Chapter 3 Flashcards
What was the original idea philosophers had about the brain? What did early scientists observe as well?
“enchanted loom;” brain is one big woven web of material (based on what brain looks like)
What did Santiago Ramón y Cajal do with regards to the brain?
new technique for staining neurons, highlighting different shapes and sizes; discovered 3 parts of neuron
What is the neuron’s cell body?
the largest component of neuron that coordinates the information-processing tasks and keeps the cell alive; contains neucleus
What are dendrites?
receive information from other neurons and relay it to cell body; comes from greek word for tree
What is the axon?
carries information to other neurons, muscles, or glands
What is the myelin sheath? What is it composed of?
an insulating layer of fatty material covering axons in many neurons; composed of glial cells
What are glial cells?
support cells found in the nervous system
Do the dendrites and axons of neurons touch each other?
no; small gap thats part of a synapse
What is a synapse?
the junction or region between the axon of one neuron and the dendrites or cell body of another
What are the three major types of neurons?
1) sensory neurons
2) motor neurons
3) interneurons
Sensory neurons receive info from _____ and convey it to ______ via ____________
receive information from the external world & convey info to brain via spinal cord
Motor neurons carry signals from ______ _____ to ____________ to produce ________; often have long _______
spinal cord; muscles; movement; axons
Interneurons connect ______ _____, _______ _____, or other _______
sensory neurons; motor neurons; interneurons
T/F Most of the nervous system is composed of interneurons
TRUE
What are the two stages of electrochemical action of neurons?
1) conduction
2) transmissions
What is conduction? Moves from the ______ to the _______
the movement of an electric signal within neurons, from the dendrites to the cell body, then throughout the axon
What is transmissions?
the movement of electrical signals from one neuron to another over the synapse
What is the neuron’s resting potential? What is it caused by?
the difference in electric charge between the inside and the outside of a neuron’s cell membrane; caused by a difference in concentration of ions
Describe briefly the process of chemical pumps and how they can create quick electrical impulses
Na+ pumped out, K+ ions are pumped inside neurons, creating potential energy; electrical stimulation opens pumps, flooding K+ out and Na+ in towards equilibrium, releasing electrical signal
What is an action potential?
An electrical signal that is conducted along a neuron’s axon to a synapse
In order for an action potential to occur, the electric shock has to reach a _______
threshold
What is a refractory period?
the time following an action potential during which a new action potential cannot be initiated
What is the name of the processes by which the electric charge travels down an axon? Describe the process
saltatory conduction; the action potential dominos/jumps across nodes of Ranvier, creating action potentials each time and thus transferring the signal
What clumps in places down the axon?
myelin sheath
What do axons normally end in? Describe them. What are they filled with?
terminal buttons, knoblike structures that branch out from the axon; filled with vesicles
What do vesicles contain? Describe them
neurotransmitters, chemicals that transmit information across the synapse to a receiving neuron’s dendrites
The dendrites of a receiving neuron contain _____, which are?
receptors; parts of the cell membrane that receive neurotransmitters and either initiate or prevent a new electric signal
What three ways are neurotransmitters cleared out of the synapse?
1) reuptake into the sending neuron
2) broken down by enzymes in the synapse (enzyme deactivation)
3) binding to autoreceptors in sending neuron; they signal cell to stop releasing neurotransmitters when theres excess
The action potential travels down the length of the ____ to the ______ ______, where it stimulate the release of ______ from ______ into the ______
axon; terminal buttons; neurotransmitters; vesicles; synapse
Define acetylcholine
a neurotransmitter involved in a number of functions, including voluntary motor control
Define Dopamine
a neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal
Define Glutamate
major excitatory neurotransmitter in the brain; enhances transmission of info between neurons
Define GABA
opposite of glutamate; primary inhibitor neurotransmitter in brain; tends to stop firing of neurons
Define norepinephrine
involved in states of vigilance, or a heightened awareness of dangers in the environment
Define Serotonin
involved in the regulation of sleep and wakefulness, eating, and aggressive behavior
Define endorphins
chemicals that act within the pain pathways and emotion centers of the brain
What are agonists?
drugs that increase the action of a neurotransmitter
What are antagonists?
drugs that block the function of a neurotransmitter
Amphetamine is a popular drug that stimulates the release of ______ and ______; also prevents _____
norepinephrine and dopamine; reuptake
Amphetamine and cocaine are both strong _____ (type of drugs)
agonists
Methamphetamine affects pathways for _____, ______, and _____ at the neuron’s _______
dopamine, serotonin, norepinephrine; synapses
T/F Meth has agonists and antagonist effects
TRUE
Prozac is a ____ type of drug that works how?
agonist; blocks re-uptake of serotonin
What is propanalol?
