exam 1 Flashcards
ch. 1-3
what is biological psychology?
The study of the physiological, evolutionary, and developmental mechanisms of behavior and experience
physiological explanation
relates behavior to the activity of the brain and other organs
ontogenetic explanation
describes the development of the structure or behavior
evolutionary explanation
examines a structure or a behavior in terms of evolutionary history (WHY it evolved)
functional explanation
describes WHY a structure or behavior evolved as it did
how is the gut involved in influencing behavior
Gut bacteria stimulate the vagus nerve, which runs from the intestines to the brain, releasing chemicals that cross the lining of the intestines and enter the blood
human brain contains _____ neurons
86 billion
neuron contains
membrane, nucleus, mitochondria, ribosomes, endoplasmic reticulum (like all other cells)
BUT also contains dendrites, soma/cell body, axon, and presynaptic terminals
dendrites
branching fibers with a surface lined with synaptic receptors responsible for bringing information into the neuron
greater surface area of the dendrite =
more information it can receive
how do yo increase the surface area of dendrites ?
dendritic spines
cell body/soma contains
the nucleus, mitochondria, and ribosomes
cell body/soma: responsible for
the metabolic work of the neuron
cell body/soma is covered with
synapses
axons
Thin fiber of a neuron responsible for transmitting nerve impulses toward other neurons, organs, or muscles
afferent axon
brings info into a structure
efferent axon
carries info away from a structure
interneurons
dendrites and axons are completely contained within the structure
______ of a neuron determines its connection with other neurons and its contribution to the nervous system
shape
motor neurons
-Has its soma in the spinal cord
-Receives excitation from other neurons
-Conducts impulses along its axon to a muscle or gland
sensory neurons
It is specialized at one end to be highly sensitive to a particular type of stimulation (touch, light, sound, etc.).
types of glia
astrocytes, oligodendrocytes, microglia, radial glia
astrocytes
-help synchronize the activity of the axon by wrapping around the presynaptic terminal and taking up chemicals released by the axon
-responsible for dilating blood vessels to bring more nutrients into brain areas with heightened activity
microglia
-remove waste material, viruses and fungi from brain
-remove dead, dying, or damaged neurons
oligodendrocytes are located in the
brain and spinal cord
Schwann cells are located
in the periphery of the body
function of oligodendrocytes and Schwann cells
build the myelin sheath that surrounds and insulates certain vertebrate axons
radial glia
guide the migration of neurons and the growth of their axons and dendrites during embryonic development
When embryonic development finishes, most radial glia differentiate into…..
neurons and a smaller number differentiate into astrocytes and oligodendrocytes
nerve impulse:
the resting potential
the state of the neuron before sending a nerve impulse
nerve impulse:
messages in a neuron develop from…
disturbances of the resting potential
nerve impulse:
at rest, the membrane maintains an electrical gradient known as…
polarization: difference in electrical charge inside vs outside the cell
the inside of the cell is…
negative (-70 mV)
the nerve impulse:
___, ___, ___, and ___ are able to pass through channels in the membrane
sodium, potassium, calcium, and chloride
nerve impulse :
when the membrane is at rest:
____ channels are closed
___ channels are partially closed, allowing a slow passage.
sodium closed
potassium partially closed
nerve impulse:
ion channels: the sodium potassium pump is..
a protein complex
the sodium potassium pump continually..
