1. Receptor cells
Transcript 1. Receptor cells
The Biological Foundations of
• The nervous system: the most complicated
system in human body where billions of
interconnected cells radiate all over the body.
• Specialized Cells of nervous system include:
1. Receptor cells: Embedded in sense organs,
(seeing – hearing – smelling – tasting –
touching). receive various types of stimulation
from environment, which are then transmitted
to the brain.
2. Effector cells: Brain sends motor signals to
the effector cells embedded in muscles and
3. Neurons: Specialized to conduct signals
from one part to another, (connect receptor
cells to effector cells).
4. Nerve: long, fibrous parts of many neurons
bundled together, and run through the bodies.
Division of nervous system:
• 1- Central Nervous System (CNS): consists of
brain and spinal cord.
• 2-Peripheral Nervous System (PNS): Branching
out from the CNS and leading to all parts of the
• Neurons from PNS convey signals from receptor
cells to the spinal cord and brain (afferent
• neurons transmit messages from brain and spinal
cord to effectors cells (efferent pathway).
• *Efferent pathway has two divisions :
• Somatic nervous system: it controls actions
that are under voluntary control.
• Autonomic nervous system :control
muscles of internal organs ( the heart,
intestine, blood vessels) and glands, usually
automatic or involuntary.
• Autonomic nervous system has two
divisions : (opposite effects).
a. Sympathetic nervous system:
• In emergency situations as meeting a snake,
lead to increase blood sugar, heart rate and
blood pressure, and inhibiting digestion
(Fight- Flight- Fright response)
b. Parasympathetic Nervous System:
• -Dominates under relaxation conditions and
tends to conserve body's energy.
• -After eating large meal, it works to aid
digestion, at the same time decreasing heart
rate and blood flow to skeletal muscles
Division of the nerves system
(Look in your book please)
Composition of neuron cell:
• A- Cell body: the life support center of the
• B- Dendrites: receive messages transmitted
from other neurons (antenna of neurons).
• C- Axons: carries neural signals to affect
the muscle fibers
Types of neuron
1- Sensory neurons: carry information form
sense organs to the brain & spinal cord.
2-Motor neurons: carry signals from brain
and spinal cord to muscles and glands .
3-Inter-neurons: connect neuron to other
• Structurally the brain is divided into the
cerebrum, cerebellum, brain stem, and
• (1) CEREBRUM
• The cerebrum is divided into two
• (2) CEREBELLUM: center for
coordination of movements and postural
(3) Brain Stem: Includes the midbrain, Pons,
and medulla oblongata.
• Medulla oblongata: contains vital centers for
respiration and cardiovascular functions.
(4) Limbic System: located above the brain
stem that includes:
- The hypothalamus is involved in temperature
regulation, appetite control, endocrine
• Hippocampus is involved in emotional
arousal and memory.
- Neurons communicate information with one
another by sending electrochemical messages
from neuron to neuron.
- Chemical substances manufactured in the
neuron, aid in the transmission of information
throughout the body.
Major Neurotransmitters in Psychology
- Control of complex movements, motivation,
cognition, and regulation of emotional
2 Nor epinephrine (Noradrenalin) :
• plays a role in changes in attention, learning
and memory, sleep and wakefulness, and
Major Neurotransmitters in Psychology…cot.
3- Epinephrine (adrenaline):
- Controls fight-or-flight response in anxiety
4- Serotonin: (inhibitory):
- Control of sleep ,wakefulness, emotions and
Major Neurotransmitters in Psychology…cot.
5- Gamma-Amino Butyric Acid (GABA):
- Drugs that increase GABA function used to
treat anxiety and induce sleep.
6- Acetylcholine: (excitatory or inhibitory).
- affect the sleep/wake cycle and to signal
muscles to become active.
Sensation and Perception
(The process where by stimulation of receptor
cells like eye, nose, ear …etc., send nerve
impulses to the brain, where they register a
touch, sound, color …etc).
- (process where the brain interprets sensation
giving them order and meaning).
Sensation and Perception…cont.
- Without sensation: perception couldn’t
occur, without perception sensations without
- Impaired perception cause (illusion).
(Any form of energy (sound, light, heat, and
pressure) to which an organism is capable of
• Stimuli and sensation have a cause and
Factors affects stimulus detection:
- (1) The intensity of stimulus.
- (2) Background noise interfere with stimulus
- (3) Motivation (rewards or punishments).
-(4) Prolonged constant stimulation: lead to
How do perceptual processes
1. Empiricist view of perceptual
- Babies enter the world with little or no
ability to see depth, form, and perceptual
- Infants learn adult like perceptions on the
basis of cues the environment provides .
2. Nativist view of perceptual development:
• Not all perceptual process are learned, some
arise from the way our sensory system
work, e.g. feeling of hunger or diaper
• 3- Interactionism view of perceptual
- Through the interaction of both biological
factors & experience perceptual process
- what we see, hears, feel, and so forth, is
partly the results of how our sensory systems
are programmed and partly the result of what
we are exposed to.
• *Expectations and perceptions:
• Psychologists have studied two ways in
which learning and experience mold our
expectations which in turn shape our
• 1-Perceptual set:
• A frame of mind that “ sets” a person to
perceive things in a certain way. We
perceive what we think we should perceive.
• - Perceptual sets establish expectations that
guide our perception, Example person who
was bitten by snake in the dark in specific
area. The sight of snake become a
• 2- Perceptual schema:
• Mental representation of objects and events
against which incoming data are compared
• - General knowledge of the world in the
form of schemas also shape our
expectations and hence our knowledge.