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The Hypothalamus
• General Anatomy– Gross Anatomy– Nuclei – Fiber Connections
• Functional Considerations– Autonomic– The "Four F's"– Other Functions
Gross anatomy of the Hypothalamus
• Gross Anatomy– Median Eminence
• Infundibulum– Pituitary Stalk
• Tuber Cinereum
– Mammilary Bodies
• Five Regions of Nuclei
OpticChiasm
Pons
Regions of the Hypothalamus
• Anterior Region
• Medial Region
• Lateral Region
• Infundibular Region– Tuberal
• Posterior Region
Nuclei of the Hypothalamus• Anterior Hypothalamus
– Preoptic
– Suprachiasmatic
• Medial Hypothalamus– Ventromedial Nucleus
– Supraoptic
– Paraventricular
• Lateral Hypothalamus– Lateral Nuclei– Medial Forebrain
Bundle (fibers)http://www.hms.harvard.edu/research/brain/atlas.html
Nuclei of the Hypothalamus
• Infundibular Hypothalamus– Tuberal Nuclei
• Posterior Hypothalamus– Posterior Nuclei– Mammilary Body Nuclei
How do these nuclei connect?
http://www-medlib.med.utah.edu/kw/sol/sss/mml/sol02273.jpg
Inputs to the Hypothalamus• Ascending
– Spinal Cord Direct– Via Reticular Formation– Sensory Cranial Nerves
• Descending– Hippocampus (via Fornix)– Amygdala (via Stria terminalis and
Amygdalo-hypothalamic tract)
– Septal Nuclei (via MFB)– Accumbens (via MFB)
Hypothalamus
Spinal CordCranial Nerves
Reticular Nuclei
Hippocampus
Septal
Amygdala
NAcs
What are the main output of the hypothalamus (neuronal or
other)? Which are ascending and which are descending?
Descending Outputs of the Hypothalamus
• Spinal Cord– Hypothalamospinal tract
– Sympathetic - Lateral Horn
– Somatic - Ventral Horn
• Cranial Nerve Nuclei – Parasympathetic
– Somatic
• Reticular Formation• Pituitary Gland
– Endocrine System
Hypothalamus
Spinal Cord
Reticular Nuclei
Cranial MotorNuclei
Brainstem
Ascending Outputs of the Hypothalamus
• Mammilothalamic Tract• Anterior Thalamus
• Medial Forebrain Bundle– Septal Nuclei– Nucleus Accumbens– Cerebral Cortex
(Orbitofrontal)
Cerebral Cortex
Ant Thal
Hypothalamus
Septal
NAcs
MFB
MTT
Functions of the Hypothalamus
• The Classic Autonomic Control
• The Four Fs
• A Laundry List of Functions
Functions of the Hypothalamus I
• Controls Autonomic Nervous System– Anterior Stimulation elicits parasympathetic
responses– Posterior Stimulation elicits sympathetic responses– Lesion Effects
• Damage to Hypothalamospinal Tract in Lateral Medulla– Horner’s Syndrome
Feeding Disorders
• Hyperphagia – Ventromedial Nucleus
• Aphagia – Lateral Hypothalamus
• Water Consumption Regulation – Adipsia and Polydipsia
Fighting and Fleeing
• Sham Rage - Undirected Agression– Damage to Descending Hypothalamic Inputs
produces Sham Rage– Hypothalamus produces rage, Cortex Controls it
• Affective Disorders– Fear and Phobia
Reproductive Behaviors
• Anterior Hypothalamus "Sex Center"– Lesions Reduce Drive– Stimulation - Hypersexuality– Control of Sex Hormones
• Sexual Dimorphism
Functions of Hypothalamus III• Motivation
– Self-Stimulation
• Memory– Korsakov’s Syndrome
• Temperature Regulation
• Circadian (etc.) Rhythms– Suprachiasmatic Nucleus
• Pituitary Control
Pituitary Control• Endocrine Hormone Regulation
– Made in Hypothalamus • Vasopressin(ADH), Oxytocin
– Made in Pituitary• Somatotropin, Somatostatin, ACTH, FSH, etc.
• Pituitary Gland– Posterior Lobe
• Hypothalamic Axons Only
– Anterior Lobes• True Gland Cells
Pituitary Posterior Lobe
• Nuclei– Supraoptic – Paraventricular Nuclei
• Hormones– Oxytocin– Vasopressin/Antidiuretic
Hormone (ADH)
• Direct Release into Blood System
Pituitary Anterior Lobe• Tuberal Nuclei (et. al.)
– Releasing Factor Peptides• GH-RF
• TSH - RF
• Etc
• Portal Capillary System• Anterior Lobe Gland Cells
– Hormone Proteins• GH
• TSH
• Etc