Chapter 3 - Biology Flashcards
what are neurons?
Nerve cells specialized for communication
how many neurons in the human brain
Approx. 85 billion
how many neuron connections are in the brain
Approx. 160 trillion
every psychological experience is based in ___
biological processes
what does a dendrite do?
projection that picks up impulses from other neurons
synapse
the terminal point of axon branch which releases neurotransmitters
node
gap in the myelin sheath of an axon which helps the conduction of nerve impulses
cell body
material needed by the neuron are made here
axon terminal
synaptic knob
axon
nerve fiber projecting from the cell body that carries nerve impulses
myelin sheath
fatty coat that insulates the axons of nerve cells, speeding the transmission of impulses
glial cells
- Help to form the blood-brain barrier (astrocytes)
- Produces myelin for neurons (oligodendrocytes)
- Response to injury; cleans away debris (microglial cells)
- May be important for learning and memory
- ratio of glial cells to neurons is around 1:1
presynaptic neuron
- the neuron that is sending message
- before the synapse
postsynaptic neuron
- the neuron that is receiving the message
- after the synapse
what is neural communication?
an electro-chemical process
what is an action potential
- The electrical impulse that travels down the axon, triggering the release of neurotransmitters
- All-or-none principle: either a neuron with “fire” or it won’t
how does neural communication work?
Energy is in the form of an electrical potential
The difference in voltage inside vs. outside the neuron
Voltages inside and outside depending on the concentration of positively charged ions and negatively charged ions
where do cells begin?
at baseline or resting potential
when is action potential triggered?
when neuron is stimulated by sufficient excitatory inputs
what is the refractory period?
More negative than the resting state
Inhibits new action potentials for about 1 ms
what happens when neurotransmitters bind?
they can excite or inhibit the post-synaptic neuron
excitatory function
depolarize the post synaptic neuron — Na + ions into cell
inhibitory function
hyperpolarize the post-synaptic neuron — Cl into cell
what are graded potentials?
Post-synaptic potentials can be excitatory or inhibitory depending on whether positively or negatively charged chemicals flow into the cell
Increase or decrease the likelihood that the post-synaptic neuron will fire
when are neurotransmitters released?
from receptors for re-uptake or inactivation
when are neurotransmitters released?
when an excitatory signal is sent
how many neurotransmitters were identified?
100
2 chemical messengers
excitatory - “excite” the neuron and cause it to “fire off the message,” meaning, the message continues to be passed along to the next cell.
inhibitory - block or prevent the chemical message from being passed along any farther.
what is glutamate?
One of the most common NTs in CNS
Excitatory functions
Learning and memory
what is toxicity?
leads to cell death
associated with schizophrenia, Alzheimer’s disease, Parkinson’s disease, epilepsy
what is Gamma-Aminobutyric acid (Gaba)
One of the most common NTs
Inhibitory functions
Learning, memory, and sleep
Too much GABA can lead to coma
Too little GABA is associated with seizures and increases emotional activity
Acetylcholine (ACh):
Excitatory
Arousal and selective attention
Sleep
Learning and memory: Memory loss in Alzheimer’s Disease (partly) associated with the destruction of acetylcholine-producing neurons
Muscle control
what are monoamines?
neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain
Dopamine
the hypothalamus is a key production site
reward and reinforcement
arousal, motivation, motor control
cocaine and opiates affect dopamine production
serotonin
Regulation of mood, temperature, appetite, behaviour
Muscle contraction and sleep
Affects learning and memory
Antidepressants mimic the effect of serotonin
norepinephrine
fight or flight response
increased heart rate and blood flow
Anandamide
Eating, motivation, and memory
Sleep, immune function
Marijuana (THC) binds to endocannabinoid receptors
Endorphins
Type of neuropeptide
Pain reduction
Opioids bind to endorphin receptors
what is plasticity?
the ability of the nervous system to change
plasticity in development
- Growth of dendrites and axons
- Synaptogenesis
- Pruning
- Myelination
neural plasticity and learning
formation of new synapses
long term potentiation of neural plasticity
the process by which connections between neurons are strengthened
— Biological changes in neurochemicals and receptors —
neural plasticity and injury
serious damage is often permanent
neurogenesis
the creation of new neurons in the brain
— limited in adults —
central nervous system (CNS)
part of the nervous system containing the brain and spinal cord that controls the mind and behavior
what is the command center?
CNS - integrates information
what is CNS protected by?
three layers of meninges and cerebral ventricles
key areas of CNS
Cerebrum
Limbic System
Brainstem
the cerebrum
the younger part of the brain
includes limbic system, basal ganglia, olfactory bulb, and cerebral cortex
two cerebral hemispheres
what is the cerebral cortex responsible for?
