the hypothalamus and autonomic control Flashcards
what does the hypothalamus do
-controls a lot of things
-fairly anterior
-motivated behaviour- rather than something that changes bodily
medial sits close to midline but not around the ventricle
-perventricular sits right next to ventricles
-function: Links body to mind via ANS and pituitary
what happens in homeostasis
1) Disruption to a vital parameter
2)Sensory inputs (varied)
3)Integration by hypothalamus
4)Autonomic NS
or
Neuroendocrine
or
Behavioural
5)Restoration of vital parameter within physiological range
what are the different Nuclei of the hypothalamus
-Paraventricular nucleus= links to anterior pituitary gland and the posterior and paraventricular nucleus
-Supraoptic nucleus
-Anterior Pituitary/ Adenohypophysis
-Posterior Pituitary/Neurohypophysis
what happens in adenohypophysis
1) neurones dont project all the way down, they stop in the pituitary stalk
2) release hormones which is taken up in the blood vessels (superior hypophyseal artery) and feeds pituitary stalk
3) hormones released travel through portal vein
4) portal vein connects one set of capillary beds to another
-Troph cells (release hormones) stimulated by releasing hormones from parvocellular neurons of the hypothalamus
-parvocellualr neurone - originate in hypothalamus and effect pituitary
what happen sin neuropophysis
-action potential travels along neurone and if stimulated Releases hormones from the magnocellular neurons directly into systemic circulation
-axons project down hypothalamus down pituitary stalk and terminate around the blood vessels
-magnocelluar neurones are large cell bodies
-oxytocin and antidiuretic hormone - axons travel along hypothalamohypophyseal tract - release controlled by the nervous system
what are the major pituitary hormones
-tropic hormones
-lactation
-oxytocin, parturition, and lactation
-ADH/ vasopressin fluid balance
whats the autonomic nervous system
-Involuntary
-Two efferent pathways:
=Sympathetic
=Parasympathetic
-Innervate effectors:
=Smooth muscle
=Cardiac muscle
=Glands
-innervate the same tissues but they have different effects
-Generally innervate the same tissue but normally have opposing effects
what can ANS function without
-the hypothalamus
-sensory (afferent) division ->
=Receptor location
Internal organs
Blood vessels
=Afferent fibres
Visceral nerves (cranial nerves)
-> brainstem nuclei ->
=E.g. cardiac
vasomotor
respiratory
->motor (efferent ) division
=Efferent fibres
Autonomic nerves
Sympathetic
Parasympathetic
=Effectors:
Smooth muscle
Cardiac muscle
Glands
what requires greater input from the hypothalamus?
-Regulation of body temperature
whats the general organisation of the ANS
-preganglionic neurones- developmentally derived from neural tube, Brainstem & spinal cord
-post ganglionic neurones- parasymapthetic : cholinergic, sympathetic : adrenergic- makes noradrenaline
-effector cells: smooth muscle cells. gland cell, cardiac muscle cell, brown adipocytes
whats the sympathetic organisation like
-Dorsal Horn
-Intermediate Grey Zone
-Intermediolateral Cell Column
-Lateral Horn
-Ventral Horn
look at slide 12
What controls sympathetic preganglionic neurons?
-Nucleus tractus solitarii (NTS)
-Ventrolateral medulla- really important in innervating preganglionic neurons and influencing output
whats Sacral Parasympathetic Organisation like
-Dorsal Horn
-Intermediate Grey Zone
-Lateral Horn
-Ventral Horn
-cholinergic
-sits in sacral spinal chord
-individual ganglia for PSN- axon sent out to ganglia
whats the Cranial Parasympathetic Organisation
-Edinger-Westphal nucleus
-Dorsal motor nucleus of the vagus
-Nucleus ambiguus
-Oculomotor nerve (CN III)cranial nerve influenced by input from visual system, outputs to muscles of eyes which charge where you’re looking
whats the importance of the vagus nerve
-The Vagus nerve (cranial nerve X) carries ~80% of total parasympathetic outflow (Vagus is Latin for wanderer).
-The Vagus nerve also carries tonnes of visceral afferents
– vagal nerve stimulation
