Lecture 12, 13, 14 - Hypothalamus Flashcards by justina han

The hypothalamus is REGIONALLY divided into: (x4)

name the nuclei contained in each region [total=12]

preoptic region (medial & lateral preoptic nuclei)
supraoptic region (ant. hypothalamic, supraoptic, suprachiasmic, paraventricular)
tuberal region (Dorso & ventromedial, arcuate, infundibulum)
mammillary region (mammillary bodies, posterior hypothalamic)

How well did you know this?

Not at all

Perfectly

the hypothalamus is FUNCTIONALLY divided into:

lateral
middle
periventricular

How well did you know this?

Not at all

Perfectly

The fornix divides which two hypothalamic functional zones?

middle and lateral

periventricular -> middle [FORNIX] -> lateral

How well did you know this?

Not at all

Perfectly

what are the functions of the PERIVENTRICULAR zone (x1)

regulates release of endocrine hormones from ANTERIOR pituitary gland

How well did you know this?

Not at all

Perfectly

What are functions of the middle zone (x3)

regulating release of OXYTOCIN & VASOPRESSIN from POSTERIOR pituitary gland
regulates autonomous system
sets biological rhythm of organism

How well did you know this?

Not at all

Perfectly

which hypothalamic nucleus regulates the organism’s biological rhythm?

suprachiasmic

How well did you know this?

Not at all

Perfectly

What are functions of the LATERAL zone ? (x3)

regulating sleep-wakefullness
regulating feeding cycle
integrates information from other hypothalamic nuclei and cortical structures engaged in emotions

How well did you know this?

Not at all

Perfectly

The hypothalamus is supplied by which artery?

the hypothalamic branch of the posterior communicating artery

How well did you know this?

Not at all

Perfectly

What is the Blood-brain barrier? What are its functions?`

a semi-permeable barrier which protects the blood flow from brain extracellular fluid (BECF) that is unique to the CNS.
made from astrocytes and endothelial cells joined by tight junctions which line the interior of CNS arteries.
allows passage of water molecules, some gases, lipid soluble substances, amino acids and glucose.
not present on circumventricular organs

How well did you know this?

Not at all

Perfectly

What are circumventricular organs? (dont list them yet)

organs which are located around the border of the ventricles,
extensive vasculature but ‘leaky’ BBB
alternate route for hormone secretion into bloodstream

How well did you know this?

Not at all

Perfectly

List the circumventricular organs (divide into the two types)

SENSORY ORGANS: sense plasma molecules in bloodstream and convey info to other brain regions for DIRECT COMMUNICATION between ANS and systemic circulation

subfornical organ
area postrema
vascular organ of lamina terminalis

SECRETORY ORGANS: secrete hormones and glycoproteins to peripheral bloodstream in repsonse to internal (brain) and external stimuli

Pineal gland
Neurohypophysis (post. pituitary gland)
sub commissural organ
intermediate lobe of pituitary gland
median eminence

How well did you know this?

Not at all

Perfectly

all CVO’s EXCEPT ____ feature extensive vasculature with ___ capilliaries, causing a “leaky” BBB

SCO (sub commissural organ)

fenestrated (perforated, presence of apertures)

How well did you know this?

Not at all

Perfectly

The Sella Turcica and Diaphram Sellae are both

dural reflections which encase the pituitary gland

How well did you know this?

Not at all

Perfectly

The hypophysis and hypothalamus together secrete a total of ___ hormones (__each), to regulate all aspects of ____(x4)

16
pit = 7, hyp = 9
growth, metabolism, development, homeostasis

How well did you know this?

Not at all

Perfectly

the anterior pituitary gland is known as___and posterior is known as ____

adenohypophysis

- neurohypophysis (contains neuronal axons from hypothalamus)

How well did you know this?

Not at all

Perfectly

The adenohypophysis (distal, intermediate) is formed from___ and the neurohypophysis is formed form the ____

ectodermal endothelium of roof of mouth

- nerve tissue of floor of diencephalon

How well did you know this?

Not at all

Perfectly

Which lobe of the pituitary gland is PART of/DEVELOPS from the hypothalamus?

Study These Flashcards

neuro/posterior (forms from floor od diencephalon aka hypothalamus)

what are hormones released by the adenohypophysis called?

Study These Flashcards

tropic hormones/ tropics

What does the adenohypophysis do?

Study These Flashcards

secretes and releases tropic hormones

- regulated by hypothalamus

how does the hypothalamus regulate the secretion and release of hormones from the adenohyp.?

Study These Flashcards

by releasing hypothalamic releasing/inhibiting hormones into the PRIMARY PLEXUS of the HYPOPHYSEAL PORTAL SYSTEM, which travels to the SECONDARY PLEXUS via the PORTAL VEINS, stimulating hormone release into the circulation.

how is the portal system different from normal blood flow?

