18 – Thalamus/Hypothalamus Flashcards
What does the forebrain consist of?
-cerebral cortex (cerebrum)
-diencephalon
Diencephalon location:
-stays in midline as during development the cerebral hemispheres grow out from it
What structures are in the diencephalon?
-thalamus
-epithalamus (pineal gland)
-hypothalamus
*anything with “thalamus”
Thalamus contains:
-large number of nuclei (grey matter)
Thalamus role:
-relay and processing centre for info going in/out of the cerebral cortex
*ALL info except the olfactory nerve
-central role in maintaining consciousness
-sleep
Thalamus role and sleep:
-coordinates neuronal firing
>bursting patterns of brain activation are blocked by the thalamus
What are some signs of a lesion in the thalamus?
-altered level of consciousness (ex. more sleepy)
-seizures
-proprioceptive deficits
-UMN signs
-maybe LMN signs for CN II and III
*can press on other structures and getting different issues/signs
Hypothalamus location:
-ventral aspect of the diencephalon
>surrounds the ventral aspect of the 3rd ventricle
What are some physiological, behavioral and hormonal responses to maintain homeostasis that the hypothalamus does?
-thermoregulation
-osmoregulation
-appetite/thirst
-sleep/wake cycles
-endocrine regulation
Hypothalamus role:
-control internal stimuli (increased CO2 and micturition)
>regulation of internal body environment
-coordinates physiological, behavioral, and hormonal responses to maintain HOMEOSTASIS
Hypothalamus lesion consequence to neuroendocrine regulation (oxytocin+ADH):
-abnormal endocrine production=multi-system malfunction
>diabetes insipidus
>Cushing’s (hyperadrenocorticism)
Hypothalamus lesion consequence to regulation for ANS:
-organ dysfunction
-inability to maintain BP
-inability to thermoregulate
Hypothalamus lesion consequences to coordination and production of defensive behaviour: (b/c it’s part of limbic system)
-increase aggression (rage behaviour)
-increase fear
-star-gazing behavior
Ex. rabies causes this so they bite another animal
Hypothalamus lesion consequences to thermoregulation:
*various regions
-heat loss center (hypothermia)
-heat retention center (hyperthermic)
*animals can change their set point
Hypothalamus lesion consequences to osmoregulation and water intake:
-abnormal water consumption
>polydipsia
>adypsia