Case 4: Limbic System Flashcards
Understand the limbic system
What are the 4 functions of the limbic system?
Homeostasis, Olfaciton, Memory and Emotion
What is the limbic system comported for?
Limbic lobes and cortical lobes
What are the 3 major cortical sutrcutrs of the limbic system?
Cingulate gyrus, parahippocampal gyrus and isthmus
others are theorbitofrontal fields and the temporal lobe
Where is the cingulate gyrus located?
Above the cingulate sulcus
Were is the parahippocampal gyrus?
Medial temporal lobe, separated from rest of temporal lobe by the collateral sulcus
What is the isthmus?
Where the cingulate and parahippocampal gyro join
What 4 cortices comprise the parahippocampal gyrus?
Piriform cortex, perirhinal core, parahippocampal cortex and entorhinal cortex
What are the relations of the uncus?
Bump on the anterior-medial parahippocmapal gyrus
How many regions and areas of the hypothalamus ar there?
4 regions and 3 areas
Ho are the areas of the hypothalamus arranged?
Meedial to lateral, relative to the third ventricle
Where is the periventricular nucleus?
Lines the third ventricle
Wha structures in the hypothalamus fdoes the formix separate?
Medial and lateral areas
What is the role of the medial hypothalamic area?
Recceives connections from the forebrain
What are the medial hypothalamic nuclei?
Preoptic, supraoptic, puberal and maxillary
Why is the supraoptic region so important?
Contains the paraventricular and supraoptic nuclei: for oxytocin and ADH
why is the suprachiasmatic nucleus so important?
Regulats circadian rhythms
what is the main input to the hypothalamus?
The subiculum via th fornix
What is the main output of the hypothalamus?
The mamillothalamic tract to the anterior thalamic nulcues
What is throne of themamillary bodies?
Memory recolleciton
What is the role of the ventromedial and dorsomedial hypothalamic nuclei?
Hunger and satiation (dorsomedial = hunger)
The neurons to the anterior pituitary lobe are ____ to the neurons to the posterior pituitary
Posterior (i.e. arcuate nucleus to the anterior lobe is posterior to the paraventricular nucleus)
The Hypothalamus connects to the ANS via which bundle
Medial forebrain bundle
The Hypothalamic fibres to the and descend from the ___ and ___ nuclei
Paraventricular and Dorsomedial
How does the hypothalamus aid excitation?
Connects to the raphe nucleus and the pontomedullar reticular formation
Which receptors are responsible for smell and there ar they location?
Olfactory receptors neurons in the ofactory mucosa
The olfactory neurons pierce the ___ __ and synapse onto the ___ and ___ cells of the ___ ___
Cribiform plate
mitral and tufted cells
Olfactory bulb
Where is th olfactory bulb located?
Olfactory sulcus
What is the role of the mitral and tufted cell?
Act as a superhighway to the olfactory cortex
The contralateral olfactory bulbs communicate with each other ia the ___ ___ nuclesu
Anterior olfactory nucleus
What order neutrons are located in the primary olfactory nulceus
2nd order neurons
Connections from the olfactory nucleus go via the lateral olfactory striae to what cortices?
pirform cortex nd perimamygdaloid nucleus
What are the 3 components of the hippocmapl formation?
Dentate gyrus, hippocampus proper and subiculum
Why is the dental greys important
It is the gateway to the hippocampus,
What does the dentate gyrus continue anteriorly as?
continues anteriorly as the uncus
Where is the hippocampus located relative to the lateral ventricle?
On the floor of the lateral ventricle
Where is the subiculum located?
Between theentorihinal cortex of the parahippocampal gyrus and the dentate + hippocampus
Illustrate the connections of the perforant pathway
CA4 granule cells give off “mossy fibers axons” to the CA3 –> Then synapse onto the schaffer cells of the dendrites of CA 1 pyramidal cells –> leave the hippocampus via the fornix
What is the role of the perforant pathway?
Entrance to the hippocampal formation
The areolar pathway connect the ___ cortex directly onto the CA_ and CA_
Entorhinal cortex directly onto the CA1 and CA3
What is the role of the CA3 cells int he hippocmapl formation?
Allow long term potentiation
From which gyrus to all afferent hippocampal fibres originate?
Parahippocampal gyrus
Which 2 other structures arecritical in memory in th limbic circuit?
Hypothalamic mamillary bodies and Anterior Thalamic Nucleus
Where do the pre-commissural fibres from the fornix lead
septal nuclei
Where do the post-commissural fibres from the fornix lead?
From the subiculum to the mammillary bodies and thalamus
