lecture 6 - diencephalon

diencephalon

part of forebrain

- deep inside the brain ; surrounds 3rd ventricle

diencephalon consists of

thalamus & hypothalamus , epithalamus & subthalamus

thalamus function

- motor control

- sensory processing : gustatory, auditory, somatosensory, visual controls sleep & wakefulness (arousal)

hypothalamus function

anterior & inferior to thalamus

- secretes hormones (endocrine) & controls physiological l functions (homeostatic) & autonomic nervous system

"HEAL "

H omeostatic

E ndocrine

A utonomic

L imbic

epithalamus function

pineal body

- secretion of melatonin & sleep wake cycles

sub thalamus function

* or subthalamic nucleus

- wedged laterally btwn thalamus & hypothalamus

- modulates motor responses

which of following structures is NOT part of diencephalon

a. hypothalamus

b. epithalamus

c. hippocampus

d. subthalamus

e. thalamus

c. hippocampus

The pineal body functions in regulating _________?

A . eating behavior

b. motor responses

c. emotional drives

d. sleep/wake cycles

d. sleep/ wake cycles

hypothalamus inputs

* bring sensory info important for physiological homeostasis

- Vagus nerve = blood pressure , distension of gut

- reticular formation in brainstem = skin temp

- optic nerve = light & darkness - used by hypothalamus to orchestrate circadian rhythms

- limbic system & olfactory nerves = used by hypothalamus to regulate eating, mating/reproduction

- internal sensory receptors = osmoreceptors , thermorecptors, glucorecptors

hypothalamus outputs

* control autonomic, endocrine & behavioral responses necessary to maintain homeostais

- autonomic nervous system ( sympathetic & parasympathtic ) = control of blood pressure , heart rate, breathing, digestion

- endocrine system (hormones) :neurally & chemically connected to & controls pituitary gland

- behavioral circulates (limbic system)

which of following is TRUE statements concerning hypothalamus

a. located above thalamus

b. concerned w/ internal body functions

c. part of mesencephalon

d. activation can lead to speech

b. concerned w/ internal body functions

PVN

- responds to stress by releasing certain hormones

most important one is .... corticotropin releasing hormone

- signals to anterior pituitary & leads to release of cortisol (major stress hormone)

PO (prooptic nucleus )

- temp regulation & for reproductive hormones

VMN ( ventromedial nucleus )

- for satiety (stop feeding) , weight regulation

SON (supra-optic nucleus )

above optic nerve

- important for osmoregulation

LH ( lateral hypothalamus area)

feeding, aggression

which assocation btwn hypothalamic subnuclei & function is FALSE

a. supraoptic n . - vasopressin secretion

b. preoptic n. - lactation

c. paraventricular n. - oxytocin

d. ventromedial n - satiety center

b. preoptic n - activation

ANSWER: temp regulation , reproductive hormones

which hypothalamic nucleus below stimulates feeding behavior ?

a. ventromedial n

b. mammillary n

c. lateral hypothalamic area

d. supraoptic n.

e. posterior hypothalamic n.

c. lateral hypothalamic area

hypothalamo-pituitary-adrenal (HPA) Axis

paraventricular nuclei (corticotropin releasing hormones) --> anterior pit ( ACTH) --> adrenal cortex (cortisol )

oxytocin

uterine contractions, breastmilk letdown

ADH (avsopressin)

pressor (increases blood pressure ) , reduced urine (antidiuretic hormone)

FALSE about hypothalamus

a. collection of subnuclei

b. bisected by 3rd ventricle

c. lateral hypothalamic area is satiety center

d. functions close association w/ amygdala & hippocampus & brainstem

c. lateral hypothalamic area is satiety center

The thalamus

a. relay station for all sensory info

b. can be subdivided into several distinct nuclei

c. sends projections to cerebral cortex

d. part of diencephalon

e. all are correct

e. all are correct