(¡)Define hormone. Write any four characterstic of hormones in humans. 

(¡¡)Name the disorder caused by the following situations :

     (a)  Under secretion of growth hormone 

     (b)  Over secretion of growth hormone 

     (c)  Under secretion of insulin 

     (d)  Deficiency of iodine 

(i)Hormones are the chemical substances which control the activities of living organisms and also their growth(1 Mark).

Characterics of hormones are :(2 Marks)

 (a) They are secreted by endocrine glands

 (b) Regulate behaviour of target cells.

 (c) To stimulate the target organs.

 (d) They are poured directly into blood and carried throughout the body

 

(ii)

(a)Dwarfism(1/2)

(b)Gigantism/Acromegaly (1/2)

(c)Diabetes melitus(1/2)

(d)Cretinism/Goitre (1/2)