Adrenal medulla : It is the centrally located tissue that lies inner to cortex. It secretes following two hormones :

1. Norepinephrine : It controls heart beat, contraction of arteries, breathing etc. at normal time.

2. Epinephrine : It is released at the time of emergency. It has the following effects.

(a) It increases heart beat and breathing.

(b) It constricts the arteries so that more blood may go into muscles.

(c) It dilates pupil.

(d) It oxidises more food so that more energy is produced.