lec 5- animal nervous system

Question 1

do plants have neurons?

Answer 1

No

Question 2

what is the only animal that doesn’t have neurons?

Answer 2

sponges

Question 3

what are the two basic types of nervous systems?

Answer 3

A nerve net (diffuse arrangement of cells) and a central nervous system

Question 4

what are the types of neurons?

Answer 4

interneurons, motor neurons, and nerves

Question 5

what are interneurons?

Answer 5

neurons that pass signals from one neuron to another

Question 6

what are motor neurons?

Answer 6

motor neurons send signals to effector cells in glands or muscles

Question 7

what are nerves?

Answer 7

nerves are a bundle of motor and sensory neurons in a long strand

Question 8

what are the parts of a neuron?

Answer 8

cell body, branched dendrites, and a long axon

Question 9

what is the junction between neurons called?

Answer 9

the junction between neurons is called synapse

Question 10

what is membrane potential?

Answer 10

Ions carry an electrical charge and this unequal distribution of ions creates an electrical potential across the plasma membrane known as membrane potential

Question 11

does the sodium potassium pump contribute to membrane potential?

Answer 11

yes, it separates charges

Question 12

are membrane potentials negative inside?

Answer 12

yes, The ions inside of the cell is usually negative while the outside is usually 0 mV

Question 13

how does the sodium-potassium pump contribute to the membrane potential?

Answer 13

it moves out three positive ions and moves in two positive ions, this results in the inside being more negative, this makes it also an electrogenic pump

Question 14

what is resting potential?

Answer 14

Resting potential is when neuron is not sending/receiving signals, causing a difference in charge across the membrane

Question 15

how is resting potential maintained?

Answer 15

due to ion gradients and potassium leaks

Question 16

what are the intracellular and extracellular concentrations of potassium, sodium, chloride, and calcium?

Answer 16

K+: high, low
Na+: low, high
Cl-: slightly low, slightly high
Ca2+: very low, very low

Question 17

what is the role of the K+ leak channel?

Answer 17

At rest, K+ leaks through and results in inside becoming negative, this buildup of negative charges begins to attract K+ and counteract the concentration gradient, eventually it reaches equilibrium and the membrane potential turns into the resting potential

Question 18

what is it called when the chemical and the electrical gradients are balanced?

Answer 18

equilibrium potential

Question 19

why is temperature used in the nernst equation?

Answer 19

because when temperature decreases, the equilibrium potential increases

Question 20

why is charge used in nernst equation?

Answer 20

because the charge has an affect on reaching the equilibrium potential

Question 21

when the permeability of an ion increases, what happens?

Answer 21

Resting/membrane potential moves towards equilibrium potential of the Na+ or K+ ions when the permeability of the ion increases

Question 22

what is the resting potential and equilibrium potentials of Na+, K+?

Answer 22

resting membrane potential:
-65 mV
equilibrium potential Na+:
+60 mV
equilibrium potential K+:
-90 mV

Question 23

what is depolarization?

Answer 23

it is when Na+ moves into the cell so the membrane potential can reach the equilibrium potential of Na+

Question 24

what is hyperpolarization?

Answer 24

it is when K+ moves out of the cell so the membrane potential can reach the equilibrium potential of K+

Question 25

what are the changes in depolarization and hyperpolarization called?

Answer 25

graded potentials

Question 26

what are the types of electrical signals from change in membrane potentials?

Answer 26

small stimulus, large stimulus, and long stimulus result in small depolarization, large depolarization, and long depolarization.

Question 27

what happens when a stimulus causes depolarization above a threshold?

Answer 27

an action potential is released from a postsynaptic neuron

Question 28

what is an action potential?

Answer 28

An action potential is a rapid temporary change in a membrane potential

Question 29

what must be surpassed for an action potential to be released?

Answer 29

threshold potential (-55 mV), goes from -65 mV to -55 mV

Question 30

what are the three phases of an action potential?

Answer 30

depolarization (membrane becomes positive), repolarization (becomes negative), hyperpolarization (becomes more negative than before)

Question 31

at what mV does repolarization occur?

Answer 31

+40 mV

Question 32

what is it called when it is hard for the neuron to initiate another action potential during the hyperpolarization phase?

Answer 32

relative refractory period

Question 33

Are all action potentials the same in magnitude in each neuron?

Answer 33

Yes

Question 34

what are action potentials most dependent on?

Answer 34

voltage-gated channels (ion channels that open and close based on changes in membrane voltage)

Question 35

what is voltage clamping?

Answer 35

a technique that allows researchers to record electrical currents from grabbing onto an axon

Question 36

what is patch clamping?

Answer 36

a technique used to measure the electrical current in one single ion channel

Question 37

what are the functional state steps of voltage gated ion channels?

Answer 37

1. Gates are either open or closed
2. During depolarization Na+ channels quickly open then spontaneously inactivate
3. During depolarization K+ channels open with delay then close when membrane repolarizes