Osmosis Anatomy of Diencephalon

Osmosis

Diencephalon + cerebrum =

forebrain

Prosencephalon

Connect cerebrum with midbrain

Diencephalon

2 major parts of the diencephalon

Thalamus

Hypothalamus

Flanks space created by the 3rd ventricle

thalamus

Bridge of gray matter that connect thalami

Interthalamic adhesion

Forms inferior part and lateral wall of 3rd ventricle

Hypothalamus

Between thalamus and hypothalamus is

hypothalamic sulcus

The diencephalon contains two endocrine glands:

posterior gland of pituitary

Pineal gland (near caudal end of thalamus)

Egg shaped structure made of gray matter that contains neuronal cell bodies

Thalamus

Part of almost every sensory pathway

Thalamus

Gathers, combines, and processes _____information before sending it to the cerebral cortex

afferent

Thalamus

The only sensory pathway that does not relay through the thalamus is the ______ system

olfactory

Thalamus modulates movement through its connections with

Basal ganglia

cerebellum

Frontal lobe

Thalamus influences motivated behavior through its connection with the

hypothalamus

frontal lobe

Thalamus alters levels of consciousness by connection with

reticular formation of the brainstem

Medial to the thalamus is the _____ wall of the 3rd ventricle

Medial

Anterior to the thalamus is the

interventricular foramen, or foramen of Monro

through which the cerebrospinal fluid, or CSF, flows from the lateral ventricles to the third ventricle

interventricular foramen, or foramen of Monro

Lateral to the thalamus there is the posterior ____ of the internal capsule

posterior

the posterior part of the thalamus, _______, is not covered by other structures and can be seen superior to the posterior aspect of the midbrain.

pulvinar

The dorsal surface of the thalamus is ____ , sitting under the lateral ventricle and the fornix, while ventrally there’s the ______ of the midbrain.

free

tegmentum

the third ventricle lies ______ and the internal capsule lies ______ to the thalamus

medially

laterally

Layer of white matter that looks like the letter Y and divides the thalamus into three parts: medial, lateral and anterior.

internal medullary lamina

Some of the most important nuclei of the _____ part of the thalamus are the ventral posterolateral nucleus, the ventral posteromedial nucleus, and the ventral lateral nucleus.

Lateral

Receives input from the medial lemniscus and the spinothalamic tract and projects to the primary somatosensory cortex.

Ventral postero-lateral (VPL) nucleus

(Thalamus)

sensations that VPL nucleus transmits (ventral postero-lateral)

V in ventral stands for the vibration; P in posterior for pain, pressure and proprioception; L in lateral for the light touch; then just add the temperature.

(thalamus)

Receives input from the trigeminal and gustatory pathways and projects to the primary somatosensory cortex

Ventral postero-medial (VPM) nucleus

(thalamus)

Sensations the VPM nucleus transmits (Ventral postero-medial)

Makeup goes on the face. The M in makeup refers to the ventral postero-medial nucleus while the face refers to somatosensations from the face as well as taste.

(thalamus)

Receives input from the cerebellum and the basal ganglia, and it projects to the motor and premotor regions of the cerebral cortex.

Ventral lateral nucleus

(thalamus)

Ventral lateral nucleus function

relays motor information and can influence movements.

(thalamus)

The _____ _______ body is a small bulge under the posterior end of the pulvinar.

medial geniculate

(Thalamus)

Receives input from the inferior colliculus via the inferior brachium and from the superior olivary complex, and then projects to the auditory cortex of the temporal lobe.

Medial geniculate body

(thalamus)

Receives input from the retina, via the optic nerve, optic chiasm and optic tract, and then projects to the primary visual cortex of the occipital lobe via the optic radiation.

Lateral geniculate

(Thalamus)

Regulates homeostasis

Hypothalamus

Using neural, blood and CSF connections, the ______ can regulate a number of processes

Hypothalamus

Function of hypothalamus TAN HATS

thirst and water intake

endocrine organs and hormone secretion of the pituitary gland, which consists of the adenohypophysis and neurohypophysis

hunger and food intake

the autonomic nervous system

temperature

sexual drive and emotional expression.

lateral and ventromedial nuclei control

appetite

(hypothalamus)

the ______ nucleus serves as a hunger center, increasing appetite and food intake

lateral

(hypothalamus)

______ nucleus, on the other hand, serves as a satiety center, decreasing appetite and food intake

ventromedial

(hypothalamus)

Anterior and posterior nuclei, control

temperature of the body

(hypothalamus)

The ______ nucleus serves as a Cooling center and uses the parasympathetic system to decrease body temperature by producing sweat and dilating blood vessels in the skin.

anterior

(hypothalamus)

The _____ nucleus, on the other hand, serves as a heating center that uses the sympathetic system to increase the temperature by constricting blood vessels in the skin, thereby decreasing sweat production and causing shivering.

posterior

(hypothalamus)

Receives input from the retina about the presence or absence of light and uses the information to regulate many biological circadian rhythms, like the sleep-wake cycle

Suprachiasmatic nucleus

(hypothalamus)

Supraoptic and paraventricular nuclei, are in charge of

hormone production

(hypothalamus)

The ______ nucleus produces vasopressin, also known as the antidiuretic hormone, or ADH. This hormone causes constriction of blood vessels, increasing peripheral vascular resistance and it also makes the kidneys reabsorb more water from their tubules into the bloodstream. These two actions ultimately increase blood pressure.

supraoptic

(hypothalamus)

The ________ nucleus, on the other hand, makes oxytocin, which stimulates contractions of the uterus while in labor, and later stimulates milk secretion while breastfeeding.

paraventricular

(hypothalamus)

SAD POX

S stands for supraoptic, AD for ADH, P for paraventricular and OX for oxytocin.

