Lecture 12 Flashcards by Alexander Lee

What are the 4 structures of the Diencephalon?

Subthalamus

Epithalamus

Thalamus

Hypothalamus

How well did you know this?

Not at all

Perfectly

The subthalamus/subthalamic nuclei are functionally a part of what?

The basal ganglia

How well did you know this?

Not at all

Perfectly

What is the largest structure of the epithalamus?

Pineal body

-innervated by sympathetic fibers

Assists in controlling circadian rhythm and impacts glandular secretions

How well did you know this?

Not at all

Perfectly

What is intramedullary lamina?

White matter that divides thalamus into anterior medial and lateral groves

(Thalamus is made of gray matter)

How well did you know this?

Not at all

Perfectly

The lateral wall of the thalamus is formed by thin sheets of cells called….

Thalamic reticular nucleus

How well did you know this?

Not at all

Perfectly

What separates the L from R thalamus. ________

the medial thalamic wall of each side formed by the thin sheets called. _______

3rd ventricle

Midline nucleus

How well did you know this?

Not at all

Perfectly

The R and L thalamus are joined in most humans brains by what is called the…

Masa intermedia/ inter thalamic adhesion

How well did you know this?

Not at all

Perfectly

What supplies blood to the thalamus?

deep branches of the posterior cerebral artery

-thalamoperforator artery

-thalamogenticulate artery

-posterior choroidal artery

How well did you know this?

Not at all

Perfectly

What are the functions of the thalamus?

Filters and processes info going to cortex from
-basal ganglia
-cerebellum
-all sensory system except olfactory

Relays input to discrete areas of cortex (regulates corticoneuronal activity)

How well did you know this?

Not at all

Perfectly

All thalamic nuclei project to the cerebral cortex except for….

Thalamic reticular nucleus

How well did you know this?

Not at all

Perfectly

Most Thalamic efferent and afferent pass through the…

Thalamic reticular nucleus

Note: many TRN neurons contain GABA (inhibitory)

How well did you know this?

Not at all

Perfectly

What are the 3 main functional groups of nuclei in the thalamus?

-Relay Nuclei

-Association Nuclei

-Nonspecific nuclei

How well did you know this?

Not at all

Perfectly

What do relay nuclei do?

Transmit info from basal ganglia, cerebellum, and sensory systems to cerebral cortex

How well did you know this?

Not at all

Perfectly

What do association nuclei do?

Process memory and emotion info

Intregrate different sensory pathways

Connect to specific areas of cerebral cortex with same areas projecting back to the nuclei (2 way talk)

How well did you know this?

Not at all

Perfectly

What do the nonspecific nuclei do?

Regulate consciousness, arousal, attention

How well did you know this?

Not at all

Perfectly

Hyper direct (stop) pathway

Projection from cortex to subthalamic nucleus in basal ganglia

Rapid inhibiton of motor responses/ stopping of action.

Inhibiton of thalamocortical motor circuits

How well did you know this?

Not at all

Perfectly

Indirect (no-go) pathways

Projection from putamen to EXTERNAL globus pallidus and subthalamic nucleus

Suppression of inhibiton of unwanted motor responses

Increases inhibitions on thalamocortical motor circuits

How well did you know this?

Not at all

Perfectly

The cerbellum projects through ______ peduncles to the thalamus, relaying signals to UMNs in primary and premotor cortices

Superior cerebellar peduncles

How well did you know this?

Not at all

Perfectly

Where is spinocerebellar output from?

From Vermis and Intermidiate zone through the superior cerebellar peduncle to thalamus

Where do afferents and efferents of the cerebro-cerebellar-cerebral loop enter and leave?

From lateral cerebellar cortex

Afferents enter cortex through middle cerebellar peduncle

Efferents leave via the superior cerebellar peduncle to thalamus

Afferents _____ the cerebellum and efferents ______ the cerebellum

But this doesn’t mean they aren’t afferent/efferent (the other one) when it enters the cortex

afferents(arrive)- enter

efferents(exit)- leave

Describe pusher syndrome/lateropulsion due to thalamic lesions

Pushing towards weaker side/ affected side

-accompanied usually by posterior push

-patients are slower to progress

Thalamic lesions can disrupt contralateral sensation. Most commony affected is ______

Proprioception

note: thalamic pain syndrome is rare but severe

The hypothalamus is separated from the thalamus by the….

Hypothalamic sulcus

What forms the posterior aspect of the hypothalamus?

mamillary bodies

Why is the hypothalamus necessary for survival?

Pairs actions to visceral functions

What are the functions of the hypothalamus?

(HEAL) Homeostatic function Endocrine Control Autonomic Control (sympathetic NS) Limbic system (emotions)

The hypothalamus controls circadian rhythm through...

light sensitive receptors sleep can be facilitated or inhibited

Additional hypothalamic functions

appetite- from hormones Thirst- from osmoreceptors Body heat regulation Sexual development/desire/nuturing behaviors

Where is the pituitary gland contained?

Sella Turcica/pitutary fossa of sephenoid bone

What is the pathway that the hypothalamus communicates with the pituitary gland?

hypothalamus -> infundibulum -> pituitary stalk -> Pituitary gland

The anterior pituitary gland comes from what kind of tissue? Meanwhile the posterior pituiary is what kind of tissue?

Anterior - Epithelial Posterior - a continuation of brain tissue

Secretions from the posterior pituitary are what?

Neuro-hormones

Neurohormones secreted by the hypothalamus cause increase/decrease in _________ secretions

anterior pituitary Note: ant pituitary gland has glandular cells that secrete into bloodstream

What hormones does the hypothalamus cause the ANT PIT to release?

GH. TSH, ACTH, LH, FSH, prolactin

What does ACTH do?

facilitates the release of corticosteroids from adrenal cortex which inhibits immune reaction/inflammation. Increases glucose production and reduces glucose use by muscles

What does LTH and FSH, prolactin do?

impacts ovaries/testes and milk production in lactating females

Where do action potentials from the hypothalamus travel to reach the posterior pituitary

pituitary stalk

What are the 2 hormones released by post pituitary

ADH- increased reabsorb of water Oxytocin - uterine contraction

What are limbic pathways and what is the order?

emotional influences on autonomic and homeostatic pathways Hippocampus > fornix > hypothal mammillary bodies Mammillary bodies> mammillothalamic tract > thalamus > limbic cortex of cingulate gyrus

The ______ has reciprocal connections with hypothalamus via stria terminalis and amygdalofugal pathway

amygdala Just know amygdala connects to hypothalamus and links emotions to sympathetic and parasympathetic nervous system

__________ (tumor) make up 10-17% of all intracranial neoplasms

Pituitary adenomas (tumor)

Pituitary adenomas (tumor) usually are _____ growing and _______

slow growing and benign

Pituitary adenomas (tumor) Can arise from any of ________________

Can arise from any of anterior pituitary cell types that secrete hormones note: these tumors are not under normal hypothal control, causing a variety of different syndromes

Even microadenomas of 1 mm or less can cause sig endocrine issues Larger ones put pressure on surrounding structures such as _____________

optic chiasm Causing bitemporal hemianopia