Lecture 1- Nervous system: neurons, sensation

Question 1

early nervous systems

Answer 1

initially a ‘neural net’- e.g. in hydra- no centralised information collection points

Question 2

basic anatomy of an invertebrate nervous system

Answer 2

CNS- made up of a chain of bilaterally segmented ganglia connected by axons
brain
peripheral NS- relaying information from the sensory neurons to the brain
visceral NS- deals with basic biology- e.g. gut, heart, spiracles

Question 3

what are ganglia (invertebrates)

Answer 3

outer ring of cell bodies containing axons and dendrites
opposite way around in vertebrates

Question 4

different types of ganglia

Answer 4

supraoesophageal ganglia- involved in brain and anterior gut
Suboesophageal ganglia- controls mouthparts and neck muscles
thoracic ganglia- innervate muscles, involved with flight and leg muscles etc
abdominal ganglia- controls movement of abdominal muscles, anus, etc

Question 5

how many ganglia in the insect brain

Answer 5

6

Question 6

brain parts in insects

Answer 6

protocerebrum- includes mushroom bodies (smell, learning, memory etc), associated with vision and eyes
deuterocerebrum- olfactory and mechanosensory information
tritocerebrum- integration of sensory input and involvement with mouthparts

Question 7

structure of the vertebrate nervous system

Answer 7

CNS- brain and spinal cord
PNS- cranial and spinal nerves, communication between the CNS and periphery
sensory neurons- receptors > CNS
motor neurons- CNS > effectors
ANS- involuntary movement (autonomic)- parasympathetic and sympathetic
SNS (somatic)- voluntary motor function- CNS > skeletal muscle

Question 8

other vert NS things to talk about

Answer 8

splitting of the brain into segments, different sensory systems etc. reflexes, neural circuits, myelination in vertebrates

Question 9

neural circuits useful for rhythmic behaviours

Answer 9

central pattern generators (CPGs)- important for behaviour like walking and breathing

Question 10

CNS vs PNS cell types

Answer 10

CNS- glial cells around a central axon, opposite to invertebrates
PNS- Schwann cells around the axon

Question 11

how can some invertebrates make up for a lack of myelin

Answer 11

squid- have very thick axons

Question 12

glial cells- functions

Answer 12

○ Provide structure and separate out different groups
○ Produce myelin in verts
○ Remove debris after injury or death
○ Help form blood-brain barrier
Guiding neurons during dev

Question 13

resting potential

Answer 13

-65mV

Question 14

equation used to determine what equilibrium potential to expect with each ion

Answer 14

Nernst equation

Question 15

example of some ion Eps

Answer 15

Ena- +60mV
Ek- -75mV

Question 16

neuron discharge patterns

Answer 16

○ Tonic, or regular spiking- typically/tonically active
○ Phasic or busrting- burst firing, called phasic
Fast spiking- high firing rates

Question 17

2 types of transmission

Answer 17

electrical (gap junctions), chemical (synapses)