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Hypothalamus, Limbic, Olfactory and Gustatory System Andres S. Javier MD
Assistant ProfessorDepartment of Anatomy
College of MedicineUERMMMCI
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System Objectives
To give an introduction of the HypothalamusTo describe the Hypothalamus by
A. Locating its regions and its boundariesB. Descrbing the hypothalamic regions and the respective nucleiC. Tracing principal afferent and efferent connections
Hypothalamus
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System Objectives
D. Enumerating the functions of the hypothalamusE. Describing the hypophyseal portal system and its role in the endocrine functionF. Naming the major hypothalamic hormones and giving their functions and source
Hypothalamus
Hypothalamus |Introduction
head ganglion of the ANS subdivision of the diencephalon weighs 4g and forms <1% of the brains total weightintegrates functions of endocrine, autonomic(visceral motor), somatic motor and limbic systemconsists of group of nuclei each playing a role in homeostasis
Hypothalamus |Introduction
crucial to the survival of the organismControl of appetiteFluid balanceElectrolyte balanceGlucose concentrationMetabolism,Sleeping Role in sexual behavior
Hypothalamus |Boundaries
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Hypothalamus |Boundaries
Hypothalamus |Boundaries
Hypothalamus |Boundaries
Structure
Rostral (Anterior) Anterior Commisure
Lamina Terminalis
Optic ChiasmaCaudal(Posterior) Mamillary BodySuperiorly Interventricular foramen Inferiorly Floor of the third ventricleMedial Third Ventricle Lateral Internal capsule
Subthalmic nucleus
Substantia innominata
Hypothalamus | Zones and Regions
ZONESPeriventricularMedialLateral
REGIONSPreopticAnteriorMiddlePosterior
Hypothalamus |Regions of Hypothalamic Nuclei
Hypothalamus |Zones
Periventricular
Suprachiasmatic nucleus
Paraventricular nucleus
Arcuate (infindibular) nucleus
Hypothalamus | Medial zone/Medial hypothalamic area
Middle orTuberal region
Dorsomedial nucleusVentromedial nucleusInfindibular (arcuate) nucleus
Posterior or Mamillary region Posterior nucleus Mammillary
nucleus
Lateral nucleus Preoptic nucleus Suprachiasmatic
nucleus Supraoptic
nucleus Tuberomammillary
nucleus
Hypothalamus | Lateral zone/Lateral Hypothalamic area
Hypothalamus |Regions of Hypothalamic Nuclei
Hypothalamus | Notes on Zones and Regions
Nuclei such as the:
PREOPTIC NUCLEUS, SUPRACHIASMATIC NUCLEUS and PARAVENTRICULAR NUCLEI overlap zones
Hypothalamus |Afferent Connections
Hypothalamus |Afferent Connections Pathway Origin Destination
Medial and spinal lemnisci, tractus solitarius, reticular formation
Viscera and somatic structures
Hypothalamic nuclei
Visual fibers Retina Suprachiasmatic nucleus
Medial forebrain bundle Olfactory mucous membrane
Hypothalamic nuclei
Auditory fibers Inner ear Hypothalamic nuclei
Corticohypothalamic fibers Frontal lobe of cerebral cortex
Hypothalamic nuclei
Hippocampohypothalamic fibers Hippocampus Hippocampus Nuclei of mammillary body
Amygdalohypothalamic fibers Amygdaloid complex Hypothalamic nuclei
Thalamohypothalamic fibers Dorsomedial and midline nuclei of thalamus
Hypothalamic nuclei
Tegmental fibers Tegmentum of midbrain Hypothalamic nuclei
Hypothalamus |Efferent Connections
Hypothalamus |Efferent Connections Pathway Origin Destination
Descending fibers in reticular formation to brainstem and spinal cord
Preoptic, anterior, posterior, and lateral nuclei of hypothalamus
Craniosacral parasympathetic and thoracolumbar sympathetic outflows
Mammillothalamic tract Nuclei of mammillary body Anterior nucleus of thalamus; relayed to cingulate gyrus
