Chapters 19 20 Single

Hypothalamus „

„

Fornix divides it into medial and lateral Medial Regions … Preoptic … Supraoptic … Tuberal … Mamillary

Preoptic Region „

Receives fibers with neuromediators …

„

Angiotensin, sleep-inducing peptides,endorphin, etc

Medial preoptic nucleus …

GrH „ „

…

Sexually dimorphic nucleus „

…

Anterior pituitary via tuberoinfundibular tract Reproduction, eating, locomotion, sexual arousal 2x larger in males

Greater activation in men viewing erotica

Supraoptic Region „

Supraoptic nucleus …

ADH „

Kidney …

…

Diabetes insipidus „

…

Excessive urine

Polydipsia „

…

Increase water retention

Excessive water intake

Blood osmolarity „

Increase = increase ADH

…

Pain, stress, morphine, nicotine, bartbituates = increase ADH … Alcohol = decrease ADH „

…

Increase urination

Axons through stalk to pituitary posterior lobe

Supraoptic Region „

Paraventricular nucleus …

Oxytocin „ „ „

…

„

Contraction of uterus Milk ejection Induce labor [Pitocin]

Axons through stalk to pituitary posterior lobe

Anterior Nucleus …

Thirst center „ „

Stimulate = intake water Tumors in children = refuse to drink regardless of severe dehydration

Supraoptic Region „

Suprachiasmatic nucleus … Regulation „ „ „

of

Sleep-wake cycle Body temperature Circadian rhythm

… Receives

input from retina … Projects to other hypothalamic nuclei „ „ „

Paraventricular Tuberal Ventromedial

Tuberal Region „

Ventromedial nucleus … Satiety … Bilateral „ „ „

„

lesions

Voracious appetite Obesity Savageness

Dorsomedial nucleus …?

Tuberal Region „

Arcuate nucleus … Dopamine … ACTH … Emotional

behavior … Endocrine function … Leptin target for apetite suppresion

Mamillary Region „

Mamillary bodies … Mamillothalamic

„

tract

Posterior nucleus … Output

of hypothalamus to brainstem

Lateral Region „

Medial forebrain bundle … Hypothalamus

„

-> reticular formation

Lateral hypothalamic nucleus … Feeding „

center

Hypocretin neurons …

Project to arcuate nucleus

… Vigilance „

Damage …

Narcolepsy

Hypothalamoneurohypophyseal „

Transports ADH & oxytocin to the neurohypophysis … Fenestrated

capillary bed … Damage to tract results in diabetes insipidus

Tuberoinfundibular Tract Arcuate & Pervientricular nuclei -> infundibular stem [pituitary] „ Releasing factors „

… Modulate

release

anterior lobe pituitary hormone

Afferents „

Retina -> suprachiasmatic nucleus … Circadian

„

Fornix -> mamillary bodies … Limbic

„

system

Amygdala … Emotion

„

rhythm

[negative]

Thalamus … Feedback

mechanism for mamillary bodies

Efferents Descending autonomic fibers „ Blood pressure „ Heart rate „ Temperature regulation „ digestion „

Hypothalamic Functions „

Posterior Pituitary endocrine release … ADH

„

& Oxytocin

Anterior Pituitary control … Releasing

„

factors

Autonomic regulation

Hypothalamic Functions „

Temperature regulation … Thermal

receptors … Heat dissipation „ „ „

Anterior regions Sweating, vascular dilation Damage = hyperthermia

… Heat „ „ „

conservation

Posterior regions Shivering, vascular constriction Damage = poikilothermia …

Body temp fluctuates with environmental temperature ƒ Aka cold-blooded

Hypothalamic Functions „

Emotional Behavior … Central

autonomic nervous system … Lesion ventromedial nucleus „

Rage reaction

… Lesion „

lateral regions

Flight response

… Pleasure

response … Unpleasant response

Hypothalamic Functions „

Feeding Behavior … Satiety

„

Drinking and Thirst … ADH

„

Sleep & Wakefulness … Sleep „

Anterior

… Wake „

center center

Posterior

Hypothalamic Functions „

Circadian Rhythm … Suprachiasmatic

nucleus … Regulates secretion of melatonin by pineal gland „

Memory … Mamillary

„

bodies

Sexual arousal … Preoptic

area