chapter 37

Question 1

what are neurons

Answer 1

nerve cells that transfer information, collection signals then transfers it

Question 2

what is a cell body

Answer 2

the inner part of the neuron; most of the organelles are located here

Question 3

what are dendrites

Answer 3

highly branched extensions that receive signals from other neurons, shorter in length, collects and stores all incoming information from axon terminals

Question 4

what are axons

Answer 4

the largest part of the cell, longer in length, less branching,

Question 5

what is depolarization

Answer 5

most cells are negative inside relative to their surroundings, there is an electrical shift causing the inside of the cell becomes positive ; open gated ion channels trigger depolarization a reduction in magnitude of membrane potential

Question 6

what is a synapse

Answer 6

the branched ends of the axons transmit signals to other cells at a junctions, which hold chemical messages called neurotransmitters

Question 7

what are neurotransmitters

Answer 7

pass information from the transmitting neuron to the receiving cells

Question 8

what are the three stages of the nervous system prodcesses

Answer 8

1) sensory imput 2) integration 3) output

Question 9

what are sensory neurons

Answer 9

transmit information detect external and internal stimuli, neurons collecting information (eye, ear, mouth)

Question 10

what are interneurons

Answer 10

information is sent to the brain where interneurons integrate the information and collect neurons

Question 11

what are motor neurons

Answer 11

transmit signals to the muscle cells, respond to stimuli

Question 12

what is the central nervous system

Answer 12

the brain and spinal cord and has much smaller in connections

Question 13

what is the peripheral nervous system

Answer 13

neurons that carry information in and out of the CNS
PNS neurons bundle together forming nerves that hold neurons creating a tube/collection of the neurons, highways for neurons to go to the same direction

Question 14

what is membrane potential

Answer 14

the difference in inside the cell (-) and the outside being (+)

Question 15

what is resting potential

Answer 15

membrane potential of a neuron not sending signals, the cell is getting ready to build up that energy to release

Question 16

what are the two ions that cannot travel across the membrane on its own

Answer 16

K+ and Na+

Question 17

what ion is being moved out of the cell

Answer 17

Na+, sodium

Question 18

what ion is being moved into the cell

Answer 18

K+, potassium

Question 19

what is a sodium potassium pump

Answer 19

uses the energy of ATP to maintain the K+ and Na+ gradients across the plasma membrane

Question 20

what are gated ion channels

Answer 20

changes in membrane potential occurs because nervous contain gated ion channels, that open or close in response to stimuli

Question 21

what is action potential

Answer 21

if depolarization shifts the membrane potential sufficiently, it results in a membrane voltage, occurs when a depolarization increases the membrane potential to a particular value called the threshold

Question 22

what are the stages that trigger action potential

Answer 22

1) resting potential 2) rising phase 3) falling phase 4) undershoot

Question 23

what is the rising phase

Answer 23

the threshold is crossed and the membrane potential increases as all gates Na+ channels are open, peak of action potential;
some gated Na+ channels are opened at first and Na+ flows into the cells

Question 24

what is the falling phase

Answer 24

voltage gates Na+ channels become inactivated and voltage gates K+ open, K+ flows out of the cell closing Na+ channels making the inside of the cell (-) until it goes back into rest

Question 25

what is undershoot

Answer 25

membrane permeability K+ is at first higher than rest, then voltage gated K+ channels close and resting potential is restored

Question 26

what is the refractory period

Answer 26

after an action potential, a second action potential cannot be initiated resulting in a temp activation of Na+ channels, moving in one direction

Question 27

what are myelin sheaths

Answer 27

an insulating layer that forms around the nerves

Question 28

what are nodes ranvier

Answer 28

gaps in the myelin sheath where voltage gates Na+ channels are formed

Question 29

what is saltatory conduction

Answer 29

action potentials in myelinated axons that jumps between the notes of ranvier

Question 30

what are chemical neurotransmitters

Answer 30

a chemical substance that is released at the end of a nerve fiber diffusing across the synapse

Question 31

what is a presynaptic neuron

Answer 31

synthesizes and packages the neurotransmitter in synaptic vesciles located in the synaptic terminal

Question 32

what are ligand gated channels

Answer 32

bind neurotransmitters and open in response to ligand binding