Chapter 1: Brain Basics P2 Flashcards
what view is the sagittal brain slice?
from the side
what view is the coronal brain slice?
form the back
what view is the horizontal brain slice?
from the top
what is the front and back orientation?
superior or dorasal
what are neurons?
- transmits signal to other nerve cells, muscles, or glands
- classified by function, location, neurotransmitters, and shape
- synapse with dendrites but can also synapse with cell bodies
what are gila?
- support cells
- clear toxins, support transport of information, and protects the system when there’s damage
- oligodendrocytes, microglia, astrocytes
what are excitatory neruons?
send signals that push their neighboring neuron toward firing (80% neurons)
what are inhibitory neurons?
send signals that suppress the activity of neighboring neurons, which regulates circuit activity (20% neurons)
what is an example of neuron example?
seizure disorders could be caused by imbalances in the activity of these neurons
what are the roles of glial cells?
- influence communication between neurons by modifying chemical environment between them
- guide neurons from side of creation to their final position in brain
- remove dead neurons, serve nutritive needs, provide structural support
- maintaining the blood-brain barrier, physical barrier preventing toxins, drugs, immune cells from entering nervous system
what are astrocytes?
regulate ion concentrations, provide nutrients to neurons, regulate, formation of new connections between neurons
what are microglia?
brains immune cells that help protect from infection/damage
what is ependymal cells?
critical role in homeostasis of cerebrospinal fluid that cushions brain and waste clearance
what are oligodendrocytes?
wrap axons in a fatty sheath called myelin
- produce myelin
what does it mean to have a large myelin?
the greater the speed with which electrical signal (action potential) travels down axon
what are nodes of ranvier?
gaps between the myelinated sections of an axon
what is gray matter?
contains the cell bodies, dendrites, and axon terminals of neurons
what is white matter?
made of axons connective other parts of gray matter to each other
which matter is on the outside and which on the inside?
- gray matter on the outside
- white matter on the inside
which part of the neuron receives information/signals?
the dendrites
what is an ion?
a charged atom
- can only cross membrane through an ion channel
what is a membrane potential?
the electric potential (or voltage) difference across the cell membrane
what voltage for a neuron at rest?
-70 millivolts (mV)
is it more negative inside or outside the neuron?
inside the neuron
what happens when membrane potential (at rest -70 mV) when potassium channels open?
becomes less negative
what is depolarization?
less negative
what is hyperpolarization?
more negative
what is an action potential?
the electrical impulse that moves down a neuron
- triggered when the sum of signals at dendrites reaches the cell’s threshold voltage (-55 mV) and opens voltage-gates ion channels
what is the first stage of an action potential
threshold: -55 mV to start an action potential
what is the second step of an action potential?
depolarization: sodium (Na+) and potassium (K+) enter the cell
what is the third step of AP?
the action potential happens at peek
what is the fourth step of AP?
repolarization: cell becomes hyperpolarized (more negative)
what is the fifth step of AP?
refectory period: because of qualities of the channels, overshoots target (voltage under -70 mV)
what is the last step of AP?
resting state
what is the myelin?
- oligodendrocytes wrapped around axon
- composed of fat: cholesterol, lipids, proteins
- electrical insulator to increase the speed of signal transmission within axon
- allows for saltatory conduction
what is a synapse?
junction between two cells where signal (neurotransmitter) travels from presynaptic cell to postsynaptic cell
what is a neurotransmitter?
chemical messenger/signal that crosses the synapse during neurotransmission
what is the first step of neurotransmission?
neurotransmitter release
- after action potential Calcium channels open to trigger NT release
what is second step of neurotransmission?
NT binds to receptor of post-synaptic cell
what is third step of neurotransmission?
post-synaptic cell has cascade of signals
what are the three types of NT clean up?
- reuptake by presynaptic cell
- diffusion into synapse
- enzyme breaks down (metabolized)
what happens after a NT enters the synaptic cleft?
binds to receptors on post-synaptic cell
what is an ionotropic channel or ligand-gated ion channel?
- NT binds directly to ion channel
- fast acting response
what is a metabotropic channel or G-protein-coupled receptor?
- NT binds to receptor
- receptor activates series of reactions, which opens channel
- longer acting response
what is an agonist?
binds to the receptor and activates it
what is an antagonist?
binds to the receptor and blocks other endogenous compounds from activating the receptor
what is Glutamate?
- ionotropic glutamate receptor
- most common excitatory NT
- depolarize post-synaptic neuron
what are the two examples of glutamate receptors?
- AMPA are fast and brief
- NMDA are slower, waves of multiple action potentials needed
- both important for learning and memory
what is GABA?
-most common inhibitory NT
- hyperpolarize post-synaptic neuron
what are ionotropic GABA receptors?
inhibit postsynaptic cell by allowing Cl-ions to enter
what are metabotropic GABA receptors?
inhibit postsynaptic cell by allowing K+ ions to leave
what are hormones?
molecule that sends cues about distant tissue activity to the brain
what are neuromodulator?
messenger released from a neuron to control groups of neurons
what is prostaglandin?
small lipids that change brain’s response to pain and inflammation
what is tay-sachs disease?
caused by genetic mutation for a gene coding for the fat-metabolizing enzyme, beta-hexosamindase A
what is Alzheimer’s disease?
the APOE gene predicts protein accumulation of amyloids in the brain
what is Huntington’s disease?
the mutation of the HTT gene leads to misfolding and accumulation of proteins
