limbic system & hypothalamus

Question 1

what are examples of the anatomical components of the limbic system?

Answer 1

• hippocampus
  -amygdala
  -cingulate gyrus
  -fornix
  -mamillary bodies

Question 2

what is the limbic system?

Answer 2

The limbic system is a complex network of brain structures primarily involved in emotions, behaviors, motivation, and memory.

Question 3

what is the hippocampus?

Answer 3

a structure located in the medial temporal lobe that is essential for the formation and structure of new memories

Question 4

what is the amygdala?

Answer 4

a structure located deep within the temporal lobes of the brain that plays a role in regulating emotions especially fear

Question 5

what is the hypothalamus?

Answer 5

-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

Question 6

where is the hypothalamus situated?

Answer 6

at the base of the brain near the optic chiasm and the pituitary gland

Question 7

how do inputs (hormonal and neural) arrive to the hypothalamus?

Answer 7

-hormonal inputs - via blood
-neural inputs via brainstem, limbic system and thalamus

Question 8

how is the output mediated from the hypothalamus- hormonal and neural?

Answer 8

• hormonal via pituitary gland
  -neural via limbic system, brain stem and thalamus

Question 9

list functions of the hypothalamus

Answer 9

-fluid & electrolyte balance
-food ingestion
-thermoregulation
-reproduction
-immune responses
-circadian rhythm

Question 10

what is the endocrine function of the hypothalamus?

Answer 10

• 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

Question 11

what are examples of input ‘stimuli’ that are carried in the blood to the hypothalamus?

Answer 11

-physical - temp & osmolality
-chemical - glucose and acid base balance
-hormone - growth and development, readiness for defence, sex etc

Question 12

what important structures in the medulla and pons send inputs to the hypothalamus regarding pressure and chemical composition changes in the vessels?

Answer 12

-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

Question 13

what are the 2 main nuclei of he hypothalamus and what are their functions?

Answer 13

1. supraoptic nuclei - play a crucial role in the production & release of ADH, which is regulated by osmoreceptors
2. paraventricular nuclei- produces and releases oxytocin - important for bonding, milk production, birth etc

Question 14

what is the pituitary gland?

Answer 14

small gland located at the base of the brain, just below the hypothalamus

Question 15

how is the hypothalamus connected to the pituitary gland?

Answer 15

via the infundibulum

Question 16

what is the pituitary gland divided into?

Answer 16

-anterior lobe (adenohypophysis)
-posterior lobe (neurohypophysis)

Question 17

what are the functions of the pituitary gland?

Answer 17

-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

Question 18

what can excess prolactin secretion lead to?

Answer 18

infertility

Question 19

what condition is associated with hypoadrenalism / adrenal insufficiency?

Answer 19

addisions disease

Question 20

what happens to the hippocampus in alzheimers disease and what symptoms are associated?

Answer 20

-degeneration of the hippocampus
-amnesia of recent events
-loss of episodic memory
- new memories are affected

Question 21

what is the fornix?

Answer 21

-C-shaped bundle of nerve fibers (white matter) in the brain that plays a crucial role in memory formation and retrieval

Question 22

what are the nucleus accumbens & septal area?

Answer 22

• 2 important nuclei in the limbic system that are involved in emotion, reward processing and motivation

Question 23

describe some of the consequences of the limbic component malfunction

Answer 23

-mood disorders eg depression and bipolar disorder
-anxiety disorders - heightened amygdala
- addiction