Chapter 1: Brain Basics P2

Question 1

what view is the sagittal brain slice?

Answer 1

from the side

Question 2

what view is the coronal brain slice?

Answer 2

form the back

Question 3

what view is the horizontal brain slice?

Answer 3

from the top

Question 4

what is the front and back orientation?

Answer 4

superior or dorasal

Question 5

what are neurons?

Answer 5

• 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

Question 6

what are gila?

Answer 6

• support cells
• clear toxins, support transport of information, and protects the system when there’s damage
• oligodendrocytes, microglia, astrocytes

Question 7

what are excitatory neruons?

Answer 7

send signals that push their neighboring neuron toward firing (80% neurons)

Question 8

what are inhibitory neurons?

Answer 8

send signals that suppress the activity of neighboring neurons, which regulates circuit activity (20% neurons)

Question 9

what is an example of neuron example?

Answer 9

seizure disorders could be caused by imbalances in the activity of these neurons

Question 10

what are the roles of glial cells?

Answer 10

• 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

Question 11

what are astrocytes?

Answer 11

regulate ion concentrations, provide nutrients to neurons, regulate, formation of new connections between neurons

Question 12

what are microglia?

Answer 12

brains immune cells that help protect from infection/damage

Question 13

what is ependymal cells?

Answer 13

critical role in homeostasis of cerebrospinal fluid that cushions brain and waste clearance

Question 14

what are oligodendrocytes?

Answer 14

wrap axons in a fatty sheath called myelin
- produce myelin

Question 15

what does it mean to have a large myelin?

Answer 15

the greater the speed with which electrical signal (action potential) travels down axon

Question 16

what are nodes of ranvier?

Answer 16

gaps between the myelinated sections of an axon

Question 17

what is gray matter?

Answer 17

contains the cell bodies, dendrites, and axon terminals of neurons

Question 18

what is white matter?

Answer 18

made of axons connective other parts of gray matter to each other

Question 19

which matter is on the outside and which on the inside?

Answer 19

• gray matter on the outside
• white matter on the inside

Question 20

which part of the neuron receives information/signals?

Answer 20

the dendrites

Question 21

what is an ion?

Answer 21

a charged atom
- can only cross membrane through an ion channel

Question 22

what is a membrane potential?

Answer 22

the electric potential (or voltage) difference across the cell membrane

Question 23

what voltage for a neuron at rest?

Answer 23

-70 millivolts (mV)

Question 24

is it more negative inside or outside the neuron?

Answer 24

inside the neuron

Question 25

what happens when membrane potential (at rest -70 mV) when potassium channels open?

Answer 25

becomes less negative

Question 26

what is depolarization?

Answer 26

less negative

Question 27

what is hyperpolarization?

Answer 27

more negative

Question 28

what is an action potential?

Answer 28

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

Question 29

what is the first stage of an action potential

Answer 29

threshold: -55 mV to start an action potential

Question 30

what is the second step of an action potential?

Answer 30

depolarization: sodium (Na+) and potassium (K+) enter the cell

Question 31

what is the third step of AP?

Answer 31

the action potential happens at peek

Question 32

what is the fourth step of AP?

Answer 32

repolarization: cell becomes hyperpolarized (more negative)

Question 33

what is the fifth step of AP?

Answer 33

refectory period: because of qualities of the channels, overshoots target (voltage under -70 mV)

Question 34

what is the last step of AP?

Answer 34

resting state

Question 35

what is the myelin?

Answer 35

- 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

Question 36

what is a synapse?

Answer 36

junction between two cells where signal (neurotransmitter) travels from presynaptic cell to postsynaptic cell

Question 37

what is a neurotransmitter?

Answer 37

chemical messenger/signal that crosses the synapse during neurotransmission

Question 38

what is the first step of neurotransmission?

Answer 38

neurotransmitter release - after action potential Calcium channels open to trigger NT release

Question 39

what is second step of neurotransmission?

Answer 39

NT binds to receptor of post-synaptic cell

Question 40

what is third step of neurotransmission?

Answer 40

post-synaptic cell has cascade of signals

Question 41

what are the three types of NT clean up?

Answer 41

- reuptake by presynaptic cell - diffusion into synapse - enzyme breaks down (metabolized)

Question 42

what happens after a NT enters the synaptic cleft?

Answer 42

binds to receptors on post-synaptic cell

Question 43

what is an ionotropic channel or ligand-gated ion channel?

Answer 43

- NT binds directly to ion channel - fast acting response

Question 44

what is a metabotropic channel or G-protein-coupled receptor?

Answer 44

- NT binds to receptor - receptor activates series of reactions, which opens channel - longer acting response

Question 45

what is an agonist?

Answer 45

binds to the receptor and activates it

Question 46

what is an antagonist?

Answer 46

binds to the receptor and blocks other endogenous compounds from activating the receptor

Question 47

what is Glutamate?

Answer 47

- ionotropic glutamate receptor - most common excitatory NT - depolarize post-synaptic neuron

Question 48

what are the two examples of glutamate receptors?

Answer 48

- AMPA are fast and brief - NMDA are slower, waves of multiple action potentials needed - both important for learning and memory

Question 49

what is GABA?

Answer 49

-most common inhibitory NT - hyperpolarize post-synaptic neuron

Question 50

what are ionotropic GABA receptors?

Answer 50

inhibit postsynaptic cell by allowing Cl-ions to enter

Question 51

what are metabotropic GABA receptors?

Answer 51

inhibit postsynaptic cell by allowing K+ ions to leave

Question 52

what are hormones?

Answer 52

molecule that sends cues about distant tissue activity to the brain

Question 53

what are neuromodulator?

Answer 53

messenger released from a neuron to control groups of neurons

Question 54

what is prostaglandin?

Answer 54

small lipids that change brain's response to pain and inflammation

Question 55

what is tay-sachs disease?

Answer 55

caused by genetic mutation for a gene coding for the fat-metabolizing enzyme, beta-hexosamindase A

Question 56

what is Alzheimer's disease?

Answer 56

the APOE gene predicts protein accumulation of amyloids in the brain

Question 57

what is Huntington's disease?

Answer 57

the mutation of the HTT gene leads to misfolding and accumulation of proteins