a) Hypothalamus maintains the constant human body temperature by regulation of the diameter of blood vessels (constriction to conserve heat during body temperature lower than normal or dilation to lose heat by increasing blood flow during body temperature higher than the normal range), shivering and sweating mechanisms.
b) Pituitary gland is associated with overall physical growth and development via its growth hormone as well as to instruct other endocrine glands to secrete their hormones via its tropic hormones.
c) Thyroxine and triiodothyronine are thyroid hormones which target all tissues and stimulate metabolic rate.
d) Sweat glands present in skin help dissipate the heat during summers by evaporation of water on the skin surface, thereby cooling the skin surface. Skin does not contain any thermoregulatory centers but only exhibit sweating as a mechanism of temperature regulation.