Psychology, by David G. Myers, 7th Edition Textbook
Chapter 02 - Neuroscience, Genetics, and Behaviors
Chapter 02 - Neuroscience, Genetics, and Behaviors
• Franz Gall developed the false theory called Phrenology – where bumps on the head
dictate personality and intelligence. But the theory did direct our attention to brain
region and function.
• Psychologists that study these connections between biology and behavior are called
Biological Psychologists.
Neural Communication
• Our Neural System is basically made up of nerve cells or neurons. Each neuron is
composed of Dendrites ~ message receiving fibers and Axons ~ message sending fibers
which are insulated by the Myelin Sheath ~ fatty cells that help \speed up impulses.
• Impulses or Action Potential is a brief electrical charge that travels down the axon as
it becomes Depolarized due to the movement of positively charged ions entering the
axon. After the transmission, the axon becomes Polarized as positive ions are pumped
out during the Refractory Period.
• The intensity of a stimulus is called the Threshold. A stimulus must exceed the
threshold in order for a transmission to occur. The neuron will either fire or it won’t.
Much like a gun, the neuron either fires or it doesn’t, there are no half-fires. This is
called the all-or-none-response; if a stimulus is really strong, only the number of
neurons firing will increase, not their speed.
• The axon terminal of the sending neuron is separated from the receiving neuron by a
tiny gap called the Synapse (or Synaptic Cleft). Once the action potential reaches the
synapse, neurotransmitters, or chemical messengers, are released into the gap where
it will bind onto specific receptor sites on the receiving neuron.
• The most well know neurotransmitter is Acetylcholine (ACh), it causes muscles to
contract in movement.
• Endorphins are natural opiates produced in the body to control pain and induce
pleasure. ("Morphine within")
• Agonists are molecules which mimics the shape of natural neurotransmitters
(Morphine)
, • Antagonists are molecules which block neurotransmitters from binding on receptor
sites
• The brain has a Blood-brain barrier which filters out unwanted chemicals in blood
stream.
Neural and Hormonal Systems
• The Nervous System is composed of the Central Nervous System (CNS) – brain and
spinal cord, and Peripheral Nervous System (PNS) – links CNS to body’s muscles and
glands by means of nerves which are bundles of sensory and Motor Neurons (they
carry incoming and outgoing information respectively).
• The Autonomic Nervous System (under PNS) has Sympathetic Nervous System –
arouses the body for defense (increase heartbeat, dilating pupils, inhibit digestion etc.)
and Parasympathetic Nervous System – calms the body after stress.
• A simple Reflex is an automatic response to stimuli (like knee-jerk) involving
messages from Sensory to Interneuron (Spinal Cord) to Motor Neuron.
• The Endocrine System (slow hormone secreting system) communicates by releasing
Hormones (chemical messengers) into the bloodstream.
• In times of stress the ANS will signal Adrenal Glands (above kidney) to release
epinephrine and norepinephrine hormones (also called adrenaline and
noradrenaline.)
• Pituitary gland is the most powerful endocrine gland, and under the influence of
hypothalamus in brain, pituitary releases hormones that regulate glands and growth.
The Brain
• Lesions – remove brain tissue
• Electroencephalogram (EEG) – measures brain electric activity
• Computed Tomograph (CT or CAT Scan) – taking x-ray photographs of brain
• Positron emission tomograph (PET Scan) – detects radioactive glucose consumption
in brain
• Magnetic Resonance imaging (MRI) – generates brain images from magnetic activity
• The brainstem – oldest portion in brain forms into the Medulla Oblongata – regulates
involuntary processes like heartbeat and breathing.
Chapter 02 - Neuroscience, Genetics, and Behaviors
Chapter 02 - Neuroscience, Genetics, and Behaviors
• Franz Gall developed the false theory called Phrenology – where bumps on the head
dictate personality and intelligence. But the theory did direct our attention to brain
region and function.
• Psychologists that study these connections between biology and behavior are called
Biological Psychologists.
Neural Communication
• Our Neural System is basically made up of nerve cells or neurons. Each neuron is
composed of Dendrites ~ message receiving fibers and Axons ~ message sending fibers
which are insulated by the Myelin Sheath ~ fatty cells that help \speed up impulses.
• Impulses or Action Potential is a brief electrical charge that travels down the axon as
it becomes Depolarized due to the movement of positively charged ions entering the
axon. After the transmission, the axon becomes Polarized as positive ions are pumped
out during the Refractory Period.
• The intensity of a stimulus is called the Threshold. A stimulus must exceed the
threshold in order for a transmission to occur. The neuron will either fire or it won’t.
Much like a gun, the neuron either fires or it doesn’t, there are no half-fires. This is
called the all-or-none-response; if a stimulus is really strong, only the number of
neurons firing will increase, not their speed.
• The axon terminal of the sending neuron is separated from the receiving neuron by a
tiny gap called the Synapse (or Synaptic Cleft). Once the action potential reaches the
synapse, neurotransmitters, or chemical messengers, are released into the gap where
it will bind onto specific receptor sites on the receiving neuron.
• The most well know neurotransmitter is Acetylcholine (ACh), it causes muscles to
contract in movement.
• Endorphins are natural opiates produced in the body to control pain and induce
pleasure. ("Morphine within")
• Agonists are molecules which mimics the shape of natural neurotransmitters
(Morphine)
, • Antagonists are molecules which block neurotransmitters from binding on receptor
sites
• The brain has a Blood-brain barrier which filters out unwanted chemicals in blood
stream.
Neural and Hormonal Systems
• The Nervous System is composed of the Central Nervous System (CNS) – brain and
spinal cord, and Peripheral Nervous System (PNS) – links CNS to body’s muscles and
glands by means of nerves which are bundles of sensory and Motor Neurons (they
carry incoming and outgoing information respectively).
• The Autonomic Nervous System (under PNS) has Sympathetic Nervous System –
arouses the body for defense (increase heartbeat, dilating pupils, inhibit digestion etc.)
and Parasympathetic Nervous System – calms the body after stress.
• A simple Reflex is an automatic response to stimuli (like knee-jerk) involving
messages from Sensory to Interneuron (Spinal Cord) to Motor Neuron.
• The Endocrine System (slow hormone secreting system) communicates by releasing
Hormones (chemical messengers) into the bloodstream.
• In times of stress the ANS will signal Adrenal Glands (above kidney) to release
epinephrine and norepinephrine hormones (also called adrenaline and
noradrenaline.)
• Pituitary gland is the most powerful endocrine gland, and under the influence of
hypothalamus in brain, pituitary releases hormones that regulate glands and growth.
The Brain
• Lesions – remove brain tissue
• Electroencephalogram (EEG) – measures brain electric activity
• Computed Tomograph (CT or CAT Scan) – taking x-ray photographs of brain
• Positron emission tomograph (PET Scan) – detects radioactive glucose consumption
in brain
• Magnetic Resonance imaging (MRI) – generates brain images from magnetic activity
• The brainstem – oldest portion in brain forms into the Medulla Oblongata – regulates
involuntary processes like heartbeat and breathing.
