Thalamus and Hypothalamus

Question 1

suprachiasmatic nucleus of hypothalamus

Answer 1

*transduces the light-dark cycle established by the sun to neural signals
*input from retina
*output via several hypothalamic nuclei
*increased activity of the suprachiasmatic nuclei INHIBITS melatonin production by the pineal gland via ANS

Question 2

what hormones modulate the hypothalamic control of eating

Answer 2

1) ghrelin
2) leptin

Question 3

ghrelin

Answer 3

*hormone from stomach that stimulates hunger

Question 4

leptin

Answer 4

*long-term hormone secreted by fat that leads to decreased hunger and increased satiety (tells you when you are full)

Question 5

posterior pituitary

Answer 5

*contains axon terminals
*hormones synthesized by the hypothalamus are stored in the posterior pituitary and released directly into blood supply
*ADH and oxytocin

Question 6

anterior pituitary

Answer 6

*contains cells that synthesize hormones
*activated by hypothalamic releasing hormones
*releases “tropic” hormones that act on glands and tissues (FLAT PeG hormones)
*FSH, LH, ACTH, TSH, prolactin, GH

Question 7

ACTH physiological effect

Answer 7

response to stress

Question 8

TSH physiological effects

Answer 8

modulates metabolism

Question 9

GH physiological effects

Answer 9

promotes growth

Question 10

prolactin physiological effects

Answer 10

milk let down

Question 11

FSH physiological effects

Answer 11

spermatogenesis
follicle growth/ovulation

Question 12

LH physiological effects

Answer 12

egg release/ovulation
spermatogenesis

Question 13

VPL nucleus (of thalamus) - information

Answer 13

all sensory information (pain, temperature, touch, proprioception, vibration) from the body
*VPL = ventral posterolateral nucleus

Question 14

VPL nucleus (of thalamus) - input

Answer 14

*spinothalamic and dorsal column/medial lemniscus tracts
*all sensation from the body (pain, temperature, vibration, proprioception) is integrated into the thalamus

Question 15

VPL (of thalamus) - output

Answer 15

somatosensory cortex

Question 16

VPM (of thalamus) information

Answer 16

1. sensory information from face (via trigeminal nerve)
2. taste

Question 17

VPM (of thalamus) input

Answer 17

trigeminal nerve
gustatory fibers

Question 18

VPM (of thalamus) output

Answer 18

somatosensory cortex

Question 19

LGN (of thalamus) information

Answer 19

vision
LGN = lateral geniculate nucleus

Question 20

LGN (of thalamus) input

Answer 20

optic nerve (CN II)

Question 21

LGN (of thalamus) output

Answer 21

calcarine fissure in occipital cortex

Question 22

MGN (of thalamus) information

Answer 22

hearing
MGN = medial geniculate nucleus

Question 23

MGN (of thalamus) input

Answer 23

superior olive & inferior colliculus (hearing information)

Question 24

MGN (of thalamus) output

Answer 24

auditory cortex in temporal lobe

Question 25

ventrolateral nucleus (VL) of thalamus - information

Answer 25

motor

Question 26

ventrolateral nucleus (VL) of thalamus - input

Answer 26

basal ganglia

Question 27

ventrolateral nucleus (VL) of thalamus - output

Answer 27

motor cortex

Question 28

thalamic syndrome

Answer 28

*occurs when a lesion destroys the thalamus *CONTRALATERAL PURE sensory loss (face, arm, and leg; **all sensory modalities lost**)

Question 29

specific inputs to thalamus

Answer 29

inputs that are reliably relayed to cortex (inputs to VPL, VPM, LGN, MGN, etc)

Question 30

regulatory inputs to thalamus

Answer 30

inputs that contribute to decisions about what form of information leaves the thalamus (cortical inputs and reticular nucleus)

Question 31

outputs of thalamus

Answer 31

*largely excitatory to cortex *local inhibitory circuits projecting to thalamic nuclei

Question 32

thalamic reticular nucleus

Answer 32

*a sheet of GABAergic (inhibitory) neurons that receives input from cortex and other thalamic nuclei *does NOT project to cortex *important source of regulatory input to nuclei in the thalamus

Question 33

general functions of hypothalamus (HEAL)

Answer 33

homeostasis, endocrine, autonomic, and limbic expression

Question 34

specific functions of hypothalamus (TANHATS)

Answer 34

-thirst and water balance -adenohypophysis control (anterior pituitary) -neurohypophysis control (posterior pituitary) -hormones and hunger -autonomic regulation -temperature regulation -sexual expression

Question 35

paraventricular and dorsal medial nuclei of hypothalamus - function

Answer 35

drive ANS function

Question 36

paraventricular and supraoptic nuclei of hypothalamus - function

Answer 36

posterior pituitary function (synthesize ADH and oxytocin, the 2 hormones released by the posterior pituitary)

Question 37

mammillary bodies of hypothalamus - function

Answer 37

limbic system

Question 38

suprachiasmatic nucleus of hypothalamus - function

Answer 38

circadian rhythym

Question 39

lateral hypothalamus - function

Answer 39

**hunger** (appetite generation - stimulated by ghrelin)

Question 40

medial hypothalamus - function

Answer 40

**satiety** (appetite suppression - stimulated by leptin)

Question 41

anterior hypothalamus - function

Answer 41

**cooling** (heat dissipation; vasodilation of vessels so heat will be lost) ## Footnote note - this is what is affected by circulating pyrogens, leading to fever

Question 42

posterior hypothalamus - function

Answer 42

**heating** (heat conservation; vasoconstriction of vessels so heat is retained)

Question 43

OVLT (organum vasculosum of lamina terminalis)

Answer 43

*a group of cells with access to blood-brain barrier *evaluates blood osmolarity and circulating pyrogens *feeds information about blood to hypothalamus

Question 44

SFO (subfornical organ)

Answer 44

*a group of cells with access to blood-brain barrier *evaluates blood osmolarity and many hormones *feeds information about blood to hypothalamus

Question 45

SCO (subcommissural organ)

Answer 45

*a group of cells with access to blood-brain barrier *evaluates osmoregulation *feeds information about blood to hypothalamus

Question 46

area postrema

Answer 46

*a group of cells with access to blood-brain barrier *evaluates toxins in blood and many hormones to cause vomiting if necessary (ex alcohol poisoning) *feeds information about blood to hypothalamus