Q2 of 39 Page 135

Give the characteristics of hormones pertaining to

(i) Site of action ………………………………


(ii) Chemical nature ………………………………………………


(iii) The manner of transportation ……………………………….

(i) The site of action of hormones is usually far away from their source and that is why the hormones are carried by blood from their source to their target cells.


(ii) Some hormones chemically are steroids, some amines, and some peptides.


For example,


Protein as hormone: insulin


Steroid as hormone: testosterone


Amines as hormone: adrenaline


(iii) The endocrine glands being ductless, secretes the hormones directly into the blood which then transports the hormones to its target cells and organs.


More from this chapter

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1

Fill in the blanks by selecting the appropriate alternative from those given in brackets.

(i) Regulation of activities inside the body is brought about by ……….. and ………………..systems. (nervous/digestive/endocrine)


(ii) Hormones are secreted directly into the ………………………………. (organs/lymph/blood.)


(iii) Chemically, some hormones are ……….., some steroids, some ……………. (proteins/amines/carbohydrates.)


(iv) Both …………………..or deficiency of hormones leads to serious consequences (excess/absence.)


(v) Hormones produced in one species usually show ……………………influence in other species. (similar/different).

 1

Mention the three types of cells of the islets of Langerhans, the name of the hormone they secrete.

(i) Alpha cells ………………………………….


(ii) Beta cells …………………………………………………………


(iii) Delta cells ……………………………………………………….

 2

Mention the two principal ways in which insulin acts:

(i) _________________


(ii) _________________

 3

Name the following conditions:

(i) Passage of much glucose in urine ………………………


(ii) Overdose of insulin makes the diabetic patient unconscious ………………………………………………