Question

1. Why are the hypothalamus and the pineal body considered part of the endocrine system as well as the nervous system?

Answer 1

Ans:- because both have endocrine function plus neural functions

​pineal gland

The pineal gland produces melatonin, which helps maintain circadian rhythm and regulate reproductive hormones.

The rhythm in melatonin production by the mammalian pineal gland is generated by the circadian timing system. The components of that system which mediate the function are: (1) visual projections through the retinohypothalamic tract to the circadian pacemaker, the suprachiasmatic nucleus (SCN) of the hypothalamus; (2) the SCN which generates a circadian signal transmitted by SCN projections to the parvocellular autonomic component of the paraventricular nucleus; (3) paraventricular nucleus projections to the upper thoracic intermediolateral cell column; (4) preganglionic sympathetic fibers to the superior cervical ganglion; (5) postganglionic sympathetic fibers from the superior cervical ganglion to the pineal.

Hypothalamus functions

Endocrine function:-

The hypothalamus is highly involved in pituitary gland function. When it receives a signal from the nervous system, the hypothalamus secretes substances known as neurohormones that start and stop the secretion of pituitary hormones.

Primary hormones secreted by the hypothalamus include:

• Anti-diuretic hormone (ADH): This hormone increases water absorption into the blood by the kidneys.
• Corticotropin-releasing hormone (CRH): CRH sends a message to the anterior pituitary gland to stimulate the adrenal glands to release corticosteroids, which help regulate metabolism and immune response.  
• Gonadotropin-releasing hormone (GnRH): GnRH stimulates the anterior pituitary to release follicle stimulating hormone (FSH) and luteinizing hormone (LH), which work together to ensure normal functioning of the ovaries and testes.
• Oxytocine etc.

neural function of hypothalamus:-

The hypothalamus is involved in many functions of the autonomic nervous system, as it receives information from nearly all parts of the nervous system. As such, it is considered the link between the nervous system and the endocrine system.

• Heart rate and blood pressure
• Body temperature
• Fluid and electrolyte balance, including thirst
• Appetite and body weight
• Glandular secretions of the stomach and intestines
• Production of substances that influence the pituitary gland to release hormones
• Sleep cycles