Diencephalon: structure and functions of this brain region
When its development begins, the central nervous system is made up of three sections: the forebrain, the mesencephalon and the hindbrain. Later these initial structures will give rise to the different parts of the adult brain, including the diencephalon.
In this article we will describe the structure and functions of the diancephalon , which includes such important regions as the thalamus and the hypothalamus and allows the correct functioning of multiple biological processes, such as the secretion of hormones and the regulation of the autonomous system.
- Related article: "Parts of the human brain (and functions)"
What is the diencephalon?
The diencephalon is a part of the brain that is situated in its medial region . This name refers to the part of the neural tube that gives rise to various brain structures as embryonic development progresses.
In particular, once differentiated, the main parts of the diencephalon are the thalamus, the hypothalamus, the epithalamus, the subthalamus and the retina . Likewise, the pituitary or pituitary gland is attached to the hypothalamus, and the optic nerve also connects with the diencephalon.
The cavity formed by these structures is the third ventricle , which cushions the effects of the injuries that could damage them. The posterior cerebral artery and the polygon of Willis allow the blood supply of the diencephalon.
Parts of the brain and the brain
The encephalon is the part of the central nervous system that is located in the cranial cavity, as opposed to the spinal cord. This organ is made up of the brain, the cerebellum and the brainstem .
The diencephalon develops from the forebrain or forebrain, one of the three parts of the encephalon at the beginning of the embryonic development of the nervous system. The other two initial sections are the mesencephalon, which will join the different parts of the brain, and the rhombencephalon, which will give place to the cerebellum, the medulla oblongata and the pons.
As the fetus grows the forebrain is divided into the diencephalon and the telencephalon ; from this will develop the cerebral hemispheres, the basal ganglia and the limbic system, including the amygdala. We describe the sections of the diencephalon in the following section.
Structure and functions of the diencephalon
The brain region we know as the diencephalon is composed of various structures. These are connected to each other and to the rest of the nervous system, both at the cortical and subcortical levels.
It is also very relevant its relationship with the endocrine system, consisting of glands that secrete hormones in the blood.
1. Thalamus
The thalamus works as a kind of relay nucleus for connections between the cerebral cortex and subcortical structures . It is fundamental for the reception of sensory inputs (with the exception of the olfactory ones, which go directly to the cortex) and its transmission to the cerebral lobes.
This structure also has a role in the regulation of consciousness and the sleep-wake cycle, and it influences motor skills through the eferences that project from the thalamus to the basal ganglia and the cerebellum.
2. Hypothalamus
The hypothalamus is located below the thalamus. The main functions of this structure include connect the nervous and endocrine systems and control the secretion of hormones from the pituitary gland and other glands.
The hypothalamus directly produces vasopressin and oxytocin, but also stimulates the endocrine glands to secrete other hormones. It is also key to the regulation of homeostasis of the organism as it intervenes in thirst, hunger, temperature, circadian rhythms, stress and other bodily processes.
- Related article: "Hypothalamus: definition, characteristics and functions"
3. Pituitary gland or pituitary gland
The pituitary gland is an endocrine gland attached to the hypothalamus . It is very important for growth, regulation of the kidneys, sexual function and reproduction, in addition to other aspects.
It consists of two lobes: the anterior pituitary gland (adenohypophysis) and the posterior pituitary gland (neurohypophysis). While the neurohypophysis secretes oxytocin and vasopressin, synthesized by the hypothalamus, the adenohypophysis produces and releases corticotropin, growth hormone, prolactin, luteinizing hormone and follicle stimulating hormone, among others.
- Maybe you're interested: "Pituitary gland (hypophysis): the nexus between neurons and hormones"
4. Epitálamo
This brain structure It is mainly composed of the pineal gland , fundamental in circadian and seasonal cycles, and habénula, involved in the function of the neurotransmitters dopamine, noradrenaline and serotonin. The epithalamus connects the limbic system with other regions of the brain.
5. Subthalamus
The subthalamus is attached to the pale globe, one of the main nuclei of the basal ganglia. Because of this, it fulfills a regulatory role in extrapyramidal and involuntary movements.
6. Retina and optic nerve
The retina develops from the diencephalon, so it is considered a part of the central nervous system . The optic nerve allows the transmission of information from the eye to the brain through its union with the diencephalon.
7. Third ventricle
The cerebral ventricles allow the circulation of cerebrospinal fluid , which performs functions similar to those of blood in the brain and spinal cord, in addition to protecting the neural tissue from bumps and injuries. The third ventricle is in the middle part of the ventricular system, below the epithalamus.
- Related article: "Cerebral ventricles: anatomy, characteristics and functions"
