limbic system & hypothalamus Flashcards
what are examples of the anatomical components of the limbic system?
- hippocampus
-amygdala
-cingulate gyrus
-fornix
-mamillary bodies
what is the limbic system?
The limbic system is a complex network of brain structures primarily involved in emotions, behaviors, motivation, and memory.
what is the hippocampus?
a structure located in the medial temporal lobe that is essential for the formation and structure of new memories
what is the amygdala?
a structure located deep within the temporal lobes of the brain that plays a role in regulating emotions especially fear
what is the hypothalamus?
-a structure positioned below the thalamus
-regulates several vital functions eg hunger, thirst, body temp, sleep etc
-also controls the release of certain hormones from the pituitary gland
where is the hypothalamus situated?
at the base of the brain near the optic chiasm and the pituitary gland
how do inputs (hormonal and neural) arrive to the hypothalamus?
-hormonal inputs - via blood
-neural inputs via brainstem, limbic system and thalamus
how is the output mediated from the hypothalamus- hormonal and neural?
- hormonal via pituitary gland
-neural via limbic system, brain stem and thalamus
list functions of the hypothalamus
-fluid & electrolyte balance
-food ingestion
-thermoregulation
-reproduction
-immune responses
-circadian rhythm
what is the endocrine function of the hypothalamus?
- it controls secretion of hormones from the pituitary gland by secreting either stimulatory or inhibitory releasing hormones
-these ‘releasing’ hormones either stimulate or suppress the secretion of hormones from the pituitary gland
what are examples of input ‘stimuli’ that are carried in the blood to the hypothalamus?
-physical - temp & osmolality
-chemical - glucose and acid base balance
-hormone - growth and development, readiness for defence, sex etc
what important structures in the medulla and pons send inputs to the hypothalamus regarding pressure and chemical composition changes in the vessels?
-nucleus solitarius in the medulla sends info from baroreceptors and chemoreceptors
-reticular formation in the medulla and pons sends info about the state of arousal
what are the 2 main nuclei of he hypothalamus and what are their functions?
- supraoptic nuclei - play a crucial role in the production & release of ADH, which is regulated by osmoreceptors
- paraventricular nuclei- produces and releases oxytocin - important for bonding, milk production, birth etc
what is the pituitary gland?
small gland located at the base of the brain, just below the hypothalamus
how is the hypothalamus connected to the pituitary gland?
via the infundibulum
what is the pituitary gland divided into?
-anterior lobe (adenohypophysis)
-posterior lobe (neurohypophysis)
what are the functions of the pituitary gland?
-regulation of growth - GH hormone
- regulation of metabolism - TSH (thyroid stimulating hormone)
-regulation of reproduction - FSH and LH
-milk production in breasts - prolactin
-regulation of water balance - ADH
what can excess prolactin secretion lead to?
infertility
what condition is associated with hypoadrenalism / adrenal insufficiency?
addisions disease
what happens to the hippocampus in alzheimers disease and what symptoms are associated?
-degeneration of the hippocampus
-amnesia of recent events
-loss of episodic memory
- new memories are affected
what is the fornix?
-C-shaped bundle of nerve fibers (white matter) in the brain that plays a crucial role in memory formation and retrieval
what are the nucleus accumbens & septal area?
- 2 important nuclei in the limbic system that are involved in emotion, reward processing and motivation
describe some of the consequences of the limbic component malfunction
-mood disorders eg depression and bipolar disorder
-anxiety disorders - heightened amygdala
- addiction
