1、Diencephalons (间脑),Diencephalons,Location: The diencephalons lie between cerebral hemispheres and midbrain and are almost entirely surrounded by the hemispheres of the cerebrum ,only the ventral surface of the diencephalons is exposed,Diencephalons,Parts: The diencephalons consist of four components
2、 or regions on each side, named dorsal thalamus (背侧丘脑), epithalamus (上丘脑), hypothalamus (下丘脑), subthalamus(底丘脑) and metathalamus (后丘脑),The diencephalons consist of five components the dorsal thalamus (thalamus) Subthalamus(底丘脑) Epithalamus(上丘脑) hypothalamus (下丘脑) Metathalamus(后丘脑),I Dorsal thalamus,
3、1. Location: is located laterally to the third ventricle, dorsally to the hypothalamus. The masses are frequently jointed by the interthalamic adhesion (intermediate mass).,2. The internal structures are sum up as follows:,Dorsal thalamus,ant. nuclear group med. nuclear group lat. nuclear group,dors
4、al part Ventral part,Ventral ant. nucleus Ventral intermediate nucleus (Ventrolateral nucleus) Ventral post nucleus (VPM, VPL),In addition:,Intralamina nuclei(板内核群) Median nuclei(中线核群) Reticular nuclei(网状核群),3. the thalamic nuclei may be classified:,Non-specific projection nuclei Association nuclei
5、Specific relay nuclei,specific sensory nuclei,medial geniculate nucleus (hearing) lateral geniculate nucleus (vision ) ventral posterior nucleus (general sensations ),VPM nucleus Receiving fibers: trigemino-lemniscus and taste fibers Efferent fibers: central thalamic radiation. Function: It is the r
6、elay nucleus of pain, tactile and thermal sensation of head and face.,Specific thalamic nuclei,VPL nucleus Afferent fibers: spinothalamic tract and med. lemniscus Efferent fibers: gives off central thalamic radiation. Function: It is the relay nucleus of pain, tactile ,thermal and conscious deep sen
7、sation of trunk and limbs.,Specific thalamic nuclei,II epithalamus,It occupies the caudal roof of the third ventricle together with adjacent areas . It includes habenular nuclei(缰核), the habenular trigone(缰三角) , the habenular and posterior commissure and the pineal body(松果体).,III subthalamus,It is t
8、he transitional area from the tegmentum of the dorsal thalamus It is a component of the extrapyramidal system.,IV metathalamus,It includes med. geniculate body and lat. geniculate body.,The lateral lemniscus enter med. geniculate nuleus, and it gives rise to the acoustic radiation. It is the relay n
9、ucleus of sound sensation.,1. med. geniculate body:,2. lat. geniculate body :,The optic tract enter lat. geniculate nuleus, and it gives rise to the optic radiation. It is relay nucleus of visual sensation.,V hypothalamus,The hypothalamus surrounds the third ventricle ventral to the hypothalamic sul
10、ci. The mammilary bodies are distinct swellings on the ventral surface.,1. Location of hypothalamus,The region bounded by the mammillary bodies, optic chiasma, and beginning of the optic tracts is known as the tuber cinereum(灰结节).,The infundibular stem (漏斗柄)arises from the median eminence just behin
11、d the optic chiasma and expands to form the infundibular process of pars nervosa of the pituitary gland(垂体).,Supraoptic(视上核) paraventricular nuclei(室旁核) Infundibular nucleus(漏斗核) Suprachiasma nucleus(交叉上核) Mamillary nucleus(乳头体核),2.Nuclei in hypothalamus,The cells of the supraoptic and paraventricul
12、ar nuclei elaborate neurohypophysial hormones ,and secretory granules in the cytoplasma are evidence of neurosecretory activity .,Axons from the nuclei constitute the hypothalamohypophysial tract, whose fibres terminate throughout the neurohypophysis where the hormones are released into capillary bl
13、ood .,3. functions of the hypothalamus:,concerned with regulating the sympathetic and parasympathetic actions, regulating body temperature, regulating food and water intake and controlling hormones production of the adenohypophysis.,VI The third ventricle,The diencephalic part of the ventricular sys
14、tem consists of the narrow third ventricle.,Cerebrospinal fluid enters the third ventricle from each lateral ventricle through the interventricular foramen (foramen of Monro).,The fluid leaves the third ventricle by way of the midbrain aqueduct, through which it reaches the fourth ventricle and then the subarachnoid space surrounding the brain and spinal cord.,
