Question

1. which endocrine gland is situated at the base of the throat, just inferior to the adams apple?

a) thyroid gland
b) pineal gland
c) pituitary gland
d) thymus gland

1. which of these hormones regulate calcium levels in the body?

a) calcitonin and parathyroid hormone (pth)
b) oxytocin and prolactin
c) insulin and glucagon
d) t3 and t4

1. parathyroid hormone (pth) is secreted by the parathyroid glands in response to low blood concentration of calcium ions. this mechanism operates by a ______.

a) humoral stimulus
b) messenger stimulus
c) hormonal stimulus
d) neural stimulus

Explanation:

1. The thyroid gland is located at the base of the throat, below the larynx (Adam's apple). The pineal gland is in the brain, the pituitary is at the base of the brain, and the thymus is in the chest.
2. Calcitonin lowers blood calcium, while parathyroid hormone (PTH) raises it, together regulating calcium levels. Oxytocin/prolactin relate to reproduction/lactation, insulin/glucagon regulate blood sugar, and T3/T4 regulate metabolism.
3. Humoral stimuli involve hormone release in response to changes in blood ion or nutrient levels, which matches PTH's release due to low blood calcium.

Answer:

1. a) Thyroid gland
2. a) calcitonin and parathyroid hormone (PTH)
3. a) humoral stimulus