Question

Secretion is under the control of neurosecretory nerve axons in
a. Pineal
b. Adrenal cortex
c. Anterior pituitary
d. Posterior pituitary

Answer 1

Hint: Neurosecretory cells are the type of neurons or nerve cells that converts the nerve signals to chemical stimuli, they present almost in all multicellular organisms, they differentiate from normal nerve cells by a big nucleus, large axon, and big cell itself.

Complete answer:
Neurosecretion is nothing but the hormones secreted by the action of the nerve cell.
Neurosecretions are peptide in nature.
Classific example for neurosecretion is oxytocin and vasopressin by the posterior pituitary gland.
Posterior pituitary gland mainly synthesis the two hormones, namely Oxytocin and vasopressin.

> Oxytocin: It is a peptide hormone, it is mainly neuropeptide.
- Oxytocin is formed from the peptide precursors which are having an OXT gene by enzymatic cleavage.
- This hormone was discovered by Henry Dale.
- This was produced by the hypothalamus and released by the posterior pituitary gland.
- This hormone is called a love hormone or cuddling hormone.
- It plays a very important role in social bonding.
- The main functions of oxytocin are related to sex, childbirth.
- During labor when there is stretching of the cervix, there is a contraction of the uterus and facilitates childbirth.
- It is produced by the stimulation of nipples during breastfeeding, which increases the bond between child and mother.
- Oxytocin is used as medication regarding childbirth.

> Vasopressin: It is also called an antidiuretic hormone, and also called arginine vasopressin.
- It is also a peptide hormone made by the peptide of neurons.
- There are two major functions for the vasopressin which include.
- In the kidney, they reabsorbed the solute free water back to the circulation which is absorbed during glomerular filtration.
- The second function is, it constricts the arterioles, so the peripheral vascular resistance increases and it increases the blood pressure in arterioles
- And they also have some functions, sometimes this hormone, may directly release into the brain and cause social behavior, sexual motivation, etc.

Hence, the correct answer is option (D).

Note: As these neurosecretory hormones are released from nerve endings or neurons, along with the endocrine activity, they also have the characteristics of neurotransmitters, as neurotransmitters are also released from the nerve endings itself.