Norden - Integrative Systems Flashcards
The three major integrative systems of the brain are ?
Hypothalamic
Limbic
Reticular
Maintains homeostasis
Hypothalamic system
How does the hypothalamus release hormones into the blood?
Through the posterior pituitary
What are three ways that the hypothalamus infleunces other structures in cns or other organs?
Through synaptic connections.
Through release of hormones into blood (posterior pituitary)
By indirectly producing substances that stimulate or inhibit the anterior pituitary to produce/ release specific hormones into the bloodstream
Adenohypophysis
Anterior lobe of pituitary
Neurohypophysis
Posterior lobe of pituitary gland
Hormones get from the hypothalamus to the anterior lobe of the pituitary gland where they will be released into circulation (after signaled by the hypothalamus) through the ____?
Hypothalamic-hypophyseal portal system
Medial preoptic area/ nuclei has in it?
Gonadotropin-releasing hormone.
This releases follicle stimulating hormone and lutinizing hormone
What is the sexually dimorphic nucleus?
The medial preoptic area/nuclei of the hypothalamus is larger in males than in females due to infleunce of testosterone
This area of the hypothalamus contains GABA-nergic neurons which promote sleep by projecting to and inhibiting areas of the posterior hypothalamus and brainstem which promote wakefullness
Lateeral proptic area/ nuclei
Paraventricular nucleus is in what region of the hypothalamus?
Supraoptic ( above optic chiasm)
What does the paraventricular nucleus produce?
Oxytocin, corticotrophin releasing hormone and thyrotropin-releasing hormone
Produced in hypothalamus.
Released from posterior pituitary into bloodstream
Facilitates parturition and contraction of mammary glands.
Also enhances feelings of connection between infants and adult bonding.
Oxytocin
released by paraventricular nucleus into hypothalamic-hypophyseal portal system. Stimulates ant. Lobe of pituitary to produce/ release adrenocorticotropic hormone
CRH
What does adrenocorticotropic hormone do?
ACTH
Induces adrenal glands to produce and release corticosteroids and catecholamines
TRH does what?
Released by paraventricular nucleus. Stimulates ant lobe pituitary. Release TSH (thyroid stimulating hormone). Which causes thyroid gland to produce thyroid hormone
Main hypothalamic nuclei that controls the parasympathetic nervous system
Anterior nucleus/nuclei
Biological clock of hypothalamus. Receives direct input from primitive retinal ganglion cells {ambient light receptors} which establish circadian rhythms
Suprachiasmatic nucleus
Has neurons which produce, store and transport anti-diuretic hormone (ADH; aka vasopressin)
Supraoptic nucleus
Dilated nerve terminals which may store anti-diuretic hormone.
Herring bodies
When released to circulation, this binds receptors in the distal tubules and collecting ducts of the kidneys and promotes the reabsorption of free water into circulation
Anti-diuretic hormone (ADH) (vasopressin)
What does damage to the supraoptic nucleus or the supraoptic-hypophyseal tract do?
Impairs the production and/or release of ADH, causes rapid loss of free water from the kidney, which can be lethal (diabetes insipidus)
Inappropriate ADH hypersecretion
Excessive retention of free water, leading to hyponatremia
Causes of inappropriate ADH hypersecretion?
Traumatic brain injury, subarachnoid hemorrhage, infection of the brain / meninges
Part of medial zone of the tuberal region of the hypothalamus which is involved in ANS activity, stress response, eating behaviour, emotions, and circadian rhythms
Dorsomedial nucleus
What happens when the ventromedial nucleus in the medial zone of the tuberal region of the hypothalamus is stimulated?
The urge to eat is suppressed
Satiety center is what?
Ventromedial nucleus of medial zone of tuberal region of hypothalamus
Releases growth hormone-releasing hormone (GHRH) into the hypothalamic-hypophyseal portal system where it stimulates the anterior lobe of the pituitary to produce/release growth hormone into the bloodstream
(2) Plays a role in appetite regulation along with the ventromedial nucleus
(3) Releases dopamine (in the hypothalamus, dopamine is referred to as prolactin-inhibiting factor) to the anterior pituitary, where it inhibits the synthesis and release of prolactin; the tuberoinfundibular pathway is one of the 4 main dopaminergic projections in the brain
Arcuate nucleus
Feeding center
Lateral hypothalamic area
Stimulation of the lateral hypothalamic area causes what?
Increased appetite and eating.
Lesions -> anorexia and death from starvation
Lesions in the lateral hypothalamic area can causse?
Anorexia
What is the function of the posterior nuclei of the hypothalamus ( mostly located in the. Mammillary region )
Main control of sympathetic nervous system
Responsible for heat conservation
Contains hypocretin/prexin neurons that maintain awake stake.
What do you get in regards to thermoregulation if you damage the posterior nuclei?
Hypothermia. These nuclei are responsible for heat regulation.
Individuals with fewer H/O (hypocretin/orexin neurons) in the posterior nuclei of the hypothalamus may develop which neurological disorder?
Narcolepsy.
These nuclei are responsible for maintaining the awake state
What two functions do the mammillary nuclei have ?
Memory, via connections to limbic system
Histaminergic neurons in mamillary nuclei play a role in arousal
Most common type of pituitary tumor?
Prolactinoma
What does prolactinomas cause?
Overproduction of prolactin
Abnormal discharge of fluid/milk from the breast
Galactorrhea
What can having increased prolactin cause?
Decreased libido
Genital atrophy
Galactorrhea
In females; amennorhea
In males; impotence
Absence or abnormal ceasing of the menses
Amenorrheaa.
Can be secondary to increased prolactin due to prolactinoma (pituitary tumor
Compromise of the optic chiasm due to pituitary tumor causes what visual problem?
Bitemporal hemianopsia
Lesions in the ventromedial nucleus cause what?
Hyperphagia, extreme obesity
When the ventromedial nucleus is stimulated, what happens?
The urge to eat is suppressed
Stimulation of the lateral hypothalamic area causes?
Increased appetite and eating
Lesions in the lateral hypothalamic area can lead to ?
Anorexia and death from starvation.
Hypothermia can result from the destruction of ?
The posterior nuclei
