Hypothalamus

Question 1

What is the function of the hypothalamus in general?

Answer 1

It controls the autonomic nervous system and the endocrine nervous system by influencing the pituitary gland, thereby indirectly controlling the body’s homeostasis.

Question 2

What are the borders of the hypothalamus?

Answer 2

It extends from the optic chiasma anteriorly to the caudal border of the mamillary bodies.

Relations:
1. Anteriorly: optic chiasma
2. Posteriorly: mamillary bodies
3. Laterally: internal capsule
4. Inferiorly (ant. To post.): optic chiasma, tuber cinereum, infundibulum, mamillary bodies.

Question 3

What are the nuclei found in the medial zone?

Answer 3

From ant. To post.:
1. Part of the pre optic nucleus
2. Anterior nucleus (assoc. with the pre optic nucleus)
3. Suprachiasmatic nucleus
4. Paraventricular nucleus
5. Dorsal medial nucleus
6. Ventral medial nucleus
7. Infundibular (Arcuate) nucleus
8. Posterior nucleus

Question 4

What are the nuclei found in the lateral zone?

Answer 4

From ant. To post.:
1. Part of the pre optic nucleus
2. Part of the suprachiasmatic nucleus
3. Supraoptic nucleus
4. Lateral nucleus
5. Tuberomamillary nucleus
6. Lateral tuberal nuclei.

Question 5

How does the hypothalamus receive and send its information?

Answer 5

By three routes:
1. Nervous connections
2. Blood stream
3. CSF

Question 6

What are the afferent connections of the hypothalamus?

Answer 6

1. Somatic & visceral afferents (sensory): they carry somatic and gustatory & visceral sensations to the hypothalamus

Collateral branches of lemniscal afferent fibers and tractus solitaries and the reticular formation

2. Visual Afferent fibers:
   Optic chiasm —> suprachiasmatic nucleus
3. Olfactory Afferent fibers: medial forebrain bundle
4. Auditory afferent fibers: haven’t been identified yet but they have to exist since auditory stimuli can influence the activities of the hypothalamus
5. Cortico-thalamic fibers:
   Frontal lobe of cerebral cortex —> hypothalamus
6. Hippocampo-hypothalamic fibers:
   Hippocampus —> fornix —> mammillary bodies —> hypothalamus
7. Amygdalo-hypothalamic fibers:
   Amygdala complex —> stria terminalis —> below the lenticular nucleus —> hypothalamus
8. Thalamo-hypothalamic fibers:
   Dorsomedial and midline thalamic nuclei —> hypothalamus
9. Regimental fibers:

Midbrain —> hypothalamus