Ch. 12 Intro To Nervous System

Front 1

The nervous system and endocrine system help do what?

Back 1

maintain homeostasis

Front 2

What is the nervous system responsible for?

Back 2

All of our behaviors memories and movements.

Front 3

What are the main structures of the nervous system?

Back 3

Brain, spinal cord, cranial nerves(12 pairs), ganglia, enteric plexuses, sensory receptors in the skin., spinal nerves(31 pairs)

Front 4

What are the three functions of the nervous system?

Back 4

Sensory, integrative(to analyze the sensory information, store some aspects, and make decisions regarding appropriate behaviors.

Front 5

What are the nervous system divisions and what do they consist of?

Back 5

CNS- brain and spinal cord
PNS- cranial and spinal nerves that contain both sensory and motor fibers. It connects CNS to muscles, glands and all sensory receptors.

Front 6

What is the capacity, and cell body of Nuron?

Back 6

Capcity- produce action potentials.
Body- single nucleos.
Cell processes= dendrites and axons.

Front 7

What cells encircle PNS axons.
Each cell produces part of the myelin sheath surrounding an axon in the PNS.

Back 7

Neurogilia

Front 8

What is the distribution of Gray and White Matter?

Back 8

White matter- primarily myelinated axons.
Gray matter- Neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, nurugilia.

Front 9

What to 2 types of electric signals do neurons communicate by?

Back 9

Action potentials(long distance) and graded potentials(local).

Front 10

What are the 4 types of ion channels?

Back 10

Leakage, ligand-gated channels,"", voltage-gated channels, mechanically gated ion channels.

Front 11

Describe a leakage (nongated channel)?

Back 11

always open.

Front 12

Describe ligand-gated channels?

Back 12

open and close in response to a stimulus.

Front 13

describe Voltage-gated channels

Back 13

respond to a direct change in the membrane potential

Front 14

Describe Mechanically gated ion channels?

Back 14

Respond to mechanical vibration or pressure.

Front 15

Describe resting membrane potential?

Back 15

Negative ions along inside of cell membrane and positive ions along outside.

Resting potential exists because concentration of ions is different inside and outside cell.

Front 16

Describe graded potentials?

Back 16

Small deviations from resting potential.
Hyperpolarization= membrane becomes more NEGATIVE.
Depolorization- membrane has become more positive.

Front 17

Describe an action potential (nerve impulse)?

Back 17

rapidly occurring events the decrease and eventually reverse the membrane potential and then restore it to the resting state.

Front 18

Describe depolarizing phase?

Back 18

Chemical or mechanical stimulus caused a graded potential to reach at least threshold(55mv).
Voltage gated Na chanelles open and rush into cell.
Positive feedback process.

Front 19

Describe Repolarizing Phase?

Back 19

When threshold potential of 55mv is reached, voltage-gated K channels open.
K channel opening is much slower than NA channel opening which caused depolarization.
When the K channels do open the Na channels are already closed.

Front 20

Describe Refractory period?

Back 20

Period of time during which neuron can not generate another action potential.

Front 21

Describe absolute refractory period?

Back 21

even very strong stimulus will not begin another AP.

Front 22

Describe Relative refractory period?

Back 22

A supra-threshold stimulus will be able to start another AP.

Front 23

Describe Continuous Conduction (unmylinated fibers)?

Back 23

step by step depolarization of each portion of the length of the axolemma.

Front 24

Describe saltatory conduction?

Back 24

Depolaarization only at nodes of Ranvier where there is a high density of voltage gated ion channels.

Front 25

What are the 2 types of synapse?

Back 25

Electrical and Chemical

Front 26

Describe electrical synapses?

Back 26

ionic current spreads to next cell through gap junctions

Front 27

Describe chemical synapse?

Back 27

one way information transfer from presynaptic neuron to a post synaptic neuron.

Front 28

What are the 3 types of chemical synapses?

Back 28

Axodendritic-axon to dentrite
Axosomatic-axon to cell body
Axoaxonic-from axon to axon

Front 29

What are the steps of a chemical synapse?

Back 29

Action potential reaches end bulb and voltage-gated Ca2 channels open.
Ca2 flows inward triggering release of neurotransmitter.
Neurotransmitter crosses synaptic cleft and binding to ligand-gated receptors.

Front 30

The effect of a neurotransmitter can be either what or what?

Back 30

Exitory(depolarizing) or inhibitory.

Front 31

Describe depolarizing post synaptic potential (EPSP).

Back 31

It results from the opening of ligand-gated Na channel.
The postsynaptic cell is more likely to reach its threshold.

Front 32

Describe an inhibitory postsynaptic potential (IPSP)?

Back 32

it results from the opening of a ligand-gated CL- or K channel.
it causes the post-synaptic cell to become more negative or hyper-polarized.
the post synaptic cell is less likely to reach threshold.

Front 33

What is the process for removal of a neurotransmitter?

Back 33

Diffusion-move down concentration gradient
Enzymatic degradation- acetylcholinesterase
Uptake by neurons or gilia cells (neurotransmitter transporters.)

Front 34

What has the capacity to repair itself CNS or PNS?

Back 34

PNS