Neuro Block 4 Week 2

Front 1

What are the 3 subdivisions of the hypothalamus

Back 1

Lateral
Medial
Periventricular

Front 2

What structure passes through the lateral zone of the hypothalamus?

Back 2

Medial Forebrain bundle

Front 3

What are the 3 nuclei associated with the lateral zone?

Back 3

Lateral Preoptic nucleus
Lateral Hypothalamic nucleus
Lateral Tuberal Nucleus/Tuberomamillary Nucleus

Front 4

What is the function of the lateral preoptic nucleus?

Back 4

Lateral preoptic nucleus is the most anterior, developmentally from the telencephalon,has no significant function

Front 5

What is the function of the lateral hypothalamic nucleus?

Back 5

• Lateral Hypothalamic Nucleus induces hunger and eating. Ablation causes anorexia and starvation.

Front 6

What is the function of the lateral tuberal nucleus/ tuberomammilary nucleus?

Back 6

These neurons release histamine, axons projecting to the forebrain, important in arousal and attention (Inhibited when sleep is needed).

Front 7

What are the 4 groups of nuclei within the medial zone of the hypothalamus?

Back 7

Preoptic area,
Supraoptic area
Tuberal area,
Mammillary area (Posterior)

Front 8

What are the nuclei associated with the preoptic area?

Back 8

Medial pre-optic nucleus (telencephalon)

Front 9

What are the nuclei associated with the supraoptic area?

Back 9

Suprachiasmatic nucleus
Anterior Hypothalamic area
Paraventricular Nucleus
Supraoptic nucleus

Front 10

What are the nuclei associated with the tuberal (middle area)

Back 10

Dorsomedial nucleus
Ventromedial nucleus
Arcuate nucleus

Front 11

What are the nuclei associated with the mammillary (posterior) area

Back 11

Posterior nucleus
Mammillary nucleus

Front 12

What is the function of the medial preoptic nucleus?

Back 12

Regulates GnRH
 Interstitial Nuclei - regulated by testosterone
 Sexually dimorphic nuclei

Front 13

What is the function of the suprachiasmatic nucleus?

Back 13

Functions in circadian rhythm. Takes input from the retina; has melatonin receptors.

Front 14

What is the function of the anterior hypothalamic area?

Back 14

 Temperature regulation (warmth)
 Dissipates heat
 Lesion (bilaterally) leads to Hyperthermia
 Also, may stimulate PSNS

Front 15

What is the function of the paraventricular nucleus?

Back 15

 Directs neuropeptide release (CRH, Oxytocin and ADH (vasopressin))

Front 16

What is the function of supraoptic nucleus?

Back 16

 Synthesizes oxytocin and ADH
 Project to the Posterior Pituitary (neurohypophysis)
 Release hormones into the circulation

Front 17

What is the function of the dorsomedial nucleus?

Back 17

Aggression and savage behavior

Front 18

What is the function of the ventromedial nucleus?

Back 18

 Satiety center (works with lateral hypothalamic area for fullness vs eating)
 Inhibit eating

Front 19

What is the function of the arcuate nucleus?

Back 19

 Projects through the median eminence into the portal circulation
 Controls the release of hormones from adenohypophysis
 hypothalamic-releasing & -inhibiting factor neurons
 Important for feeding, growth, sex cycles

Front 20

What is the function of the posterior nucleus?

Back 20

 Thermal regulation (cold)
 Bilateral lesion results in poikilothermia (inability to regulate temperature at all) d/t destruction of cold sensing neurons’ cell bodies and axons of the anterior hypothalamus nuclei’s warm sensing neurons)

Front 21

What is the function of the Mammillary Nucleus?

Back 21

 Limbic function
 Input from the hippocampus through the fornix
 Input to the thalamus (anterior nucleus) through the mammillothalamic tract

Front 22

What are the functions of the Periventricular Zone?

Back 22

• Periventricular Nucleus
o Lines the walls of the 3rd ventricle

Front 23

Describe the fornix and mammilothalamic tract

Back 23

Hippocampus -> fornix -> mamillary bodies -> mammilothalamic tract -> anterior nucleus of thalamus

Front 24

Describe the stria terminalis tract

Back 24

Amygdala -> stria terminalis -> hypothalamus -> medial zone (dorsomedial nucleus)

Front 25

Describe the Medial forebrain bundle tract

Back 25

50 parts
• Septal nucleus <-[Medial Forebrain Bundle] ->(lateral hypothalamus zone) <-[Medial Forebrain Bundle] ->Brainstem
• Extends through the entire lateral zone from rostral to caudal
• Interconnects regions through the septal nuclei

Front 26

Describe the Supraopticohypophyseal tract.

