The diencephalon as part of the brain is located between the end brain (cerebrum) and the brain stem.
Its components are:
The egg-shaped paired thalamus is the largest and, together with the hypothalamus, the most important of these structures in the midbrain and is located in the center of the brain. He limits the III. ventricle; above it runs the caudate nucleus, below which one finds hypo- and subthalamus as well as the midbrain. About the III. The ventricle is the epithalamus.Der thalamus in turn is composed of several nuclei and of marrow lamellae together. At its posterior pole lies the pineal gland (epiphysis, glandula pinealis) as part of the epithalamus.
Cerebrum (1st-6th) = end brain -
Among other things, the subthalamus contains the globus pallidus, which, from a developmental point of view, belongs to the diencephalon.
The hypothalamus forms in the brain the base of the diencephalon under the bottom of the III. Ventricle. Before this one finds the optic nerve intersection (Chiasma opticum), behind it the pituitary stalk with transition into the pituitary gland (pituitary gland). The hypothalamus is divided into different areas, which contain typical nuclei with vegetative functions. The bean-shaped pituitary gland is divided into neuro and adenohypophysis, with the neurohypophysis the rear part, the adenohypophysis on the other hand, the front part of the pituitary gland makes. The diencephalon only includes the neurohypophysis, the adenohypophysis does not belong to the brain, since it develops from the so-called Rathke pocket, which is part of the ectoderm, one of three cotyledons in embryonic development.
The structures mentioned - with the exception of the once created pituitary gland - are also found twice in total (left and right) in the brain (intermediate brain).
The thalamus as the largest part of the diencephalon fulfills various functions in the brain. In it, the switching of all information for the cerebral cortex occurs. On the one hand, he is involved in the limbic system, processes of well-being and mood, in visual, auditory and olfactory processes, and on the other hand in motor processes. The thalamus is also called the "gate to the consciousness", because it forwards sensory information to the cerebral cortex and in this way makes it aware.
The epithalamus (intermediate brain) is connected to the limbic system, the scent system, nuclei of the secretory processes of the mouth and autonomic centers of the brainstem. The epiphysis as part of the epithalamus is a gland that forms and releases the hormone melatonin. In addition, it affects the sympathetic nervous system and the control of the day-night rhythm.
The subthalamus (part of the brain) as part of the brain includes in its function the motor system, as well as the belonging to him globe pallidus, which represents as a motor center part of the basal ganglia loop.
The hypothalamus has effects on a variety of body processes. These include regeneration, performance, the daily rhythm, the female cycle, food and water intake including satiety. In addition, the hypothalamus regulates sweating, organ activity and tremors and forms various hormones: endogenous opiates, antidiuretic hormone (ADH), oxytocin and control hormones with effect on the adenohypophysis (liberins, statins). It is possible to influence these different processes via connections of the hypothalamus to limbic system, brainstem and pituitary gland.