Physiology - Lecture 2 - Nervous System (Summer2013)

Front 1

Which two body systems act as major "control" systems?

Back 1

Nervous System and Endocrine System

Front 2

What is Nervous Tissue?

Back 2

Specialized for excitability. Able to create neurotransmitter proteins

*Able to create and transport electrical impulses throughout the body.

Front 3

Description of Nervous System:

Back 3

"Hard-wired" system - there is a "physical transferring and transport of information.

Front 4

What is the purpose of the Nervous System?

Back 4

-Global regulation, cognition and movement.

Front 5

What is the pace/duration of the Nervous System responses?

Back 5

Fast response - Short lived change.

Front 6

What are the 2 main branches of the Nervous System?

Back 6

Central
Peripheral

Front 7

What are the Structures of the CNS?

Back 7

Brain and Spinal Cord

Front 8

What are the branches of the PNS?

Back 8

Afferent - sensory (from the body into the CNS)

Efferent - action (receive commands and send them outward)
*Somatic - voluntary
*Autonomic - involuntary and Visceral function
(organs and glands)

Front 9

What is sensory stimuli?

Back 9

* Somato-Sensory Info

-We are aware of these sensations - touch, pain, etc...

Front 10

What are the divisions of the Autonomic Nervous System?

Back 10

Sympathetic - Carries fight or flight and stress responses

Parasympathetic - Rest and digest functions (normally has dominance over sympathetic)

Front 11

What is Visceral Simulation?

Back 11

-We are generally unaware:

*Blood Pressure, Blood Volume, etc

(smooth muscle from the Autonomic arm will feed back stimuli to the Peripheral afferent sensors)

Front 12

What is the synaptic cleft?

Back 12

The gap between the terminal end and the dendrites where information/signals are passed between cells.

Front 13

What are Neurotransmitters?

Back 13

The Chemical Messangers in Nervous System.

Front 14

What are the 2 types of excitable cells?

Back 14

1. Muscle Cells

2. Neuronal Cells

**able to fire action potentials**

Front 15

How do other cells stimulate (give information to) a neuronal cell?

Back 15

Through the cells dendrites.

Front 16

What is the Axon Hillock?

Back 16

The first part of the axon (at the bottom of the cell body).

*It has the lowest threshold for the action potential

Front 17

In which direction to signals travel on the axon?

Back 17

Signals fire down the axon, away from the cell body.

*Nerve Fiber*

Front 18

What are the 3 parts of a neuron?

Back 18

1. Cell Body
2. Axon
3. Dendrites (dendridic tree)

Front 19

What is the Action Potential?

Back 19

-It's the ability for an action to occur on a cell membrane (the ability for a signal to start)

Front 20

What is Myelination?

Back 20

-"insulation" along the axons. This speeds up the rate of the electrical impulse down the axon. Also, helping to protect the signal from being lost.

Front 21

What Myelinate's the axon in the PNS?

Back 21

-Schwann cells

Front 22

What are the Nodes of Ranvier?

Back 22

Small spaces between Schwann cells along the axon.

*These allow the action potentials to occur at less frequent intervals (this is helping to increase the speed of the signal, while maintaining it's strength)

Front 23

What Myelinate's the axon in the CNS?

Back 23

-Oligodendrocytes

*Glial Cells (supportive cells) that send "foot like" projections to cover the axons.

Front 24

What is the organization of Neuronal Cells?

Back 24

1. A

Front 25

What are 3 classes of Neurons?

Back 25

1. Efferent Neurons
2. Afferent Neurons
3. Interneurons

Front 26

What are Efferent Neurons?

Back 26

Neurons that originate in the CNS and move towards the PNS to reach it's target cell (or effector organ). ***Long peripheral axon in the PNS and the Cell Body is located in the CNS

Front 27

What are Afferent Neurons?

Back 27

Neurons that originate in the PNS and send their signal to the CNS. Generates action potential from Specialized Sensory receptors at it's peripheral end. ***Long axon found mainly in the PNS and Cell Body is in the PNS (close to Spinal Cord)

Front 28

What is an interneuron?

Back 28

Neuron that is found only in the CNS. They connect Afferent and Efferent Neurons and provide a processing of the Afferent signal and convey the signal, starting an Efferent process.

Front 29

What is Membrane Potential?

Back 29

Represents the differences in charges (voltage difference) across a membrane (in intracellular and extracellular fluid)

Front 30

What additional particles (ions) cause the intracellular fluid to have a negative charge?

Back 30

The amino acids and proteins with a net negative charge that can't escape the cell.