Back 26

• Supraoptic and Paraventricular Nuclei  [SOHT]  Neurohypophysis (posterior pituitary)
• Axon terminals release oxytocin and ADH

Front 27

Describe the
-Tuberoinfundibular Tract

Back 27

• Arcuate nucleus [TIT] Hypophyseal portal system @ median eminence, i.e. the adenohypophysis
• TIT releases hypothalamic releasing hormones into portal system

Front 28

Describe the Hypothalamospinal Tract

Back 28

• Hypothalamus ->[HTST] -> spinal cord -> SNS & PNS
• Descending axons drive the parasympathetic and sympathetic drives

Front 29

What are the functions of the hypothalamus?

Back 29

• Body Temperature
• Feeding & Energy Metabolism
• Emergency responses to Stress
• Blood pressure and electrolyte composition
• Reproductive functions

Front 30

How does thermoregulation occur with respect to the Anterior hypothalamic nucleus?

Back 30

o Heat sensitive neurons
o Heat triggers cooling by activating parasympathetics (vasodilation) and inhibiting SNS – at sufficiently intense heat ->activation of SNS cholinergic neurons innervating sweat glands and sweating to dissipate heat ensues
o Lesion results in hyperthermia (can't cool down)
o Disease - pyroges and cytokines increase set point (fever)

Front 31

How does thermoregulation occur with respect to the Posterior nucleus?

Back 31

-Cold Sensitive neurons trigger heat conservation via sympathetic (shivering, etc)
-Activates thyroid via TSH to increase metabolism
-Bilateal lesion->poikilothermia
*Lose cold sensitive neurons and warm sensitive neuron projections descending to the brainstem

Front 32

How does stress regulation occur with regards to the hypothalamus?

Back 32

• Fight or Flight – Sympathetic activation & Parasympathetic inhibition
o Norepinephrine & Epinephrine released from the adrenal medulla
o Activation of HPA axis
 Stimulates a release of glucocorticoids (cortisol) from the adrenal cortex
o Latency in epinephrine rush after stimulation
• Stress input/Afferent Regulation from: Prefrontal Cortex, Limbic System (hippocampus/amygdala), & Brainstem
o all project to the hypothalamus, integration between system occurs and an appropriate response is devised.

Front 33

How does feeding/energy metabolism occur with regards to the hypothalamus?

Back 33

• Lateral Hypothalamic Area - feeding
• Ventromedial Nucleus - satiety
• Arcuate Nucleus
o POMC/CART neurons - stimulate decreased feeding and increased metabolism
 Release a-MSH
 Stimulated by leptin
o AgRP/NPY neurons - stimulate increased feeding and decreased metabolism
 Stimulated by ghrelin
 Inhibited by PPY and leptin
o Outputs from both are integrated at the Nucleus Tractus Solitarius (NTS) at the brainstem
o Ghrelin = stimulates feeding
o PPY & Leptin = inhibits feeding

Front 34

What symptoms would you see with a craniopharyngioma?

Back 34

• Congenital tumor from remanants of Rathke's Pouch
• Most common supratentorial tumor in children
• **Pressure of the optic chiasm ->bitemporal hemianopsia
• Hypothalamic Syndrome
o Adiposity = arcuate nucleus (loss of releasing hormones’ regulation on pituitary hormones)
o Central Diabetes Inspidus = SON & PVN (loss of Vasopressin)
o Tempature regulation disturbances = anterior and posterior hypothalamus
o Somnolence = tuberomammillary nuc (inhibited H2 release -> no arousal)

Front 35

Disturbances in memory can be related to lesions in which hypothalamic nuclei?

Back 35

• Posterior hypothalamic nuclei ->involves mammillary complex asso with inability to form new memories (episodic) for content & time specific events

Front 36

What is Kleine-Levin Syndrome?

