Call Girls In Andheri East Call 9920874524 Book Hot And Sexy Girls
Ā
Limbic system anatomy
1.
2. Limbic system
ā¢ āLimbicā from Latin word Limbus
ā¢ Means "border" or "edge".
ā¢ Separates
ā¢ Medial surface of cerebral cortex
ā¢ From diencephalon
ā¢ Consists of
ā¢ Grey matter
ā¢ Cortical structures
ā¢ Subcortical structures
ā¢ White matter
ā¢ Interconnecting fibre tracts
4. Limbic lobe
ā¢ C-shaped ring of grey matter
ā On medial surface of each cerebral
hemisphere
ā¢ Surrounding the corpus callosum
ā 1. Subcallosal area
ā 2. Cingulate gyrus
ā 3. Isthmus
ā 4. Parahippocampal gyrus
ā 5. Uncus
5. Subcallosal gyrus
ā¢ A narrow lamina of grey matter
ā¢ Lies
ā¢ Infront of lamina terminalis
ā¢ Behind the parolfactory area
6. Cingulate gyrus
ā¢ Lies dorsal to
ā¢ Corpus callosum
ā¢ Receives inputs from
ā¢ Anterior nucleus of thalamus
ā¢ Projects to
ā¢ Entorhinal cortex via cingulum
ā¢ Involved with
ā¢ Emotion formation and processing,
learning, and memory
ā¢ Lesions lead to
ā¢ Akinesia, mutism
7. Parahippocampal gyrus
Parahippocampus
ā¢ Lies in medial temporal lobe
ā¢ Medial to collateral sulcus
ā¢ Important role
ā¢ In memory encoding and retrieval
ā¢ ERC
ā¢ Funnels highly processed cortical
information
ā¢ To hippocampal formation and serves
as its major output pathway
8. Uncus
ā¢ 2 parts by tail of dentate gyrus
ā¢ Uncinate gyrus
ā¢ Intralimbic gyrus
10. Hippocampus
ā¢ Consolidation of new memories
ā¢ Lies in
ā¢ Floor & medial wall of
ā¢ Inferior horn of lateral ventricle
Called as cornu ammonis
Ancient Egyptian deity,
Ammon
nferior horn of
Lateral ventricle
11. Hippocampus
ā¢ The most sensitive
area in brain
ā¢ For Ischemic events
in hippocampus is
CA1
ā¢ Trilaminate structure
ā¢ Molecular
ā¢ Pyramidal
ā¢ Polymorphic
12. Dentate gyrus
ā¢ Longitudinal strip of grey matter
ā¢ Lies
ā¢ Medial to hippocampus
ā¢ Fused with hippocampus
ā¢ On its lateral margin
ā¢ Medial margin is crenated
Dentate
gyrus
13. Dentate gyrus
ā¢ Anteriorly it ends as tail
ā¢ Runs across the inferior
surface of uncus
ā¢ By that uncus is divided
into
ā¢ Anterior uncinated
gyrus
ā¢ Posterior intralimbic
gyrus
ā¢ Posteriorly it continues
as
ā¢ Gyrus fasciolaris
14. Gyrus fasciolaris & Indusium griseum
ā¢ Gyrus fasciolaris
ā¢ Continuation of dentate gyrus
ā¢ Indusium griseum
ā¢ Grey matter on upper surface of
corpus callosum
ā¢ Contains 2 longitudinal bands
ā¢ Medial & lateral longitudinal striae
ā¢ Anteriorly ends in paraterminal
gyrus
ā¢ Infront of lamina terminalis
Gyrus
fasciolaris
Indusium griseum
Paraterminal gyrus
22. Fibres of limbic system
ā¢ Stria terminalis
ā¢ Fornix
ā¢ Mamillo thalamic tract
ā¢ Stria medullaris thalami
ā¢ Cingulum
23. Stria terminalis
ā¢ Begins in
ā¢ Amygdaloid complex
ā¢ Runs
ā¢ Backwards in the roof of inferior
horn
ā¢ Terminates near
ā¢ Interventricular foramen
ā¢ and anterior commissure by
dividing into various bundle
ā¢ To
ā¢ Hypothalamus & septal area
Amygdaloid body
Stria terminalis
Anterior commissure
24. Fornix
ā¢ Formation
ā Axons of hippocampus is called
alveus
ā¢ Parts
ā Fimbria (flat over dentate gyrus)
ā Crus (when it becomes rounded)
ā¢ Arches upwards & forwards underneath
splenium
ā Body
ā¢ Crura curving over thalamus converge
ā¢ Lies beneath trunk of corpus of
callosum
ā Column
ā¢ Arches downwards towards anterior
commissure
ā¢ Curves posteriorly to end in mamillary
body
ā¢ Post commissural fornix
ā¢ Precommissural fornix
C-shaped group of fibers
connecting
hippocampus with mammillary body
25. Mammillothalamic tract
ā¢ Carry the impulses
ā¢ From
ā¢ Mammillary body
ā¢ To
ā¢ Anterior nucleus of thalamus
Mammillothalamic tract
Anterior nucleus of thalamus
29. Applied anatomy
ā¢ Korsakoffās syndrome
ā¢ Loss of recent memory
ā¢ Results from deficiency of thiamine
(vitamin B1)
ā¢ Leads to damage to mammillary bodies
and dorsomedial nucleus of thalamus
ā¢ Temporal lobe epilepsy
ā¢ Temporal lobe can be damaged
ā¢ Through chronic seizures
ā¢ Herpes encephalitis
ā¢ Kluver-Bucy syndrome
ā¢ Bilateral ablation of amygdaloid
ā¢ Hyperphagia & hyper sex
30. Functions
ā¢ Olfaction
ā¢ Olfactory tract divides into lateral,
intermediate and medial stria
ā¢ Lateral stria
ā¢ Terminate in primary olfactory cortex of the
uncus
ā¢ Some fibres
ā¢ To hippocampal gyrus ā Memory of smell
ā¢ To amygdala ā Emotion of smell
33. Function ā Emotions & behaviours
ā¢ Emotion
ā¢ Any stimulus produces fear, anger, rage
or sadness
ā¢ Without conscious awareness
ā¢ Due to increased activity in amygdala
37. Medial column
ā¢ Lie
ā¢ Lateral to nuclei of
median column
ā¢ Nuclei
ā¢ Neurons are large in size
ā¢ So column can be named
as
ā¢ Magnocellular column
ā¢ Giganto cellular nucleus
ā¢ Pontine tegmental
reticular nucleus
ā¢ Cuneiform and sub
cuneiform nuclei
38. Lateral Column
ā¢ Lie
ā¢ Lateral to medial column
ā¢ Nuclei
ā¢ Made up of small cells
ā¢ This column is known as
Parvocellular column
ā¢ Control mainly the
visceral functions
39. Functional divisions
ā¢ On the basis of functions
ā¢ Two systems namely
ā¢ Ascending reticular activating system
ā¢ Descending reticular activating system
40. Ascending reticular activating system
ā¢ Responsible for maintaining
ā¢ Alertness & consciousness
ā¢ Most of the ascending tracts
passing through brain stem
ā¢ Gives collaterals to lateral part of
reticular formation
ā¢ From lateral part of reticular formation
to intralaminar & reticular nuclei of
thalamus
ā¢ From these nuclei fibres project to
cerebrum
41. Descending reticular system
ā¢ Has
ā¢ Descending pathways from reticular
formation to
ā¢ Autonomic centres in brain stem
ā¢ Lateral & anterior horns of spinal cord
