What Is the Epithalamus?

The hypothalamus is located above and behind the thalamus and forms the peripheral marginal portion of the third ventricle roof. Including the pineal gland, zygomatic triangle, zygomatic zygomatics, thalamic medulla, and posterior zygomatics.

The hypothalamus is located above and behind the thalamus and forms the peripheral marginal portion of the third ventricle roof. Including the pineal gland, zygomatic triangle, zygomatic zygomatics, thalamic medulla, and posterior zygomatics.

Chinese name

Hypothalamus

Foreign name

epithalamus

Make up

Cerebral medulla, zygomatic triangle, zygomatic union, pineal gland

Features

Smell, vision

Composition of the hypothalamus:

The hypothalamus is located around the top of the third ventricle and includes the pineal gland, iliac triangle, and pith. Pineal gland: It is a flat cone-shaped body, shaped like a pine nut. Located in the middle of the two superior humps, it is attached to the top of the third ventricle by zygomatic and posterior commissures. Pineal somatic cells can synthesize melatonin, and experiments have shown that they can inhibit the secretion of pituitary gonadotropin, so pineal gland has an inhibitory effect on the gonads and reproductive system. Resection of the pineal gland, or pineal tumor, can cause precocious puberty. The synthesis of melatonin and norepinephrine is strong in dark conditions. Due to the change of circadian rhythm, the synthesis of melatonin has a rhythmic periodic change, which affects the physiological cycle of the body, so the pineal gland is related to the biological clock. . Sacral Triangle: Contains the sacral nucleus, which emits the sacral nucleus. The interphalangeal tract terminates in the midfoot and some mid suture nuclei of the midbrain, as well as the midbrain reticular structure and the central gray matter around the midbrain aqueduct. The pith is a complex fiber bundle that starts from the anterior nucleus, septum nucleus, lateral preoptic area, and medial part of the pale globus, and finally sacral nucleus. The medulla, phrenic nucleus, and zygomatic nucleus bundle can be used as one of the visceral pathways from the mesencephalon to the midbrain.

Anatomy of the hypothalamus :

1. The hypothalamus:

The hypothalamus is a subdivision of the mesencephalon, located posteriorly above the dorsal thalamus, and includes the sacroiliac triangle, the sacroiliac joint, the medullary stratum of the thalamus, the pineal gland, and the posterior commissure. The deep sacral nucleus of the sacral triangle is the sacral ganglia of lower animals. The human hypothalamus has not progressed much with biological evolution. The tritium and its connections mainly belong to the limbic system. The thalamic medulla extends backwards and finally expands the iliac triangle. The zygomatic triangles on both sides are connected at the rear, that is, the zygomatics, and the rear is connected to the cone-shaped pineal gland. The pineal gland is an endocrine gland, and phylogeny originates from the parietal eye of lower animals. Sympathetic cervical ganglia have fibers that penetrate the cerebellum and finally the pineal gland. The pineal gland is sensitive to light and is related to changes in endocrine regulation caused by light.

There are many origins of thalamic medullary fibers, mainly from the septal nucleus and the lateral area of the hypothalamus. They stop at the sacral nucleus in the sacral triangle, and the sacral nucleus and some myelinated fibers cross the midline to form a zygomatic union. The metatarsal nucleus sends out a lame interfacial tract (post-flexor tract), which ends in the midbrain nucleus and midbrain covered dorsal nucleus. In the latter, fibers participate in the dorsal longitudinal tract and stop at the visceral motor nucleus and reticular structure of the brainstem. This is a pathway for emotional activity and olfactory impulses to the brainstem to affect visceral activity.

2. Pineal gland:

The pineal gland is an unpaired structure that is tapered with a pointed downward and a bottomed up, about 5-8 mm long and about 4 mm wide. It is located in the sulcus between the two superior colliculus of the midbrain and consists of many sizes. Composition of unequal cell clumps. Reticulated connective tissue surrounds cell clumps with many blood vessels. Cell clumps contain glial and parenchymal cells. The parenchymal cells are lightly stained and have mitochondria, pigment granules, and secretory granules. The pineal gland is an endocrine gland that secretes anti-androgenic factors and has a role in stopping sexual maturity in children. It can also secrete pineal hormone and has the function of lowering blood sugar.

The pineal gland, also known as the adrenal gland, is located between the posterior upper part of the mesencephalon, the pressure part of the corpus callosum, and the midbrain superior colliculus. It is a cone-shaped body that is light red and is connected to the mesencephalon by a thin stem. The stem is divided into upper and lower thin plates, and the pineal crypts of the third ventricle are between the two plates. The pineal gland is 8-10mm long, about 6mm wide, about 4mm thick, and weighs about 0.2g. The human pineal gland is most developed at the age of 7 and gradually shrinks. The pineal gland is closely related to the top organ as a photoreceptor in phylogeny, so it is considered to be related to light sensitivity.

The pineal gland contains high levels of serotonin, norepinephrine, and melatonin. Serotonin is stored at the nerve endings and the ends of pineal cell processes. Norepinephrine is present in the sympathetic nerve and its terminals. It is a neurotransmitter; it is released in the form of exocytosis when the nerve is excited. Now it has been determined that the main role of melatonin is to inhibit the secretion of follicle-stimulating hormone and luteinization by the pituitary

Diseases of the thalamus and thalamus:

Thalamus syndrome:

Tumor and vascular diseases are the most common causes of thalamic lesions and can produce thalamic syndrome. In 1906, some scholars first described the thalamus syndrome in detail (it should be the posterolateral thalamus syndrome). The main symptoms of this group are due to thalamic geniculate circulatory disorders. Clinically, the following manifestations of the hypothalamus on one or both sides can occur.

(1) Declining feeling of contralateral leaning:

As the lateral thalamic nucleus group, especially the retroabdominal nucleus, is damaged, various sensory deficiencies can occur. It is characterized by impairment of all sensations on the opposite limb of the lesion; deep and fine sensations are more severe than superficial sensations; sensory disorders of the body and trunk are more important than the face;

(2) Spontaneous pain of contralateral sideways:

Contralateral sideways spontaneous pain is also called thalamic pain. It is caused by the involvement of the inner nucleus pulposus and the central nucleus, and it is often manifested as persistent and unbearable pain on the opposite limb of the lesion.

(3) For facial expression movement disorders:

When the thalamus is damaged, due to the interruption of the reflex pathway from the thalamus to the subcortical (extrapyramidal) nucleus, detached dyskinesia may occur on the side of the lesion, that is, when the patient cries and laughs, the expression of the lesion on the side is lost, but The facial muscles did not appear paralyzed when the patient performed random movements.

(4) Involuntary contralateral sideways movement, intentional tremor, or ataxia:

Due to the lesions of the lateral thalamus nucleus, the fibers associated with the red nucleus, cerebellum, and pale globules are damaged, chorea occurs, and hand, foot and asthma are present, and a special posture-thalamic hand due to finger movements.

(5) Emotional disorders:

Emotional disorders are caused by impaired connections between the thalamus and the limbic system, manifested as emotional instability, and strong crying or laughing.