Answer
The best answer is "a". external:internal
The nervous system is primarily responsible for responses to the external environment. The endocrine system responds to the internal environment
Work Step by Step
The nervous system and the endocrine system work together to control the activities of other body systems and to maintain homeostasis. So close is this cooperation that these two systems are sometimes thought of as one , namely the neuroendocrine system.
There is no doubt that the nervous system is responsible for detecting changes in the internal environment. It does so through sensory receptors in such organs as ears, eyes, and the skin. But there are also internal sensory receptors-- in joints, muscles and inner ears. Furthermore, there are aortic arch and carotid sinus baroreceptors, chemoreceptors in carotid bodies and medulla, as well as mechanoreceptors and chemoreceptors in the GI tract.
The close cooperation of the endocrine and nervous systems is exemplified by the relationships between the hypothalamus and the pituitary gland -- anterior pituitary (AP), and posterior pituitary (PP).
The anterior pituitary secretes several trophic hormones, for example, ACTH, LH and TSH that stimulate adrenal cortex, gonads, and thyroid gland respectively. But the secretion and release of these hormones from the AP are under the control of factor/hormones-- stimulating and inhibiting-- which are secreted in hypothalamic nuclei and reach the the AP by way of a portal system. In addition, the hormones oxytocin and vasopressin(ADH) which are stored in the posterior pituitary (PP) or pars nervosa, are secreted by neurons in the supraoptic nucleus(ADH) and the paraventricular nucleus (oxytocin) of the hypothalamus.
Oxytocin and antidiuretic hormones are transmitted to the PP by neurons that pass through the infundibulum.
