B&B Week 5 Flashcards
(266 cards)
where is the hypothalamus located?
inferior to the thalamus and forms the walls and floor of the inferior portion of the third ventricle
how is the hypothalamus divided functionally?
can be divided into functional areas of nuclei along a lateral/medial axis and anterior/posterior axis
what is the function of the hypothalamus?
main regulator of homeostasis in the body
what is the function of the lateral region of the hypothalamus?
carries two way signals between forebrain and brainstem
eating, arousal
what is the function of the medial zone of the hypothalamus?
most functionally important nuclei are here
ADH secretion, satiety, GH secretion
what is the function of the anterior zone of the hypothalamus?
cooling of body temp, sleep, eating
what is the function of the posterior zone of the hypothalamus?
up regulation of body temp
arousal
wakefulness
what are the afferents that feed into the hypothalamus?
general somatic, visceral, gustatory information from SC and brainstem
limbic afferents–> from hippocampus (via fornix to mamillary bodies) and from amygdala
olfactory info
cortical info from forebrain
thalamus
retinal collaterals
what are the efferents that flow from the hypothalamus?
descending fibres to brainstem and spinal cord (visceral motor nuclei)
ascending fibres to forebrain
what is the function of the limbic system?
together with the hypothalamus, the limbic system provides an anatomical substrate for emotional, drive related and motivated aspects of behavior
comprises both cortical and subcortical structures
what are the cortical structures associated with the limbic system?
LIMBIC LOBE–> parahippocampal, cingulated and subcallosal gyri, which are interconnected by the cingulum
what are the subcortical structures associated with the limbic system?
hippocampus, amygdala, septal nuclei
what structure gives rise to the efferents that carry limbic information out into the forebrain, brainstem and spinal cord?
hypothalamus
where is the hippocampus?
cortex, in the medial temporal lobe
forms the floor of the lateral ventricle
what is the hippocampus responsible for?
learning and memory
it is informed of all sensations
regulates behavior, autonomic function, and endocrine function
where is the amygdala found?
deep within the uncus, rostral to the hippocampus
sits above and in front of the temporal horn of the lateral ventricle and is anterior to the tail of the caudate nucleus
what are the following portions of the amygdala responsible for?
- basolateral nuclei
- central nuclei
- corticomedial nuclei
- emotional significance to a stimulus–> integrates sensory information
- regulate visceral responses to emotional stimuli (fight/flight, physiological changes due to emotional state)
- smell of food and emotional response to food (appetite) and also release of cortisol
where are the septal nuclei located?
medial wall of the frontal lobe
what do the septal nuclei connect to?
olfactory bulb, hippocampus, amygdala
cholinergic neurons that have projections to hypothalamus, amygdala, hippocampus and frontal cortex
what does the papez circuit do?
experience of emotion involves reciprocal interactions between cortex and diencephalon
what structures are considered part of the limbic system?
hypothalamus (though it is structurally part of the diencephalon, the hypothalamus is functionally part of the limbic system), hippocampus, amygdala, septal nuclei, (papez circuit), parahippocampal, cingulated and subcallosal gyri
what structures make up the papez circuit?
mammillary bodies–> thalamus anterior nuclei–> cingulate cortex–> hippocampus–> back to mammillary bodies
each of these communicates with other structures
what are the key neurotransmitters of the limbic system and the hypothalamus?
NE, dopamine, serotonin
what physiological systems do the hypothalamus and the limbic system regulate in order to maintain homeostasis?
- endocrine secretion
- autonomic function
- homeostatic functions
- thermoregulation
- food intake
- body water regulation
- fluid balance
- blood pressure
- sleep wake cycles/circadian rhythms - basic drives
- motivation
- goal oriented behaviors
- emotional behaviours - learning and memory (hippocampus only)