Question

What are the functions of thalamus, hypothalamus and pineal gland?

Answer 1

Hint: Thalamus, Hypothalamus and Pineal gland are all parts of the Diencephalon, whose main function is to relay sensory and motor information. It is also responsible for consciousness, alertness and sleep.

Complete answer:
-Thalamus: This part of the brain is made up of numerous nerve cells, mostly neuron cell bodies. The part composed of cell bodies/nuclei is called gray matter, some parts are made of axons called white matter.
The primary function of the thalamic gray matter is to process and pass on/relay sensory signals. All sensory signals like visual, auditory, somatosensory (touch) and gustatory signals (taste), except olfactory signals are processed and relayed from the sensory receptors to the cerebral cortex via the thalamus.
 Along with sensory signals, thalamus also relays motor information and plays a pivotal role in emotional response, memory and arousal.
-Hypothalamus: Though hypothalamus is a very small part of the brain, it is very crucial for regular functions of the body. It is responsible for maintaining homeostasis by regulating heart rate and blood pressure.
This part of the brain is also the link between the nervous system and the endocrine system, as it regulates secretion of hormones like TSH, ACTH, GnRH and Oxytocin from the pituitary gland. These hormones ensure the functioning of the gastrointestinal tract, heart, muscles and reproductive organs. ACTH triggers the production of the stress hormone, cortisol while oxytocin is a behavioural hormone which also helps in childbirth and lactation.
-Pineal Gland: This is an endocrine gland that secretes melatonin which modulates the sleeping cycle. This orients the circadian rhythm and develops the 24-hour oscillation of internal functions according to the Earth’s rotation.

Note:
Thalamus, hypothalamus and pineal gland belong to the largest part of the brain that is the forebrain. Forebrain is divided into two main parts: diencephalon and telencephalon.
Pineal gland is also called the “third eye” due to its location deep into the brain and its association with light.