PSY 250 Lecture Notes - Lecture 5: Schwann Cell, Resting Potential, Acetylcholine
Chapter 2: Communication within the Nervous System
- The Cells that Make us Who we Are
- To understand behavior and disorders you need to understand how the brain
works
- Neurons: specialized cells that convey sensory information into the brain; carry
out the operations involved in thought, feeling, and action; and transmit
commands out into the body to control muscles and organs
- 100 billion neurons in the brain
- Neurons
- Responsible for our movements, thoughts, memories, and emotions
- Basic Structure: The Motor Neuron
- Cell Body: the most prominent part of the neuron (soma)
- Filled with a watery liquid called cytoplasm and contains
organelles (largest one is the nucleus which contains
chromosomes)
- Other organelles are responsible for converting nutrients
into fuel for the cell, constructing proteins, and removing
waste materials
- Motor Neuron: carries commands to the muscles and organs
- Dendrites: extensions that branch out from the cell body to receive
information from other neurons
- Axon: extends like a trail from the cell body and carries
information to other locations and is covered by the myelin sheath
- Terminals: branches at the end of the axon culminate in swellings
also called end bulbs and contain neurotransmitters
- Neurotransmitters: the neuron releases to communicate with a
muscle or an organ or the next neuron in a chain
- Other Types of Neurons
- Sensory Neurons: carry information from the body and from the
outside world into the brain and spinal cord (same components as
motor neurons)
- Motor neurons are called multipolar neurons and sensory neurons
can be unipolar or bipolar neurons
- Interneurons: connect one neuron to another in the same part of the
brain or spinal cord
TYPE
FUNCTION
FORM/LOCATION
DESCRIPTION
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Motor
Conducts messages
from brain and spinal
cord to muscles and
organs
Multipolar;
throughout nervous
system
Axon, dendrites
extend in several
directions from cell
body
Sensory
Carries information
from body and world
to brain and spinal
cord
- Unipolar; outside
brain
- Bipolar; outside
brain and spinal cord
- Single short stalk
from cell body
divides into two
branches
- Axon and dendritic
processes are on
opposite sides of cell
body
Interneuron
Conducts information
between neurons in
same area
Multipolar; brain and
spinal cord
Has short axon that
communicates locally
(with nearby neurons)
- The Neural Membrane and its Potentials
- The most critical part of a neuron is the membrane
- Made up of liquid and protein and is very thin
- Holds the cell together and controls the environment within and
around the cell
- It is selectively permeable
- Polarization: there is a difference in electrical charge between the
inside and outside of the cell
- Voltage: a difference in electrical charge between two points, such
as the poles of a battery or the inside and outside of a cell
- Resting Potential: the difference in charge between the inside and
outside of the membrane of a neuron at rest
- Ions: atoms that are charged because they have lost or gained one
or more electrons
- Force of Diffusion: ions move through the membrane to the side
where they are less concentrated
- Electrostatic Pressure: ions are repelled from the side that is
similarly charged and attracted to the side that is oppositely
charged
- Sodium-Potassium Pump: consists of large protein molecules that
move sodium ions through the cell membrane to the outside and
potassium ions back inside
- Action Potential: an abrupt depolarization of the membrane that
allows the neuron to communicate over long distances
- There is always a chain reaction of action potentials because one
causes another that causes another and then returns to its resting
potential
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The cells that make us who we are. To understand behavior and disorders you need to understand how the brain works. Neurons: specialized cells that convey sensory information into the brain; carry out the operations involved in thought, feeling, and action; and transmit commands out into the body to control muscles and organs. Responsible for our movements, thoughts, memories, and emotions. Cell body: the most prominent part of the neuron (soma) Filled with a watery liquid called cytoplasm and contains organelles (largest one is the nucleus which contains chromosomes) Other organelles are responsible for converting nutrients into fuel for the cell, constructing proteins, and removing waste materials. Motor neuron: carries commands to the muscles and organs. Dendrites: extensions that branch out from the cell body to receive information from other neurons. Axon: extends like a trail from the cell body and carries information to other locations and is covered by the myelin sheath.
