Neuron Quiz

Question 1

steps for depolarization and repolarization of the neuron

Answer 1

an impulse is received. if it is -55mV or greater, action potential occurs by the sodium gates opening to let Na+ ions through the membrane and bringing the neuron to a voltage of +35mV. The sodium gates then close and the potassium gates open to release K+ outside of the membrane until a voltage of -90mV is reached. The gates then close and the sodium potassium pump starts running to bring the cell back to a resting potential of -70mV so it can transmit another impulse

Question 2

what is the gap between the synaptic knob and the postsynaptic membrane called

Answer 2

synaptic cleft

Question 3

what does myelin do

Answer 3

It protects myelinated neurons and speeds up the rate of nerve impulse transitions.

Question 4

what is the resting potential voltage

Answer 4

-70mV`

Question 5

What is a motor neuron?

Answer 5

Nerve cells in the central nervous system that transmit signals to the sensory systems, glands, and muscles to regulate voluntary and involuntary movements.

Question 6

What does an Effector do?

Answer 6

Brings internal conditions back into a normal range

Effectors can be muscles or glands that enact the necessary changes.

Question 7

What is stimulus threshold?

Answer 7

The minimum amount of stimulus needed to generate a nerve impulse by opening enough sodium channels, measured at -55mV.

Question 8

what is the rate of exchange for the sodium potassium pump

Answer 8

pumps 3 Na+ out and 2 K+ in for every molecule of ATP

Question 9

What is an axon and what does it do?

Answer 9

A long cylindrical extension of a neuron’s cell body that transmits impulses away from the cell body along its length to the next neuron.

Question 10

what are the 4 steps that occur at the neural synapse

Answer 10

1. the impulse travels down the axon into the synaptic terminal
2. the synaptic vesicles move toward and fuse with the presynaptic membrane based on Ca+ entering the terminal
3. the neurotransmitters are released into the synaptic cleft
4. neurotransmitters bind to the receptor proteins and affect the postsynaptic neuron based on wether the transmitters were excitatory or inhibitory

Question 11

maximum membrane voltage before repolarization begins to occur

Answer 11

+35mV

Question 12

voltage at hyperpolarization

Answer 12

-90mV

Question 13

What does the control centre do after receiving information from the sensor?

Answer 13

Activates an effector

This action is necessary to reverse the change detected.

Question 14

What is a synaptic vesicle?

Answer 14

A small secretory vesicle found inside the synaptic terminal that stores and transports neurotransmitters.

Question 15

What is the neurilemma?

Answer 15

The outermost cytoplasmic layer/cell membrane of a Schwann cell.

Question 16

What are dendrites and what do they do?

Answer 16

Short, branching terminals on a nerve cell (neuron) that receive signals from other neurons or sensory receptors and relay the impulse to the cell body. They are numerous and highly branched.

Question 17

What happens after the sensor detects a change in a negative feedback process?

Answer 17

Signals a control centre

This signaling is crucial for the next steps in restoring homeostasis.

Question 18

what type of neurons are only found in the CNS and transmit impulses from sensory to motor neurons

Answer 18

interneurons

Question 19

What are nodes of Ranvier?

Answer 19

Gaps in the myelin sheath insulating the axon of a myelinated nerve cell.

Question 20

What is summation?

Answer 20

The process of combining electrical impulses at a neuromuscular junction to determine if an action potential is created.

Question 21

What is a neuromuscular junction?

Answer 21

The synapse between a motor neuron and a muscle cell.

Question 22

True or False: The effector’s role is to maintain or restore homeostasis.

Answer 22

True

Effectors are essential for returning the system to its normal state.

Question 23

What is the all or none principle?

Answer 23

The principle that describes how a nerve impulse can’t exist in different strengths; it either occurs or does not occur based on the voltage provided by the stimulus.

Question 24

what does the cell body of a neuron do

Answer 24

It processes input from the dendrites and relays it to the axon if the input is large enough.

Question 25

what is another name for a nerve impulse

Answer 25

action potential

Question 26

What is the role of the Control Centre?

Answer 26

Activates the effector based on information received from the sensor ## Footnote The control centre processes information and coordinates the response.

Question 27

What is the cell body of a neuron?

Answer 27

The main part of a neuron that contains the nucleus and other organelles and serves as the site of the cell's metabolic reactions

Question 28

is the neuron polarized or depolarized at rest

Answer 28

polarized

Question 29

What is a neuron?

Answer 29

The structural and functional unit of the nervous system that consists of a nucleus, cell body, dendrites, axons, and a myelin sheath. Neurons are specialized to respond to physical and chemical stimuli to conduct electrochemical signals.

