Summary PYC1501 Notes, Assignments and Exam preparation material
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Course
PYC1501 - Basic Psychology (PYC1501)
Institution
University Of South Africa (Unisa)
These notes include a full out exam and assignment preparation that will help you achieve your study goals. It includes questions after each section based on past papers; 2020 assignment questions, answers and guidelines; as well as 2020 exam questions (answers excluded). Passed with distinction by...
Human nervous system: The structure of the neuron
Neurons:
• The basic element of the communication network.
• Carries messages throughout the body
➢ The message is transmitted from the dendrites through the cell body and down
the axon to the axon terminals
• There are two types of Neurons
➢ The Sensory: These neurons carry information detected from the senses
(Example: Eyes) from the environment to the spinal chord and brain.
➢ The Motor: These neurons conduct messages from the spinal cord and brain to
the muscles and glands
Dendrites:
• The Dendrites are the extensions of the cell body.
• The Dendrites are the main connection with the axons of other neurons.
➢ The neuron begins with a number of dendrites.
➢ Each dendrite is like a thin wire consisting more thinner wires to collect the neurons.
The cell body (soma):
• The soma is surrounded by the dendrites.
• While the dendrites are the main connection with the axons of other neurons, some
of these axons may connect directly to the soma.
• This means that the soma will receive messages from other neurons through the
dendrites surrounding the soma.
• Inside the soma is the cell nucleus.
➢ This means that the soma is the control center of the cell, because it controls all
metabolic activities in the cell.
➢ The metabolic activities are the processes that keep the cell alive and allow it to
function properly.
The Axon:
• The axon receives the messages (stimulation) from the dendrites and the surface
connections with the soma.
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, • When the message reaches a particular level, the axon hillock initiates an impulse that
runs along the axon.
• Axons are enclosed in a white fatty sheath called myelin, which insulates the axon.
• The process whereby an impulse moves much faster by jumping from node to node
when travelling through the myelin sheath is called saltatory conduction.
➢ The myelin sheaths are separated by small gaps, called nodes of Ranvier. The axon is not
insulated at these gaps or nodes.
➢ When an axon is insulated with myelin, it can conduct impulses much faster than those
that are un-myelinated, because the impulse jumps from node to node.
❖ The effect of not having properly myelinated axons is seen in the disease multiple
sclerosis, which attacks the myelin.
❖ The result is that messages are not transmitted properly and the person with that
disease becomes disabled.
❖ *Dendrites and soma are not enclosed in myelin*
The Axon Terminals
• The Axon Terminals are also called the telondendria.
• Each Axon Terminals end in a small knob, called a bouton terminal.
• Each of these bouton terminals connects to a dendrite branch from a following neuron.
• Inside the boutons are tiny containers, called vesicles, which is filled with
neurotransmitters.
• Neurotransmitters are chemical substances that play an important role in conduction a
message from one neuron to the next.
The Synapse
• The junction between the axon tip of the sending neuron and the dendrite or cell body
of the receiving neuron.
• The tiny gap at this junction is called the synaptic gap or cleft.
• The synaptic transmission process: Nerve impulse stimulates boutons, vesicles attach to
membrane, neurotransmitters released and attach to receptors on postsynaptic
membrane
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, Questions of The Human Nervous System: Structure of
the Neuron:
Question 1:
Question 2:
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,Question 3:
Question 4:
Choose the correct words from the list below to fill in the missing words in the following
statements (A-E)
Myelin sheath, soma, axon, neuron membrane, dendrites, axon terminals
The basic functionals parts of a neuron are
A The branchlike nerve fibres called the …. and the …. (cell body) which together receive
information signals
B The ….. which conduct signals to another point in the nervous system and
C The ….. which make synaptic contact with other neurons and transmit signals to other
neurons.
D The axon is surrounded by a ….. that insulates the axon.
E The selectively permeable …. plays an important role in generating, transporting and
transmitting the nerve impulses.
Answer
A Dendrites, Soma
B Axon
C Axon Terminals
D Myelin Sheath
E Neuron Membrane
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, Human nervous system: Impulse conduction in the neuron
Sensory Organs:
• Messages are relayed from the sensory organs (such as the eye and the ear) to the brain
• These organs are stimulated by information from the environment.
• This information (called stimuli) is translated into energy that can be relayed by the
neurons.
➢ Example: When a sound reaches the era, the energy of the sound (the auditory
stimulus) stimulates the ear, which translates it into electrochemical energy that
stimulates the neuron.
➢ When the neuron is stimulated, it generates a nerve impulse.
➢ This means that the sensory organs translate external stimuli into internal stimuli which
are conducted to the brain and form nerve impulses.
Impulse Conduction:
• The process by which messages are relayed on the neurons and from one neuron to the
next.
• This section deals with the way neurons function.
• Impulse conduction is a basis for all human behaviour.
• Impulse conduction can contribute to individual differences in behaviour.
• Impulse conduction communicates information from the external and internal environments.
• Impulse conduction depends on the presence or absence of neurotransmitters.
• Impulse conduction is the basic form of sending information in the nervous system.
• Nerve cells are specially adapted for impulse conduction.
• The stimulus is a form of energy received by the senses and converted into a form of
energy that can be understood by the nervous system.
• With regard to impulse conduction in the neuron, the resting membrane potential
occurs when the sodium ions are positive charged and the potassium ions are positive
charged. The total electrical charge on the inside of the membrane is negative.
There are two main processes from Impulse conduction:
➢ Electrical: The nerve impulse begins in the first segment of the axon and travels down
the axon to the terminals because of electrical events at the cell membrane
➢ Chemical: The passage of the nerve impulse from one neuron to another is a chemical
process. There is a small gap (called synapse) between the structures of one neuron and
another. This process also determines whether or not the impulse will be conducted
across the gap to the next section.
The Neuron define as “electrically charged”
• Each neuron has two poles, one negative and one positive.
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