hypothalamus & autonomic control

Question 1

how many major nuclei in hypothalamus

Answer 1

11

Question 2

2 nuclei from hypothalamus to remember

Answer 2

paraventricular nucleus
supraoptic nucleus

Question 3

homeostasis process

Answer 3

1. disruption to vital parameter
2. disruption detected by sensory inputs
3. integration of sensory and contextual inputs by hypothalamus
4. output
5. restoration of parameters

Question 4

3 output areas from homeostasis

Answer 4

ANS - motor
neuroendocrine - hormones released from neurons
behavioural

Question 5

2 parts of the pituitary gland

Answer 5

anterior = adenohypophysis
posterior = neurohypophysis - derived from neural tube

Question 6

neurons in adenohypophysis (anterior pituitary)

Answer 6

parvocellular neurons - small diameter
release neurohormones = aka releasing hormones as they stimulate release of other hormones
carried through portal vein from one capillary bed to another
bind to receptors on troph cells - stimualted to release another hormone

Question 7

neurons in neurohypophysis (posterior pituitary)

Answer 7

magnocellular neurons - large diameter
axons go down through pituitary stork
directly release hormones into areas surrounding circulation in posterior pituitary

Question 8

ANS - 2 efferent pathways

Answer 8

sympathetic - fight or flight
parasympathetic - rest and digest

Question 9

ANS - innervate effectors (3)

Answer 9

smooth muscle - lungs, intestines
cardiac muscle
glands

generally innervate same tissue with opposing effects for para/sympathetic systems

Question 10

origins of 2 efferent pathways

Answer 10

sympathetic = thoracic and lumbar spinal cord
parasympathetic = brain stem and sacral spinal cord

Question 11

3 divisions of ANS

Answer 11

sensory = receptors (internal organs, blood vessels) and afferent fibres (visceral nerves - cranial)

brainstem = e.g. cardiac, vasomotor, respiratory – variations in hypothalamic control here depending on parameter = greater input for body temp but less for pupillary constriction/dilation and salivation (simple cause and effects)

motor = efferent fibres (autonomic nerves), effectors (smooth muscle, cardiac muscle, glands)

Question 12

organisation of ANS

Answer 12

preganglionic neurons –> postganglionic neurons –> effector cells

pre -> post = acetylcholine synapse
post -> effector = adrenergic synapse

Question 13

preganglionic neurons

Answer 13

found in brainstem and spinal cord
send axons out from here
have acetyl-cholinergic synapses

Question 14

postganglionic neurons

Answer 14

have adrenergic synapses

Question 15

IML

Answer 15

intermediolateral cell column
in spinal cord - find preganglionic sympathetic neurons here from T1 (thoracic) to L3 (lumbar) of spinal cord
controlled by RVLM (rostral-ventrolateral medulla)

Question 16

parasympathetic organisation

Answer 16

preganglionic neurons have long axons to go to organs they are needed to innovate
acetylcholine synapses for pre and postganglionic (G protein coupled receptor)

Question 17

cranial parasympathetic organisation (2 nerves)

Answer 17

oculomotor nerve - CN-III (cranial nerve 3)
from Edinger-Westphal nucleus in midbrain
controls iris and dilation of pupil

vagus nerve - CN-X (cranial nerve 10)
from dorsal motor nucleus of vagus and nucleus ambiguous
controls 80% of parasympathetic outflow amd carries many visceral afferents