Involved in thermoregulation and sexual behavior. It also produces gonadotropin-releasing hormone that stimulates the adenohypophysis to release the follicle stimulating hormone, or FSH, and the luteinizing hormone, or LH, which are necessary for normal gonad functioning.

Preoptic nucleus

(hypothalamus)

the ______ creates the floor and the inferior part of the lateral walls of the third ventricle.

hypothalamus

Anterior to the hypothalamus is the

optic chiasm

The hypothalamus also has a region called the _____ area, which is located rostrally in the hypothalamus near the lamina terminalis, with the optic chiasm inferiorly and the anterior commissure superiorly.

preoptic

Most inferiorly of the hypothalamus, there’s the _____ _____, which contains a small bump called the median eminence that connects with the stalk of the posterior lobe of the pituitary gland.

tuber cinereum

Posteriorly, the hypothalamus includes the ______ bodies and spreads to the border of the interpeduncular fossa of the midbrain, with the floor of this fossa known as the posterior perforated substance.

mamillary

The mammillary bodies are two rounded structures that are a part of the _____ system.

limbic system

Contain mammillary nuclei that receive input from the hippocampus via the fornix.

Mamillary bodies

(hypothalamus)

The mammillary nuclei then project to the anterior nuclei of the thalamus via the _______ tracts.

mammillothalamic

(hypothalamus)

There is also a connection between the mammillary bodies and the midbrain tegmentum via the mammillary ______ .

peduncles

(hypothalamus)

On the ventral aspect of the brain, the mammillary bodies can be seen anterior to the posterior ______ _______ , between the cerebral peduncles and posterior to the tuber cinereum.

perforated substance

believed to play a role in learning and memory.

Mamillary bodies

(hypothalamus)

VPM (thalamus) transmits

somatosensation from face and taste

The ______ is the posterior part of the gland, which develops from the ventral side of the hypothalamus.

neurohypophysis

It contains axons of the supraoptic and paraventricular nuclei, which carry ADH and oxytocin to the _______ to be stored.

neurohypophysis

The anterior part is called the ________ and develops from Rathke’s pouch, which is an ectodermal diverticulum from the roof of the primitive oral cavity. Connected to the hypothalamus through a system of blood vessels called the hypophyseal portal system.

adenohypophysis

This system starts with the _____ hypophyseal artery located on both sides of the gland, which is a branch of the internal carotid artery. It enters the median eminence and forms the first capillary plexus. Blood from the first plexus is gathered into hypophyseal portal veins that enter the adenohypophysis and form the second capillary plexus. Then the blood drains into the hypophyseal veins and joins the systemic circulation.

superior

The neurons of the hypothalamic nuclei produce releasing hormones and release-inhibiting hormones, pack them into granules and transport them via their axons to the _____ _____ where they release them into the first capillary plexus.

median eminence

These hormones from the hypothalamus reach the second capillary plexus and instruct the ______ to increase or decrease hormone release.

adenohypophysis

The pituitary gland sits in the middle of the _____ bone, in a depression called the sella turcica.

sphenoid

Superiorly to pituitary gland, there’s the ______ ________ of the hypothalamus.

median eminence

the posterior lobe of the pituitary gland has a stalk, called the _______

infundibulum

_____ to the pituitary gland there’s the optic chiasm, while _______ to it, there are the mammillary bodies.

anterior

posterior

The pituitary gland is closely related to the _______ sinuses, which almost enclose the pituitary gland on each side

cavernous

if we switch to the ventral side of the brain, we can see the _______ sitting between the optic chiasm, anteriorly, and the mammillary bodies, posteriorly.

infundibulum

pine cone shaped gland

pineal gland

Regulation of the sleep-wake cycle by production of melatonin, a hormone that helps us fall asleep

Pineal gland

Receives information from the retina about the presence or absence of light, which allows it to know if it is day or night. Once it gets darker, the _____ gland starts releasing melatonin into the bloodstream and the CSF of the third ventricle, which prepares us for sleep.

pineal

It is also believed that the _____ gland can influence the hormone secretion of other endocrine glands, like the pituitary, parathyroid, endocrine pancreas, adrenal glands and gonads.

pineal

Sits just caudal to the thalamus and is attached to it by a hollow stalk filled with CSF from the third ventricle.

Pineal gland

The pineal gland protrudes posteriorly, lying superior to the superior ______ .

colliculi

It is also a part of the central nervous system that doesn’t have the blood-brain barrier.

Pineal gland

The ______ is a part of the forebrain that sits between the cerebral hemispheres, connecting the cerebrum with the midbrain.

diencephalon

Major nuclei of the thalamus are: ventral postero-lateral (VPL), which relays information from the spinothalamic tract and medial lemniscus; ventral postero-medial (VPM), which relays information from trigeminal and gustatory pathways; lateral geniculate body, which relays visual system information; medial geniculate body, which relays auditory information; and the ventral lateral nucleus, which relays information from motor systems.

Thalamus nuclei recap

The hypothalamus regulates homeostasis and controls hormone production of the pituitary gland. It has several nuclei: lateral and ventromedial nuclei that regulate appetite; anterior and posterior nuclei that regulate body temperature; suprachiasmatic nucleus that regulates circadian rhythms; supraoptic and paraventricular nuclei that produce ADH and oxytocin; and the preoptic nucleus that is related to thermoregulation and sexual behavior.

Hypothalamus nuclei recap

The pituitary gland contains the neurohypophysis, which is a part of the diencephalon and secretes ADH and oxytocin, and the adenohypophysis that develops from Rathke’s pouch. It secretes hormones that influence other endocrine glands in the body. The pineal gland secretes melatonin and regulates the sleep-wake cycle.

Pituitary and pineal gland recap