1 Nervous System Topography Flashcards Preview

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Flashcards in 1 Nervous System Topography Deck (31)
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1
Q

What are the basic components of the CNS and the PNS (3 each)

A
2
Q

Grey and white matter can be found in the central nervous system.

  • Distinguish between the composition of grey matter and white matter.
  • Why is white matter white?
A
  • Grey matter is composed of cell bodies and dendrites (highly vascular)
  • White matter is composed of axons (+ supporting cells)
  • Oligodendrocytes- many axons for one cells*
  • Schwann cells- one axon for one cell*
3
Q

In the peripheral nervous system, identify the equivalent structures of the following:

  • Grey matter
  • White matter
A
  • The PNS equivalent of grey matter is a ganglion
  • The PNS equivalent of white matter is a peripheral nerve
  • Beware ‘basal ganglia’ in CNS (only ganglia in CNS)*
4
Q

How many segments does the spinal cord consist of?

A

The spinal cord is composed of 31 segments

5
Q

Describe the structure of a spinal cord segment

A
  • Central core of grey matter
  • Outer shell of white matter

Each segment connects with a mixed spinal nerve through dorsal sensory roots and ventral motor roots

6
Q

Identify three components of white matter

A
  • Funiculus
  • Tract
  • Fasciculus
7
Q

What is a funiculus?

A
  • A funiculus is a segment of white matter containing multiple distinct tracts
  • Impulses travel in multiple directions
8
Q

What is a tract?

A
  • A tract is an anatomically and functionally defined white matter pathway connecting two distinct regions of grey matter
  • Impulses travel in one direction (unidirectional)
9
Q

What is a fasciculus?

A

A fasciculus is a subdivision of a tract supplying a distinct region of the body

10
Q

Identify the three different regions of grey matter

A
11
Q

What is a nucleus?

A

A nucleus is a collection of functionally related cell bodies (grey matter)

(motor neurones supplying a given muscle arise from multiple segments and form a distinct population of neurones- a nucleus)

12
Q

What is a cortex?

A

A cortex is a folded sheet of cell bodies found on the surface of a brain structure (grey matter) (1-5mm thick)

13
Q

What is a fibre?

A

A fibre is an axon in association with its supporting cells e.g. oligodendrocytes (synonymous with axon)

14
Q

What are the three types of fibres found in the nervous system and what do they connect?

A
    • Association fibres
      • Connect cortical regions within same hemisphere
    • Commissural fibres
      • Connect left and right hemipheres/cord halves
    • Projection fibres
      • Connect cerebral hemipheres with cord/brainstem and vice versa
15
Q

What are the three components of the brainstem?

A
16
Q

What is the function of the:

  • midbrain (mesencephalon)?
  • pons?
  • medulla?
A
17
Q

Which cortices are found in the following locations:

  • Precentral gyrus
  • Postcentral gyrus

Identify them on the following image:

A
  • Precentral gyrus: contains primary motor cortex
  • Postcentral gyrus: contains primary sensory cortex

(remember we motor forwards –>)

18
Q

What is the optic chiasm?

A

The optic chiasm is a site where fibres in the visual system cross over

19
Q

What is the uncus?

A
  • The uncus is a part of the temporal lobe that can herniate, compressing the midbrain
  • It has an important olfactory role
20
Q

What are the medullary pyramids?

A

The medullary pyramids are a location of descending motor fibres

21
Q

What is the role of the parahippocampal gyrus?

A

The parahippocampal gyrus is a key cortical region for memory encoding

22
Q

Identify the following coloured sturctures in the diagram and state their role/functions:

A
23
Q

Having developed from a hollow tube, the brain is itself hollow.

What are the cavities in the brain called?

A

The cavities in the brain are called ventricles

24
Q

Describe the layout of the ventricular system

A
25
Q

What is found inside the brain ventricles?

A

The ventricles each contain choroid plexus, which makes a total of 600-700ml of cerebrospinal fluid per day

26
Q

What functions does CSF have?

A

CSF has both metabolic and mechanical functions

27
Q

Describe the circulation of cerebrospinal fluid

A

CSF circulates through the ventricular system and subarachnoid space before being reabsorbed at the arachnoid granulations in the superior sagittal sinus (and some other sites)

28
Q

FIll in the missing labels:

A
29
Q

Identify the structures shown by the coloured lines on the image:

A
30
Q

What are arachnoid granulations?

A
31
Q

Describe the flow of CSF from the lateral ventricles to the venous blood.

A