23.3 Hypothalamus Flashcards
What are the neural connections via the large fibre bundles?
Largely reciprocal.
What foetal structure is the hypothalamus derived from?
Diencephalon
How does the hypothalamus relate to the ventricular system?
Forms floor and ventral walls of 3rd ventricle.
Draw the position of the hypothalamus in the brain.
What are the main parts of the hypothalamus?
- Anterior -> Divided into the chiasmatic and tuberal
- Posterior
What are the main nuclei of the hypothalamus that you need to know?
- Suprachiasmatic nucleus
- Anterior hypothalamus
- Posterior hypothalamic area
- Supraoptic/paraventricular nucleus
- Median eminence/arcuate nucleus/paraventricular nucleus
- Ventromedial nucleus
- Lateral hypothalamus
- Mammillary body
Label the hypothalamic nuclei.
Label the hypothalamic nuclei.
Summarise the physiological functions of the hypothalamus.
- Maintaining internal environment:
- Temperature control
- Reproductive functions
- Biological clock
- Control of blood flow
- Behaviour
- Memory
What are the two ways in which the hypothalamus can carry out its functions?
- Regulation of the autonomic nervous system
- Release of hormones (neuro-endocrine)
What things does the hypothalamus detect and how?
- Blood osmolarity
- Blood nutrient levels
- Blood hormone levels
- Blood temperature
It detects this directly (using neurons that are sensitive to these things) and indirectly (using input from peripheral receptors and other parts of the brain that are sensitive to these factors).
What does the hypothalamus receive input from?
[IMPORTANT]
- Sensory systems
- Retina
- Olfactory system
- Cutaneous receptors
- Visceral receptors
- Higher centres
- Hippocampal formation
- Amygdala
- Orbitofrontal cortex
- Brainstem nuclei
- Locus coeruleus
- Raphe
- Periaqueductal grey
Via what does the hypothalamus receive visceral sensory input?
[IMPORTANT]
Reticular formation and solitary tract
What parts of the brainstem does the hypothalamus receive input from?
[IMPORTANT]
- Raphe nucleus
- Periaqueductal grey
- Locus coerulus
Via what does the hypothalamus receive input from the orbitofrontal cortex?
[IMPORTANT]
Mediodorsal thalamus
What does the hypothalamus output to?
[IMPORTANT]
- Thalamus
- Anterior pituitary (via portal stream)
- Posterior pituitary (just passing through)
- Brainstem parts:
- Amygdala
- Periaqueductal grey
- Others
What are the main large fibre bundles that connect the hypothalamus? Where do they go?
[IMPORTANT]
- Fornix -> From the hippocampus to the mammillary bodies
- Stria terminalis -> From amygdala to the medial thalamus
- Mammillothalamic tract -> From the mammillary bodies to the dorsal tegmental nuclei, the ventral tegmental nuclei, and the anterior thalamic nuclei
- Medial forebrain bundle -> From anterior nuclei to the midbrain, and vice versa
Fornix Function
Carries information from the hippocampus to the mammillary bodies of the hypothalamus.
(Shown in red)