The Homeostatic Brain

Question 1

tuber cinereum

Answer 1

grey swelling on ventral surface of the brain in region between mammillary bodies and optic chiasm

Question 2

where is the hypophysial portal system?

Answer 2

median eminence

Question 3

what are the 3 regions of they hypothalamus and how are they defined?

Answer 3

anterior/preoptic- anterior cerebral and anterior communicating arteries

tuberal- posterior communicating artery

posterior- posterior communicating, posteroir cerebral and basilar arteries

Question 4

medial peroptic area

Answer 4

preoptic/anterior region

thermosensitive neurons for temperature regulation

gonadotropin secretion- reproductive and sexual behavior

Question 5

suprachiasmatic nucleus

Answer 5

preoptic/anterior region

circadian rhythms

Question 6

ventromedial nucleus

Answer 6

tuberal region

reproductive and sexual behaviors

glucose homeostasis and regulation of food intake

Question 7

lateral hypothalamic area

Answer 7

tuberal region

feeding area- regulation of food intake

Question 8

median forebrain bundle

Answer 8

limbic afferent to hypothalamus

hypothalamus to brainstem, amygdala, retina, and olfactory system. regulates somatic and metabolic activities associated w/ stress

Question 9

fornix

Answer 9

limbic afferent to hypothalamus

connects hypothalamus to mammillary bodies

mammillary bodies to the anterior nuclei of the thalamus

Question 10

stria terminalis

Answer 10

limbic afferent to hypothalamus

hypothalamus to amygdala

Question 11

afferents to hypothalamus from brainstem

Answer 11

dorsal longitudinal fasciculus

median forebrain bundle

Question 12

afferents to hypothalamus from retina

Answer 12

retinohypothalamic tract

Question 13

major limbic hypothalamic efferents

Answer 13

mammillothalamic tract

median forebrain bundle

Question 14

major reticular system hypothalamic efferents

Answer 14

mammillothalamic tract

Question 15

major autonomic hypothalamic efferents

Answer 15

median forebrain bundle

dorsal longitudinal fasciculus

Question 16

supraopticohypophyseal tract

Answer 16

carries axons from supraoptic and paraventricular nuclei to the posterior pituitary (neurohypophysis)

carry NTs AVP and oxytocin

Question 17

oxytocin

Answer 17

released in response to sexual stimulation, uterine dilation, nursing, and stress

during late pregnancy, produces uterine contraction and milk secretion

implicated w/ increasing trust, empahty, eye contact etc.

lack of oxytocin may be associated w/ autism

Question 18

pair bonding

Answer 18

oxytocin and AVP send neuronal contractions centrally and are important of affiliative states- maternal instincts, pair bonding, aggression, love

Question 19

tuberoinfundibular tract

Answer 19

parvocellular neurons in periventricular regions of hypothalamus influence hormonal release from anterior pituitary

Question 20

where do sex hormones feedback?

Answer 20

negative on GnRH in hypo

negative on anterior pituitary for FSH and LH

Question 21

neuronal control of HPG axis

Answer 21

cells within preoptic area that synthesize and release peptide GnRH

show bursting behavior- critical for appropriate release of gonaotropic hormones

dont express sex hormone receptors- presynaptic neurons do

Question 22

kisspeptin

Answer 22

presynaptic neurons that synthesize kisspeptin and act on G coupled proteins that regulate GnRH neurons

also play role in energy homeostasis and body fat.

regulated by circadian rhythms

act as sensors of the environment to make sure reproduction only occurs when conditions are right

Question 23

importance of sex hormones in the brain in development

Answer 23

lots of receptors in POA

act in development to impoart permanent in neural structures that underlie man of the sexual differentiated aspects of the brain

Question 24

sexually differentiated brain areas in rodents

Answer 24

VMN and POA

Question 25

steroid hormones regulate VMN and POA circuits in these 2 ways

Answer 25

activational effects of gonadal steroids in the brain- activational effects of gonadal steroid are required for cyclicity in females, sex specific behaviors organizational effects- act during a critical period to impart specific differences- POA is most well studies

Question 26

master circadian regulator

Answer 26

suprachiasmatic nucleus creates a cycle length of 24 hours- intrinsic, but also effected by environmental cues such as light- receive input from retina effects eating, sleeping, energy, and temp via connections fo PVN, VMN, LHA

Question 27

how is the circadian rhythm generated?

Answer 27

individual neurons in the SCN have transcription factors (CLOCK BMAL1, Cry, and Per) that regulate each other on a 24 cycle

Question 28

what brain areas are important for feeding

Answer 28

ventromedial nucleus and arcuate (satiety) and lateral hypothalamic area (feeding)

Question 29

casein kinases

Answer 29

regulate stability of circadian rhythm transcription factors mutations cause shorter circadian rhythms FASPS

Question 30

orexigenic v anorexigenic

Answer 30

stimulates feeding vs suppresses feeding

Question 31

ghrelin

Answer 31

acute signal that initiates food intake, decrease energy utilization and increase adiposity acts on same neurons as leptin produced in stomach when stomach is empty

Question 32

CCK

Answer 32

acute info about gastro fil via vagal afferents to solitary nucleus and to limit meal size

Question 33

leptin

Answer 33

provides peripheral signal from body to brain that reflects state of nutrition produced by white adipose cells designed to maintain adequate fat stores during lean times along with insulin, has access to hypothalamus b/c of compromised BBB near areas postrema

Question 34

leptin receptors

Answer 34

large numbers in hypothalamus encoded by db gene, coming in short and long form- long form is important members of cytokine superfamily- use JAK kinase

Question 35

effects of leptin binding

Answer 35

occurs w/ high fat inhibit production of AgRP, NPY and stimulate POMC (a-MSH) in arcuate nucleus AgRP and NPY are orexigenic, a-MSH is anorexigenic

Question 36

which nuclei house anorexigenic neurons and which nuclei house orexigenic neurons

Answer 36

anor- paraventricular PVN ore- perifornical area PFA, Lateral hypothalamic area LHA

Question 37

estrogen receptor related alpha

Answer 37

expressed in LHA and other areas linked to feeding upregulated w/ caloric restriction ESRAA null female mice are small and do not gain weight, show increased compulsive behaviors

Question 38

orexin

Answer 38

expressed in LHA, helps regulate food intake and energy expenditure inhibit by leptin and increased by ghrelin orexinergic narcolepsy- loss of orexin neurons