4. Forebrain Flashcards
forebrain: define
refers to cerebellar hemispheres & diencephalon
(aka prosencephalon)
what are the 3 components in the diencephalon?
- thalamus
- hypothalamus
- epithalamus
thalamus: function
- major relay for sensory information to the cortex (except olfaction) & between cortical structures
- “egg shaped” bunch of nuclei; many discrete nuclei, diff’t nuclei receive diff’t modality information
- part of diencephalon
hypothalamus: function
regulates homeostasis and influences hormone release
epithalamus: function
influences sleep and wakefulness thru pineal gland
(posterior aspect of diencephalon)
what sensory info does NOT pass through thalamus?
The olfactory nerve (CN 1) travels directly to the frontal lobe through the cribriform plate
- this is the only sense that does not travel to the thalamus before accessing the forebrain.
thalamus:
processes involved
- perception
- timing
- attention
- alertness
- movement
- awareness
- consciousness
how are thalamic nuclei organized/arraged?
in 5 diff’t groups
- anterior
- medial
- ventral
- lateral
- posterior
Cranial nerve 1:
- key characteristics/actions
- sensory/motor
- innervates…
- clinical sign
- only sensory info that goes directly to nuclei in cortex (not thru thalamus)
- SENSORY ONLY
- inn. nasal mucosa to contribute to olfaction/sense of smell
- CC: impaired sense of smell
pathway of sensory info from olfaction
olfactory nerves in nose –> through cribriform plate –>
olfactory bulb –> olfactory tract –> nuclei in cortex
cranial nerve 2
- key characteristics/actions
- sensory/motor
- innervates…
- clinical sign
- optic nerve; originates in RETINA
- SENSORY ONLY
- contributes to vision
- CC: blindness in all or part of visual field
course of optic nerve
retina, where optic nerve originates –>
through optic chiasm –>
optic tract –>
thalamus?
optic chiasm
x-shaped structure where some fibers of optic nerve cross and innervate structures on contralateral side; some continue on and innervate ipsilateral side
hypothalamus: define
group of small nuclei
rostral to brainstem
hypothalamus: how does it regulate homeostasis?
- influences pituitary gland
- regulates food/water intake
- regulates sleep/wake cycle
- regulates Parasymp and symp nervous systems
KEY CONCEPT: hypothalamus has several discrete nuclei involved in homeostatic functions
many discrete nuclei involved in homeostatic functions