PSYC 1101 Chapter Notes - Chapter 2: Blood Sugar, Positron, Cerebral Hemisphere
6 Jun 2018
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Notes On The Biology of the Mind
Neural and Hormonal Systems
Biology, Behavior and Mind
● Franz Gall → phrenology → studying bumps on the skull could reveal things about
people’s talents
● Localization of function
● Cells → organs → organ systems → organism → family → community → culture →
therefore, we are biopsychosocial systems
Neural Communication
Neurons
● Nerve cells
● Cell body with fibers
● Dendrites → receive info
● Axon → passes message along
● Myelin sheath → insulates axons and speeds up impulses
● Multiple sclerosis → degeneration of myelin sheath
● Glial cells → support nerve cells
The Neural Impulse
● Neuron fires action potential down axon
● Computer activity is faster than reflexes
● Ions are exchanged in neural communication
● When the ions outside the nerve are positive and inside are negative, it is called resting
potential
● Selectively permeable → the axon’s surface is very selective over what is allowed
through
● Depolarization → when ions are let through the cell membrane
● Refractory period → the neuron pumps the Na+ ions back outside
● Excitatory → like pushing a neuron’s accelerator - “go”
● Inhibitory → like pushing the brake - “stop”
● Threshold → when excitatory are stronger than inhibitory → action potential
● Neural impulses either occur or they don’t
How Neurons Communicate
● Synapse → space between neurons
● Neurotransmitters → chemical messengers that travel across the synapse
● Reuptake → when left over neurotransmitters float away and are broken down by
enzymes
How Neurotransmitters Influence Us
● Effects of neurotransmitters vary with the receptors they stimulate
● Acetylcholine plays a role in learning and memory
find more resources at oneclass.com
find more resources at oneclass.com
● Dopamine → movement, attention, learning, emotion
● Serotonin → mood, hunger, sleep, arousal
● Norepinephrine → controls alertness, arousal
● GABA → inhibitory neurotransmitter
● Glutamate → excitatory neurotransmitter, memory
● ACh → when released, muscles contract
● Endorphins → good feelings (runner’s high)
How Drugs and Other Chemicals Alter Neurotransmitters
● When on drugs, brain stops producing natural opiates
○ → Withdrawal when off the drug, because the brain has no opiates (natural or
otherwise)
● Agonist molecules → increase neurotransmitter’s action
● Antagonist molecules → decrease neurotransmitter’s action
The Nervous System
● Central Nervous System (CNS) → brain and spinal cord → makes decisions
● Peripheral Nervous System (PNS) → gathers infor and transmits CNS decisions to other
parts of the body
● Nerves → link CNS with sensory receptors
● Sensory neurons → carry info from receptors inward → afferent
● Motor neurons → carry messages from CNS to rest of body → efferent
● Interneurons → process info between sensory input and motor output
The Peripheral Nervous System
● Somatic → voluntary control of skeletal muscles
● Autonomic → controls glands and internal organic muscles (heart pumping blood)
○ Sympathetic → arouses and expends energy → accelerates heartbeat when
nervous etc.
○ Parasympathetic → conserves energy and calms
○ Both work together to maintain homeostasis
The Central Nervous System
● 40 billion neurons connecting with 10,000 other neurons
○ Means 400 trillion synapses
● “Distrust big round numbers, such as the familiar but undocumented claim that the
human brain has 100 billion neurons.” (62)
● Neural networks → work groups of clustered neurons
● Learning strengthens connections between neurons
● Spinal cord → sends info two ways → connects PNS and brain
● Ascending fibers → send up sensory info
● Descending fibers → send motor control info
● Reflexes → automatic responses to stimuli → most simple composed of single sensory
and single motor neuron
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Franz gall phrenology studying bumps on the skull could reveal things about people"s talents. Cells organs organ systems organism family community culture therefore, we are biopsychosocial systems. Myelin sheath insulates axons and speeds up impulses. Multiple sclerosis degeneration of myelin sheath. When the ions outside the nerve are positive and inside are negative, it is called resting potential. Selectively permeable the axon"s surface is very selective over what is allowed through. Depolarization when ions are let through the cell membrane. Refractory period the neuron pumps the na+ ions back outside. Excitatory like pushing a neuron"s accelerator - go . Inhibitory like pushing the brake - stop . Threshold when excitatory are stronger than inhibitory action potential. Neural impulses either occur or they don"t. Neurotransmitters chemical messengers that travel across the synapse. Reuptake when left over neurotransmitters float away and are broken down by enzymes. Effects of neurotransmitters vary with the receptors they stimulate.