pumps 3 sodium ions OUT
draws 2 potassium ions IN
ion channels maintain
the electrical gradient
ion channels (sodium potassium pump) uses ___ transport
active (uses ATP)
electrical and concentration gradients both work to
pull sodium into the cell, but they slowly leak out, carrying a + charge with them
the resting potential remains stable until…
the neuron is stimulated
hyperpoalrization
increasing the polarization or the difference between the electrical charge
depolarization
decreasing the polarization to 0
the threshold of excitation
a level above which any stimulation produces a massive depolarization
the action potential is
a rapid depolarization of the neuron
stimulation past the threshold of excitation triggers an action potential
voltage activated channels
membrane channels whose permeability depends on the voltage difference across the membrane
when sodium channels are opened…
+ charged sodium ions rush in and a nerve impulse occurs
after a action potential occurs…
sodium channels are closed
the neuron is returned to its resting state after an action potential by…
opening the potassium channels: potassium, ions flow out and take their + charge with them
the ______ pump restores the original distribution of ions
sodum potassium
blocking sodium channels
local anesthetic drugs bloc sodium channels and prevent action potentials from occurring
the all or non law
the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it
refractory periods
after an action potential, a neuron has a refractory period, where the neuron resists the production of another action potential
absolute refractory period
the first part of the period in which the membrane cannot produce an action potential
relative refractory period
second part in which it takes a stronger than usual stimulus to trigger an action potential
propagation of an action potential
transmission of an action potential down the axon
in a motor neuron, the action potential begins…
at the axon hillock: where the axon exits the soma
myelin sheath
insulating material made of fats and proteins
at each node of Ranvier
the action potential is regenerated by a chain of positively charged ions pushed along by the previous segment
saltatory conduction
the jumping of the action potential from node to node
provides rapid conduction of impulses
conserves energy for the cell
local neurons
have short axons, exchange info with neighbors, do NOT produce action potentials
local neurons produce
graded potential: membrane potentials that vary in magnitude and do not follow the all or none rule
graded potentials depolarize or hyper polarize in proportion to…
the stimulation
Sherrington investigated how neurons communicate with each other by studying reflexes in a process known as a reflex arc. He found that:
- Reflexes are slower than conduction along an axon
- Several weak stimuli present at slightly different times
- As one set of muscles becomes excited, another set relaxes
Sherrington: The difference in speed of conduction in a reflex arc from a previously measure action potential must be accounted for by
the time it took for communication between neurons
temporal summation
repeated stimuli can have a cumulative effect and can produce a nerve impulse when a single stimulus is too weak
spatial summation
synaptic input from several locations can have a cumulative effect and trigger a nerve impulse
excitatory postsynaptic potential (EPSP)
graded depolarization that decays over time and space
_____ is the basis for temporal and spatial summation
EPSP
Sherrington found that during the reflex that occurred,
the leg of a dog that was pinched retracted while the other 3 legs were extended
inhibitory postsynaptic potential (IPSP)
temporary hyperpolarization of a membrane
IPSPS occurs when
synaptic input selectively opens the gates for + charged potassium ions to leave the cell or negative charged chloride ions to enter the cells
___ serves as a brake that suppresses excitation
IPSP
spontaneous firing rate
periodic production of action potentials despite synaptic input
_____s increase the number of action potentials above the spontaneous firing rate
EPSP
_____s decrease the number of action potentials below the spontaneous firing rate
IPSP
presynaptic neuron
neuron that delivers the synaptic transmission
postsynaptic neuron
neuron that receives the message
Otto Loewi’s experiment found that
stimulating one nerve released something that inhibited heart rate, and stimulating a different nerve released something that increased heart rate.