Mammillotegmental tract Nuclei of mammillary body Reticular formation in tegmentum of midbrain
Multiple pathways Hypothalamic nuclei Limbic system
Hypothalamus | Connections with the Hypophysis Cerebri
Connected by two pathways:
Nerve fibers that travel from the supraoptic and paraventricular nuclei to the posterior lobe of the hypophysis
Long and short portal blood vessels that connect sinusoids in the median eminence and infundibulum with capillary plexuses in the anterior lobe of the hypophysis
Hypothalamus |Connections of the Hypothalamus With the Hypophysis Cerebri
Hypothalamic Regulatory Hormone Anterior Pituitary Hormone Functional Result
Growth hormone–releasing hormone (GHRH)
Growth hormone (GH) Stimulates linear growth in epiphyseal cartilages
Growth hormone–inhibiting hormone (GHIH) or somatostatin
Growth hormone (reduced production)
Reduces linear growth in epiphyseal cartilages
Prolactin-releasing hormone (PRH)
Prolactin (luteotropic hormone, LTH)
Stimulates lactogenesis
Prolactin-inhibiting hormone (PIH), dopamine
Prolactin (luteotropic hormone, LTH) (reduced production)
Reduces lactogenesis
Corticotropin-releasing hormone (CRH)
Adrenocorticotropic hormone (ACTH)
Stimulates adrenal gland to produce corticosteroids and sex hormones
Thyrotropin-releasing hormone (TRH)
Thyroid-stimulating hormone (TSH)
Stimulates thyroid gland to produce thyroxine
Luteinizing hormone–releasing hormone (LHRH), ? follicle-stimulating releasing hormone (FRH)
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
Stimulates ovarian follicles and production of estrogen and progesterone
Hypothalamic Regulatory Hormone Origin
Growth hormone–releasing hormone (GHRH)
Infundibular or arcuate nucleus
Growth hormone–inhibiting hormone (GHIH) or somatostatin
Suprachiasmatic nucleus
Prolactin-releasing hormone (PRH) ?
Prolactin-inhibiting hormone (PIH), dopamine
?
Corticotropin-releasing hormone (CRH) Paraventricular nuclei
Thyrotropin-releasing hormone (TRH) Paraventricular and dorsomedial nuclei and adjacent areas
Luteinizing hormone–releasing hormone (LHRH)
Preoptic and anterior nuclei
Hypothalamus | Functions
AUTONOMIC CONTROL
Basic Functions:1. Regulation and control of certain
aspects of visceral activity, particularly those affected by the ANS and pituitary gland
2. Control of the motor activity, both somatic and visceral, of emotional perceptions
Hypothalamus | Functions
AUTONOMIC CONTROL
Anterior and preoptic area - influence parasympathetic responses
Posterior and lateral nuclei - stimulation causes sympathetic responses
Hypothalamus | Functions
ENDOCRINE CONTROL
Paraventricular nuclei• OxytocinSupraoptic nuclei• Anti-diuretic hormone (ADH) or
vasopressin- hypothalamo-hypohyseal tractArcuate and ventromedial nuclei (Medial
Zone)• releasing hormones/ inhibitory releasing
hormones- hypothalamo-hypophyseal portal vessels
Hypothalamus | Functions
TEMPERATURE CONTROL
Anterior hypothalamic area - HEAT LOSS CENTER
– controls mechanism that dissipate heat loss >> cutaneous vasodilatation and sweating >> decreased body temperature
Lesion: hyperthermia
Hypothalamus | Functions
TEMPERATURE CONTROL
Posterior hypothalamic area – HEAT GAIN CENTER
- stimulation causes vasoconstriction of skin blood vessels and inhibition of sweating>> peripheral vasoconstriction and shivering >> increased body temp
Lesion: hypothermia
Hypothalamus | Functions
REGULATION OF FOOD AND WATER INTAKE
Lesion: Anorexia
Lateral region – HUNGER OR FEEDING CENTER (initiates
feeling of hunger)Medial/Ventromedial region – SATIETY CENTER (inhibits eating)Lateral region – THIRST CENTER (increase in the desire to
drink)
Lesion: Uncontrolled Voracious appetite
Hypothalamus | Functions
Hypothalamus | Functions
EMOTION AND BEHAVIOR
