Hypothalamus

Question 1

What is the major function of the hypothalamus:

Answer 1

Serves to integrate autonomic and endocrine functions with behavior, particularly those behaviors concerning basic homeostatic requirements of everyday life.

Question 2

To which major systems is the hypothalamus functionally related?

Answer 2

1. ANS
2. Endocrine
3. Limbic

Question 3

The hypothalamus forms the walls and floor of the:

Answer 3

3rd ventricle

Question 4

Separates the thalamus from the hypothalamus:

Answer 4

Hypothalamic sulcus

Question 5

Hypothalamus us delimited anteriorly by the ______ and posteriorly by the ______.

Answer 5

Optic chiasm, mammillary bodies.

Question 6

The medial and lateral zones of the hypothalamus are separated by the _______ (ventrally) and ________(dorsally).

Answer 6

Fornix, mammillothalamic tract.

Question 7

The lateral zone of the hypothalamus is transversed by the fibers of the ________.

Answer 7

Medial forebrain bundle.

Question 8

This hypothalamic nuclei induces eating when stimulated, and causes anorexia and starvation when ablated. Contains important peptide NTs that increase food intake.

Answer 8

Lateral hypothalamic area

Question 9

This hypothalamic nucleus contains large neurons that release histamine. Thought to play an important role in attention and arousal, and is actively inhibited during sleep.

Answer 9

Tuberomammillary (lateral tuberal) nucleus.

Question 10

This hypothalamic nucleus houses neurons that regulate gonadotropin secretion from the adenohypophysis. It also contains the interstitial nuclei of the anterior hypothalamus, one of which is sexually dimorphic and developmentally regulated by testosterone.

Answer 10

Medial preoptic nucleus - located within the preoptic region.

Question 11

This hypothalamic nucleus receives direct input from the retina. It plays a critical role in the control of circadian rhythmicity. Lesions result in insomnia.

Answer 11

Suprachiasmatic nucleus

Question 12

This hypothalamic nucleus contains neurons that sense warmth and initiate responses to dissipate excessive heat. Inflammatory cytokines and pyrogens also act here to alter body temperature set points. Bilateral lesions result in hyperthermia.

Answer 12

Anterior hypothalamic nucleus

Question 13

This hypothalamic nucleus contains neurons that synthesize and release AVP, oxytocin, CRH.

Answer 13

Paraventricular nucleus

Question 14

This hypothalamic nucleus contains neurons that synthesize AVP and oxytocin.

Answer 14

Supraoptic nucleus

Question 15

This hypothalamic nucleus is involved in blood pressure regulation. May produce aggression when stimulated.

Answer 15

Dorsomedial nucleus

Question 16

This hypothalamic nucleus inhibits the urge to eat when stimulated.

Answer 16

Ventromedial nucleus

Question 17

This hypothalamic nucleus controls the release (or non-release) of various adenohypophyseal hormones.

Answer 17

Arcuate nucleus

Question 18

This hypothalamic nucleus contains neurons that sense cold and initiate heat conservation/production responses. Bilateral lesions produce poikilothermia (inability to thermoregulate).

Answer 18

Posterior hypothalamic nucleus

Question 19

This hypothalamic nucleus receives a major input from the hippocampus via the fornix. Damage here is associated with memory disturbances due to extensive interconnectivity with the hippocampus.

Answer 19

Mammillary nucleus

Question 20

Function of the fornix:

Answer 20

Fiber tract that connects the mammillary bodies of the hypothalamus to the hippocampus. Also structurally divides the medial zone from the lateral zone.

Question 21

Interconnects the amygdaloid complex with the medial zone of the hypothalamus:

Answer 21

Stria terminalis

Question 22

The most complex fiber pathway in the CNS. Extends throughout the entire lateral hypothalamic zone, interconnecting regions from the septal nuclei to the brainstem.

Answer 22

Medial forebrain bundle.

Question 23

This tract conducts fibers from the supraoptic and PVN to the neurohypophysis. Axons of the large neurons that synthesize either AVP or oxytocin.

Answer 23

Supraopticohypophyseal tract

Question 24

This tract conducts fibers from the arcuate nucleus to the hypophyseal portal system. Axons that carry neuropeptide release or inhibiting factors which act upon anterior pituitary cells.

Answer 24

Tuberoinfundibular tract

Question 25

This tract contains descending axons that regulate spinal cord preganglionic neurons of both sympathetic and parasympathetic divisions of the ANS. Damage here may induce Horner’s syndrome.

Answer 25

Hypothalamospinal tract.

Question 26

What is the role of the hypothalamus in stress responsiveness?

Answer 26

Serves to integrate signaling from different areas of the brain, the input from which varies according to the nature of the stressor, and to produce an appropriately coordinated set of responses involving outflow through autonomic, endocrine, limbic, and other systems.

Question 27

Clinical: child with bitemporal hemianopia, adiposity, diabetes, temperature regulation disturbances, somnolence.

Answer 27

Craniopharyngioma

Question 28

Lesions involving mammillary bodies:

Answer 28

Associated with inability for form new memories for context and time-specific events.

Question 29

Clinical: Adolescent male with hypersomnolence, episodic compusive eating, hypersexual.

Answer 29

Klein-Levin Syndrome

Question 30

Input to the hypothalamus comes through:

Answer 30

Lateral region

Question 31

Output to the hypothalamus goes through:

Answer 31

Periventricular region

Question 32

Outcome of anterior/posterior hypothalamus activation:

Answer 32

Either behavioral or physiological.

Question 33

Function of medial hypothalamus:

Answer 33

Regulates feeding behavior. Lesion causes overeating. Prader-Willi syndrome, craniopharyngioma.

Question 34

Describe lateral medullary syndrome:

Answer 34

Loss of pain and temperature sensation on contralateral body and ipsilateral face.

Most often due to stroke involving PICA.

Question 35

Common things that result in Horner’s syndrome (2):

Answer 35

1. Pancoast tumor (ipsilateral lung and eye constricted)

2. Damage to ICA (ipsilateral side)

Question 36

Major function of PAG:

Answer 36

Implements basic behavior based on safe/threatening environment.