Midterm 2: Neurons and Nervous System Slides

Question 1

Why are neurons different from other body cells?

Answer 1

They’re excitable cells that exhibit electrical activity (receive, process, and send it)

Question 2

Cell body structure and function

Answer 2

Contains nucleus and abundant protein synthesis organelles; main component of cell; 5-140 micrometers in diameter

Question 3

What are other names for the cell body?

Answer 3

Perikaryon, soma

Question 4

Dendrite function and structure

Answer 4

Extensions from cell body where electrical signals are received

Question 5

Axon hillock function

Answer 5

Site where electrical activity is generated (then sent down axon to axon terminals)

Question 6

Axon function, structure, and other name

Answer 6

Function: generate and conduct signals away from soma
Structure: abundant microtubules for transport
Also called nerve fibers

Question 7

Axon terminal structure

Answer 7

Contain neurotransmitter-filled vesicles

Question 8

Myelin sheath function and structure

Answer 8

Speed up electrical activity (lipid sheath that wraps around axon)

Question 9

What are Nodes of Ranvier?

Answer 9

Gaps in myelin sheaths along axon (in between the “bundles”)

Question 10

What do afferent/sensory neurons do?

Answer 10

Send information to the CNS

Question 11

What do interneurons do?

Answer 11

Connect neurons within CNS

Question 12

What do efferent/motor neurons do?

Answer 12

Send information from CNS

Question 13

What do multipolar neurons look like and what function do they usually have? Where are they found?

Answer 13

Many dendrites and one axon; motor neurons and interneurons; found in brain and spinal cord

Question 14

What do bipolar neurons look like and what function do they always have? Where are they found?

Answer 14

Only two extensions from cell body; uniquely sensory/afferent neurons; found in ears, nose, eyes

Question 15

What do unipolar neurons look like and what function do they usually have?

Answer 15

Have short single process and divide into two long branches; function as sensory neurons

Question 16

What is a synpase?

Answer 16

Junction formed by two neurons - allows communication to continue from one neuron to another

Question 17

Axosomatic synapse

Answer 17

Axon terminal of one neuron meets body of another

Question 18

Axodendritic synapse

Answer 18

Axon terminal of one neuron meets dendrites of another

Question 19

In diffusion, what pushes molecules to move?

Answer 19

Chemical driving force (set by concentration differences across cell)

Question 20

What are the ingredients for diffusion to occur?

Answer 20

Driving force (always there) and membrane permeability (not always there)

Question 21

What happens at the threshold/critical point of an action potential (very generally)?

Answer 21

Slow change in voltage suddenly speeds up

Question 22

What is a graded potential and where does it occur?

Answer 22

Slight fluctuation in electrical activity in the cell body and dendrites (action potentials do not occur here)

Question 23

Where do charges come from in the ECF?

Answer 23

Positive from Na+, negative from Cl-

Question 24

Where do charges come from in the ICF?

Answer 24

Positive from K+, negative from large protein anions

Question 25

What is the function of a membrane with regards to electrical activity?

Answer 25

Serve as a charge separator (physically separates charges from meeting)

Question 26

What is the overall charge inside a cell?

Answer 26

Negative (relative to outside)

Question 27

Which ions move into and out of the cell (at rest)?

Answer 27

Na+ wants in, K+ wants out

Question 28

Function of sodium/potassium pump

Answer 28

Maintain concentration gradient and never let cell reach equilibrium and lose excitability

Question 29

Depolarization

Answer 29

Cell becomes more positive (less negative than resting potential)

Question 30

Hyperpolarization

Answer 30

Cell becomes less positive (more negative than resting potential)

Question 31

Repolarization

Answer 31

Membrane potential returns to resting value

Question 32

What is the purpose of action potentials?

Answer 32

Facilitate communication

Question 33

What is divergence in neurons?

Answer 33

Input from multiple neurons at once; neuron sends and receives multiple signals at any time

Question 34

When is a VGSC at each of its states?

Answer 34

Closed at resting potential (-70 mV) Open from -55 mV to 30 mV Inactive from 30 mV back to -70 mV

Question 35

When is a VGKC at each of its states?

Answer 35

Closed at resting potential (-70 mV) to 30 mV | Open from 30 mV to -80 mV

Question 36

What triggers the opening of the voltage-gated channels?

Answer 36

When threshold is reached: VGSC opens right away, VGKC has delayed opening)

Question 37

Schwann cells function

Answer 37

Make myelin in PNS

Question 38

Oligodendrocyte function

Answer 38

Make myelin in CNS

Question 39

What are the channel types from least to most permeable?

Answer 39

Leak, ligand-gated, voltage-gated

Question 40

What is an EPSP?

Answer 40

Excitatory postsynaptic potential: NT binds to ligand channel and positive ions flow through

Question 41

What is an IPSP?

Answer 41

Inhibitory postsynaptic potential? NT binds to ligand channel and negative ions flow through