Neurons

Question 1

What are the three stages of all neuronal circuit paths?

Answer 1

Sensory input
Integration
Motor Response

Question 2

What is sensory input?

Answer 2

sensory neurons will detect stimuli and transmit a signal

like sound or touch

Question 3

What is integration?

Answer 3

signal is transferred to interneurons for analysis/evaluation

Question 4

What is motor response?

Answer 4

a processed signal is then relayed to motor neurons to trigger response to muscles/glands

Question 5

What is the central nervous system?

Answer 5

interneurons that integrate and process signals, and the select an appropriate response

Question 6

What is the peripheral nervous system?

Answer 6

carries information from the sensory neurons to the interneurons for processing, and relays processed signal from CNS to motor neurons.

Question 7

Describe the structure of neurons.

Answer 7

Cell body: organelles are located
Dendrites: branched extensions that receive signals from other neurons
Axon: typically longer extension that transmits signals to other cells
Axon Hillock: area where electrical signals are typically generated

Question 8

How do neurons interact?

Answer 8

Through synapses

Question 9

What is a synapse?

Answer 9

junction between branches ends of an axon and another cell

Question 10

What is a synaptic terminal

Answer 10

specialized end of the axon, which passes signals the neuron on the other side of the synapse, via neurotransmitters

Question 11

What are neurons insulated by?

Answer 11

Glia

Question 12

What are glia cells?

Answer 12

support cells for neurons that nourish, insulate, support, and help maintain neurons

Question 13

What is the membrane potential for a non-signaling neuron called?

Answer 13

Resting potential

Question 14

What are sodium-potassium pumps?

Answer 14

along the neuron’s membrane use ATP to actively transport Na+ and K+ against their gradients
Makes two gradients

Question 15

What are the two gradients?

Answer 15

Na+ is higher outside the cell

K+ is higher inside the cell

Question 16

How does a negative charge build up inside the cell?

Answer 16

diffusion imbalance between Na+ and K+

Question 17

Where does voltage stabilize at?

Answer 17

-70mV

Question 18

What is the resting potential?

Answer 18

the difference in charge is stored energy which can be used for impulses
the membrane is highly polarized

Question 19

What are gated ion channels?

Answer 19

they open and close in response to stimuli, which will alter membrane permeability
causes ions to rapidly cross the membrane which leads to change in membrane potential

Question 20

What does the resting potential get converted to?

Answer 20

action potential

Question 21

What is the threshold?

Answer 21

voltage where enough depolarization has occurred that voltage gated ion chases are opened, causing huge Na+ influx

Question 22

Describe the resting stage.

Answer 22

Stage 1: Resting Potential
most of the voltage gated Na+ and K+ channels are closed
negative inside

Question 23

Describe the depolarization stage.

Answer 23

Stage 2
a stimulus opens some channels and allows Na+ to enter and depolarization to begin opening some voltage gated Na+ channels

Question 24

Describe rising phase. (action potential generated)

Answer 24

Stage 3

the threshold is reached, and most voltage gated Na+ channels open first, to let in large amount of Na+ in

Question 25

Describe the falling phase. (refractory period)

Answer 25

Stage 4
Most voltage gated Na+ channels are inactivated blocking Na+ inflow, stopping the Positive Feedback Loop
Voltage gated K+ Channels now open to permit K+ to leave the cell, making it negative again

Question 26

Describe the undershoot phase. (Hyperpolarization)

Answer 26

voltage gated K+ channels remain open for a bit longer while other channels reset, which hyperpolarizes the cell, leading to an undershoot in membrane potential
resting potential is restored

Question 27

How does electrical current flow?

Answer 27

by electrical synapses, where current flows from one neuron to another via cytoplasmic bridges (gap juntioncs)

Question 28

What are chemical synapses?

Answer 28

a chemical neurotransmitter relays signal information across the space between cells (Synaptic Cleft)

Question 29

What triggers the opening of voltage gated Ca2+ channels?

Answer 29

open in response to an action potential, which lets Ca2+ enter cell

Question 30

Where are neurotransmitters stored?

Answer 30

within the presynaptic cell in synaptic vesicles

Question 31

How is the action potential generated?

Answer 31

neurotransmitters bind to ligand gated ion channels on dendrites of the postsynaptic cell