Question 30

what produces myelin

Answer 30

neurilemma of shwann cell

Question 31

what do the nodes of Ranvier do

Answer 31

They cause the membrane of the axon to be exposed, allowing action potentials to occur only at these nodes.

Question 32

What is a sensory neuron?

Answer 32

A nerve cell that carries information about changes in external and internal environments to the central nervous system, sending signals from the outer part of the body back to the CNS.

Question 33

What is myelin and what is it composed of?

Answer 33

The fatty insulating layer around the axon of a nerve cell that is composed of Schwann cells.

Question 34

What is a Negative Feedback Loop?

Answer 34

The main homeostatic mechanism that works in the body to keep a variable ## Footnote Negative feedback loops help maintain stability in physiological processes.

Question 35

What is an interneuron?

Answer 35

The central nodes of neural circuits that enable communication between sensory or motor neurons and the central nervous system, located only in the brain or spinal cord.

Question 36

What is a Stimulant/Stimulus?

Answer 36

Something that causes a change in the internal conditions ## Footnote This term refers to any factor that can initiate a response in a biological system.

Question 37

what does acetylcholine do to effectors

Answer 37

stimulate skeletal muscles and slow down the strength and rate of cardiac muscle contraction

Question 38

what type of neuron transmits nerve impulses from a receptor to the CNS

Answer 38

sensory

Question 39

What is a glial cell?

Answer 39

Support cells of the nervous system that nourish neurons, remove their waste, defend against infection, and provide a supporting framework for all nervous system tissue.

Question 40

What is a Schwann cell?

Answer 40

A type of insulating glial cell that wraps around the axon of a neuron to create a myelin sheath.

Question 41

What is a synaptic terminal?

Answer 41

A bulb at the end of the axon in which neurotransmitter molecules are stored and released.

Question 42

is the neuron depolarized or polarized when transmitting an impulse

Answer 42

depolarized

Question 43

What is a synapse?

Answer 43

The junction between two neurons or between a neuron and an effector (muscle or gland).

Question 44

where do depolarization and repolarization steps occur

Answer 44

at the node of Ranvier on the axon

Question 45

what ions exist outside of the axon and which ones exist inside the axon when the nerve cell is at rest

Answer 45

Na+ is on the outside, K+ and Cl- are on the inside

Question 46

saltatory conduction

Answer 46

process by which action potentials are transmitted from one node of Ranvier to the next along a myelinated axon

Question 47

What does a Sensor/Receptor do?

Answer 47

Detects a change in the internal environment ## Footnote Sensors or receptors are crucial for monitoring internal conditions.

Question 48

What is acetylcholine?

Answer 48

The primary neurotransmitter of both the somatic nervous system and the parasympathetic nervous system, which can either be excitatory or inhibitory depending on the receptor.

Question 49

volatge at resting

Answer 49

-70mV

Question 50

what happens to the neurotransmitters after they have done their job

Answer 50

they are broken down by enzymes and then swept up by glial cells that return the transmitters back to the presynaptic neuron

Question 51

What is acetylcholinesterase?

Answer 51

An enzyme that breaks down acetylcholine into acetic acid and choline through hydrolysis.

Question 52

Summarize how a negative feedback process operates.

Answer 52

A sensor detects a change, signals a control centre, which activates an effector to restore balance ## Footnote This process is vital for maintaining internal stability.

Question 53

stimulus threshold voltage

Answer 53

-55mV

Question 54

What is resting potential?

Answer 54

The potential difference across the membrane in a resting neuron when it is polarized and able to generate a nerve impulse, measured at -70mV.

Question 55

what happens if the neurotransmitter is inhibitory

Answer 55

the wont bind to the sodium gates and the gates will remained closed causing the nerve impulse to end

Question 56

what happens if the neurotransmitter is excitatory

Answer 56

it will bind to the sodium gates and open them so that the nerve impulse continues

Question 57

Fill in the blank: In a negative feedback process, a _______ detects a change that disrupts a balanced state.

Answer 57

[Sensor/Receptor] ## Footnote This component is essential for initiating the feedback mechanism.

Question 58

What is the refractory period?

Answer 58

The brief time (a few milliseconds) between the triggering of an impulse along an axon and the axon’s readiness for the next impulse, during which the neuron is hyperpolarized and returning to its resting potential.

Question 59

What is action potential?

Answer 59

The change in charge that occurs when the gates of the K+ channels close and the gates of the Na+ channels open after a wave of depolarization is triggered in an axon.

Question 60

what type of neuron transmits impulses from the CNS to the effectors

Answer 60

motor

Question 61

What is a neurotransmitter?

Answer 61

Chemical messengers secreted by neurons that carry a neural signal from one neuron to another or from a neuron to an effector such as a gland or muscle fiber.