Neurons

Question 1

What are neurons?

Answer 1

structural and functional units of the nervous system that react to physical and chemical changes in their environment and send nerve impulses to other neurons/other cells outside the nervous system

Question 2

What are the three parts of a neuron?

Answer 2

the cell body, axon, and dendrite

Question 3

What is the cell body?

Answer 3

the round structure between the dendrites and axons that contains the nucleus as well as other structures that help maintain the health of the neuron

Question 4

What are dendrites?

Answer 4

thin, tree-like objects that carry signals from other neurons to the cell body, and the communication done with other cells is through electro-chemical stimulation

Question 5

What are axons?

Answer 5

the part of the neuron that carries a nerve impulse away from the cell body

Question 6

What is the myelin sheath?

Answer 6

it is only found on larger neurons, it acts as a protective covering for the axons, it helps with speed and efficiency of impulse transportation, and if its damaged then the transport of impulses can become difficult

Question 7

What is a schwann cell responsible for?

Answer 7

the production and maintenance of myelin sheaths

Question 8

What are nodes of ranvier?

Answer 8

the narrow gaps between schwann cells which allow for the exchange of ions that allow for the formation of an action potential which let nerve impulses travel quickly

Question 9

What are axon terminals?

Answer 9

bulbous endings of the axons that hold the neurotransmitters necessary for neuron communication

Question 10

What are nerves?

Answer 10

bundles of axons that include neurological cells that provide physical support, insulation, and nutrients

Question 11

How do nerve impulses move?

Answer 11

nerve impulses travel across complex neural pathways and move from neuron to neuron, crossing via synapses

Question 12

What is action potential?

Answer 12

a rapid sequence of depolarization and re-polarization that involves the transfer of potassium and sodium ions in and out of the membrane

Question 13

What are nerve impulses?

Answer 13

a bioelectric current spreads across the membrane, causing action potential to occur, which progresses down the axon in a wave of action

Question 14

What do the steps in nerve impulses allow to happen?

Answer 14

they allow the nerve impulse to travel down the axon and move to the next neuron

Question 15

What is all or nothing?

Answer 15

if a neuron responds to a physical or chemical stimulus around it, it responds completely - in regards to input, a greater intensity of stimulation does not produce a stronger impulse, just more impulses per second

Question 16

What is a refractory period?

Answer 16

the brief time between nerve impulses where a stimulus can’t generate another nerve impulse, it ensures that a stimulus only travels one direction on the neuron, which is down the axon

Question 17

Where does action potential lead nerve impulses from?

Answer 17

dendrites, the cell body, axons, and axon terminals

Question 18

What happens when nerve impulse reaches the axon terminals?

Answer 18

its at the point where it will communicate with the dendrites of another neuron in a place called a synapse

Question 19

What are synapses?

Answer 19

the space between two communication neurons, the neuron who has the message sends it to the neuron receiving it by releasing neurotransmitters into the synapse via the axon terminals, these neurotransmitters are absorbed by the dendrites of the receiver neuron

Question 20

What are the two reactions that stem from dendrites’ absorption of neurontransmitters?

Answer 20

inhibitory (turning a process off) and excitatory (turning a process on)

Question 21

What are the 3 types of neurons?

Answer 21

sensory neurons, inter neurons, and motor neurons

Question 22

What do sensory neurons do?

Answer 22

bring sensory information to the CNS from peripheral body parts

Question 23

What do inter neurons do?

Answer 23

take the impulses from sensory neurons and transmit them to appropriate parts of the brain to be processed

Question 24

Where are inter neurons?

Answer 24

the brain and spinal cord

Question 25

What do motor neurons do?

Answer 25

carry impulses from the CNS to muscles or glands in order to cause a contraction/the glands to secrete