Biology of the Mind (Modules 4-6) Flashcards
Neuron
A neuron cell; the basic building block of the nervous system
Sensory neuron
Neurons that cary incoming information from the sensory receptors to the brain and spinal cord
Motor neuron
Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
Interneurons
Neurons within the brain and spinal cord that communicate internally and between the sensory inputs and motor outputs
Action potential
A neural impulse; a brief electrical charge that travels down an axon
Resting potential
When there’s a positive charge outside of the neuron and a negative charge inside of a neuron
Depolarize
When there is an influx of Na+ ions into the neuron upon the firing of a neuron, temporarily changing charges
Refractory period
Period during which Na+ ions are pumped back outside of the neuron, returning to its resting state
Threshold
The level of stimulation required to trigger a nuclear impulse
Synapse
Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
Synaptic gap
Tiny gap at the synapse, between two neurons
How wide is a synaptic gap?
Less than a millionth of an inch wide
Neurotransmitters
Chemical messengers that cross the synaptic gaps between neurons; travel across synapse and bind to receptor sites on the receiving neuron, influencing whether that neuron generates a neural impulse
Summarize the process of neurotransmission
1) Electrical impulses (action potentials) travel down a neuron’s axon until reaching the synapse
2) When an action potential reaches an axon terminal, neurotransmitter molecules are released. These molecules cross the synaptic gap to bind to receptor sites on the receiving neuron. This allows electrically charged atoms to enter the receiving neuron and excite or inhibit a new action potential.
3) The sending neuron reabsorbs excess neurotransmitter molecules (re-uptake).
Re-uptake
A neurotransmitter’s reabsorption by the sending neuron
Endorphins
“Morphine within” – natural, opiate-like neurotransmitters linked to pain control and to pleasure
Acetylcholine (ACh)
Function: Enables muscle action, learning and memory
Malfunctions: With Alzheimer’s disease, ACh-producing neurons deteriorate
Dopamine
Function: Influences movement, learning, attention and emotion
Malfunctions: Excess dopamine, receptor activity is linked to schizophrenia; lack of dopamine is connected to tremors, decreased mobility and Parkinson’s disease
Serotonin
Function: Affects mood, hunger, sleep and arousal
Malfunctions: Undersupply of serotonin is linked to depression, prozac and some other antidepressant drugs raise serotonin levels
Norepinephrine
Function: Helps control alertness and arousal
Malfunction: Undersupply can depress mood
GABA (gamma-aminobutyric acid)
Function: A major inhibitory neurotransmitter
Malfunction: Undersupply linked to seizures, tremors and insomnia
Glutamate
Function: A major excitatory neurotransmitter; involved in memory
Malfunction: Oversupply can overstimulate brain, producing migraines or seizures (which is why some people avoid MSG in food)
Agonist
May be similar enough to a neurotransmitter to mimic its effects or it may block the neurotransmitter’s re-uptake
Ex. Opiate drugs (amplify normal sensations), black widow spider venom (blocks)
Antagonist
Block a neurotransmitter’s function
Ex. Botulin, a poison that can form in improperly canned food, causes paralysis by blocking ACh release
Nervous System
The body’s speedy, electrochemical communication network consisting of all the nerve cells of the peripheral and central nervous systems
Central Nervous System
The brain and spinal cord
Nerves
Bundled axons that form neural cables connecting the CNS with muscles, glands and sense organs
Neural networks
Interconnected neural cells; with experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results. Computer simulation of neural networks show analogous learning.
Reflexes
A simple, automatic response to a sensory stimulus, such as the knee-jerk response
Peripheral Nervous System
The sensory and motor neurons that connect the CNS to the rest of the body
Somatic Nervous System
The division of the PNS that controls the body’s skeletal muscles, AKA skeletal nervous system
Autonomic Nervous System
The part of the PNS that controls the glands and the muscles of internal organs, includes the sympathetic nervous system and the parasympathetic nervous system
Sympathetic Nervous System
Division of the ANS that arouses the body, mobilizing its energy in stressful situations
Parasympathetic Nervous System
Division of the ANS that calms the body, conserving its energy
Endocrine System
The body’s “flow” chemical communication system; a set of glands that secrete hormones into the bloodstream
Hormones
Chemical messengers that are manufactured by the endocrine glands, travel through bloodstream and affect tissues
Adrenal glands
A pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress
Pituitary glands
The endocrine system’s most influential gland; under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
Lesion
Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue
Electroencephalogram
An amplified recording of the waves of electrical activity that sweep across the brain’s surface. These waves are measured by electrodes placed on the scalp.
PET
A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
MRI
A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy. AKA magnetic resonance imaging.
fMRI
AKA functional MRI. A technique for revealing blood flow and brain activity by comparing successive MRI scans. fMRI scans show brain function.
Brainstem
The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automative survival functions
Medulla
The base of the brainstem; controls heartbeat and breathing
Reticular formation
A nerve network in the brainstem that plays an important role in controlling arousal
Thalamus
The brain’s sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
Cerebellum
The “little brain” at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance
The Limbic System
Neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives
Amygdala
Two lima bean-sized neural clusters in the limbic system; linked to emotion
Hypothalamus
A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland and is linked to emotion and reward
Cerebral Cortex
The intricate fabric of interconnected neural cells covering the cerebral hemisphere; the body’s ultimate control and information processing center
Glial cells
Cells in the nervous system that support, nourish and protect neurons
Frontal lobes
Portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments
Parietal lobes
Portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position
Occipital lobes
Portion of the cerebral cortex lying at the back of the head; includes areas that receive information from visual fields
Temporal lobes
Portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, such receiving information primarily from the opposite ear
Motor cortex
An area at the rear of the frontal lobes that controls voluntary movements
What happens when we stimulate the motor cortex on one side of the brain?
There will be movement of body parts on the opposite side of the body.
Sensory cortex
Area at the front of the parietal lobes that registers and processes body touch and movement sensations
Association areas
Areas of the brain that integrate information, uncommitted to sensory or muscular activity, links sensory inputs with stored memories
Plasticity
The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience
When are our brains most plastic?
When we are young
Neurogenesis
The formation of new neurons
Corpus collosum
the large band of neural fibers connecting the two brain hemipheres and carrying messages between them
Split brains
A condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callossum) connecting them
What is one reason we would surgically split the corpus callossum?
Treat refractory epilepsy
What are some differences we see in split-brained people?
Split-brained people can perform two tasks independent of each other.
Ex. Drawing a circle with one hand and a square with the other at the same time
