Cells and Tissues of The Nervous System

Question 1

How do glial cells contast to neurons?

Answer 1

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

Question 2

How many axons/dendrites does a typical neurone have?

Answer 2

Typically - mutliple dendrites and one axon

Question 3

Describe the nucleus in a neurone

Answer 3

loose chromatin, prominent nucleolus.

Question 4

What are the cell organelles within a nerve cell?

Answer 4

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

Question 5

What is the metabolic rate of a nerve cell?

Answer 5

High

Question 6

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

Answer 6

Cell body - perikaryon

Axon - axoplasm

Question 7

What is special about the life of a nerve cell

Answer 7

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

Question 8

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

Answer 8

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

Question 9

What is the effect of myelination of axons?

Answer 9

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

Reduces the decay of action potentials

Question 10

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

Answer 10

Central - oligodendrocytes

Peripheral - Schwann cells

Question 11

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

Answer 11

Cytoplasm becomes extruded leaving only the cell membrane

Question 12

What is the effect of MS on the myelin sheath?

Answer 12

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

Question 13

What is the cause of MS

Answer 13

Unknown

Question 14

What type of neurones are multipolar?

Answer 14

Interneurones and motor neurones

Question 15

Where do you find bipolar neurones?

Answer 15

Olfactory mucosa

Retinal nerve fibres

Question 16

What type of nerve fibres are pseudonipolar?

Answer 16

Sensory neurones

Question 17

What composes the grey matter of the CNS?

Answer 17

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

Question 18

What forms white matter?

Answer 18

Collection of myelinated axons

Question 19

What are tracts?

Answer 19

Bundles of axons carrying specific information within the white matter

Question 20

What forms nerves and ganglia?

Answer 20

Nerves - myelinated axons

Cell bodies - ganglia

Question 21

What are the glial cells of the CNS?

Answer 21

Astrocytes

Oligodendrocytes

Ependymal cells

Microglial cells

Question 22

What are the glial cells of the PNS?

Answer 22

Scwhann cells

Satellite cells

Question 23

What is the function of astrocytes?

Answer 23

Chemical concentration maintenance

Waste disposal

Responsible for the blood brain barrier

Question 24

What is the function of satellite cells of the PNS?

Answer 24

Satellite cells surround sensory and autonomic ganglia and regulate their microenvironment

Question 25

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

Answer 25

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

Question 26

What is the role of microglial cells?

Answer 26

Ingest cells and pathogens - phagocytosis Immune function

Question 27

What is the function of ependymal cells?

Answer 27

Filters blood to produce CSF

Question 28

What is the brainstem responsible for?

Answer 28

Vital centres eg: cardiorespiratory, Pathway for fibre tracts

Question 29

What is the cerebellum responsible for?

Answer 29

Balance and coordiantion

Question 30

Where is the seat of consciousness?

Answer 30

Cerebrum

Question 31

What does the nervous system form from?

Answer 31

The neural tube

Question 32

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

Answer 32

Question 33

What are the secondary vesicles?

Answer 33

Question 34

When do the primary and secondary vesicles form?

Answer 34

Primary - week 4 Secondary - week 5

Question 35

What are ventricles of the brain?

Answer 35

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

Question 36

What do ventricles contain?

Answer 36

CSF

Question 37

What are the lateral ventricles?

Answer 37

C shaped cavities which lie in the cerebral hemishpheres

Question 38

Where is the 3rd ventricle?

Answer 38

Within the diencephalon

Question 39

What connects the lateral ventricles with the 3rd ventricle?

Answer 39

The interventricular foramen

Question 40

Where does the cerebral aqueduct lie?

Answer 40

In the midbrain

Question 41

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

Answer 41

Diamond-shaped lies in the hindbrain

Question 42

Describe the dura mater

Answer 42

Tough and fibrous and has dural folds

Question 43

Describe the pia mater

Answer 43

Vascularised and dips into the folds of the brain

Question 44

What is the subdural space?

Answer 44

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

Question 45

What contains CSF

Answer 45

Subarachnoid space

Question 46

Where do you find CSF?

Answer 46

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)

Question 47

Where is CSF produced?

Answer 47

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

Question 48

What aids movement of CSF?

Answer 48

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

Question 49

Where is CSF absorbed?

Answer 49

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.

Question 50

What is the protective mechanism of dural folds?

Answer 50

Protect and support different parts of the brain Help separate the areas of soft tissue to stop them from rubbing together

Question 51

What is the falx cerebri?

Answer 51

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.

Question 52

What is the tentorium cerebelli?

Answer 52

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.

Question 53

What is the falx cerebelli?

Answer 53

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

Question 54

What is the diaphragm sellae?

Answer 54

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

Question 55

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

Answer 55

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

Question 56

What three things make up the blood brain barrier?

Answer 56

Endothelium - tight junction Thick basal lamina Foot process of astrocytes

Question 57

Where is the blood brain barrier absent?

Answer 57

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

Question 58

What type of drugs are able to enter the CNS?

Answer 58

Drugs have to be lipid soluble or use suitable vectors