Please enable JavaScript.
Coggle requires JavaScript to display documents.
NS 34 - Limbic System + Hypothalamus (i) (Limbic system (hippocampus…
NS 34 - Limbic System + Hypothalamus (i)
levels of processing
lowest = hypothal (homeostasis based on int inputs
limbic system (societal homeostasis, based on ext inputs @ basic primitive survival level)
highest = associated neocortices (societal homeostasis based on religion, society, culture etc -> refines behaviour appropriately)
septum pellucidum
separates lat ventricles
hangs off corpus callosum
attaches to upper fornix
Hypothal
integrates signal from int organs + fluid-filled cavities
part of diencephalon
functions: fluid-electrolyte balance, food ingestion, thermoregulation, reproduction, immune response, circadian rhythms, regulates ANS (hence emotional responses)
2 types of inputs...
blood
temp, osmolarity, glucose, pH, hormones
neural
nucleus solitarius in medulla (baro + chemo Rs)
reticular formation in medulla + pons (state of neural arousal)
2 types of outputs...
blood
hypothal directly releases ADH + oxytocin
also releases releasing/antireleasing factors that go to ant pit via hypophyseal venous portal system - causes amplification
neural
ANS: temp, high or flight, appetite, thirst
limbic: instinct motor behavioural responses
hypothalamic nuclei
to post pit (neurohypophysis)
supraoptic nucleus (ADH)
paraventricular nucleus (oxytocin)
to ant pit (adenohypophysis)
median eminence (releasing/antireleasing factors)
hypothal/pit tumours
endocrine problems (altered hormone levels)
high prolactin: infertility
high cortisol: Cushing's syndrome
hypoadrenalism: Addison's
low ADH: diabetes insipidus
growth disorders, sexual dysfunction (hypogonadism, precocious puberty), eating problems
compression of optic chiasm -> bitemporal hemianopsia (tunnel vision)
Limbic system
forms @ border of di + tel encephalon
cingulate gyrus (wraps around CC, carries tracts)
hippocampus
under inf horn of lat ventricles in temporal lobe
composed of allocortex (as opposed to neocortex)
3 layers of cells
degenerates in AD, if bilateral can't form new memories
fornix
attaches mamillary bodies (short-term memory) to hippocampus (long-term memory)
partial decussation @ crus cerebri, beside uncut (hence why smells can elicit memories)
amygdala
tip of tail of caudate nucleus, ant to inf horn of lat ventricle, close to the hippocampus, in the frontal portion of the temporal lobe
stimulation - fear + aggression
overactivity - phobias + rage
ablation - calmness + hypersexuality
nucleus accumbens
dopaminergic activity (reward, reinforcement,wellbeing)
cocaine inhibits dopamine reuptake
amphetamines stimulate dopamine release
motor emotional expression
posture, body language
entorhinal cortex (decides how memories are made)
pentane gyrus (episodic memory formation)
medial dorsal nucleus (in thal, contributes to memory)
mamillary bodies