Study These Flashcards

NORMAL:
heart -> artery -> capillary -> vein -> heart

PORTAL SYSTEM:
heart -> artery -> capillary network -> portal vein ->2nd capilary network -> vein -> heart

what are Somatrophs?

Study These Flashcards

they are hormone secreting neurons of the adenohypophysis which secrete SOMATOTROPIN or HUMN GROWTH HORMONE (hGh).
they are the most plentiful endocrine cell in the anterior pituitary.

Hypoglycemia increases production of ___

hyperglycemia increases production of__

Study These Flashcards

GHRH (growth hormone releasing hormone)

- GHIH

high amount of hGH (human growth hormones) increases?

Study These Flashcards

blood-glucose level

describe the functions and properties of the neurohypophysis

- posterior pituitary gland - part of hypothalamus - does NOT secrete hormones - STORES & RELEASES hormones - oxytoncin, vasopressin - contains axons from hypothalamus

The neurohypophysis recieves axons (thus hormones) from which two hypothalamic nuclei?

- paraventricular (oxytocin) | - supraoptic (vasopressin)

The adenohypophysis receives blood supply from the ___and drained by the ____. the neurohypophysis recieves blood from the ___ and is drained by the ____.

- superior hypophyseal artery - anterior hypophyseal vein - inferior hyp. artery - posterior hyp. vein

The adenohypophysis is part of the parvocellular or magnocellular neurosecretory system?

- parvocellular

the hypothalamus has 5 afferent projections. What are they and where do they originate (specifically) and which nuclei do they terminate?

- fornix (from SUBICULAR CORTEX of hippocampal formation to ANTERIOR NUCLEUS OF THALAMUS, MEDIAL HYPOTHALAMUS & MAMMILLARY BODIES) - stria terminalis (from medial amygdala to medial hypothalamus & Bed nucleus) - ventral amygdalofugal pathway (from basolateral amygdala to lateral hypothalamus and midbrain) - Medial forebrain bundle (septal area) - retinohypothalamic fibres (retina)

what are two efferent projections from the Hypothalamus?

- mammillothalamic (mammillary bodies -> anterior nucleus of thalamus, control of emotional expression part of papez circuit) - mammillotegmental (mammillary bodies -> midbrain tegmentum, for hypothalamic control of autonomic systems)

Which three pathways allow hypothalamic control of the ANS?

- Dorsal longitudinal fasciculus - medial forebrain bundle - mammillotegmental pathway

Which hypothalamic nucleus gives rise to the DLF and where does this pathway innervate? what is its function?

- paraventricular nucleus - along brainstem and all levels of spinal cord - mediate sympathetic & parasympathetic NS

Which hypothalamic nucleus gives rise to the MFB and where does this pathway innervate? what is its function?

- paraventricular nucleus (incl. fibres from basal forebrain and septal nuclei) - same as DLF - mediate sympathetic & parasympathetic NS

Which hypothalamic nucleus gives rise to the Mammillotegemental tract and where does this pathway innervate? what is its function?

- mammillary bodies - autonomic nuclei of brainstem (pontine & midbrain reticular formation) - mediate ONLY parasympathetic NS

What are paravertebral/sympathetic chain ganglia?

- chains of ganglia of the sympathetic NS, which exist next to the spinal cord. - fibres from the spinal cord, which enter these ganglia are called PREGANGLIONIC fibres - fibres that exit these ganglia to innervate visceral organs are called POST-GANGLIONIC fibres. - the existence of this chain allows for preganglionic fibres to travel vertically through the chain and innervate higher or lower levels of the spinal cord.

does the sympathetic nervous system INCREASE or DECREASE blood-sugar level?

INCREASE

what is the major difference between parasympathetic and sympathetic nervous systems?

the effects of the parasympathetic NS are LOCALISED and TEMPORARY

Which hypothalamic nucleus is the MASTER BIOLOGICAL CLOCK?

SCN - suprachiasmic nucleus - synchronises inner clock with environmental/social clock - follows circadian rhythm (24hrs)

the SCN always communicates with other hypothalamic nuclei via the ___

PVN

which neurotransmitter is MOST used by the SCN?

GABA

explain the concept of melatonin release during day and night

DAY: daylight EXCITES GABAergic neurons in the SCN hence, inhibiting neurons which communicate with the PVN, leading to inhibited melatonin production. NIGHT: lack of light DOES NOT excite inhibitory function of GABAergic neurons in the SCN, hence excitatory neurons project to PVN which then encourage production of melatonin.

Lecture 12, 13, 14 - Hypothalamus Flashcards

(41 cards)