Hypothalamus Limbic systemPrefrontal cortex
Lateral nuclei – stimulation may cause signs and symptoms of
rage and hyperactivity (lesion: passivity)Ventromedial nuclei – stimulation may cause passivity ( lesion: rage)
Hypothalamus | Functions
CONTROL OF CIRCADIAN RHYTHM(Sleep-wakefulness regulation)
ThalamusLimbic systemReticular activating systemHypothalamus Suprachiasmatic nucleus - via connections with ARAS Lesion of anterior part of hypothalamus-interfere
with rhythm of sleeping and waking Lesion of dorsolateral mammillary region-produce
somnolence
Hypothalamus |Functions of the Main Hypothalamic Nuclei Hypothalamic Nucleus Presumed Function
Supraoptic nucleus Synthesizes vasopressin (antidiuretic hormone)
Paraventricular nucleus Synthesizes oxytocin
Preoptic and anterior nuclei Control parasympathetic system
Posterior and lateral nuclei Control sympathetic system
Anterior hypothalamic nuclei Regulate temperature (response to heat)
Posterior hypothalamic nuclei Regulate temperature (response to cold)
Lateral hypothalamic nuclei Initiate eating and increase food intake (hunger center)
Medial hypothalamic nuclei Inhibit eating and reduce food intake (satiety center)
Lateral hypothalamic nuclei Increase water intake (thirst center)
Suprachiasmatic nucleus Controls circadian rhythms
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System End
To give an introduction of the HypothalamusTo describe the Hypothalamus by
A. Locating its regions and its boundariesB. Descrbing the hypothalamic regions and the respective nucleiC. Tracing principal afferent and efferent connections
Hypothalamus
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System End
D. Enumerating the functions of the hypothalamusE. Describing the hypophyseal portal system and its role in the endocrine functionF. Naming the major hypothalamic hormones and giving their functions and source
Hypothalamus
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System Objectives
To give an introduction of the Limbic SystemTo demonstrate knowledge and understanding of the limbic system by
A.Identifying the structures that comprise the limbic systemB.Enumerating the sources of input and output of the limbic systemC.Describing the major circuit of the limbic system (Papez Circuit)D. Naming disorders involved
Limbic System
Limbic System |Introduction
Limbic (“border”) Systemconsists of a diverse group of structures that would include phylogenetically ancient cortical areas a group of associated subcortical nuclei as well as associated pathways that interconnect regions of the telencephalon, diencephalon and brainstemmodulates hypothalamus whereby influencing functions of endocrine and the ANS
Limbic System |Introduction
Limbic (“border”) SystemFunctions
species preservation self preservation expression of fear, motivation, as well as
memory and learning Structures
AmygdaloidCingulateHippocampal formationMamillary BodiesParahippocampal formationSubcallosalAnterior thalamic nucleus
Limbic System |Hippocampal Formation
Hippocampal FormationIncludes:
HIPPOCAMPUS PROPER (Ammon’s horn/Cornu ammonis)
DENTATE GYRUS PARAHIPPOCAMPAL GYRUS
involved in the consolidation of short-memory into long term memory
Limbic System |Structures
Hippocampal Formation |
Hippocampal Formation |
Hippocampal Formation |
Hippocampal Formation
Hippocampal Formation
Hippocampal Formation and Amygdaloid
Structure |Hippocampal Functions
Hippocampal FormationBoth morphological and functional evidence support the thesis that the hippocampus has no direct relationship with the sense of smell
The hippocampus maybe concerned with recent memory
The hippocampal formation appears to have a role in the expression of emotion
