Revision theme 2

Question 1

What is the function of the Cerebellum?

Answer 1

• posture/balance
• coordination of voluntary movements
• motor learning
• It compares movement intended to movement actually occurring

Question 2

Functional subdivisions of the cerebellum and it’s inputs

Answer 2

• Vestibulocerebellum = Floccularnodular lobe
• Spinocerebellum = Vermis
• Cerebrocerebellum = Cerebellar hemispheres

Question 3

Somatotopic map of cerebellum

Answer 3

Vermis = Trunk
Hemispheres = Limbs

= Contains 2 maps of the body

Question 4

Lobar anatomy of cerebellum

Answer 4

• Synapse on deep motor nuclei before exiting cerebellum

Vermis = Fastigual nucleus

Paravermis = Interposed nucleus

Hemisphere = Dentate nucleus

Vestibulocerebellum (Floccularnodular lobe) bypass deep nuclei and pass to vestibular nuclei = balance and eye movements.

Question 5

Cerebellar output

Answer 5

Vermis - Fastigual nucleus = medial descending systems (truncal control) - Motor execution

Paravermis - interposed nucleus = Lateral descending systems - Motor execution

Dentate = areas 4 and 6 = Motor planning

Vestibular = balance and eye movements

Question 6

Spinocerebellum

Answer 6

• Control of muscle tone and posture
• Afferent neurons from spinocerebellar tracts to vermis then synapse in fastigual nucleus.
• Efferent neurons to vestibular and reticulo spinal tracts - extending, balance and posture

Question 7

ANS

Answer 7

• Involuntary

- Innervates smooth muscle, cardiac muscle and glands

Question 8

Sympatheic

Answer 8

Fight or flight = maximises use of metabolic resources

Sandwiched between parasympathetic
T1- L2

Question 9

Parasympathetic

Answer 9

Rest and digest = Conserves metabolic resources

Brainstem
S2 - S4

Question 10

ANS pathway = disynaptic

Answer 10

preganglionic axons (myelinated) > sympathetic or parasymp ganglia > postsynaptic axon > effector

except sympathetic supply to adrenal medulla

Question 11

ANS neutrotransmission autonomic ganglia

Answer 11

• Acetylcholine is main neurotrasmitter in autonomic ganglia

- Binds to nicotinic (ionotropic) receptors in postsynpatic neurons.

Question 12

Neurotrasmission postganglionic sympathetic neurons

Answer 12

• Noadrenaline is main neurotransmitter (except sweat gland use ach)
• binds to adrenergic receptors (metabotropic)

a1 = BV smooth muscle antagonist = prazosin (hypertension)
b1 = Heart = antagonist - atenolol (hypertension)
b2 = bronchial smooth muscle. Antagonist = salbutamol.

Question 13

Neurotransmission adrenal medulla

Answer 13

= ach
= Bind nicotinic receptors on chromatin cells
= cause release of adrenaline/NoA
= direct activation of sympathetic effector organ

Question 14

Postsynpatics neurotransmission parasym

Answer 14

= ach
= binds muscarinic receptors
= metabotropic
= atropine is antagonist

Question 15

Sympathetic

Answer 15

Cardiac = increases pacemaker activity
and contractile force

Bronchi = dilate

sweat = sweat secretion

Hair = piloerection

Skin = vasoconstriction in skin but vasodilation in muscles

abdomen = inhibition of peristalsis, secretion of adrenaline from adrenal cortex

Eyes = pupils dilate

Question 16

Sympathetic trunk/chain

Answer 16

• interconnected paravertebral ganglion
• preganglionic fibres enter symp trunk though white rami communicans (t1-l2). Postganglionic fibres gray rams communicans.

Question 17

Preganglionic fibres

Answer 17

• either synapse in ganglion

- or pass through into splanchnic nerves to synapse in prevertebral ganglia

Question 18

postganglionic fibres

Answer 18

• more numerous = mass response at multiple levels
• from sympathetic trunk go to periphery to viscera.
  Viscera via medial branches/plexus.

from prevertebral ganglia, posganglionic fibres for plexus around viscera.

Question 19

Cervical sympathetic

Answer 19

• 3 inter-connected ganglia = superior, middle inferior
• posganglionic either pass through gray rami communicants to spinal nerves (upper limb)
• Piggy back down common carotid to heart
• Piggy back up ica/eca into head

External carotid plexus > submandibular and carotid glands
Internal carotid plexus > dilate pupils, lacrimal glands

Question 20

Horner’s syndrome

Answer 20

• disruption of sympathetic supply to head
• pupil is constricted (miosis)
• eyelid (ptosis - droopy)
• skin of face = anhydrosis

Question 21

Thoracic sympathetic

Answer 21

• 12 thoracic ganglia
• postganglionic fibres exit via grey rami communicans to spinal nerves or medial branches to heart and lungs
• preganglionic exit via splanchnic nerves to abdomen

Question 22

Thoracis splanchnic nerves

Answer 22

• synapse in prevertebral ganglia
• celiac ganglion (upper)
• superior mesenteric ( midgut)
• aorticorenal (kidney)
• postganglionic fibres form prevertebral plexus arounds viscera

Question 23

Lumbar sympathetic

Answer 23

4 lumbar sympathetic trunk ganglion
- postganglion exit via grey rami communicans to spinal nerves
- preganglionic exit trunk via lumbar splanchnic to pelvis
(inf mesenteric)

Question 24

Sacral sympathetic

Answer 24

4 ganglia

• postganglionic exit via grey rami communicans to spinal nerves (lower limbs)
• sacral splanchnic nerves (post) to pelvis organs

Question 25

Prasympathetic preganglionic fibres

Answer 25

- brainstem - gray matter spinal cord s2-s4 - all ganglia located close to target organ

Question 26

Cranial nerves (parasympathetic)

Answer 26

- ocularmotor > ciliary ganglion > sphincter pupillae - facial > pterygopalatine ganglion > lacrimal gland - facial > submandibular gland - glossopharyngeal > otic ganglion > parotid - vagus > heart, lungs, abdominal viscera

Question 27

sacral parasympathetic

Answer 27

s2-s4 - preganglionic fibres exit via pelvic splanchnic nerves to pelvis - synapse in walls of target organs parasymp supply bladder - contraction bladder wall and inhibition of sphincter. urination rectum - inhibition of rectal sphincter defacaetion - sexual = vasodilation in erectile tissues

Question 28

ENS

Answer 28

aerbauchs - muscuar contraction meissners - gland secretions truly autonomic!