Diencephalon and Brainstem Flashcards
What is the only visible surface of the diencephalon
The Inferior surface
The thalamus is a sensory relay system except for
Olfaction
The right and left thalamus communicate via the
Interthalamic adhesion
Boundaries of the thalamus
- Medial
- Lateral
- Inferior
- Superior
- Anterior
- Posterior
- Wall of the 3rd ventricle
- Against wall of internal capsule
- Continuous with the tegmentum
- Small layer of white matter
- Posterior boundary of the inter ventricular foramen, which is where CSF flows from the lateral ventricle to the 3rd ventricle.
- Pulvinar (overhangs the superior colliculus)
What divides the thalamus into three divisions?
The internal medullary lamina. White matter.
3 divisions of important nuclei in the thalamus
- Anterior superior
- Medial posterior
- Lateral posterior
- Ventral tier
- Dorsal tear
What is the role of the anterior superior portion of the thalamus
Projects to the cingulate gyrus apart of the limbic system. Plays a role in short term memory and emotion.
What is the role of the medial posterior portion of the thalamus
Contains numerous nuclei that are involved with integration of somatic, olfactory and visceral information and their relations to emotions. This portion is the closest to the third ventricle.
What are the two branches of the lateral posterior division of the thalamus?
- Ventral tier
- Ventral anterior projects to the secondary motor cortex and the ventral lateral nuclei projects to the primary motor cortex.
- Ventral posterior projects to the somatosensory cortex. - Dorsal tier
- LGN to optic radiations then primary visual cortex
- MGN gathers auditory info from contralateral ear and sends to auditory cortex.
- Pulvinar is related to visual attention. Unclear on specifics.
The sub thalamus is known for?
What does it contain?
Fine motor controls. it contains many nuclei and cranial ends of the substantia nigra and red nucleus.
The sub thalamus is located between which two structures
The thalamus and the midbrain.
Epithalamus is located near the
posterior thalamus (by the pulvinar end)
Epithalamus contains which two structures
The pineal gland (secretes melatonin in response to detection of light by the retina)
The habenular nucleus. Connects the R and L nuclei with commissural fibers. Integration center for olfaction, visceral and somatic afferent integration.
Hypothalamus role
Afferent- Any afferent signal, anywhere in the body, can go to the hypothalamus.
Efferent- Major output to parasympathetic, sympathetic, thalamus, limbic system, reticular formation (consciousness)
Other- Hormones and blood via the pituitary.
You could compare which structure in the diencephalon to the vagus nerve
The hypothalamus. wants to be involved with everything
The pineal gland is connected to the retina via the
Midbrain.
Pinealocytes
Endocrine cells that secrete inhibitory substances (melatonin when retina senses darkness). Melatonin goes to pituitary gland and slows production of hormones.
Efferent connections from the hypothalamus to the pituitary gland. Why is this a special connection?
Because the hypothalamus communicates with both, the posterior and anterior portions of the pituitary gland.
Hypothalamus to posterior lobe by the infundibulum
Hypothalamus to anterior lobe by bloodstream through the hypothalamic-hypophyseal portal system.
What is the role of the hypothalamus
Essential for life. Controls homeostasis via the autonomic NS and endocrine system and influences emotional behavior.
Almost all bodily functions are influenced by the hypothalamus.
- Eating
- Emotion
- Circadian rhythms
- Temperature
The brainstem is divided into which 2 divisions
- The hindbrain/rhombencephalon- Metencephalon (pons) and myelencephalon (medulla)
- Mesencephalon/midbrain
The medulla is bound inferiorly by the __ and superiorly by the ___
Spinal cord
Pons
Anterior surface of the medulla contains which 3 main structures
Contains 2 pyramids (contain corticospinal tract fibers) which are divided by the anterior median fissure.
At the inferior end of the pyramids, there is a crossing over of the fibers, called the decussation of the pyramid.
On either side of the pyramids, there is an olive, which contain olivary nuclei.
The superior part of the posterior medulla makes up the floor of
the 4th ventricle
What structure connects the brainstem to the cerebellum?
The brainstem is connected to the cerebellum by the middle cerebellar peduncles. On the lateral surface of the pons.