Lecture 2

Question 1

What does the nervous system do

Answer 1

• Survival and reproduction
• sensing the environment and controlling behaviour
• maintaining homeostasis

Question 2

Ganglia

Answer 2

A grouping of neurons

Question 3

What are the two most predominant cell types in the nervous system

Answer 3

• Neurons
• Glia

Question 4

CNS consists of

Answer 4

Brain and spinal cord

Question 5

PNS consists of

Answer 5

• peripheral nerves
• peripheral ganglia
• ENS

Question 6

Components of the neuron Input zone

Answer 6

• soma/cell body
• Dendrites

Question 7

Function of the neuron input zone

Answer 7

• receives a majority of signals from other neurons

Question 8

Summation zone

Answer 8

Axon hillock

Question 9

What generates an AP in a neuron

Answer 9

Initial segment of the axon hillock

Question 10

What is the role of the axon hillock

Answer 10

• input summation
• AP generation

Question 11

Conduction zone

Answer 11

Axon

Question 12

How long can axons be

Answer 12

> 1m

Question 13

Axon function

Answer 13

Carry electrical signals

Question 14

Output zone

Answer 14

• axon terminals

Question 15

Axon terminal function

Answer 15

• contact input zones of other neurons
• release of neurotransmitters

Question 16

How many neurons in the human brain

Answer 16

~85 billon

Question 17

Neuron zones

Answer 17

• input zone
• summation zone
• conduction zone
• output zone

Question 18

What are the primary neuron morphologies

Answer 18

• multipolar
• bipolar
• unipolar
• Anaxonic

Question 19

Multipolar axons

Answer 19

Multiple processes emanate from cell body

Question 20

What is the most common neuron morphology in the CNS

Answer 20

Multipolar

Question 21

Why do multipolar neurons have so many processes

Answer 21

Dendrites increase SA for receiving input
-> increased computational capacity

Question 22

Bipolar neurons

Answer 22

2 processes emanate from the cell body

Question 23

Unipolar neuron

Answer 23

One process emanates from the cell body then branches into dendrites and axon terminal

Question 24

What is common example of a unipolar neuron

Answer 24

Sensory neuron in periphery

Question 25

Anaxonic neuron

Answer 25

- no distinct axon - all processes look alike

Question 26

Where are Anaxonic neurons common

Answer 26

In the retina

Question 27

Which neuron morphology is the least common

Answer 27

Anaxonic

Question 28

What is the ratio of glia:neuron in the brain

Answer 28

2:1

Question 29

How many synapses are there in the human brain

Answer 29

~100 trillion

Question 30

Glial cells in the CNS

Answer 30

- oligodendrocytes - astrocytes - microglia - ependymal cells

Question 31

Glial cells in PNS

Answer 31

- Schwann cells - Satellite cells

Question 32

Oligodendrocytes

Answer 32

Form the myelin sheath around neurons in CNS

Question 33

Myelin sheath

Answer 33

Fatty sheath that insulates axons and increases AP conduction

Question 34

Astrocytes

Answer 34

- provides nutrients - maintains EC - Structural support - regulates neuron excitability and synaptic strength

Question 35

What produces gleotransmitters

Answer 35

Astrocytes

Question 36

Microglia

Answer 36

Mount the immune response - phagocytosis of debris and synapses

Question 37

Ependymal cells

Answer 37

Line the ventricles - circulate and produce cerebrospinal fluid

Question 38

Difference between oligodendrocytes and Schwann cells

Answer 38

Schwann - can only myelinate one axon, in PNS Oligodendrocytes - can myelinate multiple axons, in CNS

Question 39

Schwann cells

Answer 39

Form the myelin sheath in PNS

Question 40

Satellite cells

Answer 40

Provide nutrients and structural support to PNS neurons

Question 41

What kind of input can neurons receive

Answer 41

Excitatory and inhibitory

Question 42

Are myelin sheaths continuous

Answer 42

No - they have nodes of Ranvier

Question 43

What is the function of the nodes of ranvier

Answer 43

Speeds up conduction

Question 44

Are all axons myelinated

Answer 44

No

Question 45

Do neurons work independently

Answer 45

No - they are organised into networks

Question 46

What is “information processing” in the nervous system

Answer 46

The throughput and balance of excitatory and inhibitory signals across networks of neurons

Question 47

What is a nerve

Answer 47

A collection of many axons from different neurons surrounded by connective tissue

Question 49

How do axons within a nerve vary

Answer 49

- in diameter - in myelination (y/n)

Question 50

What kinds of synapses are there

Answer 50

- electrical/ gap junctions - chemical

Question 51

What are the key features of a electrical synapse

Answer 51

- very fast - ion flow from cell to cell - may be bidirectional

Question 52

Are electrical or chemical synapses faster

Answer 52

Electrical

Question 53

What does a chemical synapse use to communicate

Answer 53

Neurotransmitters to jump the cleft

Question 54

Is chemical synapse strength static

Answer 54

No - can be modified to be stronger or weaker

Question 55

what direction can an AP flow through a chemical synapse

Answer 55

Unidirectional- from pre-synaptic to post

Question 56

Do APs differ between neurons

Answer 56

No- they are the same across neurons

Question 57

How does a non-specific AP translate to a specific input in the brain

Answer 57

The brain is organised into functional regions

Question 58

Where in the brain has a sensory “map” of the body

Answer 58

The somatosensory cortex

Question 59

Is the sensory map in the brain proportional to body region area

Answer 59

No- regions with high receptor density occupy disproportionately larger areas

Question 60

What’s the primary control of motor in the brain

Answer 60

Primary motor cortex

Question 61

What does it mean when a larger proportion of the motor cortex is dedicated to an area

Answer 61

More fine control of that area eg. Lips for speech

Question 62

Afferent information

Answer 62

Sensory input goes from PNS to CNS

Question 63

Efferent information

Answer 63

Motor output from CNS to PNS

Question 64

Sympathetic nervous system

Answer 64

Fight, flight, fright

Question 65

Parasympathetic system

Answer 65

Rest and digest - inc. ENS

Question 66

Why is the ENS important

Answer 66

Controls the digestive system - has more neurons than the spinal cord

Question 67

ESPS

Answer 67

Excitatory post-synaptic potential - brings neuron closer to AP threshold

Question 68

IPSP

Answer 68

Inhibitory post-synaptic potential - takes neuron further from AP threshold