Cells and Tissues of the Nervous System Flashcards Preview

Systems: Neurology AB > Cells and Tissues of the Nervous System > Flashcards

Flashcards in Cells and Tissues of the Nervous System Deck (76)
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1
Q

What are the divisions of the nervous system?

A

CNS (brain and spinal cord)

PNS (cranial and spinal nerves)

2
Q

What are the divisions of the PNS?

A
  • Sensory (afferent) division

- Motor (efferent) division

3
Q

What are the divisions of the motor (efferent) division?

A
  • Somatic motor

- Autonomic

4
Q

What are the divisions of the ANS?

A
  • Sympathetic

- Parasympathetic

5
Q

What are neurons?

A

Structural and functional units which are excitable cells

6
Q

What are impulses carried as in neurons?

A

Action potentials

7
Q

What are glial cells?

A

Non excitable supporting cells which are much smaller than neurons

8
Q

What is the structure of a typical neuron?

A

Multiple dendrites with one axon

9
Q

How do the impulse transmissions travel in neurons?

A

Impulse transmission is by action potentials which can travel in only one direction from cell body to synaptic terminal

10
Q

What is found inside the nucleus of an axon?

A
  • Loose chromatin

- Prominent nucleolus

11
Q

What cell organelles are present in neurones?

A
  • Mitochondria
  • rER (Nissl bodies)
  • Diffuse Golgi apparatus
12
Q

What is the metabolic rate of axons?

A

High

13
Q

What is the cytoplasm in the cell body of neurons?

A

Perikaryon

14
Q

What is the cytoplasm in the axon of neurons?

A

Axoplasm

15
Q

What is meant by neurons being long living and amitotic?

A

After development they will persist. If it dies it will not regenerate however, the axon can regrow.

16
Q

What part of the neuron can grow back if damaged?

A

Axon

17
Q

What happens if the cell body of a neuron is damaged?

A

The loss is irreversible

18
Q

What is the function of the myelin sheath?

A

Increase conduction speed in axons by ‘salutatory conduction’

19
Q

What is the myelin sheath formed by in the PNS?

A

Schwann cells

20
Q

What is the myelin sheath formed by in the CNS?

A

Oligodendrocytes

21
Q

In myelinated axons, what is formed?

A

Mesoaxon

22
Q

What happens when Schwann cells wrap around axons?

A

The cytoplasm of the cell gets extruded leaving only the cell membrane

23
Q

Give an example of a condition which involves demyelination.

A

Multiple sclerosis

24
Q

What happens to the myelin sheath in MS?

A

Patchy loss/scarring of myelin sheath (demyelination)

25
Q

What does demyelination cause?

A

Nerve conduction across affected axons becomes abnormal

26
Q

What is the cause of MS?

A

Cause is unknown

May be linked to autoimmunity or viral illness

27
Q

What can be seen on MRI of MS?

A

Whitish plaques of demyelination

28
Q

What country has the highest prevalence of MS in the world?

A

Scotland

29
Q

What is the prognosis of MS?

A

Variable

30
Q

What types of neuron are there?

A
  • Multipolar
  • Bipolar
  • Pseudounipolar
31
Q

What type of neurons are multipolar neurons?

A
  • Interneurons

- Motor neurons

32
Q

What type of neurons are bipolar neurons?

A
  • Olfactory mucosa

- Retinal nerve fibres

33
Q

What type of neurons are pseudounipolar neurons?

A

Sensory neurons

34
Q

How are cell bodies and non-myelinated axons organised?

A

Form grey matter (if diffuse) or nuclei (if localised)

35
Q

How are myelinated axons organised?

A

Form white matter (diffuse) or tracts (bundles of axons carrying specific information within the white matter)

36
Q

In the periphery, what do myelinated axons form?

A

Nerves

37
Q

In the periphery, what do cell bodies form?

A

Ganglia

38
Q

Where are neuroglia found?

A

PNS and CNS

39
Q

What neuroglia are found in the PNS?

