anatomy

Question 1

What are the landmarks that surround the hypothalamus?

Answer 1

Hypothalamic sulcus

anterior sulcus

lamina terminalis

chismatic cistern

optic chiasm

interpeduncular cistern

mammillary body

midbrain mass intermedia

Question 2

What does the 3rd ventricle seperate?

what is the floor of the hypothalmus?

Answer 2

walls of the hypothalmus

The floor of the hypothalamus includes the tuber cinereum and median eminence

Question 3

What are the medial/lateral amd anterior/posterior of the hypothalmus?

Answer 3

medial/lateral- optic tracts

anterior-optic chiasm

posterior- posterior perforated substance

Question 4

hypothalmus with nuclei and tracts?

Answer 4

Question 5

What descends the hypothalmic grey?

Answer 5

the fornix (circled in green)

Question 6

What doe sthe fornix connect?

Answer 6

a large, myelinated limbic fiber bundle that connects hippocampus to mammillary nucleus

Question 7

optic tracts

Answer 7

Question 8

What is a major landmark of the hypothalamus?

Answer 8

Optic Chiasm

Question 9

What does the fornix divide the hypothalamus into?

Answer 9

medial zone

lateral zone

periventricular zone is adjacent to the 3rd ventricle

Question 10

What is lateral to the lateral hypothalamus?

What does it include?

Answer 10

Lateral to lateral hypothalamus is the substantia innominata (part of the general area called the basal forebrain)

Area includes nucleus basalis of Meynert, a major player in cortical function

Question 11

What passes rostrocaudally through the lateral hypothalamic zone?

Answer 11

Medial forebrain bundle

Question 12

What is the hypothalamic nuclei subdivided into?

What lies between the 3rd ventricle and the fornix in the medial hypothalamic zone?

Answer 12

anterior (preoptic)

middle(tuberal)

posterior (mammillary)

Between 3rd ventricle & fornix column are 10 nuclei named for position or shape

Question 13

What nuclei lie in the anterior zone?

Answer 13

5 nuclei: 3 anteriormost named in relation to the optic system

Preoptic nucleus

suprachiasmatic nucleus

supraoptic nucleus

anterior nucleus

paraventricular nucleus

Question 14

What nuclei lie in the middle zone?

Answer 14

3 nuclei

Ventromedial

dorsomedial

arcuate

Question 15

Which nuclei lie in the posterior zone?

Answer 15

2 nuclei

posterior

mammillary

Question 16

Which tract ascends out of the mammillary nucleus?

Answer 16

mammillothalmic tract

Question 17

How does the lateral hypothalmus send and receive fibers?

What is the cousre of the medial forebrain?

Answer 17

Lateral hypothalamus sends and receives fibers via medial forebrain bundle (MFB) as do other parts of the hypothalamus.

MFB courses from forebrain rostrally through brainstem caudally.

Question 18

What is the tubermammillary nucleus of the LHA function for the brain?

Answer 18

part of the brain’s sleep-wake circuitry and is involved in wakefullness (cortical arousal).

Question 19

Where is the only source of orexineergic nuerons in the CNS?

what is the role of orexin?

where does orexin neurons output to?

Answer 19

Lateral hypothalamus is the only source of orexinergic neurons in the CNS.

Neurotransmitter orexin plays a primary role in wakefullness.

Orexin neurons output to other neurotransmitter systems involved in arousal.

Question 20

What is the affect of dysregulatin orexin?

Answer 20

Dysregulation or degeneration of LHA orexin neuron circuits is implicated in excssive sleepiness (hypersomnolence), cataplexy (loss of muscle tone), and narcolepsy (sudden wake to REM sleep-like state).

Question 21

What type of regulation is the lateral hypothalmus involved in?

What is the affect of stimulating the lateral hypothalmus?

What do lesions in the lateral hypothalmus produce?

Answer 21

Lateral hypothalamus is involved in appetite control (regulation of food intake)

stimulation causes hyperphagia

lesion produces anorexia

Question 22

What is the function of the Ventromedial hypothalmus?

What does stimulation of the ventromedial cause?

What does lesions of the ventromedial hypothalmus cause?

Answer 22

LHA in regulation of food intake

Considered a satiety center (deciding when to stop eating)

stimulation inhibits eating (anorexia)

lesion causes overeating (hyperphagia)

Question 23

How does leptin(anorexigenic) and ghrelin (orexigenic) molecules gain acces to the hypothalamic feeding regulation nueral network?

