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Psychology 110 Module #4 Biopsychology – The Nervous System and the
Endocrine System
Sem. 2 - 2015
Essential Question: How do the nervous system and endocrine systems’ components contribute to
behaviour and mental processes?
STUDENT OUTCOMES:
Upon completion of this module, I will be able to:
___identify and describe the functions of the parts of a neuron
___explain the process of neural transmission
___explain the roles of neurotransmitters in neural transmission
___ understand the relationship between neurotransmitters and drugs
___identify and describe the divisions of the nervous system
___distinguish between the endocrine and nervous system
Vocabulary: are you familiar with these terms?
Neuron Dendrite Soma Axon Axon terminal Action potential Refractory period Synapse
Resting potential All-or-none principle Neurotransmitter Receptor cells Antagonist Agonist
Central nervous system Peripheral nervous system Somatic nervous system Hormone
Autonomic nervous system Sympathetic & Parasympathetic nervous system Endocrine system
NEURONS: THE BUILDING BLOCKS OF THE NERVOUS SYSTEM. The nervous system is the
body’s electrochemical communication system. When your brain tells your body to do
something, that message travels through your nervous system. Your nervous system, along
with your sensory system, gathers information so that your brain can respond appropriately to
different stimuli (i.e. stubbed toes, smell of cotton candy). Your brain, spinal cord and nerves
are formed from nerve cells or neurons, the basic building blocks of the nervous system.
Parts of a neuron – definitions:
Dendrite –
Soma –
Nucleus –
Axon terminal button –
Axon –
Myelin sheath –
Neurons are highly specialize and unique cells of the nervous system. A neuron exists only to
perform 3 tasks:
1. Receive information in the form of electrochemical impulses from other neurons
2. Carry the information down its length
3. Pass the information to the next neuron in line
Everything you do and have done depends on the functioning of this system. Neurons can
either “FIRE” (send an impulse down its length) or “not FIRE”. All memories, feelings, tastes,
moods, etc. all emerge from a certain sequence of neurons firing or not firing.
How neurons communicate - When a neuron fires, changes occur both within a neuron and
between neurons:
The neural impulse – communication within a neuron
When a neuron _____________ the neural impulse is called an _________________
_______________________. It is a brief __________________ ______________________ that
travels down the __________________ of a neuron. It works its way from the dendrites to the
axon terminals. This action potential represents the _______ condition of the neuron. Each
action potential is followed by a brief _________________ ___________________ known as
the ___________________________ period, when a neuron after firing, cannot generate
another action potential. Think of a camera flash that has to recharge before it can be used
again. After the refractory period, the neuron is capable of another action potential when it is
stimulated. When the neuron is recharged, at rest, and capable of generating another action
potential, a _____________________ ________________________ exists.
An interesting fact about how a neuron fires is called the all-or-none principle. This means that
a neuron always fires with the same intensity no matter what the stimulation is. It doesn’t
matter if there is a strong stimulation or weak stimulation at the cell’s dendrites. As long as
there is enough energy to trigger the neuron, it will fire with the same intensity. Read the
comparison of a neuron to a toilet! p. 99
Communication between neurons
How do messages travel from one neuron to the next?
At every place where an axon terminal of one neuron and the dendrite of an adjacent neuron
meet, there is a tiny fluid filled gap called a synapse that action potentials cannot jump. In this
gap, chemical messengers known as neurotransmitters travel across the synapse to carry the
information from one neuron to the next. The neurotransmitters can come to rest only in
receptor sites designed to fit their shape, just as a key can open locks only with a certain
configuration.
** Handout – Neurotransmitters and Drugs
The Structure of the Nervous System - The nervous system has 2 major components:
1. Central nervous system (CNS) – includes the brain and the spinal cord. The brain is where
most of the information processing takes place, and the spinal cord is the main pathway
information follows as it enters and leaves the brain.
2. Peripheral nervous system (PNS) contains all sensory nerves and motor nerves that
connect the brain and the spinal cord to the rest of the body. The peripheral nervous system
divides into 2 subsystems:
Somatic nervous system –
Autonomic nervous system -
The autonomic nervous system has 2 subdivisions:
Sympathetic -
Parasympathetic -
Chart from text p. 106, Figure 6.6
Endocrine System
The body’s other system for communicating information is called the ___________________
___________________________. This system is slower to awaken and slower to shut down
than the nervous system. It consists of a set of _________________ that produce
________________________. Hormones are chemical ___________________________ that
circulate throughout the body in the blood. Hormones and ___________________________
are similar in function. Both carry ________________________ and both communicate by
locking into ________________________________ sites. The most important gland is the
________________ __________________, the endocrine system’s __________________ gland.
The pituitary gland in conjunction with the brain, controls the other endocrine glands. See
diagram pg. 108 text.