Chapter 39: Neurons Flashcards
What is the main purpose of the nervous system?
You receive lots of stimuli and the nervous system determines what you respond to
What are the 4 components of neural signaling?
reception, transmission, integration, response
What is neural signaling?
the process by which an animal responds appropriately to a stimulus
What is reception? neurons involoved?
(detection of a stimulus) is performed by neurons and by specialized sensory receptors
What is transmission? neurons involved?
is the sending of a message along a neuron to another neuron or to a muscle or gland
What is integration? neurons involved?
sorting and interpretation of neural messages and determination of the appropriate response
What is response? neurons involved?
output or action resulting from the integration of neural messages
What are the 3 functional classes of neurons?
afferent neurons, interneurons, efferent neurons
What are afferent neurons? aka?
transmit stimuli from their sensory receptors to interneurons, aka sensory neurons
What are interneurons?
integrate the information to formulate an PNS appropriate response
What are efferent neurons?
carry signals indicating a response away from the interneuron to the effectors (muscles and glands) – motor neurons are efferent neurons that carry signals to skeletal muscle
What is an axon hillock? location?
site of origin of axon, between cell body and start of axon
How long can an axon be?
1 mm to more than 1 m long
What are glial cells?
include several types of non-neuronal cells that provide nutrition and support to neurons
What are the different types of glial cells?
astrocytes, oligodendrocytes/Schwann cells
What are astrocytes?
(in the vertebrate CNS) closely cover the surfaces of blood vessels, providing physical support and
maintaining concentrations of ions in the ISF, star like
What are oligodendrocytes/Schwann cells?
Oligodendrocytes in the CNS and Schwann cells in the PNS wrap around axons to form insulating myelin sheaths
What are the nodes of Ranvier?
gaps between Schwann cells that speed signal transmission
What is a neural circuit composed of?
an afferent (sensory) neuron, one or more interneurons, and an efferent neuron
What is the peripheral nervous system (PNS)?
In vertebrates, afferent and efferent neurons form the peripheral nervous system (PNS)
What is the central nervous system (CNS)?
Interneurons form the central nervous system (CNS), consisting of the brain and spinal cord
What is a nerve? can it be seen with the naked eye?
bundle of neuronal tails, can be seen
What is ganglia? location, examples?
neurons outside CNA, aka PNA, form the plexuses, examples have ganglia in the name
What is nuclei? location, examples?
concentration of cells in CNA, grey matter of brain, weird names for examples
What is a voltage? Why is it formed? importance?
creates membrane potentail across plasma membrane caused by a difference of charge by ions
What is the resting potential?
from -40 t0 -90 mV
averages about -70 mV