Front 31

What 2 things influence an Ion?

Back 31

1. Electrical Gradient

2. Chemical Gradient

Front 32

What is the electrical gradient?

Back 32

- The tendency of Ions to be attracted to an area with an opposite charge.

Front 33

What is equilibrium across a cell's membrane?

Back 33

-No net driving force = no net movement

Front 34

What is the equilibrium potential?

Back 34

the voltage where an ion’s
electrical gradient balances out it’s chemical gradient

Front 35

An Ion's equilibrium potential is dependent on what?

Back 35

An ion’s equilibrium potential is dependent on the valence of that ion and it’s concentration gradient (difference across the membrane).

Front 36

Which direction is K+'s concentration gradient?

Back 36

Out of the cell

Front 37

Which direction is K+'s electrical gradient?

Back 37

Into the cell (due to the net negative charge of the inside of the cell)

Front 38

What is the Equilibrium Potential for K+?
What is the Equilibrium Potential for Na+?

Back 38

- 90mV - K+ is conflicted b/c the electrical gradient and concentration gradient are in opposite directions.

+ 60mV - Na+'s gradients don't conflict - the cell would need to be at least -60mV inside the cell to cause conflict.

Front 39

What is a cell's Resting Membrane Potential contingent upon?

Back 39

1. the ions present and their individual equilibrium potentials
2. the relative permeability of the membrane to each ion.

-70mV (therefore higher permeability to the -90mV K+)

Front 40

Describe the steps of the Action Potential:

Back 40

***all or nothing event***

Depolarization - becoming more positive in charge (very rapid after crossing threshold) *Na+ rushes in
****hit peak and inactivated Na+ gates
Repolarization - coming back down into negative charge. *K+ gates open and K+ leaves the cell, causing repolarization.

Hyper-Repolarization - going further negative resting potential. *K+ gate is slow to close and causes a further drop. (important to resetting Na+ gates)

Resting Membrane Potential - when nothing is happening

Front 41

What are voltage gated ion channels?

Back 41

-Channels that are only triggered to open or close by specific voltages

Front 42

What is the threshold?

Back 42

It's the average voltage that is required for an action potential

Front 43

What are 2 types of synapses?

Back 43

1. Chemical
2. Electrical

Front 44

What is a Chemical Synapse?

Back 44

A signal by either a (+) or (-) neurotransmitter

Front 45

What are 3 neurotransmitters used in a chemical synapse?

Back 45

1. Amino Acid
2. Monoamines
3. Catecholamines

Front 46

What are monoamines?

Back 46

N.T. derived from a single Amino Acid that's been chemically modified.

Front 47

What are Catecholamines?

Back 47

Group of N.T.'s derived from Tyrosine.

Front 48

What are Neuroactive Peptides?

Back 48

Released with N.T.'s to modify the action site. Changes the reaction to the N.T. Intensifies sensitivity to the N.T.

-Shorter chaines than Amino Acids.

*Oxytocin
Somatostatin
Endorphin

Front 49

What are 4 Modulatory Transmitters?

Back 49

1. Noripinephrine
2. Serotonin
3. Dopamine
4. Acetylcholine ***

Front 50

Electrical Synapses

Back 50

- Gap Junctions that allow for the spread of the signal from the post synapse to the pre synapse
***not as common as chemical***

Front 51

What is the neuromuscular Junction?

Back 51

-A synapse between the axon terminals of motor neurons and skeletal muscle

Front 52

What is the synaptic cleft?

Back 52

The space between the post and the pre synaptic membrane (between cells)

*this is where signals cross

Front 53

What is the axon terminal?

Back 53

The end of the axon where the "firing" occurs.

Front 54

What is the process of the Ca++ gated action potential

Back 54

- As the terminal Depolarizes, the Ca++ channels are stimulated and opened.

- This stimulates the vesicles of neurotransmitters to release into the synaptic cleft
***AcytelCOA***

- AcytelCOA binds to the receptor and causes the opening of a cationic channel to open - leading to depolarization and triggers action potential

Front 55

What is Glutamic Acid?

Back 55

- the main stimulatory/excitatory N.T. seen in the CNS.

Front 56

What is Aminobutyric Acid?

Back 56

- "GABA" is the main inhibitory N.T. in the CNS

**ALSO Glycine is common

Front 57

List of Catecholamines derived from Tyrosine:

Back 57

Dopamine
Norepinephrine
Epinephrine

Front 58

Amino Acid Derived N.T.s

Back 58

Acetylcholine
Serotonin
Histamine