L11 Flashcards
part of the forebrain which lies above the midbrain, between the lower parts of the 2 cerebral hemispheres.
DIENCEPHALON
DIENCEPHALON consists of:
- Thalamus
- Subthalamus (directly above midbrain)
- Hypothalamus (lies in front of subthalamus)
- Metathalamus (lateral & medial geniculate body)
- Epithalamus ( pineal body, 2 habenular nuclei & commissures & posterior commissure)
lies between the 2 halves of the diencephalon?
The third ventricle
anterior end of the thalamus is narrow and rounded and forms the?
posterior boundary of the IVF
medial surface of the thalamus forms?
Lateral wall of 3rd V
(interthalamic adhesion B/W to thalami on medial surface )
The posterior end of thalamus is expanded to form the :
pulvinar
….. of thalamus is continuous with the tegmentum of the midbrain?
inferior surface
-thalamus is covered on its superior surface by a thin layer of white matter, called the……………
and on its lateral surface by another layer called ……………
stratum zonale
the external medullary lamina.
The gray matter of the thalamus is divided by a vertical sheet of white matter, into medial and lateral halves called?
internal medullary lamina
LATERAL PART of the thalamus subdivided into
Dorsal tier and a Ventral tier ( parts or nuclei )
DORSAL TIER OF THE NUCLEI: Include:
• Lateral dorsal nucleus
• Lateral posterior nucleus
• Pulvinar.بس ذا مهم منه
VENTRAL TIER OF THE NUCLEI: Include: مهم كله
• Ventral anterior nucleus = VLA
• Ventral lateral nucleus ( intermediate) = VLI
• Ventral posterior nucleus = VLP divided > VLPM + VLPL
Anterior relation of the thalamus :
IVF
Column of fornix
Ant commissure
Posterior relation of the thalamus :
-pineal gland
-post. Commissure
-hebenular commissure
-medial & lateral GB
Medial relation of the thalamus :
-3rd v
-inter-thalamic connection
Lateral relation of the thalamus :
-post. Limb of Internal capsule
-lentiform N
-external capsule
-colostrum
-extreme capsule
-insula
Superior relation of the thalamus :
-fornix
-caudate
-corpus callosum
-stria terminalis
-thalamus-strate vein
Inferior relation of the thalamus :
-hypothalamus
-sub-thalamus
-hypothalamic sulcus
White matter of thalamus :
Internal medullary lamina
External medullary lamina
NUCLEI OF THALAMUS include the:
• Intralaminar nuclei,
• Midline nuclei,
• Reticular nucleus,
• Medial and lateral geniculate bodies.
+ الاساسيات
thalamus is an important relay station for two sensory-motor axonal loops involving the cerebellum and the basal nuclei which are :
1) The cerebellar-rubro-thalamic-cortical-ponto-cerebellarloop
(2) The corticalstriatal-pallidal-thalamic-corticalloop
, (Both of which are necessary for normal voluntary movement)
CONNECTIONS of ANTERIOR PART OF THE THALAMUS
Afferent:
• From the mammillary nuclei through the mammillothalamic tract.
• From the hypothalamus and cingulate gyrus
Efferent:
to the cingulate gyrus and hypothalamus
Function:
(With limbic system in emotional recent memory)
CONNECTIONS of MEDIAL PART OF THE THALAMUS
Afferent:
• From the olfactory cortex, amygdaloid nucleus and hypothalamic nuclei
Efferent :
to prefrontal cortex
Function
((integration of sensory information, including somatic, visceral, and olfactory information, emotional feelings))
CONNECTIONS of LATERAL PART OF THE THALAMUS ((DORSAL TIER)):
مو مهمه
dorsal nuclei
interconnections with other thalamic nuclei and with the parietal lobe, cingulate gyrus, and occipital and temporal lobes. مو مهم مره
CONNECTIONS LATERAL PART OF THE THALAMUS of VLA
Afferent:
reticular formation
the substantia nigra
the corpus striatum
thalamic nuclei
( basal nuclei )
Efferent :
to the motor areas and the premotor cortex
Function:
influences the activities of the motor cortex.
Ventral lateral nucleus. ال
اللي هي VLI نفسها
بس اضافه على ال afferent
cerebellum & red nucleus.
CONNECTIONS of Ventral posterior nucleus VLPL ,VLPM:
Afferent:
VLPM > receives ascending trigeminal and gustatory ( trigeminal lemniscus )
VLPL> receives ascending sensory tracts, the (medial and spinal lemnisci.)