major sequence of events allowing communication between neurons across the synapse:
*The _____synthesizes chemicals that serve as neurotransmitters
*Action potentials travel down the _____
*Released molecules diffuse across the cleft, attach to receptors, and alter the activity of the ________
*The neurotransmitters _______________________: either taken back to presynaptic for recycling or diffuse away
*The neuron synthesizes chemicals that serve as neurotransmitters
*Action potentials travel down the axon
*Released molecules diffuse across the cleft, attach to receptors, and alter the activity of the postsynaptic neuron
*The neurotransmitters separate from their receptors: either taken back to presynaptic for recycling or diffuse away
neurotransmitters
chemicals that travel across the synapse and allow communication between neurons
types of neurotransmitters
amino acids -
modified amino acid-
monoamines
neuropeptides
purines
gases
amino acids - GABA, glutamate, glycine
modified amino acid- acetylcholine
monoamines- indoleamines (serotonin), cathecholaines (dopamine, norepinephrine, epinephrine)
neuropeptides- endorphins, substrate P, neuropeptide Y
purines- ATP, adenosine
gases- NO
neurotransmitters are synthesized from
substances provided by diet
how long does transmission across the synaptic cleft take
fewer than 0.01 ms
the effect of a neurotransmitter depends on
its receptor on the postsynaptic ccell
two kinds of neurotransmitter effects
inotropic and metabotropic
inotropic effects:
occurs when a neurotransmitter attaches to receptors and immediately opens ion channels
Relies on glutamate or GABA
metabotropic effect
occurs when neurotransmitters attach to a receptor and initiate a sequence of slower and longer lasting metabolic reactions
When they attach to a metabotropic receptor, it BENDS the receptor protein that goes through the membrane of the cell- allows a portion of the protein inside the neuron to react with other molecules
___ effects include taste, smell, and pain
metabotropic
neuromodulators
Release requires repeated stimulation
Release peptides trigger other neurons to release same neuropeptides
Diffuse widely and affect any neurons via metabotropic receptors
duration of effects: neuropeptides vs neurotransmitters
neuropeptides: minutes
neurotransmitters: milliseconds
place synthesized: neurotransmitters vs neuropeptides
neurotransmitters: presynaptic terminal
neuropeptide: cell body
released by: neurotransmitters vs neuropeptides
neurotransmitter: single action potential
neuropeptides: repeated depolarization
____ drugs attach to the same receptors as endorphins
opiate
Stimulant drugs (amphetamine and cocaine) increase the release
dopamine from the presynaptic terminal
negative feedback from the postsynaptic cell
Autoreceptors:
Autoreceptors: detect amount of transmitter released and inhibit further synthesis and release
negative feedback form the postsynaptic cell:
Postsynaptic neurons:
respond to stimulation by releasing chemicals that travel back to the presynaptic terminal where they inhibit further release
CNS
brain + spinal cord
PNS:
connects brain + spinal cord to rest of the body
PNS breaks down into
somatic nervous system and autonomic nervous system
somatic nervous system
voluntary muscles and conveys sensory info to the CNS
autonomic nervous system
controls heart, intestines, and other organs
autonomic nervous system breaks into
sympathetic and parasympathetic nervous systems
sympathetic nervous system
-prepares organs for rigorous activity
-Increases heart rate, blood pressure, respiration
-Release mostly norepinephrine as a neurotransmitter
parasympathetic nervous system
-facilitates vegetative and nonemergency responses
-Composed of long axons extending from the spinal cord and short postganglionic fibers that attach to the organs themselves
-Release mostly acetylcholine as a neurotransmitter
the spinal cord communicates with…
the sense organs and muscles, except those of the head
the spinal cord: entering ___ roots carry sensory info and exiting ___ roots carry motor info
entering dorsal roots
exiting ventral roots
dorsal root ganglia
Cell bodies of the sensory neurons located in clusters of neurons outside the spinal cord
the spinal cord consists of 2 types of matter:
Grey matter: center of spinal cord; densely packed with cell bodies/dendrites
White matter: myelinated axons that carry info from grey matter to brain or other areas of the spinal cord
occipital lobe
Posterior end of cortex
Responsible for visual input
parietal lobe
Touch sensations and info from muscle-stretch receptors and joint receptors
Eye, head, and body positions from info from muscles/joints
Spatial information and numerical information
temporal lobe
Lateral portion of each hemisphere near the temples
Auditory information and essential for processing language
Aspects of vision, including movement and some emotion and motivation behaviors
frontal lobe
Contains the prefrontal cortex and the precentral gyrus
Higher functions
Prefrontal cortex
integration center for all sensory info
precentral gyrus
primary motor cortex; control of fine movement
