A and B are the two systems of control and coordination in the human body. The messages in system A are transmitted in the form of chemical substances C which travel comparatively slowly through the blood stream. The substances C are made in tissues D present in the head and trunk of human body. The messages in system B are transmitted very quickly in the form of electrical impulses through fibres E. The effect of messages transmitted by system B usually lasts for a much shorter time as compared to those transmitted by system A.

(a) Name the system A. What does system A consist of?


(b) Name the chemical substance C.


(c) What is tissue D? Name any five such tissues in the human body.


(d) Name the system B. What does system B consist of?


(e) Name the fibres E.


(f) State whether system A controls the working of system B or system B controls the working of system A.

(a) In above question, the system A is endocrine system. System A (Endocrine system) consists of glands.

(b) The chemical substance C is hormones.


(c) The tissue D is endocrine glands. Pineal, thyroid, pancreas, pituitary and ovaries are five such tissues in the human body.


(d) The system B is nervous system. The system B (nervous system) consists of brain, spinal cord and nerves.


(e) The fibre E is nerve fibres.


(f) The system B (nervous system) controls the functioning of system A (Endocrine system).


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