The Hypothalamus Flashcards
outdated views saw the HT as a ___ tot the TH
ventral addition
what revealed the expansive roles of the HT?
gene expression
What is the HT formed by?
the most rostral part of the neural tube
the HT generates all of what from its alar plates?
the telencephlon
The HT generates the telencephalon from its what?
its alar plates
what is the most crucial centre in the developing human brain?
the HT
what are misunderstandings of the proper anatomical position of the HT due to?
lack of appreciation of the effect of the cervical flexure in the developing neural tube
what pushes the HT into its adult position under the TH?
the severe bend in the embryonic neuraxis
What has the first two neural segments?
HT
What are the neural segments in the HT?
the terminal prosomere
the peduncular prosomere
What are the first two neural segments?
the terminal prosomere
the peduncular prosomere
what does the terminal HT prosomere give rise to from its alar plate?
the telencephalon and eye
the terminal HT prosomere gives rise to the telencephalon and eye from its what?
its alar plate
what does the terminal HT prosomere give rise to from its basal plate?
the posterior pituitary gland
the terminal HT prosomere gives rise to the posterior pituitary gland from its what?
its basal plate
what is the peduncular HT prosomere connected to in the diencephalon
prosomere 3 in the diencephalon
rostrally, what is the prominent HT anatomical landmark?
the optic chiasm
caudally, what is the prominent HT anatomical landmark?
the mamillary body
in the HT, what landmark is between the optic chiasm and mamillary body?
the pituitary stalk
what is the most rostral part of the HT above?
the optic chiasm
what is the HT nucleus immediately above the optic chiasm called?
the suprachiasmatic nucleus
what does the suprachiasmatic nucleus serve as?
the brains 24 hour clock
What do neurons in the suprachiasmatic nucleus have that allow them to be the brains 24-hour clock?
internal timing systems
how can the internal timing system of neurons in the suprachiasmatic nucleus be adjusted?
with light intensity info from the optic nerves
where does light intensity info that adjusts SCN neurons arrive from?
the optic nerve
in complete darkness, the SCN reverts to a cycle of how long?
25 hours
what is the brains clock essential for timing?
peaks of hormonal secretion from endocrine glands
what is the main landmark in the central part of the HT?
the pituitary stalk
what is the central part of the HT with the pituitary stalk called?
the tuber cinerum
during vertebrae evolution what has become organized in a hierarchy of modules in the brain?
complex movements and behaviours
during vertebrae evolution complex movements and behaviours have become organized in a:
hierarchy of modules in the brain
what is at the top of the hierarchy of complex movements and behaviors in the brain?
survival behaviours relating to the individual as well as the species
what do survival behaviours include?
eating
drinking
defensive behaviours
reproduction
basic movement patterns to explore the immediate surrounds
what part of the brain are survival behaviours primarily controlled?
the HT
how many main groups of control centres are there in the HT for survival behaviours?
2
what nuclei in the HT controls defense, reproduction and ingestion behaviours?
the ventrolateral nucleus
where in the HT is the ventrolateral nucleus?
the medial half of the HT
each set of survival behaviours is related to:
one particular set of HT nuclei
what HT nuclei initiates foraging and exploratory behaviours?
nuclei in the mamillary body
where are the nuclei in the mamillary body that initiate foraging and exploratory behaviours?
caudal HT
nearby MB: the substantia nigra and ventral tegmental area
what are examples of foraging/exploratory behaviours that nuclei in the mamillary body initiate.
turning the head + eyes towards an object of interest
running to explore surroundings
what is described as the ‘leader in the endocrine orchestra’?
the pituitary gland
what is described as the ‘conductor in the endocrine orchestra’?
the HT
The HT has powerful neurons groups that control what in the pituitary gland?
hormonal secretion
what controls hormonal secretion in the pituitary gland?
the HT
the HT directly instructs and controls hormonal secretion where?
in the pituitary gland
large neurosecretory cells in paraventricular and supraoptic nuclei send axons where?
to the posterior pituitary
what send their axons to the posterior pituitary?
large neurosecretory cells in paraventricular and supraoptic nuclei
the posterior pituitary releases what into the bloodstream?
oxytocin and vasopressin
what does oxytocin do?
stimulates contraction of the uterus at birth
initiates milk secretion after birth
plays a role in adult pair bonding and maternal-infant attachment
what is another name for vasopressin?
anti-diuretic hormone (ADH)
what does vasopressin/ADH do?
increases blood pressure
controls urine production
where does vasopressin influence?
kidney tubules
where does oxytocin influence?
mammary glands
uterus muscles
what does the HT less directly control?
the anterior pituitary
does the HT control the anterior or posterior pituitary more directly?
the posterior pituitary is controlled more directly
What does PVN stand for?
paraventricular nucleus
what does SCN stand for?
suprachiasmatic nucleus
cells in the PVN release tiny amounts of releasing hormone into what?
specialized blood portal system
cells in the PVN release tiny amounts of what into the blood portal system?
releasing hormone
the blood portal system carries releasing hormones from the PVN to where?
the anterior pituitary
the blood portal system connecting the anterior pituitary and PVN consists of what?
2 capillary sets connected by a portal vein
what does the 1st capillary bed in the anterior pituitary portal system do?
collects releasing hormones from the HT
what do the small portal veins in the anterior pituitary portal system do?
transport releasing hormones to the 2nd capillary bed in the anterior pituitary
what do releasing hormones from the HT reach in the anterior pituitary?
endocrine secreting cells
what does releasing hormone stimulate in the anterior pituitary?
the release of major hormones from the anterior pituitary cells
in the anterior pituitary, what are the major hormones whose releases are stimulated by releasing hormones from the PVN/HT?
growth hormone (GH),
thyroid-stimulating hormone (TSH),
adrenocorticotrophic hormone (ACTH),
follicle-stimulating hormone (FSH),
prolactin (PRL),
luteinizing hormone (LH).
