Cells and Tissues of The Nervous System Flashcards Preview

Nervous System (Year 2 GM) > Cells and Tissues of The Nervous System > Flashcards

Flashcards in Cells and Tissues of The Nervous System Deck (58)
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1
Q

How do glial cells contast to neurons?

A

In contrast to neurones they are non-excitable and are much smaller

2
Q

How many axons/dendrites does a typical neurone have?

A

Typically - mutliple dendrites and one axon

3
Q

Describe the nucleus in a neurone

A

loose chromatin, prominent nucleolus.

4
Q

What are the cell organelles within a nerve cell?

A

Mitochondria, rER( Nissl bodies), diffuse Golgi apparatus.

5
Q

What is the metabolic rate of a nerve cell?

A

High

6
Q

What is the name given to the cytoplasm in the cell body and the axon?

A

Cell body - perikaryon

Axon - axoplasm

7
Q

What is special about the life of a nerve cell

A

Long living and amitotic - meaning the nucleus can divide without mitosis

8
Q

What part of a neurone can be damaged and will grow back?

A

Axon can grow back but if the cell body is damaged the loss is irreversible

9
Q

What is the effect of myelination of axons?

A

Myelin sheath: Increase conduction speed in axons by ‘saltatory conduction’

Reduces the decay of action potentials

10
Q

What is the myelin sheath formed by in the central and peripheral nevous system?

A

Central - oligodendrocytes

Peripheral - Schwann cells

11
Q

What happens to the cytoplasm of a schwann cell that is wrapped around an axon?

A

Cytoplasm becomes extruded leaving only the cell membrane

12
Q

What is the effect of MS on the myelin sheath?

A

Patchy loss/scarring of myelin sheath (demyelination)à nerve conduction across affected axons abnormal

13
Q

What is the cause of MS

A

Unknown

14
Q

What type of neurones are multipolar?

A

Interneurones and motor neurones

15
Q

Where do you find bipolar neurones?

A

Olfactory mucosa

Retinal nerve fibres

16
Q

What type of nerve fibres are pseudonipolar?

A

Sensory neurones

17
Q

What composes the grey matter of the CNS?

A

Collection of cell bodies+ non-myelinated axons form grey matter (if diffuse) or nucleii (if localised)

18
Q

What forms white matter?

A

Collection of myelinated axons

19
Q

What are tracts?

A

Bundles of axons carrying specific information within the white matter

20
Q

What forms nerves and ganglia?

A

Nerves - myelinated axons

Cell bodies - ganglia

21
Q

What are the glial cells of the CNS?

A

Astrocytes

Oligodendrocytes

Ependymal cells

Microglial cells

22
Q

What are the glial cells of the PNS?

A

Scwhann cells

Satellite cells

23
Q

What is the function of astrocytes?

A

Chemical concentration maintenance

Waste disposal

Responsible for the blood brain barrier

24
Q

What is the function of satellite cells of the PNS?

A

Satellite cells surround sensory and autonomic ganglia and regulate their microenvironment

25
Q

Which two cell types are responsible for the myelination of nerve axons?

A

Oligodendrocytes and schwann cells

Outside the CNS, non-myelinated nerve cells are still wrapped by scwann cells but there is no myelin sheath

26
Q

What is the role of microglial cells?

A

Ingest cells and pathogens - phagocytosis

Immune function

27
Q

What is the function of ependymal cells?

A

Filters blood to produce CSF

28
Q

What is the brainstem responsible for?

A

Vital centres eg: cardiorespiratory,

Pathway for fibre tracts

29
Q

What is the cerebellum responsible for?

A

Balance and coordiantion

30
Q

Where is the seat of consciousness?

A

Cerebrum

31
Q

What does the nervous system form from?

A

The neural tube

32
Q

What are the three primary vesicles that form from the neural tube?

A
33
Q

What are the secondary vesicles?

A
34
Q

When do the primary and secondary vesicles form?

A

Primary - week 4

Secondary - week 5

35
Q

What are ventricles of the brain?

A

The cavity of the neural tube persists in the adult brain as spaces called ventricles

36
Q

What do ventricles contain?

A

CSF

37
Q

What are the lateral ventricles?

A

C shaped cavities which lie in the cerebral hemishpheres

38
Q

Where is the 3rd ventricle?

A

Within the diencephalon

39
Q

What connects the lateral ventricles with the 3rd ventricle?

A

The interventricular foramen

40
Q

Where does the cerebral aqueduct lie?

A

In the midbrain

41
Q

Where does the 4th ventricle lie and what is it shaped like?

A

Diamond-shaped lies in the hindbrain

42
Q

Describe the dura mater

A

Tough and fibrous and has dural folds

43
Q

Describe the pia mater

A

Vascularised and dips into the folds of the brain

44
Q

What is the subdural space?

A

•The subdural space is a potential space which is traversed by blood vessels penetrating into the CNS

45
Q

What contains CSF

A

Subarachnoid space

46
Q

Where do you find CSF?

A

Inside the cavity of brain (ie the ventricles) and central canal of spinal cord.

Is also present surrounding the brain and spinal cord in between the layers of meninges which are coverings of the brain (between the pia and arachnoid)

47
Q

Where is CSF produced?

A

CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles. CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen

48
Q

What aids movement of CSF?

A

The circulation of CSF is aided by the pulsations of the choroid plexus and by the motion of the cilia of ependymal cells

49
Q

Where is CSF absorbed?

A

CSF is absorbed across the arachnoid villi into the venous circulation and a significant amount probably also drains into lymphatic vessels around the cranial cavity and spinal canal.

50
Q

What is the protective mechanism of dural folds?

A

Protect and support different parts of the brain

Help separate the areas of soft tissue to stop them from rubbing together

51
Q

What is the falx cerebri?

A

It is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres of the human brain.

52
Q

What is the tentorium cerebelli?

A

The cerebellar tentorium or tentorium cerebelli(Latin: “tent of the cerebellum”) is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.

53
Q

What is the falx cerebelli?

A

The falx cerebelli is a small sickle shaped fold of dura mater, projecting forwards into the posterior cerebellar notch as well as projecting into the vallecula of the cerebellum between the two cerebellar hemispheres

54
Q

What is the diaphragm sellae?

A

The diaphragma sellae or sellar diaphragm is a flat piece of dura mater with a circular hole allowing the vertical passage of the pituitary stalk. It retains the pituitary gland beneath it in the fossa hypophyseos as it almost completely roofs the fossa hypophyseos of the sella turcica, a part of the sphenoid bone

55
Q

Which substances does the blood brain barrier prevent entering the brain?

A

Harmful amino acids and ions present in the blood stream and blood cells

56
Q

What three things make up the blood brain barrier?

A

Endothelium - tight junction

Thick basal lamina

Foot process of astrocytes

57
Q

Where is the blood brain barrier absent?

A

In a few circumventricular organs: parts of the hypothalamus and posterior pituitary

58
Q

What type of drugs are able to enter the CNS?

A

Drugs have to be lipid soluble or use suitable vectors