export_hypothalamus

Question 1

What does the hypothalamus do?

Answer 1

Controls visceral, autonomic, endocrine, and emotional function.

Question 2

Where is the hypothalamus located?

Answer 2

It extends from the anterior perforated substance and optic chiasm to the optic tracts and the mamillary bodies.

Question 3

What are the 4 major structures within the hypothalamus

Answer 3

1. Pre-optic area 2. Medial hypothalamic area 3. Lateral hypothalamic area 4. Median eminence

Question 4

Features of the lateral hypothalamic area

Answer 4

Contains the lateral hypothalamic nucleus

Question 5

Features of the median eminence

Answer 5

Funnel like extension of the tuber cinereum. Region where the CNS interacts with the pituitary.

Question 6

Features of the medial hypothalamic area.

Answer 6

The medial hypothalamic area is continuous with the periaqueductal gray. It contains the supraoptic, tuberal and mamillary regions - which correspond to the anterior, middle and posterior regions respectively.

Question 7

Supraoptic region of the hypothalamus.

Answer 7

AKA the anterior region of the medial hypothalamus. Contains the 1. paraventricular and supraoptic nuclei which secrete oxytocin and vasopressin. 2. anterior hypothalamic nucleus. 3. suprachiasmatic nucleus - biologic clock with afferent input from the retinas.

Question 8

Tuberal region of the hypothalamus

Answer 8

Region where the fornix separates the hypothalamus into the medial and lateral positions.

Question 9

Mamillary region

Answer 9

Contains the mamillary bodies and the posterior hypothalamic nuclei.

Question 10

General input to the hypothalamus

Answer 10

1. Pyriform cortex –> amygdala –> stria terminalis –> hypothalamus and hippocampus. 2. Closed loop: CG —> entorhinal cortex –> hippocampus –> hypothalamus –> anterior thalamic nucleus back to the cingulate gyrus.

Question 11

Sources of hypothalamic input

Answer 11

1. Medial forebrain bundle 2. Fornix 3. Stria terminalis 4. Mamillary peduncle 5. Dorsal longitudinal fasciculus 6. Retinohypothalamic tract 7. Nucleus solitarius

Question 12

Medial forebrain bundle

Answer 12

Sends information related to basic emotional drives and smell. From the basal olfactory areas, septal nuclei, periamygdala, and subiculum to the lateral preoptic and lateral hypothalamic areas.

Question 13

Fornix

Answer 13

Brings information from the hippocampus to the mamillary bodies.

Question 14

Stria terminalis

Answer 14

Also brings information related to emotional drive and smell. It arises from the amygdala and travels within the terminal sulcus between the thalamus and the caudate to the anterior and pre-optic nuclei.

Question 15

Mamillary peduncle

Answer 15

Brainstem reticular formation to the lateral mamillary nucleus.

Question 16

Dorsal longitudinal fasciculus

Answer 16

Midbrain’s central gray –> periventricular hypothalamus.

Question 17

Retinohypothalamic tract

Answer 17

Involved in circadian rhythms Runs from the retinal ganglion cells to both suprachiasmatic nuclei.

Question 18

Nucleus solitarius

Answer 18

The rostral portion of the nucleus solitarius is involved in taste and projects fibers to the medial hypothalamus The caudal portion of the nucleus solitarius is involved in visceral sensation and projects fibers to the lateral hypothalamus.

Question 19

What are the major hypothalamic output tracts?

Answer 19

1. Mamillothalamic 2. Dorsal longitudinal fasciculus 3. Medial forebrain bundle 4. Stria terminalis 5. Mamillotegmental tract 6. Descending autonomic projections 7. Supraoptichypophyseal tract 8. Tuberohypophyseal tract

Question 20

Output of the mamillothalamic tract

Answer 20

Mamillary bodies to the anterior thalamic nucleus.

Question 21

Output of the dorsal longitudinal fasciculus

Answer 21

Mamillary bodies to the midbrain tegmentum and central gray.

Question 22

Output of the medial forebrain bundle

Answer 22

Lateral hypothalamus to the hippocampus

Question 23

Output of the stria terminalis

Answer 23

Runs from the hypothalamus to the amygdala

Question 24

Output of the mamillotegmental tract

Answer 24

Mamillary bodies to the midbrain ventral and dorsal tegmentum

Question 25

Output of the descending autonomic projections

Answer 25

Paraventricular, lateral hypothalamic, posterior hypothalamic nuclei to the dorsal motor nucleus of 10, nucleus solitarius, nucleus ambiguous, medulla and the spinal intermediolateral cell column.

Question 26

Output of the supraoptichypophyseal tract

Answer 26

Supraoptic and paraventricular nuclei to the posterior pituitary gland. Leads to the release of the oxytocin, vasopressin, cholecystokinin, enkephalins, and angiotensin.

Question 27

Output of the tuberohypophyseal tract

Answer 27

Arcuate nucleus of the tuber region to the median eminence and the infundibular stem. Releases hormones into the fenestrated capillaries of the portal hypophyseal tract.

Question 28

Seven basic roles of the hypothalamus

Answer 28

1. Parasympathetic -\> anterior and ventromedial hypothalamic nuclei. 2. Sympathetic -\> Posterior and lateral hypothalamic nuclei. 3. Decreases body temperature -\> anterior hypothalamic nuclei 4. Increases body temperature -\> posterior hypothalamic nuclei 5. Satiety center -\> Medial hypothalamic nucleus 6. Feeding center --\> Lateral hypothalamic nucleus 7. Arousal center --\> Posterior hypothalamic nucleus

Question 29

Where is the pituitary gland located

Answer 29

Within the sella turcica of the sphenoid bone

Question 30

Components of the pituitary gland

Answer 30

1. Adenohypophysis 2. Neurohypophysis

Question 31

Features of the adenohypophysis

Answer 31

Represents 75% of the gland and has an ectodermal origin from the roof of the stomodeum. Three components: 1. Pars tuberalis - includes stalk and median eminence of the hypothalamus 2. Pars intermedia 3. Pars distalis - no direct arterial supply

Question 32

Features of the neurohypophysis

Answer 32

Represents 25% of the gland and has a diencephalic origin. Three subcomponents. 1. Pars nervosa 2. Infundibulum 3. Supraoptic and paraventricular nuclei

Question 33

Which arteries contribute to the hypophyseal portal system

Answer 33

The superior and inferior hypophyseal arteries. The superior hypophyseals feed the infundibulum and median eminence. The inferior hypophyseals supply the posterior pituitary lobe.