
Eye pupil dilates |
Eye pupil constricts. |
Urinary bladder Muscles relax |
Urinary bladder Muscles contracts |
14.) What are the two principal tasks of insulin?
Ans: (i) Promotes glucose utilization by the body cells. (ii) Stimulates deposition of extra glucose in the blood as glycogen in the liver.
15.) Explain the following terms:
(i) synapse : The impulse passing through a nerve fibre can either operate on its target (a muscle or gland) or it can pass via the dendrites of another neuron to continue its transmission. The synapse is the location of the meeting. Chemical reactions take place at synapse during transmission.
(ii) stimulus : a factor or a sudden change in the organism’s internal or external environment that affects how it behaves.
(iii) impulse : A wave of electrical disruption known as an impulse crosses a nerve cell and its fibre.
16.) Draw a diagram to show the arrangement of the bones inside the middle ear.
17.) Write short notes on the following :
(i) myopia : Myopia is a condition where nearby objects are clearly seen but not the distant ones by those suffering from myopia because the image of the object is formed in front of the retina.
(ii) taste buds: For taste, the material comes into direct touch with the sensory cells found in the tongue’s taste buds.
(iii) accommodation of the eye : Accommodation is the process of focusing the picture on the retina. Accommodation is achieved by varying the elastic lens’s curvature.
18.) How do sympathetic and parasympathetic nervous systems act differently on
(i) pupil of the eye: sympathetic nervous systems dilates and by parasympathetic nervous systems act constricts
(ii) urinary bladder: sympathetic nervous systems makes muscles relax and by parasympathetic nervous systems act makes muscle contract
19.) Draw a labelled diagram of the cross section of the spinal cord and the nervous pathway of a simple reflex concerned with it.
20.) Explain the role of ciliary muscles in our eyes
Ans: Circular ciliary muscles contract and have a tendency to shrink the circumference of the eyeball in that area. It helps for visibility of near vision.
21.) Taking the example of thyroxine secretion, explain what is meant by feedback mechanism?
Ans: TSH-RH (TSH- Releasing Hormone), which is released by the hypothalamus, tells the anterior pituitary to release TSH (thyroid stimulating hormone). Thyroxine production is stimulated by the TSH in the thyroid. The pituitary halts the secretion of TSH if the blood thyroxine level rises. The thyroid is stimulated to secrete more thyroxine when the blood level of the hormone drops. With a feedback mechanism, the initial point of an action gets feedback on whether to keep going, speed up, slow down, or even stop.
Also See: Next Chapter No. 18 Question Answer