Structure |Functional Significance of the Amygdaloid
Amygdaloid Olfactory senseFear and Anger ResponsesVisceral and Autonomic responsesSomatic ResponsesEndocrine Responses
Structure |Hippocampus and Dentate Group
Points
Cortical structure of the parahippocampal gyrus is six-layered Gradual transition from a six --> three layers as cortex is traced into the hippocampus
MOLECULAR PYRAMIDALPOLYMORPHIC
Dentate gyrus also has three layers, but pyramidal is replaced by GRANULAR
Layers|
Connecting Pathways | Limbic System
Components
ALVEUSFIMBRIAFORNIXMAMMILOTHALAMIC TRACTSTRIA TERMINALIS
Connecting Pathways | Limbic System
Connecting Pathways | Limbic System
Limbic System |Afferent and Efferent Connections
Fibers arising in the CINGULATE GYRUS SEPTAL NUCLEI(nuclei lying within the midline close to the anterior commissure)
pass posterior in the fornix HIPPOCAMPUS pass across the midline to the opposite hippocampus in the commissure of the fornix. INDUSIUM GRISEUM pass posteriorly in
the longitudinal striae ENTORHINAL AREA DENTATE AND PARAHIPPOCAMPAL GYRI
Limbic System |Afferent Connections of the Hippocampus
Fibers pass posterior to the anterior commissure enter the MAMMILLARY BODY, and end in
the MEDIAL NUCLEUS to end in ANTERIOR NUCLEI of the thalamus to enter TEGMENTUM of the midbrain
Fibers pass anterior to the anterior commissure to end in the SEPTAL NUCLEI. LATERAL
PREOPTIC AREA and ANTERIOR PART OF HYPOTHALAMUS
Fibers join the stria medullaris thalami to reach the HABENULAR NUCLEI
Limbic System |Efferent Connections of the hippocampus
Limbic System |Papez Circuit
Hippocampus Alveus Fimbrae Fornix Mamillary bodies Anterior nucleus of thalamus Cingulate gyrus Entorhinal cortex back to Hippocampus
Korsakoff’s psychosisAlzheimer’s diseaseHippocampal ablationAnterograde Amnesia
Disorders of the Limbic System
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System End
To give an introduction of the Limbic SystemTo demonstrate knowledge and understanding of the limbic system by
A.Identifying the structures that comprise the limbic systemB.Enumerating the sources of input and output of the limbic systemC.Describing the major circuit of the limbic system (Papez Circuit)D. Naming disorders involved
Limbic System
BREAK FOR
5 MINUTES
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System Objectives
To give an introduction of the Olfactory SystemDemonstrate knowledge and understanding of the pathways for olfaction by
A.Enumerating the structures that comprise the rhinencephalonB.Stating the receptors for smellC.Tracing the olfactory pathwaysD. Naming some clinical disorders involving olfactory pathways
Olfactory System
RHINENCEPHALON “nose brain” Oldest part of the cerebrum
phylogenetically Has been since subordinated in man to
non-olfactory portions of cerebrum “macrosmatic” vs “microsmatic” Odors generate complex associations of
ideas, images and personal interpretations modified by past experiences
ACTIVATOR and SENSTIZER of other neural systems
Olfactory System | Introduction
RHINENCEPHALON Includes structres that are believed to be
concerned with smell:
OLFACTORY NERVE OLFACTORY BULB OLFACTORY TRACT OLFACTORY STRIAE (medial,
intermediate, and lateral) ANTERIOR OLFACTORY
NUCLEUS(within olfactory bulb, tract and striae)
Olfactory System | Introduction
RHINENCEPHALON Includes structres that are believed to be
concerned with smell: ANTERIOR PERFORATED SUBSTANCE SUBCALLOSAL( or paraolfactory area) ANTERIOR PORTIONS OF THE
PARAHIPPOCAMPAL AREA(including uncus)
HIPPOCAMPAL FORMATION(beneath parahippocampal gyrus)
PREPYRIFORM CORTEX (extending from the olfactory stria to the rostral amygdaloid region)
AMYGDALOID COMPLEX(part)
Olfactory System | Introduction
Olfactory System