Complex cognition: responsible for analyzing sensory experiences and higher-level brain functions
Ex: language, metacognitions; reasoning
parts of the frontal lobes
central sulcus
motor cortex
prefrontal cortex
central sulcus
divides the frontal lobe from the rest of the cerebral cortex
motor cortex
involved in voluntary movement
size of area reflects precision of motor control
prefrontal cortex
personality, planning, decision making
self awarness
language — Broca Area
parietal lobes
upper - middle portion o cerebral cortex
parts of parietal lobes
somatosensory cortex: just behind the central sulcus. sensations of touch, pain, pleasure
important functions of parietal lobes
spatial perception and tracking
relays information to motor cortex
temporal lobes
lower part of cerebral cortex
important functions of temporal lobes
responsible for controlling and directing various functions:
hearing
language comprehension - Wernicke’s area
memory storage
object and facial recognition
where is occipital lobes located?
rear of the brain
occipital lobes important funtion?
visual processes (visual cortex)
humans have comparatively large visual cortex
basal ganglia
sub - cortical structures
what is basal ganglia involved in?
voluntary movement
- action selection
- motor preparation
-timing
-task switching
what disorders are associated with damage to basal ganglia?
motor disorders
thalamus
major sensory relay station
- sends information to specialized processing centres
hypothalamus
involved in regulating behavior
- hunger, sexual behavior, emotional behavior
- sleep, body temp. hormone function, movement
amygdala
involved in the excitement, arousal, fear
emotional experiences
Hippocampus
critical for memory formation
episodic + somatic memory
what is episodic memory?
type of memory that allows us to remember specific events or experiences that have happened to us in the past.
what is somatic memory?
In the context of trauma and PTSD, “somatic memory” may refer to the way that the body holds onto memories of traumatic experiences, even when the person doesn’t consciously remember them.
In the context of movement and physical activity, “somatic memory” may refer to the way that the body learns and remembers how to perform movements and tasks.
In the context of biology and anatomy, “somatic memory” may refer to the way that genetic information is stored in somatic cells (non-reproductive cells in the body) and passed on to new cells as they divide.
where is the brain stem located?
located at the rear of the brain, under cortex and other strutures
what functions does brain cell perform?
basic functions that keep us alive and is involved in some higher-level functions
what are the important parts of the brain stem?
reticular activating system
Pons
Medulla
Cerebellum
what does the reticular activating system do? (part of brain stem)
arousal and maintenance of arousal
Ex: waking us from sleep and keeping us awake (we take this for granted)
what is pons? (part of brain stem)
connect cortex to cerebellum
a major bridge between the cerebellum controls a variety of major functions
what is the medulla? (part of brain stem)
responsible for heartbeat and breathing
controls other vital functions
what is the cerebellum (part of the brain stem)
motor and cognitive functions
explain the spinal cord
thick bundle of nerves that conveys signals between the brain and body
what do sensory neurons do? (spinal cord)
carry messages from sensory receptors to the brain
what do motor neurons do? (spinal cord)
carry messages aways from the CNS to muscles and glands
what do interneurons do?
relay information from sensory neurons to motor neurons
Ex: reflexes
What is the peripheral Nervous System (PNS)
Nerves in the body that extends outside the central nervous system
What are key branches of PNS?
Somatic Nervous System: Carries information from CNS to body
- Regulates voluntary movement
Autonomic Nervous System: Allows brain to interact with organs
- Regulates involuntary actions
somatic nervous system
carries information from CNS to the body
regulates voluntary movement
autonomic nervous system:
allows brain to interact with organs
regulates involuntary actions
what are the two branches of the autonomic nervous system?
sympathetic nervous system: fight or flight functions
Parasympathetic nervous system: Rest and digestion
what was phrenology?
theory in 1800s
founded by Franz Gall
incorrect map of the mind
what did bumps on the skull correspond to in Phrenology?
enlarged areas of the brain
what did enlarged areas of the brain indicate in phrenology?
greater psychological capacities
what was phrenology based on?
anecdotes (personal stories or observations that are shared by individuals as a way of providing insight into their own experiences or the experiences of others)
what was falsifiable? (altered or represented falsely)
phrenology
what are lesions?
A change in the structure of a tissue or an organ due to injury or disease usually results in the impairment of normal function.
Ex: head injury; surgery
what is useful for observing loss of function?
lesions (especially when damage is localized)
lesions are changes to structure or tissue, everyday life accidents like car accidents or sports
what is direct stimulation?