Answer 23

qprobably through the median eminence, one of the leaky-capillaried circumventricular organs (CVO)

Question 24

What is the anterior hypothalamic nucleus regulate?

What does the anterior (preoptic) area have for this regulation?

Answer 24

Anterior hypothalamic nuc. is involved in temperature regulation

anterior (preoptic) area has both cold and heat sensitive neurons (thermostat)

at high blood temperature, regulates mechanisms of heat dissipation

Question 25

What is the posterior hypothalamic nucleus involved in? How does it regulate this?

Answer 25

Posterior hypothalamic nucleus is involved in temperature regulation regulates mechanisms of heat production when blood temp. is low

Question 26

What is the dorsalmedial hypothalamic nucleus involved in? What does stimulation of the dorsalmedial hypothalamic nucleus?

Answer 26

Dorsomedial hypothalamic nuc. is involved in regulating emotion (aggression) Stimulation can elicit defensive-aggressive behaviors (“sham-rage”) in the absence of any contextual elicitors.

Question 27

How does the mammillothalmic tract reach the anterior nucleus?

Answer 27

mamillothalamic tract ascends into and through thalamus to reach anterior nuc.

Question 28

external view of the mammillothalmic tract. large vertically oriented myelinated bundle

Answer 28

Question 29

Which tract is the main regulator ofthe autonomic system?

Answer 29

paraventricular nucleus Projects to both parasympathetic & sympathetic preganglionic neurons via the hypothalmospinal Hypothalamospinal tract lesion effects would include ipsilateral Horner syndrome

Question 31

What is the suprachiasmatic nucleus helps regulate? where does it receive input/output from?

Answer 31

Suprachiasmatic nuc. is involved in regulation of circadian rhythms (≈ 24hr) Receives retinohypothalamic fibers with info about presence/absence of light Output via sympathetic system stimulates pineal to secrete melatonin in the dark

Question 32

What lies on the floor of the 3rd ventricle and what is it continuous with?

Answer 32

infundibulum it is continuous with the pituitary the pituitary is regulated by the hypothalamus

Question 33

What are the cells of the pituitary?

Answer 33

Adenohypophysis is secretory cell rich (dark, cell bodies stained with H&E) Neurohypophysis is axon rich (pale, poorly stained with H&E)

Question 34

What is the median emminance?

Answer 34

The median eminence is a ridge of gray just posterior to the pituitary stalk

Question 35

What is Supraoptic and the paraventricular nucei involved in? How are oxytocin and antidiuretic hormone transported? Where does nerve terminals release these hormones?

Answer 35

in neuroendocrine regulation via posterior pituitary (neurohypophysis; pars nervosa) ## Footnote Oxytocin and antidiuretic hormone (ADH) [argenine vasopressin (AVP)] are transported via supraopticohypophyseal tract axons to posterior pituitary Nerve terminals release hormones near inferior hypophyseal a. capillaries

Question 37

Where does the supraoptic and paraventricular nuclear axons project? What are these projections where does the axon terminals dump oxytocin and ADH?

Answer 37

Supraoptic and paraventricular nuclear axons project to posterior pituitary These projecting neurons are large (magnocellular) Axon terminals dump oxytocin & ADH into space around fenestrated capillaries

Question 38

Where does the stimulus for ADH (to retain water) originate?

Answer 38

from osmolality detecting neurons of the nearby organum vasculosum of the lamina terminalis (OVLT)

Question 39

What role doe the MFB play in oxytocin release?

Answer 39

MFB plays a major role in reproduction by transmitting feedback from cervix (prepartum) and breast (postpartum) to hypothalamus to stimulate oxytocin release

Question 40

What role does the proptic and arcuate nuclei play in neuroendocrine release? where does their axons terminate?

Answer 40

preoptic & arcuate nuclei are involved in neuroendocrine regulation via anterior pituitary (adenohypophysis; pars distalis) Axons terminate near superior hypophyseal a. leaky capillaries in the medial eminence of the infundibulum

Question 41

Where does the preoptic and arcuate axons dump regulatory axons?

Answer 41

preoptic & arcuate axons dump regulatory hormones (trophic [tropic] factors) into portal veins anterior pituitary cells in turn dump hormones into systemic veins

Question 42

The 2 pathways of neuroendocrine integration (parvi- and magno- )

Answer 42