Which part of the brain does the hypothalamus belong to?

Label the endocrine glands in the figure.

$(a)$ Define hormone. Write four characteristics of hormones in humans.
$(b)$ Name the disorder caused by the following situations:
$(i)$ Under secretion of growth hormone
$(ii)$ Over secretion of growth hormone
$(iii)$ Under secretion of insulin
$(iv)$ Deficiency of iodine

Give the scientific names of the following regions of the human brain:
$(i)$ Region for sight.
$(ii)$ Region which controls salivation.

Explain the mechanism of reflex action.

What are voluntary and involuntary actions? Give one example of each.