Bio 172 Ch 45

Front 1

A rapid, temporary change in electrical potential across a membrane

Back 1

action potential

Front 2

The difference in concentration of a solute across a cell membrane.
Ions and molecules flow from areas of high concentration to areas of low concentration.

Back 2

concentration gradient

Front 3

The combination of a concentration gradient and an electrical charge gradient, affects the amount of energy required for passage of charged ions across a cell membrane.

Back 3

electrochemical gradient

Front 4

The membrane potential at which there is no net movement of a particular ion in or out of a cell. Generally, this is the voltage at which the electrical gradient equals and opposes the concentration gradient of that ion.

Back 4

equilibrium potential

Front 5

A protein-regulated pore in the cell membrane that allows only certain ions to pass through.

Back 5

ion channel

Front 6

A difference in electrical charge across a cell membrane, a form of potential energy.

Back 6

membrane potential

Front 7

A cell that is specialized for the transmission of nerve impulses. Typically, it has
dendrites, a cell body, and a long axon that forms synapses with other neurons

Back 7

neuron

Front 8

The membrane potential of a cell in its resting, or normal, state.

Back 8

resting potential

Front 9

An active transport mechanism (i.e., one requiring energy) for pumping sodium and/or potassium ions across a cell membrane.

Back 9

sodium-potassium pump

Front 10

An ion channel that opens or closes at particular membrane potentials.

Back 10

voltage-gated channel

Front 11

nerve cells that send signals to effector cells in glands or muscles

Back 11

motor neurons

Front 12

a direct response to a signal that bypasses the brain

Back 12

reflex

Front 13

cell body, includes the nucleus

Back 13

soma

Front 14

a difference of electrical charge btw any two points

Back 14

electrical charge or voltage

Front 15

flow of charge

Back 15

electric current

Front 16

pores in a membrane that allow only specific ions to pass through

Back 16

ion channels

Front 17

potassium channels are sometimes called ___________, because they allow K+ to flow out of the cell.

Back 17

leak channels

Front 18

the membrane potential at which there is no net movement of a particuolar ion into or out of a cell

Back 18

equilibrium potential

Front 19

to change membrane potential from its peak (a less negative or slightly positive) state back to its normal state, or slightly below

Back 19

repolarize

Front 20

Neurons are said to have _________, because they are capable of generating action potentials that propagate rapidly along the length of their axons

Back 20

excitable membranes

Front 21

a technique for imposing a certain constant membrane potential on a cell, used to investigate ion channels

Back 21

voltage clamping

Front 22

a technique for studying the electrical currents that flow through individual ion channels, by sucking a tiny part of a membrane to the hollow tip of a microelectrode

Back 22

patch clamping

Front 23

A long projection from a neuron that propagates an action potential.

Back 23

axon

Front 24

The location where an axon joins the cell body of a neuron; the site where
action potentials are first triggered

Back 24

axon hillock

Front 25

A short extension from a neuron’s cell body that receives neurotransmitters from other neurons.

Back 25

dendrite

Front 26

To change a membrane potential from its resting negative state to a less negative, or even positive, state

Back 26

depolarize

Front 27

A change in membrane potential at a neuron
dendrite that makes an action potential more likely. The change is usually a depolarization.

Back 27

excitatory postsynaptic potential (EPSP)

Front 28

To change a membrane potential from its resting negative state to a more
negative state.

Back 28

hyperpolarize

Front 29

A change in membrane potential at a neuron
dendrite that makes an action potential less likely. The change is usually a hyperpolarization.

Back 29

inhibitory postsynaptic potential (IPSP)

Front 30

An ion channel that opens or closes in response to the presence of a certain molecule.

Back 30

ligand-gated channel

Front 31

A molecule that conveys information from one neuron to the next, or from a neuron to a muscle or gland; released from the end of an axon and diffuse a very short distance to the next cell, in which they can trigger an action potential.

Back 31

neurotransmitter

Front 32

The connection between two neurons or between a neuron and a muscle cell, consisting
of a tiny space into which neurotransmitters are released.

