BIOL 3P64 Lecture Notes - Lecture 6: Suboesophageal Ganglion, Thoracic Ganglia, Supraesophageal Ganglion
Lecture Set #6: Nervous System and Circulatory System
Nervous System
A & B: Brain and subesophageal ganglion
C-E: 3 thoracic ganglia
F-J: 5-8 abdominal ganglia
Thoracic ganglia important for movement
Abdominal ganglia important for digestion, excretion, reproduction
Modifications
General Overview
Insect transmit signals from sensory organs to ganglia
Ganglia sends signals to muscles, causes contractions
Many reflex arcs (neural pathway that controls reflexes), bypass the insect brain
Sensory nerve—synapse—motor nerve
Several structures have a neurosecretory function
Secretes hormones which initiate events like moutling, sex
maturation, diapause (diapause-undergo a period of
suspended development.)
Neuron Basics
Soma- the cell body of a neuron
Axon- propagates electrical impulses AWAY from the
soma
Dendrite- conducts electrical impulses INTO the soma
No myelin sheath
Glial cells removed unwanted materials around
neurons
Types of neurons
Unipolar: one protoplasmic process (neurite) extends
from the cell body.
Bipolar: neuron which has two
extensions. Bipolar cells are specialized sensory
neurons for the transmission of special senses.
Multipolar: possesses a single axon and
many dendrites (and dendritic branches), allowing for the integration of a great deal of information from other neurons
Afferent (sensory) neurons: usually bipolar, sometimes multipolar. Dendrites associated with sense organs or
receptors. Carry info TOWARD the central nervous system (CNS)
Efferent (motor) neurons: unipolar cells that conduct signals AWAY from the CNS and stimulate responses in muscles
and glands
Interneurons (association) neurons: unipolar cells (often w/ several collaterals and/or branching axons) that conduct
signals WITHIN the CNS
Individual neurons connect at synapses
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Document Summary
Lecture set #6: nervous system and circulatory system. A & b: brain and subesophageal ganglion. Abdominal ganglia important for digestion, excretion, reproduction. Insect transmit signals from sensory organs to ganglia. Ganglia sends signals to muscles, causes contractions. Many reflex arcs (neural pathway that controls reflexes), bypass the insect brain. Secretes hormones which initiate events like moutling, sex maturation, diapause (diapause-undergo a period of suspended development. ) Soma- the cell body of a neuron. Axon- propagates electrical impulses away from the soma. Dendrite- conducts electrical impulses into the soma. Glial cells removed unwanted materials around neurons. Unipolar: one protoplasmic process (neurite) extends from the cell body. Bipolar cells are specialized sensory neurons for the transmission of special senses. Multipolar: possesses a single axon and many dendrites (and dendritic branches), allowing for the integration of a great deal of information from other neurons. Afferent (sensory) neurons: usually bipolar, sometimes multipolar. Carry info toward the central nervous system (cns)