EXAM #2

Question 1

How many fused gangliconic masses compose the insect brain? What is the location of these masses in relation to the esophagus?

Answer 1

The insect brain is composed by 3 ganglionic masses, located dorsally to the esophagus:
Protocerebrum: Optic lobe + mushroom bodies;
Deuterocerebrum: Antennal lobe;
Tritocerebrum: signal from body;

Question 2

How are mouthparts innervated?

Answer 2

Mouthparts are innerveted by subesophogael ganglion nerves.

Question 3

Nerve cell components and function.

Answer 3

Soma (cell body)
Nucleus
Dendrite (recieves stimuli)
Axon (transmits stimuli to another neuron)
Axon terminal

Question 4

What are the four basoc types of neurons?

Answer 4

Sensory
Interneurons
Motor neurons
Neuroendocrine cells

Question 5

How do nerve cells work?

Answer 5

There is a flow of electricity along a dendrite. When two neurons interface, a synapse occurs. The resting potential is more negative inside than outsise. Na+ channels open after stimulation and influx of Na+ inside become more positive than outside. This depolarization lasts for a short period until other pumps restore resting potential. Depolarization travels down nerve cells until synapses is reached. Signals perpetuated across synapses by difusion of chemicals.

Question 6

What is the effect of pyrethroid insecticides in the nervous system?

Answer 6

Pyrethroids impede the sodium channels’ gate to shut down, causing the influx on fto continue which unables the cell to reset for the next neural impulse. This will cause cell colapse.