Unit 4 Neuron System Function (Biology)

List the three functional regions of a neuron

receptive, conducting, secretory

What is included in the receptive region of a neuron

dendrites and cell body

What is included in the conducting region of a neuron

axon

What is included in the secretory region of a neuron

axon terminal

Dendrites are short, ___ processes

branched

Dendrites transmit input from other neurons toward the ___ ___

cell body

Another name for the cell body

soma

Nissi bodies are ___ of ___

congregations of ribosomes

What can be found in the cell body of a neuron

nissi bodies, mitochondria, cytoskeleton

Neurons do not contain ___ so they ___ divide and reproduce

centrioles, cannot

Axons ___ and ___ action potentials

generate and conduct

Sensory neurons are usually ___ (unipolar/multipolar)

unipolar

Motor neurons are usually ___ (unipolar/multipolar)

multipolar

Interneurons are usually ___ (unipolar/multipolar)

multipolar

Glial cells ___ neurons

support

Two functions of glial cells: ___ and ___

structural support and protection

Glial cells will ___ and fill in space when neurons die

divide

List the four types of glial cells in the central nervous system

astrocytes oligodendrocytes, microglia, ependymal

Astrocytes ___ neurons and blood vessels in place

anchor

Ependymal cells manufacture, secrete, and circulate ___ fluid

cerebrospinal

Microglial cells are immunity ___

phagocytes

Oligodendrocytes produce an ___ barrier called the ___ ___

insulating, myelin sheath

The myelin sheath ___ the speed of action potential conduction

increases

Myelinated axons make up the ___ matter

white

Cell bodies and dendrites make up the ___ matter

gray

Multiple sclerosis is a degenerative disease that attacks ___

myelin

Action potential is a ___, ___, and ___ change in membrane potential along the axon of a neuron

large, sudden, and transient

Ion (leak) channels are ___ open

always

Ion pumps open with ___

ATP

Ion (leak) channels move ions ___ their concentration gradient

down

Ion pumps move ions ___ their concentration gradient

up

Ion (leak) channels create the ____

resting membrane potential

Resting state occurs when the interior of the cell is ___ ___ in charge

less positive

In the Na/K pump, sodium is pushed ___ the cell (up its concentration gradient)

outside

In the Na/K pump, potassium is pushed ___ the cell (up its concentration gradient)

inside

List the two types of membrane gated channels

voltage, chemical

Chemically gated channels lead to ___ local potentials

reversible

Multiple local potentials can lead to a(n) ___ ___

action potential

Action potentials are only generated in the area around the ___ ____

axon hillock

List the two types of voltage gated channels in action potentials

sodium and potassium

Depolarization is when voltage gated sodium channels ___ and sodium goes ___

open, into

When the action potential repolarizes, the sodium channels ___ and the potassium channels ___

close, open

Action potential propagation is a(n) ___ ____ event

all or nothing one directional

Transfer of signals between neurons

Synaptic transmission

Examples of target cells

neuron, muscle, gland

The neuronal synapse can be ___ or ___

electrical or chemical

___ synapse makes up the majority of synapses in the vertebrate nervous system

chemical

Chemical synapses are ___ efficient

more

This ion is important for synaptic signaling

calcium

An influx of ___ causes a release of neurotransmitter into the cleft

calcium

Dopamine is ___ (short/long) term

short

Serotonin is ___ (short/long) term

long

This neurotransmitter is associated with taking and wanting more, like a craving

dopamine

This neurotransmitter is associated with contentment, fulfillment

serotonin

Psychoactive drugs target levels of ___

neurotransmitters

Generalized anxiety occurs because of a low GABA. GABA is a(n) ___.

inhibitor

Depression occurs because of low ___ levels

serotonin