Olfactory System
Olfactory System
Olfactory System
Primary Olfactory Cortex – (Area 34)
a. Prepiriform/ Piriform areasb. Periamygdaloid
Secondary Olfactory Cortex – (Area 28)a. Entorrhinal area- association cortex for olfaction; site of overlap between limbic and olfactory systems
* Olfactory afferent pathway – projects directly into the cerebral cortex
Olfactory System | Cortex
Connections are numerous and complex
Pathways for triggering autonomic responses Via the MEDIAL
FOREBRAIN BUNDLE Via STRIA MEDULLARIS Via LIMBIC SYSTEM
Olfactory System | Reflexes
Primary sensory neurons in olfactory epithelium Pass through cribriform plate Synapse on secondary neurons in the olfactory bulb(mitral and tufted cells) Tufted cells synapse in the anterior olfactory nucleus and send projects to all olfactory areas
Mitral cells send collaterals to the anterior olfactory nucleus and project only to the lateral olfactory area Olfactory tract Olfactory trigone Olfactory stria
Olfactory System | Pathway
Medial - Projects to the frontal lobe(medial
olfactory area)- Mediates emotional response to odors and
has connections to the limbic systemIntermediate- Projects to the anterior perforated
substanceLateral- Projects to lateral olfactory area- Important ConnectionsLOS Stria Medullaris HabenulaLOS Pyriform Lobe, prepyriform cortex,
periamygdaloid area, uncus, insula(Primary olfactory complex) Entorhinal complex
Olfactory System | Olfactory Stria
Anosmia CSF Rhinorrhea
Olfactory System | Disorders
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System End
To give an introduction of the Olfactory SystemDemonstrate knowledge and understanding of the pathways for olfaction by
A.Enumerating the structures that comprise the rhinencephalonB.Stating the receptors for smellC.Tracing the olfactory pathwaysD. Naming some clinical disorders involving olfactory pathways
Olfactory System
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System Objectives
Demonstrate knowledge and understanding of the pathway for taste sensation by
A.Describing the receptor for tasteB.Naming the cranial nerves that subserve taste sensationC.Tracing the pathway for taste
Gustatory System
Gustatory System |Taste Receptors
Gustatory System |Taste Receptors
Gustatory System |Afferent Innervation for Taste Sensation
Gustatory System |Taste Pathway
Gustatory System |General Visceral Afferent Innervation
Limbic System
Olfactory System
Gustatory System
Hypothalamus
Hypothalamus, Limbic, Olfactory and Gustatory System End
Demonstrate knowledge and understanding of the pathway for taste sensation by
A.Describing the receptor for tasteB.Naming the cranial nerves that subserve taste sensationC.Tracing the pathway for taste
Gustatory System
ReferencesSnell, R.S. Clinical Neuroanatomy, 7th ed., Lippincott
Williams & Wilkins, 2010.Carague-Lansang, E.N., et al. Lansang Notes: Modules
in Neuroanatomy, 4th ed., UERMMMC: Quezon City, 2006.
Blumenfeld, H. Neuroanatomy through Clinical Cases, 2nd ed., Sinauer Associates, Inc., 2010.
Fisch, A. Neuroanatomy Draw It to Know It, 1st ed., Oxford University Press, 2009.
Netter, F. Atlas of Neuroanatomy and Neurophysiology, 1st ed.,Icon Custom Communication, 2002.
Junquiera, L.C., and Carneiro, J. Basic Histology Text and Atlas, 11th ed., McGraw-Hill Companies. 2007
Patestas, M.A. and Gartner L.P. A Textbook on Neuroanatomy, 1st ed., Blackwell Publishing, 2006
God bless you! To laugh often and much;
to win the respect of intelligent peopleand the affection of children,to leave the world a better place,to know even one life has breathed easierbecause you have lived,this is to have succeeded.- Ralph Waldo Emerson
For in him we live and move and have our being. Acts 17:28