Part of class of drugs called beta blockers that obstruct a receptor site for norepinephrine in the heart
L-dopa is an _____ for dopamine; how?
agonist; dopamine is created by modifying L-dopa, so if L-dopa is ingested, neurons will make more dopamine
Central nervous system is composed of what?
brain and spinal cord
The peripheral nervous system connects the ____ to the body’s ___ and _____
CNS; organs; muscles
Two divisions of PNS are:
1) somatic nervous system- set of nerves that conveys info between voluntary muscles and CNS
2) autonomic nervous system- set of nerves that prepares the body for action n challenging or threatening situations
Two divisions of ANS are:
1- sympathetic= prepares body for action
2- parasympathetic = helps body return to normal resting state
Name 8 attributes of sympathetic nervous system arousal
1) dilate pupil
2) relaxes bronchi
3) increases heartbeat
4) stops digestive activity
5) stimulates glucose release from liver
6) stimulates kidney secretion
7) relaxes bladder
8) stimulates ejaculation in males
What is a reflex arc?
a neural pathway that controls reflex actions
The spinal cord is continuous with this part of the brain; define it
hindbrain, an area of the brain that coordinates info coming into and out of the spinal cord
Name for structures that make up the hindbrain
1) medulla
2) reticular formation
3) cerebellum
4) pons
Define medulla
an extension of the spinal cord into the skull that coordinates heart rate, circulation, and respiration
Define reticular formation
regulates sleep, wakefulness, and levels of arousal
Define cerebellum
a large structure of the hindbrain that controls fine motor skills
Define the pons
a structure that relays info from the cerebellum to the rest of the brain
What sits on top of the hindbrain? What two structures compose it?
midbrain; tectum and tegmentum
Define tectum
orients an organism in the environment
Define tegmentum
involved in movement and arousal
The forebrain is divided into what?
cerebral cortex and subcortical structures
Define cerebral cortex
outermost layer of the brain, visible to the naked eye, divided into 2 hemispheres
Define subcortical structures
areas of the forebrain housed under the cerebral cortex near the center of the brain
Define Thalamus
it relays and filters info from the senses and transmits info to the cerebral cortex
Define hypothalamus
regulates body temperature, thirst, hunger, and sexual behavior
What is the limbic system?
a group of forebrain structures including the hypothalamus, the hippocampus, and the amygdala; where the subcortical structures meet the cerebral cortex
Define hippocampus
critical for creating new memories and integrating them into a network of knowledge so that they can be stored indefinitely in other parts of the cerebral cortex
Define amygdala
located at the horns of the hippocampus, plays a central role in many emotional processes, particularly the formation of emotional memories
Define basal ganglia
set of subcortical structures that directs intentional movements
Define corpus callosum
connects large areas of the cerebral cortex on each side of the brain and supports communication of info across hemispheres
What are the raised parts of the cortex called? What about the indentations?
gyri; sulci
What does the occipital lobe do?
processes visual information
What does the parietal lobe do?
processes info about touch; contains somatosensory cortex
What does the temporal lobe do?
responsible for hearing and language
What does the frontal lobe do?
specialized areas for movement, abstract thinking, planning, memory, and judgment
What are association areas?
composed of neurons that help provide sense and meaning to information registered in the cortex
_______ ______ are active when an animal performs a behavior, such as reaching for or manipulating an object, and are also activated when another animal observes that animal performing the same behavior
Mirror neurons
What is the main function of the pituitary gland?
releases hormones that direct the functions of many other glands in the body
What are epigenetic marks?
chemical modifications to DNA that can turn genes on or off
What are the two widely studies epigenetic marks?
DNA methylation and histone modification
Define DNA methylation
adding a methyl group to DNA; switches off gene
Define histone modification
adding chemical modifications to proteins called histones that are involved in packaging DNA; switch genes on or off
T/F epigenetic marks alter DNA sequences to affect gene expression
FALSE- they influence gene expression without altering underlying DNA sequence
Heritability is a measure of the _______ of ______ traits among individuals that can be accounted for by ______ factors; calculated as a ______
variability; behavioral; genetic; proportion
What is the ontogeny, compared with the phylogeny, of the brain?
Ontogeny is how the brain develops within a given individual; phylogeny is how it developed within a particular species (much slower process)
What is the structural difference between the brain of a reptile or bird, and the brain of a mammal?
reptiles and birds have almost no cerebral cortex, whereas mammals have a highly developed cerebral cortex
Language processing is a _____ (left/right) brain activity
left
What is an electroencephalograph
a device used to record electrical activity in the brain
How does the EEG record electrical activity in the brain?
electrodes are placed on outside of head and amplify electrical signals to make visual record
Whats the difference between structural and functional brain imaging?
structural- info about basic structures in brain; damage
functional- activity of brain during tasks
What does fMRI track in an active brain?
difference between oxygenated and deoxygenated hemoglobin