A
  • Satellite cells

- Schwann cells

40
Q

What neuroglia are found in the CNS?

A
  • Ependymal cells
  • Microglia
  • Oligodendrocytes
  • Astrocytes
41
Q

What is the function of satellite cells?

A

Surround neuronal cell bodies

42
Q

What is the function of Schwann cells?

A

Myelination

43
Q

What is the function of ependymal cells?

A

Line ventricles

44
Q

What is the function of astrocytes?

A
  • Have end feet
  • Surround synapses and capillaries
  • Help in K buffering
45
Q

What is the function of oligodendrocytes?

A

Myelination

46
Q

What is the function of microglia?

A

Involved in phagocytosis and scar tissue formation

47
Q

In development, in which embryological layer does the neural plate form?

A

Surface ectoderm

48
Q

How does the neural plate become the neural tube?

A

It folds over

49
Q

What do the neural crest cells do?

A

They migrate and form many structures and organs

50
Q

What does the neural tube form?

A

Nervous system

51
Q

What happens to the neural tube as soon as it is formed?

A

It divides into 3 primary vesicles during week 4 and secondary vesicles during week 5

52
Q

What do the vesicles of the neural tube develop into?

A

Brain

53
Q

What are the primary vesicles of the neural tube?

A
  • Prosencephalon (forebrain)
  • Mesencephalon (midbrain)
  • Rhombencephalon (hindbrain)
54
Q

What are the secondary vesicles of the neural tube?

A
  • Telencephalon
  • Diencephalon
  • Mesencephalon
  • Metencephalon
  • Myeloncephalon
55
Q

What do the cavities of the neural tube persist as?

A

Ventricles

56
Q

What do the ventricle contain?

A

CSF

57
Q

Where do the lateral ventricles lie?

A

Cerebral hemispheres

58
Q

What does the interventricular foramen connect?

A

Lateral ventricles to the III ventricle within the diencephalon

59
Q

Where does the cerebral aqueduct lie?

A

Midbrain

60
Q

Where does the IV ventricle lie?

A

Hindbrain

61
Q

What are the 3 layers of covering of the CNS?

A
  • Dura mater
  • Arachnoid mater
  • Pia mater
62
Q

What are the features of the dura mater?

A
  • Tough
  • Fibrous
  • Has dural folds
63
Q

What are the features of the pia mater?

A
  • Vascularised

- Dips into the folds of the brain

64
Q

What is the subdural space?

A

A potential space which is traversed by blood vessels penetrating into the CNS

65
Q

What does the subarachnoid space contain?

A

CSF

66
Q

What is the CSF?

A
  • The fluid inside the cavity of the brain and central canal of the spinal cord
  • It is also present surrounding the brain and spinal cord between the layers of meninges (Pia and arachnoid)
67
Q

What is the CSF responsible for?

A

Maintenance of ICP

68
Q

Where is the CSF formed?

A

Choroid plexus

69
Q

Where is the CSF absorbed?

A

Arachnoid villi

70
Q

What are the layers of the scalp?

A
  • Skin
  • Cutaneous tissue
  • Aponeurosis
  • Loose areolar tissue
  • Pericranium
71
Q

What dural folds are there within the brain?

A

-Falx cerebri
-Tentorium cerebelli
-Falx cerebelli
Diaphragma sellae

72
Q

What is the blood brain barrier?

A

Is a protective mechanism that helps maintain a stable environment for the brain and prevents harmful amino acids & ions present in the bloodstream and blood cells from entering the brain.

73
Q

What are the components of the BBB?

A
  • Endothelium tight junction
  • Thick basal lamina
  • Foot processes of astrocytes
74
Q

Where is the BBB absent?

A

BBB is absent in a few ‘circumventricular’ organs: parts of hypothalamus, posterior pituitary.

75
Q

How does the BBB affect drug delivery to the CNS?

A

Plays a major role in drug delivery to CNS. Drugs have to be lipid soluble or use suitable vectors.

76
Q

Where is the CSF circulated?

A

Subarachnoid space