Lecture 5 Flashcards Preview

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Flashcards in Lecture 5 Deck (44):
1

What accounts for more cells in the cerebellum than the cerebrum?

folia, higher density, smaller cells

2

Three lobes of the cerebellum?

anterior, posterior, flocculonodular

3

First lobe formed during development in the cerebellum.

flocculonodular, in between anterior (formed 2nd) and posterior (formed 3rd)

4

Deep Cerebellar Nuclei

3 sets within deep white matter; fastigial, globose and emboliform (interposed), dentate

5

Fastigial Nucleus

associated with vermal zone, oldest portion, closest to the midline, medial descending systems-->motor execution

6

Globose and Emboliform (Interposed) Nuclei

associated with paravermal zone, lateral descending systems-->motor execution

7

Dentate Nucleus

newest portion and most important, controls coordination, associated with the lateral physiologic zone

8

Vermal Zone

vestibulocerebellum, controls balance and equilibrium, midline

9

Paravermal Zone

spinocerebellum; gets a huge amount of proprioceptive input from the body; length, tightness, movement of muscles; surrounding vermal

10

Lateral Zone

neocerebellum, gets its information from the neocortex; comparator system, compares information from cortex to information from the body about movement, sends out corrective signals; lateral to paravermal zone

11

What occurs when a patient has a neocerebellar tumor?

movements will be jerky (ataxia), can't send out corrective signals

12

Nystagmus

Pt will have a problem of conjugate eye movement which may originate in the cerebellum

13

Inferior Cerebellar Peduncle

smallest, contains the Dorsal Spinocerebellar tract - carrying sensory information from muscle spindles, GTO (all proprioceptive info), “what you are actually doing”, contains the Cuneocerebellar tract - information from the neck region, where your head goes your body will follow

14

Middle Cerebellar Peduncle

laterally from pons and largest of all the peduncles, contains Corticopontocerebellar tract - carries the motor “plan” (what you want to do)

15

Superior Cerebellar Peduncle

Ventral and Rostral Spinocerebellar Tract - carrying proprioceptive information; Dentorubral and Dentothalamic tracts - output information from deep cerebellar nuclei to red nucleus and eventually thalamus

16

Juxtarestiform Body

olivocerebellar tract

17

Morphological Organization of the Cerebellum

Molecular Layer - relatively cell free; Purkinje Cell Layer - one cell layer thick (very large cells); Granule Cell Layer - looks grainy because the cells are densely packed

18

Two different types of input into cerebellum.

Inputs can arise from spinal cord (external cuneate nucleus, reticular nuclei, or pontine nuclei) - strong excitatory in nature and are called mossy fibers; Inputs can arise from the inferior olivary nucleus - very excitatory in nature

19

All output in the cerebellum is from ________ ____.

Purkinje cells - travel to deep cerebellar nuclei and is strongly inhibitory in nature

20

Hypotonia

reduced muscle tone

21

What can result from lesions of the cerebellum?

hypotonia, asynergia hypo- or hyperdysmetria, lack of check (rebound), terminal "intention" tremor, dysdiadochokinesia

22

Asynergia

uncoordinated

23

Hypo- or Hyperdysmetria

Unable to measure distances correctly, pt will either not reach far enough or reach too far and knock it over

24

Lack of Check (Rebound)

pt will not be able to stop muscles from rebounding

25

Dysdiadochokinesia

unable to coordinate palms up and palms down repetitively

26

Dysarthria

unable to coordinate speech (slurred)

27

Granule Cell

send an axon up into the molecular layer; here, it will bifurcate and run the length of a folia
called a parallel fiber, will synapse on basket and stellate cells (inhibit) or direct synapse on purkinje cells (excitatory)

28

After being stimulated by granule cells, they will inhibit purkinje cells.

stellate and basket cells

29

Three functional pathways of the basal ganglia.

motor, cognitive, affective

30

Teeter-Totter Theory

Need to have a biochemical balance in the brain

31

Parkinson's Disease

Paralysis Agitans (too little movement - too much inhibition), best known of the basal ganglia disorders, treat with dopamine but usually only works for 10 years before receptors get down-regulated and stop working

32

Huntington's Disease

Pt moves ALL the time (too much movement), too much excitation, looked for too much dopamine in other parts of the basal ganglia

33

Fetal/Neonatal Intraparenchymal Infarcts (Cerebral Palsy)

Strokes within the brain of infants or neonates, lesion at or around the basal ganglia at the time of birth, Pt will present with motor problems that will either look like Parkinson’s or Huntington’s disease depending on what part of the basal ganglia is affected

34

The tonsils of the cerebellum sit right in the ______ _______.

foramen magnum

35

Why can swelling of the cerebellum be fatal?

herniate downwards through foramen magnum; this will put pressure on the brain stem; which will affect the cardiac regions of the medulla

36

Terminal intention tremor

occurs towards end of motion as corrective signals are being sent (neocerebellum - lateral zone)

37

Resting tremors in Parkinson's disease.

In many cases this will stop when they are moving; problem in basal ganglia (Specifically substantia nigra)

38

Essential tremor.

tremors that occur all the time

39

Why is the cerebellum affected by alcohol before the cerebrum?

it has more cells and the BBB

40

Archicerebellum

Vestibulospinal system, Vermal zone to fastigial nuclei, Balance

41

Paleocerebellum

Rubrospinal System, Girdle control: control stability before you can have mobility

42

Neocerebellum

Corticospinal System, rest of the volitional control of the body

43

Climbing fibers and mossy fibers come through the _______ cerebellar peduncle to cerebellum.

inferior

44

Enlargement of lateral ventricles is a tip off for ____________ __________.

Huntington's Disease, caudate nucleus atrophy