Neuro-3

Question 1

What is the somatogastric ganglions function in the lobster?

Answer 1

This drives the gastric mill which grinds the food ingested by the lobster
Meaning that it controls the rhythmic contractions of the stomach and the teeth

Question 2

What is the rhythm seen in the lobster which drives the gastric mill?

Answer 2

The LP motor neuron will fire first in each cycle and activate a constrictor muscle
This is followed by PY motor neurons which cause constriction of a second muscle
Finally the PD will fire which stimulates a dilator muscle
This cycle also occurs due to reciprocal inhibition

Question 3

What are electrical synapses?

Answer 3

When two cells are electrically connected so that when one fires the other will fire
This can allow extremely co-ordinated activity between cells

Question 4

What is neuromodulation?

Answer 4

These are things which are capable of changing the function of the circuit, for example they may switch the rhythm of a circuit on and off

Question 5

How is swimming in the Lamprey generated?

Answer 5

There are spinal segments which are muscles controlled by individual neurons, these must be controlled in a precise pattern to generate the motions required for swimming with a wave of contraction moving along the body through activation of alternating segments

Question 6

What are the two compartments of nerves in the spinal cord?

Answer 6

A dorsal compartment which contains sensory nerves and a ventral compartment which contains the motor nerves

Question 7

What is the alternating rhythm that is desired in swimming?

Answer 7

Alternating activity of the muscle on each side of the organism this is regulated by having dual action of excitatory nerves on each segment which fire in co-ordination with inhibitory neurons which shuts down the entire muscle block on the other sides of the lamprey
This inhibitory neuron is turned off by the actions of an interneuron