Neuro - Cells of Nervous System

Question 1

What does the CNS consist of?

Answer 1

2 cerebral hemispheres
brainstem
spinal cord

Question 2

What does the PNS consist of?

Answer 2

Fibres originating from the CNS

Question 3

What are the hemispheres?

Answer 3

Also called telencephalon - form the main cerebral cortex

Question 4

How many lobes are in each hemisphere?

Answer 4

4

Question 5

What are the main lobes of the hemispheres?

Answer 5

frontal
temporal
parietal
occipital

Question 6

What is the role of the frontal lobe?

Answer 6

Executive functions: 
memory
cognition 
recognition 
primary motor cortex

Question 7

What is the role of the parietal lobe?

Answer 7

Contain primary somatosensory complex

Question 8

What is the role of the temporal lobe?

Answer 8

Processing of sound with the primary auditory complex

Question 9

What is the role of the occipital lobe?

Answer 9

Contains primary visual complex for sight perception

Question 10

What does the brainstem consist of?

Answer 10

Mid brain
Pons
Medulla

Question 11

What is the function of the brainstem?

Answer 11

Important functions such as control of respiration and heart rate, and is the target or source for the majority of cranial nerves

Question 12

What is the role of the cerebellum?

Answer 12

Conscious motor coordination, balance and posture

Question 13

What is the role of the spinal cord?

Answer 13

Acts as a channel for neural transmission and has some role in reflex responses.

Question 14

What are gryi?

Answer 14

The outfoldings on the outermost layer of the cortex

Question 15

What are sulci?

Answer 15

The valleys formed between gyri

Question 16

What separates the frontal from the parietal lobe?

Answer 16

Central sulcus

Question 17

Why can’t neurones be classified on the bases of their shape and size?

Answer 17

Due to their polymorphous structure

Question 18

Define mature neurones

Answer 18

Non-dividing excitable cells whose main function is to receive and transmit information in the form of electrical signals

Question 19

What are the 4 main classes of morphology of neurones?

Answer 19

Unipolar
Bipolar
Pseudo-unipolar
Multipolar

Question 20

What is a unipolar neurone?

Answer 20

Starts of with nucleus and ends with a single axonal projection

Question 21

What is a bipolar neurone?

Answer 21

Two projections on either side of the nucleus: axon and dendrite

Question 22

What is a pseudo-unipolar neurone?

Answer 22

Starts of with one original projection from the nucleus but then bi-furcates into 2 projections

Question 23

What is a multipolar neurone?

Answer 23

Multiple projections from the cell body.

Question 24

What are the 3 main classes of multipolar neurone?

Answer 24

Pyramidal cells
Purkinje cells
Golgi cells

Question 25

What are pyramidal cells?

Answer 25

Pyramid shaped cell body

Question 26

What are purkinje cells?

Answer 26

GABA neurones found in the cerebellum (inhibitory)

Question 27

What are Golgi cells?

Answer 27

GABA neurones found in the cerebellum (inhibitory)

Question 28

What is the soma?

Answer 28

Cell body or perikaryon. | Contains nucleus and ribosomes as well as neurofilmaents which are important for structure and transport

Question 29

What is the axon?

Answer 29

Long process (nerve fibre), originates from soma at axon hillock, and can branch off in collaterals

Question 30

What usually covers the axon?

Answer 30

Myelin which allows for faster conduction

Question 31

What are dendrites?

Answer 31

Projections from the cell body (every projection except for axons). They are responsible for receiving signals whereas axons are important for sending signals

Question 32

What are astrocytes?

Answer 32

Most abundant cell type in the brain. Structural cells important for neuronal maturation, synapse formation and cell repair.

Question 33

What are oligodendrocytes?

Answer 33

Myelin producing cells in the CNS

Question 34

What are Schwann cells?

Answer 34

Myelin producing cells in the PNS

Question 35

Aside from location, what is the main difference between oligodendrocytes and Schwann cells?

Answer 35

Oligodendrocytes can send numerous projections to cover multiple axonal segments. Schwann cells can only cover one segment each

Question 36

What are microglia?

Answer 36

Immune cells of the CNS and act similarly to macrophages

Question 37

What are ependymal cells?

Answer 37

Epithelial cells lining the inside of fluid filled vesicles - regulate the production and movement of CSF

Question 38

Define the resting membrane potential

Answer 38

Ionic imbalance between the intracellular and extracellular of a neurone due to unequal ion distribution

Question 39

What does an ionic imbalance of the cell membrane give?

Answer 39

electromotive force (EMF)/potential difference.

Question 40

What do we call the outside of the cell?

Answer 40

Zero reference point

Question 41

What is the typical range form resting membrane potential?

Answer 41

-50 to -90mV so we average to -70mV

Question 42

Where is a greater potential (difference) found in neurones?

Answer 42

Areas adjacent to the membrane

Question 43

What are the 4 main physiological impermeant ions?

Answer 43

Sodium Potassium Chloride Calcium

Question 44

What ions are found highly concentrated inside the cell?

Answer 44

Potassium

Question 45

What ions are found highly concentrated outside the cell?

Answer 45

Sodium Chloride (Calcium found at low concentration but inside the cell is even lower)

Question 46

At RMP, what channels are closed?

Answer 46

VGSCs, VGKCs

Question 47

What causes the beginning of depolarisation?

Answer 47

Action potential begins to open VGSCs so sodium begins to enter the cell. Membrane potential goes to -40mV

Question 48

What is the result of the beginning of depolarisation?

Answer 48

Threshold reached, massive sodium influx into cell to +10mV.

Question 49

Why do sodium channels open first?

Answer 49

Naturally faster kinetics

Question 50

What happens after the opening of VGSCs?

Answer 50

VGKCs open at a slower rate, causing a potassium efflux from the cell.

Question 51

What is result of potassium efflux?

Answer 51

Repolarisation to a very low potential

Question 52

We do we reconfigure the imbalance between sodium and potassium?

Answer 52

Na+/K+ ATPase

Question 53

What is the resting configuration of Na/K ATPase?

Answer 53

Allows sodium ions inside the cell to enter the vestibule

Question 54

What is the active configuration of Na/K ATPase?

Answer 54

Conformational change from phosphorylation of ATP leads to opening on the extracellular side so sodium leaves and potassium can enter there vestibule - transported back into cell as pump returns to resting configuration.

Question 55

What about myelin prevents AP spreading across?

Answer 55

High resistance and low capacitance

Question 56

How do Nodes of Ranvier induce saltatory conduction?

Answer 56

Intermittent gaps allow for AP to jump between nodes to the terminal.

Question 57

What are synapses?

Answer 57

Small gaps between neurones

Question 58

What is the need for synapses?

Answer 58

Electrical signal cannot jump between synaptic cleft therefore electrical energy use be converted to chemical energy via synapses.

Question 59

What is stage 1 of synaptic transmission?

Answer 59

Action potential propagates along axon with VGSCs and VGKCs - causes calcium influx due to depolarisation.

Question 60

What is stage 2 of synaptic transmission?

Answer 60

Neurotransmitter release due to calcium influx - exocytosis of NTs

Question 61

What is stage 3 of synaptic transmission?

Answer 61

NTs diffuse across cleft and bind to post-synaptic terminal.

Question 62

What is stage 4 of synaptic transmission?

Answer 62

Binding at the post synaptic terminal induces perpetuation of propagation and then the NTs are degraded or taken back into terminal via transporter proteins.