Back 32

synapse

Front 33

The potential to which a membrane must be depolarized to initiate an
action potential.

Back 33

threshold potential

Front 34

any poison that specifically affects neuron function

Back 34

neurotoxin

Front 35

takes place when the occcurrence of an event makes the same event more likely to occur

Back 35

positive feedback

Front 36

toxin that wipes out the resting potential of neurons

Back 36

ouabain

Front 37

Na+ channels are ________, once they hae opened and closed, they are less likely to open again for a short period of time

Back 37

refactory

Front 38

specialized cells that wrap around axons of neurons outside the brain and spinal cord, providing electrical insulation

Back 38

Schwann cells

Front 39

cells (not neurons, no conduction) that provide support, nourishment, and insulation

Back 39

Glia

Front 40

multiple layers of myelin, a lipid, that are wrapped around the axons of neurons to provide electrical insulation

Back 40

Myelin sheath

Front 41

a point on a neuron's axon between sections of myelin sheath where an action potential can be regenerated

Back 41

node of Ranvier

Front 42

a human autoimmune disease caused by the immune system attacking the myelin sheaths that insuolate nerve axons

Back 42

Multiple Sclerosis

Front 43

tiny neurotransmitter-containing vesicles at the end of an axon that can fuse with the axon membrane to release a neurotransmiter into a synapsis, stimulating the next neuron or effector cell

Back 43

synaptic vesicles

Front 44

a neuron that releases neurotransmitters to another neuron at a synapse

Back 44

presynaptic neuron

Front 45

a neuron that recieveds neurotransmitters from antoher neuron at a particular synapse

Back 45

postsynaptic neuron

Front 46

a gap of a synapse, the space between two communicating nerve cells across which neurotransmitters diffuse

Back 46

synaptic cleft

Front 47

a molecule that binds to a specific site on a recptor moleculde

Back 47

ligand

Front 48

chemical signals produced inside a cell in response to a chemical signal that arrives at the cell surface

Back 48

second messengers

Front 49

the additive nature of posstsynaptic potentials

Back 49

summation

Front 50

if a membrane at the axon hillock depolarizes past the ________, enough sodium channels open to trigger positive feedback and an action potential

Back 50

threshold

Front 51

what 2 distinct systems do the cells of the PNS control?

Back 51

afferent division and efferent division

Front 52

transmits sensory information to CNS

Back 52

Afferent division

Front 53

carries commands from CNS to the body

Back 53

Efferent division

Front 54

What two systems is the efferent division divided into?

Back 54

somatic nervous system and autonomic nervous system

Front 55

controls skeletal muscles

Back 55

somatic nervous system

Front 56

controls internal processes such as digestion and heart rate

Back 56

autonomic nervous system

Front 57

part of autonomic nervous system that stimulates relaxation, repair, and rebuilding, such as reduced heart rate and increased digestion

Back 57

parasympathetic nervous system

Front 58

part of the autonomic nervous system that stimulates fight or flight responses, such as increased heart rate and blood pressure

Back 58

sympathetic nervous system

Front 59

anteriormost part of brain, divided into right and left hemispheres. involved in memory, interpretation of information, decision making, and conscious thought

Back 59

cerebrum

Front 60

posterior section of brain involved in coordination of complex muscle movements including locomotion and balance

Back 60

cerebellum

Front 61

a small region of the brain that relays information to the cerebellum and is involved in the control of breathing

Back 61

pons

Front 62

responsible for rythmic body functions such as hear rate, respiration, and digestion

Back 62

medulla

Front 63

involved in complex decision making

Back 63

frontal lobe

Front 64

involved in integrating sensory and motor control

Back 64

parietal lobe

Front 65

recieves and interprets visual information

Back 65

occipital lobe

Front 66

functions in memory, interpretation of information from the ears, and language

Back 66

temperal lobe

Front 67

a thick band of neurons that connects the two cerebral hemishpers of the brain

Back 67

corpus callosum

Front 68

an enduring, adaptive change in an individuals behavior that resuolts from specific experience(s)

Back 68

learning

Front 69

retention of learned information

Back 69

memory