The posterior pituitary gland is not a 'true' endocrine gland because

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because

Serum differs from blood in

Osteoporosis, an age related disease of skeletal system , may occur due to

Name a peptide hormone which acts mainly on hepatocytes, adipocytes and enhances cellular glucose uptake and utilization.

Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of blood from the body.