PSY1011 Lecture Notes - Lecture 8: Somatic Nervous System, Autonomic Nervous System, Neuroglia
15 May 2018
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PSY1011
WEEK 8 – BIOLOGICAL PSYCHOLOGY
Lecture Objectives:
• Distinguish the parts of the neurons and what they do.
• Describe the electrical responses of neurons and what makes them possible.
• Explain how neurons use neurotransmitters to communicate with each other.
• Describe how the brain changes as a result of development, learning and injury.
• Identify what roles different parts of the central nervous system play in behaviour.
• Clarify how the somatic and autonomic nervous system work in emergency and everyday
situations.
• Describe what hormones are and how they affect behaviour.
• Identify the brain-stimulating, -recording, and -imaging techniques.
• Evaluate results demonstrating the brain's localisation of function.
Biological Psychology: The psychological specialty focused on the physical and chemical
changes that cause, and occur in response to, behaviour and mental processes.
Nervous System: A complex combination of cells who primary function is to allow an organism
to gain information about what is going on inside and outside the body and to respond
appropriately.
3.1 THE NERVOUS SYSTEM
Cells of Nervous System
➢ Neurons: Fundamental units of the nervous system; nerve cells.
➢ Glial Cells: Cells in the nervous system that hold neurons together and help them
communicative with one another.
Common features of neurons
❖ Neurons have an outer membrane that acts like a fine screen, letting some substances
pass in and out while blocking others.
❖ Nervous system cells have a cell body, which contains a nucleus (only red blood cells
have no nucleus). The nucleus carrier the genetic information that determines how a
cell will function.
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2
❖ Nervous system cells contain mitochondria, which are structures that turn oxygen and
glucose into energy. This process is especially vital to brain cells.
• Types of neurons
1. Sensory neurons (afferent neuron or affector) – specialise in transmitting (sending)
information from sensory receptors, sense organs, tendons or muscles to the CNS
2. Motor neurons (efferent neuron or effector) – specialise in sending information to cells
in bodily organs, muscles and glands from the CNS
3. Interneurons (connecting neuron) – send messages between sensory and motor
neurons within the CNS, relaying information from one to the other (because sensory
and motor neurons rarely every connect directly)
Dendrites
• A dendrite is an extension of a neuron that detects and receives information from other
neurons.
• Dendrites receive information from other neurons, which they carry from the synapse to
the soma. The message is then transmitted along the axon
• Most dendrites have outgrowths called dendritic spines
• Each spine provides a site with receptors where a neuron can connect with and receive
information from a neighbouring neuron.
• The euos apailit to go e dediti spis is assoiated ith ad deostates
neuroplasticity
• A neuron may have from 1 to 20 dendrites each with one to many branches and the total
number of spines on the branches may be in the hundreds or thousands meaning that a
single neuron can have many thousands of connections to other neurons through its
dendritic branches and spines
• Each dendritic spine may have multiple kinds of receptors to gather different types of
chemical messages (carried via neurotransmitters) from other neurons
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Axon
• The axon is a nerve fibre that extends from the soma (cell body that controls maintenance
of the neuron) and carries neural information to other neurons (or cells in muscles and
glands)
• Some axons have two or more offshoots and some can be up to a metre long
Myelin
• The axons of many neurons are myelinated.
• Myelin is a white, fatty substance (made up of types of glial cells) that surrounds and
insulates the neuron (a bit like plastic tubing around copper wires of an electrical cord)
• Without the coating (called the myelin sheath) interference from the activity of other
nearby axons may occur. Myelin sheath also allows for the rapid movement of messages
along the axon without being interrupted or distorted
• The myelin sheath is not continuous along the full length of the axon, rather it occurs in
segments that are separated by small unmyelinated gaps (nodes of Ranvier). The neural
message jumps from node to node and this is believed to speed up transmission
• Axons with myelin are white rather than grey.
Axon terminals
• Axon terminals are found at the end of the axon branch and function to transmit messages
to the next neuron
• Each axon terminal has a small knob-like swelling at its tip called a terminal button (or
synaptic vesicle, synaptic knob or synaptic button)
• The terminal button is a small structure like a sac that stores and secretes neurotransmitter
that is manufactured by the neuron and carries its chemical message to other neurons or
cells.
• Although they never touch, the axon terminals of one neuron link with the dendrites of the
next neuron
Action Potential
❖ An abrupt wave of electrochemical changes travelling down an axon when neuron
becomes depolarised.
❖ When a neuron detects a stimulus, they become ecited and an Action Potential is
fied.
❖ Neurons = Rest/Excited.
❖ An AP begins at a sense organ or the dendrites of a neuron and will propagate along the
length of the axon.
❖ The AP is an all or nothing event - it ill eithe happe o it ot at all.
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Document Summary
Identify what roles different parts of the central nervous system play in behaviour. situations: describe what hormones are and how they affect behaviour. Identify the brain-stimulating, -recording, and -imaging techniques: evaluate results demonstrating the brain"s localisation of function. Biological psychology: the psychological specialty focused on the physical and chemical changes that cause, and occur in response to, behaviour and mental processes. Nervous system: a complex combination of cells who primary function is to allow an organism to gain information about what is going on inside and outside the body and to respond appropriately. Neurons: fundamental units of the nervous system; nerve cells. Glial cells: cells in the nervous system that hold neurons together and help them communicative with one another. Neurons have an outer membrane that acts like a fine screen, letting some substances pass in and out while blocking others. Nervous system cells have a cell body, which contains a nucleus (only red blood cells have no nucleus).
