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Chapter 7: Control and Coordination

Q1: Name the parts (i),(ii),(iii),(iv),(v)and (vi) as shown in the figure .

Ans:

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     (i) Receptors in skin

    (ii) Sensory neurons

    (iii) Effector

    (iv) Motor neurons

    (v) Relay neuron

    (vi) Spinal cord

  

Q2: Name the hormones in the plant which causes the following:

(a) Growth of stem.

(b) Falling of senescent leaves

(c) Elongation of cells.

(d) Cell division.

Ans:

(a) Gibberellin

(b) Abscisic acid

(c) Auxin

(d) Cytokinin

 

Q3:List the Endocrine gland from the figure given below.

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     Ans:

(i) Thymus

(ii) Thyroid gland

(iii)Pituitary gland

(iv)Pineal gland

 

Q4: Explain Tropic movements.Support it by giving example.

Ans:

The Tropic movements is defined as the growth movement of the plant, is because of the external stimuli. It can either be towards or away from the stimulus.

Example:Haptotropism is the Growth movements by plants due to contact with a solid object.

 

Q5: If the consumption of Iodine is low in the diet, what is the effect in our body.

Ans:

If the intake of iodine is low, the release of thyroxine from the thyroid gland will be decreased due to which fat,carbohydrate and protein metabolism will be affected.

Thus a person may have goitre problem in case if the intake of iodine is lowered.

 

Q6: Answer in one word:

(i) The changes in females during the time of puberty is due to which hormone?

(ii)Which hormone is responsible for deficiency of Dwarfism?

(iii)Which hormone is rise in sugar level?

(iv)Which hormone is responsible for the synthesis of Iodine?

Ans:

(i) Oestrogen

(ii) Growth hormone

(iii) Insulin

(iv) Thyroxine

 

Q7: Answer in one word

(i) Which endocrine gland is related with brain?

(ii) Name the gland that produces digestive hormones and enzymes?

(iii) Which endocrine is related with kidneys?

(iv) The endocrine gland, which is, absent in females and is found in males?

Ans:

(i) Pituitary gland

(ii) Pancreas

(iii) Adrenal

(iv) Testes.

 

LONG ANSWERS TYPE QUESTIONS

 

Q8: List the main parts of human brain and write the function of those parts?

Ans:

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Forebrain: Composed of cerebrum.

Midbrain:  Composed of hypothalamus.

Hindbrain: Composed of cerebellum, medulla oblongata and pons.

 

The main parts in our brain are:

(i) Cerebrum: It is the most important and one of the largest part of the our brain which is further divided into two hemispheres, called cerebral hemisphere.

Functions: The Cerebrum –

(a) Controls voluntary action of body.

(b) Helps in sensory perception.

(c) is responsible for memorizing things.

 

(ii) Hypothalamus:

(a) lies below the cerebrum.

(b) Controls the sleep and the wake-up cycle.

(c) Controls the urge for drinking and eating .

 

(iii) Cerebellum:

(a) Lies below to the cerebrum, at the back side of the whole structure.

(b) Controls the motor functioning,such as when riding a cycle cerebellum brings the perfect combination of steering and pedaling.

 

(iv) Medulla:

(a) Forms the brain stem along with pons.

(b) Lies at the base of brain and goes up to the spinal cord.

(c) The most important function is that it controls the involuntary functions, such as heart-beat, respiration etc.

 

Q9: State the important functioning of these hormones:

(i) Thyroxine

(ii) Insulin

(iii) Adrenaline

(iv) Growth hormone

(v) Testosterone

Ans:

(i) It regulates carbohydrate, fats, protein metabolism.

(ii) It regulates sugar level in blood.

(iii) It is responsible for blood flow to various organs.

(iv) It regulates growth and development.

(v) It changes the body features relating with puberty in males.

 

Q10: List various plant hormone, along with their physiological effect on the growth and development of plants.

Sol:

The different plant hormone are

(a) Auxin

(b) Gibberellin

(c) Cytokinin

(d) Abscisic acid

The Physiological effects on growth and development in plants are:

(a) Auxin is responsible for cell elongation, root formation, inhibition of abscission, cell division and fruit growth.

(b) Gibberellin helps in growth in stems and leaves, higher fruit yield and overcoming dormancy.

(c) Cytokinin supports cell division, prevention of senescence, differentiation and overcoming apical dominance.

(d) Abscisic acid influence dormancy, senescence, abscission, checking excessive activity of growth hormone and closure of stomata under water stress.

 

Q11: Why the signal flow in a synapse only from the axonal end of one neuron to the dendritic end of another neuron but the reverse is not possible?

Sol:

A chemical substance is released when the electrical signal reaches the axonal end of a neuron and this chemical diffuses to the dendrite end of another neuron, which generates electrical signal. Thus, at the axonal end, the electrical signal converts into chemical signal and because at the dendrite end of neuron these chemicals are not present thus reverse, action is not possible.

 

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