The Hypothalamus and Autonomic Control

Question 1

nuclei of hypothalamus

Answer 1

11 major
- paraventricular nucleus - autonomic and neuroendocrine response
supraoptic nucleus

Question 2

structure

Answer 2

connected to pituitary by stalk then splits into
1 - anterior pituitary/adenohypophysis - not neural tissue
2 - posterior pituitary/neurohypophysis - neural tissue

Question 3

adenohypophysis

Answer 3

parvocellular (small diameter) neurons trigger release of neurohormone ‘releasing hormone’ through portal vein = stimulates troph cells to release their own hormones

Question 4

neurohypophysis

Answer 4

magnocellular (large diameter) neurons release hormones directly into systemic circulation

Question 5

major pituitary hormones

Answer 5

tropic
lactation
oxytocin, parturition and lactation
ADH/vasopressin - fluid balance

Question 6

autonomic nervous system

Answer 6

involuntary
2 efferent pathways
- sympathetic
- parasympathetic
innervate effectors:
smooth muscle, cardiac muscle and glands
usually have opposing effects

Question 7

ANS pathway

Answer 7

sensory division - receptors, afferent fibres e.g. visceral nerves —–> brainstem nuclei —–> motor division - efferent fibres e.g. autonomic nerves
degress of hypothalmic control depends on parameter
e.g. blood vol/osmolality changes and thermoregulation involves hypothalamus a lot

Question 8

organisation of ANS

Answer 8

pre ganglionic = all found in CNS (brainstem and spinal cord)
post ganglionic = PNS, uses ACh

Question 9

sympathetic organisation

Answer 9

sympathetic nervous system runs from T1 to L3 of spinal cord

- pre ganglioninc neurons

Question 10

internediolateral cell column

Answer 10

T1-L3
in lateral horn
where pre gang symp neruons are found
exit via ventral horn

Question 11

dorsal horn

Answer 11

sensory input

Question 12

ventral horn

Answer 12

motor neurons

Question 13

peripheral nerve

Answer 13

dorsal and ventral horn join together to form it
most pre gang sympathetic neurons neurons leave via ventral horn and join sympathetic chain - run alongside spinal cord or go to prevertebral ganglion (adrenergic)

Question 14

what controls sympathetic pre gang neruons?

Answer 14

ventrolateral medulla (nucleus)
experiment in cat, stimulate medulla, see excitation in spinal cord when probe was placed in ventrolateral medulla
also nucleus tractus solitarii

Question 15

sacral parasympathetic organisation

Answer 15

dorsal and ventral horn - much bigger as full of neurons
pre gang neurons are still found - leave out of ventral root, pass through peripheral nerve to ganglion in wall of end organ

Question 16

cranial parasympathetic organisation

Answer 16

mid brain - Edinger Welstphal nucleus - contains CNIII - oculomotor nerve, pupil constriction
medulla - dorsal motor nucleus of vagus - vagus nerve CN X, 80% total parasympathetic outflow. nucleus ambiguus