Back 36

• Hypothalamic lesion in adolescent males
• Produces:
o Episodic compulsive eating
o Hypersomnolence
o Hypersexuality
• May results from decreased DA tone during symptomatic phase of the syndrome

Front 37

What symptoms would you see with lesions to the following nuclei of the hypothalamus?
-suprachiasmatic nucleus

Back 37

suprachiasmatic nucleus – regulates circadian rhythm
• Lesion = Insomnia - can treat with melatonin

Front 38

What symptoms would you see with lesions to the following nuclei of the hypothalamus?
-anterior nucleus

Back 38

anterior nucleus – senses warmth & dissipates heat
• Lesion = Hyperthermia

Front 39

What symptoms would you see with lesions to the following nuclei of the hypothalamus?
-posterior nucleus

Back 39

posterior nucleus – senses cold & conserves heat
• Poikilothermia (d/t anterior nucleus axons being damaged too)

Front 40

What symptoms would you see with lesions to the following nuclei of the hypothalamus?
--lateral hypothalamus

Back 40

lateral hypothalamus – stimulate feeding and appetite; “lateral hypothalamus makes you grow laterally”
• Weight loss, loss of appetite

Front 41

What symptoms would you see with lesions to the following nuclei of the hypothalamus?
-medial hypothalamus

Back 41

medial hypothalamus – satiety/inhibition of appetite via ventromedial nucleus
• Weight gain
• Prader-Willi syndrome - insatiable hunger/chronic feeling of hunger; d/t partial chromosome 15q deletion

Front 42

What are the prominent symptoms found in a spinal cord lesion?

Back 42

• Weakness and/or sensory loss
• GI symptoms
o constipation (decreased frequency due to decreased motility)
o stool retention (which is a sphincter problem)
• GU symptoms
o urgency or incontinence (or both)
o Normal urinary control needs sympathetic and parasympathics
• Sexual Side Effect
o erectile dysfunction

Front 43

What is the cause of Autonomic Bowel Dysfunction, i.e. Hirschsprungs? What is the primary symptom?

Back 43

• Failure of neural crest to migrate into the distal colon leads to absence of myenteric plexus ganglion cells
• Results in colon dilatation and over distention, hypertrophies
• Also see problems in other organs d/t failed migration

Front 44

What are the causes of Autonomic Bladder Dysfunction? How can they each be treated?

Back 44

• Hyperactive bladder (PSNS overactive) or Underactive Sphincter (SNS underactive)
o Treat with anticholinergic to relax bladder wall


• Hypoactive bladder (PSNS underactive) or Hyperactive Sphincter (SNS overactive)
o Treat with anti-adrenergic to relax the sphincter or self-catheter

Front 45

What are the ANS pathways involved in papillary constriction and dilation?

Back 45

• Sympathetic: causes dilation
o Tectospinal tract ->Pre-ganglionic fibers ->Superior Cervical Ganglion Post-ganglionic fibers ->Internal Carotid Plexus ->Dilator Pupillae Muscle and Levator Palpibrae
o Post-ganglionic fibers also go to the External Carotid Plexus ->Facial Sweating
• Parasympathetic: causes constriction
o Edinger-Westphal Nucleus ->CN III (dorsal aspect)-> Sphincter Pupillae and Ciliary muscles of lens

Front 46

What are the 3 major signs/symptoms of Horner’s Syndrome?

Back 46

= Ipsilateral Sympathetic Lesion
• Ptosis
• Miosis
• Anhydrosis

Front 47

What is the difference between True and Partial Horner’s? Where do the lesions occur that produce them each?

Back 47

• True Horner’s:
o Lesion must occur BEFORE the post-ganglionic fibers separate onto the internal and external plexuses
o Example: Pancoast tumor (i.e. apical lung tumor) compressing sympathetic chain, more common on right side
• Partial Horner’s:
o Lesion at the internal carotid plexus
o Oculosympathetic palsy = only get ptosis and miosis (NO ANHYDROSIS)
• SNS innervation carrying sweating travels on external carotid artery

Front 48

What is anisocoria caused by? How can the 2 causes be distinguished?

Back 48

• = asymmetrical pupil
• d/t:
o 1) PSNS lesion -> dilation in affected eye since sympathetic unopposed
o 2) SNS lesion -> constriction in affected eye since parasympathetic unopposed
• ddx based on observation of both pupils in light & darkness