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