Hypothalamus

Question 1

what is the median eminence?

Answer 1

anterior portion of infundibulum where hypothalamic neurons release regulatory factors carried by the portal vessels to anterior pituitary (“adenohypophysis”)

Question 2

what are mammillary bodies?

Answer 2

paired structures that are functionally part of the limbic system

Question 3

medial and lateral zones of the hypothalamus are separated by what ventrally and what dorsally?

Answer 3

ventrally: fornix
dorsally: mammillothalamic tract

Question 4

name three major nuclei of lateral zone of hypothalamus, from anterior to posterior

Answer 4

lateral preoptic nucleus, lateral hypothalamic area, lateral tuberal (tuberomammillary) nucleus

Question 5

function of lateral hypothalamic area

Answer 5

• induces eating when stimulated
• ablation causes anorexia and starvation
• contain neurotransmitters that increase food intake

Question 6

function of lateral tuberal (tuberomammillary) nucleus

Answer 6

• releases histamine to forebrain

- involved in attention and arousal, actively inhibited during sleep

Question 7

function of suprachiasmatic nucleus

Answer 7

• circadian rhythmicity

- lesion causes insomnia

Question 8

function of anterior hypothalamic nucleus

Answer 8

• temperature regulation, sense warmth and dissipate excessive heat by activating parasympathetic nervous system
• bilateral lesions –> hyperthermia

Question 9

function of paraventricular nucleus

Answer 9

synthesis and release of AVP, oxytocin, CRH

Question 10

function of supraoptic nucleus

Answer 10

synthesis of AVP and oxytocin

Question 11

function of dorsomedial nucleus

Answer 11

blood pressure regulation

Question 12

function of ventromedial nucleus

Answer 12

inhibits urge to eat, relays ingestion-related signals to brainstem

Question 13

function of arcuate nucleus

Answer 13

• controls release of adenohypophyseal hormones
• produce hypothalamic-releasing and inhibiting factors
• plays a role in feeding behavior

Question 14

function of posterior nucleus

Answer 14

• thermoregulation, sense cold and initiate heat conservation/production via sympathetic outflow
• bilateral lesions –> poikilothermia (inability tor thermoregulate)

Question 15

function of mammillary nucleus

Answer 15

• receives input from hippocampus via fornix

- project to anterior nucleus of thalamus via mammillothalamic tract

Question 16

fornix is a tract between what?

Answer 16

mammillary bodies and hippocampus

Question 17

mammilothalamic tract is a tract between what?

Answer 17

mammillary bodies and anterior nucleus of thalamus

Question 18

stria terminalis is a tract between what?

Answer 18

amygdala and hypothalamus

Question 19

medial forebrain bundle is a tract between what?

Answer 19

septal nuclei and brainstem

Question 20

supraopticohypophyseal tract is a tract between what?

Answer 20

hypothalamus and neurohypophysis

Question 21

tuberoinfundibular tract is a tract between what?

Answer 21

arcuate nucleus and hypophyseal portal system at the median eminence

Question 22

function of hypothalamospinal tract

Answer 22

regulate spinal cord preganglionic neurons of both sympathetic and parasympathetic nervous system

Question 23

neuropeptides that signal increased feeding and concomitant decrease in metabolism

Answer 23

AgRP (agouti-related peptide) and neuropeptide Y

Question 24

neuropeptides that signal decreased feeding and concomitant increase in metabolism

Answer 24

alphaMSH and CART

Question 25

nucleus that acts as satiety center

Answer 25

NTS (nucleus of the solitary tract)

Question 26

ghrelin

Answer 26

hormone released from stomach prior to a meal to stimulate feeding

Question 27

PPY (polypeptide Y)

Answer 27

hormone released from GI tract immediately following a meal to inhibit feeding

Question 28

what does CCK release from the GI tract do?

Answer 28

produces satiety at the NTS level

Question 29

leptin

Answer 29

released by fat cells to signal a decrease in feeding (inhibits AgRP/NPY neurons and stimulates alphaMSH/CART neurons)

Question 30

orexin

Answer 30

hypothalamic hormone that induces feeding

Question 31

MCH (melanin-concentrating hormone)

Answer 31

hypothalamic hormone that induces feeding

Question 32

craniopharyngioma

Answer 32

- pressure on optic chiasm --> bitemporal hemianopsia - pressure on hypothalamus --> hypothalamic syndrome (adiposity, diabetes insipidus, temperature regulation disturbances, somnolence)

Question 33

inability to form new memories is a sign of a lesion where?

Answer 33

posterior hypothalamic lesion involving mammillary bodies

Question 34

Klein-Levin syndrome

Answer 34

- primarily in adolescent males - hypersomnolence - episodic compulsive eating - hypersexuality - decrease in dopaminergic tone