hypothalamus

Question 1

what are the functions of the hypothalamus based on input

Answer 1

• direct sensing via receptors within hypothalamus
• indirect via blood (temp, osmotic pressure, hormones)
• indirect via nerves

Question 2

list the nuclei in the hypothalamus and their respective functions

Answer 2

paraventricular = oxytocin, ADH, TRH, CRH
supraoptic = oxytocin and ADH
suprachiasmatic = biological clock/circadian rhythm
lateral = arousal and hunger
arcuate = energy, GnRH, GHRH, NP-Y
Mammillary = wakefulness

Question 3

explain how the hypothalamus uses thermoreceptors

Answer 3

• neurons in the anterior hypothalamus: respond to heat with peripheral vasodilation and sweating
• neurons in the posterior hypothalamus: respond to cold with peripheral vasconstriction, piloerectin and shivering

Question 4

explain how the hypothalamus uses osmoreceptors

Answer 4

• resond to increase in blood osmolarity and respond via:
• anti diuretic hormone (ADH)
• ADH release from supraoptic nucleus
• secreted via posterior pituitary
• kidneys concentrate urine (retain water)
• stimulate neurons within the thirs centre in the latreal hypothalamus

Question 5

how does the yypothlamus regulate energy balance

Answer 5

• neurons in arcuate nucles sense blood glucose and hormones
• lepting (fullness) and ghrelin (hunger) sensed
• satiety centre responds to high glucose levels and inhibits eating
• appetite centre responds to low glucose levels and stimuates eating

Question 6

how does the hypothalamus regulate biological clock

Answer 6

• light sensed by retina
• transmitted via nerve pathways
• arrive at hypothalamus, specifically, the suprachiasmatic nucleus
• stimautlates the pineal gland and other pathways (make meltaonin)

Question 7

describe secretory neuron function

Answer 7

• cell bodies arise from the nuclei of hypothalamus
• axons descend into the posterior pituitary
• stimulates release of hypothalamic hormones (oxytocin and ADH) stored in posterior pituitary
• nerves terminate on blood vessels and release hormone directly into circulation

Question 8

explain the 2 major ways the hypothalamus and pituitary communicate

Answer 8

Neuronal Communication: The hypothalamus contains specialized neurons that produce and release certain hormones called releasing hormones (e.g., corticotropin-releasing hormone, gonadotropin-releasing hormone). These releasing hormones are transported via blood vessels to the anterior pituitary gland, where they stimulate or inhibit the release of specific pituitary hormones. This communication occurs through a system of blood vessels called the hypothalamic-pituitary portal system, which directly connects the hypothalamus to the anterior pituitary.
Hormonal Feedback: The pituitary gland secretes various hormones (e.g., growth hormone, thyroid-stimulating hormone) that regulate the function of other endocrine glands throughout the body. These hormones often exert negative feedback on both the hypothalamus and the pituitary gland. When the levels of certain hormones in the bloodstream rise, they signal back to the hypothalamus and the pituitary gland to decrease the production and release of the releasing hormones and pituitary hormones, respectively. This feedback loop helps maintain hormonal balance in the body.

Question 9

what are the major releasing hormones and what are their functions

Answer 9

Question 10

what are the major inhibitory hormones and what do they do

Answer 10