Neuronal Tissues

Question 1

What is the Broadmann Area of the Primary Visual Cortex?

Answer 1

Broadmann Area 17

Question 2

What is the Broadmann Area of the Primary Motor Cortex?

Answer 2

Broadmann Area 4

Question 3

What Are the Broadmann Areas of the cerebral cortex?

Answer 3

Regions of the cerebral cortex with their own distinct function

52 in total

Each area has its own particular inputs and outputs

Question 4

What are the components of a typical neurone?

Answer 4

Cell body (containing the nucleus)

Dendrites

Axon hillock

Axon

Axon collaterals

Axon terminals

Myelin sheath

Question 5

What are the functions of neurones?

Answer 5

Receive and integrate incoming information from sensory receptors or other neurones

Chemically transmit information to other neurones or effector organs

Question 6

What are dendrites?

Answer 6

Branched protoplasmic extensions

They propagate the electrochemical input from other cells to the cell body of a neurone

They branch off from the cell body to receive incoming action potentials from other neurones

Question 7

How much of a neurone can a dendrite occupy?

Answer 7

Up to 95%

Question 8

What is the role of the cell body in a neurone?

Answer 8

Houses the organelles (nucleus, cytoplasm, mitochondria, ribosomes, etc.)

Produces neurotransmitters which are subsequently stored in synaptic vesicles

Question 9

What is the role of the axon hillock?

Answer 9

It is a part of the cell body with a high density of voltage gated Na channels

Is the sight at which action potentials are triggered due to the high density of voltage gated Na channels

Question 10

Myelinated axons

Answer 10

Have a diameter greater than 1 micrometer

Myelination allows saltatory conduction

Action potential passes between nodes of ranvier

This is very rapid (up to 120m/s)

Question 11

What is the role of a sensory neurone?

Answer 11

Sends information from the sensory organs (receptors) into the CNS

Therefore also called Afferent neurones

Question 12

What is the role of a motor neurone?

Answer 12

Carry messages from the CNS to operate muscles and glands

Also referred to as efferent neurones

Question 13

What is the role of an interneurone?

Answer 13

These carry messages from one set of neurones to another

Bring information from different sources into one location In the CNS

Question 14

What are neuronal pathways?

Answer 14

These are used to link separate neurones

Question 15

What is the role of oligodendrocytes?

Answer 15

Oligodendrocytes are responsible for producing and maintaining the myelin sheath in the CNS to create white matter

Each oligodendrocyte can myelinate multiple axons

Question 16

What are the components of myelin?

Answer 16

Myelin basic protein and proteolipid protein make up approximately 80% of myelin

Other proteins include myelin associated glycoprotein (which facilitates the interactions between the axon and myelin

Question 17

What are the benefits of myelinated axons?

Answer 17

Increases the nerve conduction and velocity

Decreases the size of nerves as a result

Question 18

What is the role of microglia in the CNS?

Answer 18

Act as the macrophages of the CNS essentially

Begin inactivated but become activated by pathogens

Comprise 5% of the cells in the brain

They are phagocytic and immune cells but also promote repair

Apoptotic clearance

Question 19

What are the roles of Astrocytes in the CNS?

Answer 19

Provide structural support to the CNS

Supply glucose

Maintain the ionic environment via removal of K

Uptake leftover neurotransmitters in the synaptic clefts

Repair the CNS

Form the blood brain barrier

Question 20

What are the developmental functions of Astrocytes?

Answer 20

Regulate neuro and gliogenesis (they’re stem elements of the CNS)

Neuronal pathfinding

Regulate synaptogenesis

Question 21

What are the structural functions of astrocytes?

Answer 21

Form the scaffold of the CNS, therefore defining the functional architecture of the brain and spinal cord

Astrocytes form a continuous syncytium and integrate other neural cells into this syncytium

Question 22

What are the blood brain barrier related functions of Astrocytes?

Answer 22

Form the glial-vascular interface

Regulate the cerebral microcirculation

Question 23

What are the metabolic functions of astrocytes?

Answer 23

Provide energy substrates for neurones

Collect neuronal waste

Question 24

What are the homeostatic functions of astrocytes?

Answer 24

Control the microenvironment of the CNS

Regulate the concentrations of K following the fluctuations which occur after neuronal activity

Regulate extracellular pH

Remove neurotransmitters from the extracellular space

Question 25

What are the signalling functions of astrocytes?

Answer 25

Modulate synaptic transmission

Metabolise and synthesise neurotransmitters

Release neurotransmitters

Question 26

What are the 2 subtypes of astrocytes and how do they differ?

Answer 26

Fibrous astrocytes are located in white matter areas

Protoplasmic astrocytes are located in grey matter

Question 27

What is the role of astrocytes in the glutamate-glutamine shuttle?

Answer 27

They take up approximately 80% of glutamate released at the synapse

They then convert this to glutamine and release it so the presynaptic terminal can uptake it

It is then converted back to glutamate

Question 28

What are the roles of ependymal cells in the CNS?

Answer 28

They line the ventricles of the brain and the central canal of the spinal cord

Aid in homeostasis of the CSF due to the close contact with it as well as the Brain parenchyma

Also contribute towards the formation of CSF and assist in its circulation via cilia movement

Question 29

What is the blood brain barrier?

Answer 29

Highly selective permeability barrier which has evolved to determine substances can enter the brain and provides immune privilege to the CNS

Question 30

What cells are present in the blood brain barrier?

Answer 30

Astrocytes

Peri yes

Blood endothelial cells

These are arranged in neurovascular bundles

Question 31

How does the permeability of the blood brain barrier change with age?

Answer 31

Decreases

Dysregulation of the blood brain barrier is evidenced in Alzheimer’s disease and delirium, as well as other neurodegenerative disorders

Question 32

What are the roles of Schwann cells and how do they differ from oligodendrocytes?

Answer 32

They are the Neuroglia of the PNS

Aren’t present in the CNS

Important for regeneration and they provide substrate for the axon to grow along

Myelinates a single axon

Question 33

What are Satellite cells?

Answer 33

Located exclusively in the peripheral ganglia (sensory, parasympathetic and sympathetic)

Wrap around neuronal cell bodies forming a complete envelope

Function isn’t 100% clear but considered to support neurones, supply nutrients, regulate exchange of materials between the interstitial fluid and neurones

Similar to what astrocytes do in CNS

Question 34

How are Neuroglia different to neurones?

Answer 34

Do not generate any action potentials

Are able to divide

Form the myelin sheathes

Question 35

What are gliomas?

Answer 35

Tumours derived from glial cells

Highly malignant and grow rapidly

Difficult to access surgically so radiotherapy is the go to treatment option

Usually inside the cranium so also referred to as intra-axial tumours

Question 36

What is a neuroblastoma?

Answer 36

Rare tumour

Outside of the cranium, typically the adrenal glands, abdomen, thoracic cavity, neck and spine

Derived from the neural crest cells from the nervous system

Survival rates vary depending on the subtype

Initial prognosis is typically good

However survivors often develop neurological problems approximately 30 years later

Treatment depends on the subtype