The direct application of electrical current to the surface of the cortex
Used by Penfield and others to map the cortex
what are electroencephalograms (EEGs)
the electrode on a person’s scalp which picks up brain waves
event-related potentials
measures by the milisecond
what is a non-invasive - systemic investigation of the brain?
EEGs
EEGs have good ____ resolution
temporal
EEgs have poor ___ resolution
spatial
what is structural imaging?
produces images of the different structures of the bain
what are computerized tomograohy
X-rays
what is magnetic resonance imaging?
magnetic field
how does a CT scan work?
head in a large tube, taking Xrays from different angles
how does MRI work?
large tube using strong magnetic field
produces clear images, especially with respect to soft tissue
good for investigating concussion or tumour
what is positron emission tomography
Increased blood flow to active areas of the brain
A radioactive isotope is tracked by the scanner
functional magnetic resonance imaging (fMRI)
Blood oxygen level-dependent (BOLD signal)
- No radioactive isotope
Shows the brain in action
- Both structures and activity is seen
- Time lag (several hundred milliseconds to 6 seconds)
Transcranial Magnetic Stimulation
An electromagnetic pulse is delivered to a specific part of the brain
- Strong pulse inhibits the function
- Can be used on healthy volunteers
weak pulse can ___ function
increase
who can TMS be used on and why?
healthy volunteers
- no need to cut brain open
what has TMS been used to investigate?
different processes
can be more experimental with these technologies as they are not harmful
what has weak pulse been used for?
depression
what is magnetoencephalography? (MEG)
Measures electromagnetic fields produced by groups of neurons
Directly measures neural activity
MEG has high ___ resolution
high temporal resolution (measures activity down to the millisecond)
may produce an alternative to FMR (more directly)
What is not an exact picture of the brain?
brain imaging
What is not an exact picture of the brain?
brain imaging
what is an fMRI? (measures the small changes in blood flow that occur with brain activity)
a computer-generated image of the brain and activation sites. its based on indirect measures
what is the subtractive method
Measure baseline, then subtract it from “active” condition
what are genes?
basic units of heredity. made up of small segments of DNA.
what are genotypes?
the complement of genes an organism inherits
what are chromosomes?
small structures within the nucleus of cells that carry many genes
What is DNA?
Comprised four bases (G, T, C, A)
Different genes are coded by different sequences of these bases
phenotype
observable characteristics of an organism, which result from the interaction of genetics and environment
what is natural selection
Organisms adapted to their environments are better able to survive and reproduce
when does the process of natural selection happen?
over generations of organisms, not within a single organism
what is sexual selection?
some traits make organisms more able to access or attract a mate
These traits will be passed on more frequently compared to less desirable or less adaptive traits and will
not all traits are ___
adaptive
what is the meaning of “not all traits are adaptive”?
traits that currently exist may have been important at one point, but no longer confer a survival or mating advantage
what used to be adaptive but may not be anymore?
traits
some traits that were adaptive are not longer adaptive
true of humans in modern society
what contributes to ideas of losing favor as a means to understand complex behavior?
social Darwinism and Eugenics
what is social darwinism?
belief that some individuals and societies are naturally more fit for survival and success than others, based on the principles of natural selection and evolution.
what is social Darwinism?
belief that some individuals and societies are naturally more fit for survival and success than others, based on the principles of natural selection and evolution.
what is Eugenics?
the idea that some people are born better than others, and that society can be improved by encouraging “better” people to have children and discouraging “worse” people from having children.
the belief that people’s abilities and qualities are inherited and that by controlling who has children, they can create a better and more successful society.
now considered to be deeply unethical
what is a key concept of evolution and behavior?
no single gene codes for a behavior
combinations of genes influence behavior
what does research regarding evolution and behaviour focus on?
estimating heritability of traits and bahaviours
what does research focus on regarding evolution and behavior?
focuses on estimating heritability of traits and behaviors
heritability
An estimate of the variability in a trait that can be attributed to genetics within a group
what traits differ in heritability?
high heritability of height
moderate heritability for personality
what does heritability estimate?
only applies to groups/populations, not individuals
who do heritability estimates apply to ?
particular groups in specific environments - they are not generalizable
what are the twin studies?
Monozygotic and dizygotic twins
used to study heritability
idea behind twin studies
twins separated at birth
similarities between them allow for estimate of heritability
what are adoption studies?
compare children to adoptive and biological parents
what does evolutionary psychology not promote?
genetic determinism
what is the result of genes and environment?
complex behaviours
What do we do with information about the heritability of traits and behaviors?
Selecting traits in children