Efferent :
thalamocortical pass through the posterior limb of the internal capsule and corona radiata to the (((primary somatic sensory areas of the cerebral cortex in the postcentral gyrus (areas 3, 1, and 2)))
MGB, LGB of the thalamus connections ?
MGB - >
inferior colliculus ( afferent )
primary auditory cortex 41, 42 ( efferent )
( hearing )
LGB - >
Superior colliculus , optic tract ( afferent )
Area 17 ( efferent )
( Vision )
HYPOTHALAMUS
Extend
-optic chiasma to the caudal border of the mammillary bodies
-Anterior to the hypothalamus is an area that, extends forward from the optic chiasma to the lamina terminalis and the anterior commissure, it is referred to :
preoptic area.
-HYPOTHALAMUS forms
floor and the inferior part of the
(lateral walls ) of the (((third))) ventricle.
-lateral boundary of the hypothalamus is formed by:
internal capsule.
ونازله بـ midbrain
-Hypothalamus below related structures, from anterior to posterior:
(1) the optic chiasma,
(2) the tuber cinereum and
(3) infundibulum
(4) the mammillary bodies.
Parts of hypothalamus
-Medial zone nuclei of hypothalamus lying medial to the :
Or
-Lateral zone nuclei lying lateral to the :
plane of the fornix and the mammillothalamic tract
-hypothalamic nuclei in medial zone :
(1) Part of the preoptic nucleus مشتركه
(2) The anterior nucleus, which merges with the preoptic nucleus;
(3) Part of the suprachiasmatic nucleus مشتركه
(4) The paraventricular nucleus;
(5) Dorsomedial nucleus;
(6) Ventromedial nucleus;
(7) Infundibular (arcuate) nucleus
(8) Posterior nucleus.
-hypothalamic nuclei in lateral zone :
(1) part of the preoptic nucleus مشتركه
(2) part of the suprachiasmatic nucleus, مشتركه
(3) the supraoptic nucleus,
(4) the lateral nucleus,
(5) the tuberomammillary nucleus,
(6) the lateral tuberal nuclei
- hypothalamus receives information from the rest of the body through:
- Nervous connections,
- The bloodstream,
- Cerebrospinal fluid.
AFFERENT CONNECTION of hypothalamus
- Somatic and visceral afferents.
- Visual afferents
- Olfaction travels through the medial forebrain bundle
- Auditory afferents
- Corticohypothalamic fibers
- Hippocampohypothalamic fibers
- Amygdalohypothalamic fibers
- Thalamohypothalamic fibers
- Tegmental fibers
-General somatic sensation and gustatory and visceral sensations reach the hypothalamus through :
1-collateral branches of the lemniscal afferent fibers
2- tractus solitarius
3- reticular formation
-Visual afferents leave the optic chiasma and pass to the:
suprachiasmatic nucleus.
-Olfaction travels through :
the medial forebrain bundle
-Amygdalohypothalamic fibers pass from the amygdaloid complex tothe hypothalamus through :
the stria terminalis &
by a route that-passes inferior to the lentiform nucleus.
-Thalamohypothalamic fibers arise from the:
dorsomedial and midline thalamic nuclei
EFFERENT CONNECTION of hypothalamus ?
1-Descending fibers to the brainstem and spinal cord ( for autonomic). descend through a series of neurons in the reticular formationمهم
2-hypothalamus is connected to the parasympathetic nuclei of the oculomotor, facial, glossopharyngeal, and vagus nerves in the brainstem.
3-The mammillothalamic tract
4- mammillotegmental tract
5- efferent to the limbic system.
-(This pathway is relayed to the cingulate gyrus)?
The mammillothalamic tract
(reticulospinal fibers ) connect the hypothalamus with sympathetic cells of origin in the lateral gray horns of the ……. thoracic segment to the …………. lumbar segment of the spinal cord and the sacral
parasympathetic outflow at the level of the………………………. sacral segments of the spinal cord.
ايlevel?
first
second
second, third, and fourth
-hypothalamus is connected to the hypophysis cerebri (Pituitary gland) by two pathways:
- Nerve fibers that travel from the supraoptic and paraventricular nuclei to the ((posterior lobe))
اللي يطلعون ADH ,Oxytocin - Long and short portal blood vessels ((anterior lobe of the hypophysis))
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