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Basic Structure of Neuron

 

The basic 

a. Ty1

2 

3

b. NTr

ch

to

__

ch

ex

in

__

structure and

ypes of Neur. Sensory (a

  

. Motor (eff

 . Associatio

   

Nerve Impulseransmission o

hanges across

o be _______

___________

harged in rela

xcess of ____

nside . Large n

___________

d function of 

ons fferent) 

ferent) 

n or Interneu

e Transmissioof a nerve imp

s the membra

____________

______ charge

ation to the o

___________ 

negatively cha

___________ 

the nervous 

urons 

on pulse along a

ane of the ne

___, indicatin

e inside and o

outside of the

 ions on the o

arged protein

of the cell m

Nervous S

system is the

 

 neuron occu

euron. The me

g that there i

outside the ce

 neuron.  Pol

outside and a

ns help maint

embrane. Wh

System  

e neuron.  

urs as a result

embrane of a

is a difference

ell. The inside

arization is es

an excess of _

tain the overa

hen the neur

t of  ________

an unstimulat

e between th

e is   _______

stablished by

____________

all negative ch

on is at _____

1 | P

 

__________ 

ted neuron is 

he 

____________

y maintaining 

______  ions o

harge on the 

___________

a g e  

said 

___ 

an 

on the 

___       

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Draw in the Schwann Cells (Myelin Sheath)

Role of the Myelin

Myelin speeds up the transmission of a nerve impulse by acting as an electrical insulator.

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Sensory (afferent) ×  A neuron that runs from a receptor

INTO the central nervous system.

×  Examples include pain, temperature, pressure and light touch.

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Motor Nerve (efferent) ×  Runs AWAY from the central

nervous system out to a muscle or gland (effector).

×  Will cause the body to do something.

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Association or Interneuron ×  Found in the central nervous system

(CNS) and is the relay between a sensory and a motor nerve.

Nerve Impulse Transmission Transmission of a nerve impulse along a neuron occurs as a result of _________________ changes across the membrane of the neuron. The membrane of an unstimulated neuron is said to be ____________________, indicating that there is a difference between the _________________ charge inside and outside the cell. The inside is ____________________ charged in relation to the outside of the neuron. Polarization is established by maintaining an excess of ______________ ions on the outside and an excess of ________________ ions on the inside .

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Large negatively charged proteins help maintain the overall negative charge on the ______________________ of the cell membrane. When the neuron is at _________________ ____________________, the inside of the neuron is maintained at _________________ mv. When a stimulus travels along the plasma membrane, the neuron will open or close specific ion gated channels.

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Events of Nerve Impulse Transmission

Action potential When an impulse travels down the plasma membrane; _________ gated channels will open. Once the _________________ __________________ reaches -50mv, all of the Na+ channels will open. This is commonly referred to as the __________________________ potential and the neuron must fire. (“All or nothing principle”)

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Box 1 

Box 2 

Box 3 

Box 4 

¾ W  

 Label the 

Resting pohyperpola

What type of t

graph showi

otential, threarization, dep

transport is th

ing an action 

shold potentpolarization 

his considered

potential usi

ial, action po

d? Why? 

ing the follow

tential, repol

 

 

 

 

 

 

 

 

 

 

 

wing word ba

arization, ref

ank. 

fractory perio

3 | P

 

od, 

a g e  

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Depolarization Once all the sodium channels open, this is referred to as _________________________. The sodium channels will remain open until the membrane potential reaches approximately __________________ mv. Once the membrane potential reaches +35mv, ________ channels will close and ____________channels will open.

Repolarization As a result, K+ leaving the cell makes the membrane potential increasingly ________________________. This is known as _______________________ and the combination of depolarization and repolarization is called the __________________ potential. The potassium channels will remain open until the membrane potential reaches ___________ mv and the membrane is said to be ______________________.

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Box 1 

Box 2 

Box 3 

Box 4 

¾ W  

 Label the 

Resting pohyperpola

What type of t

graph showi

otential, threarization, dep

transport is th

ing an action 

shold potentpolarization 

his considered

potential usi

ial, action po

d? Why? 

ing the follow

tential, repol

 

 

 

 

 

 

 

 

 

 

 

wing word ba

arization, ref

ank. 

fractory perio

3 | P

 

od, 

a g e  

Hyperpolarization Where are the Na+ and K+ ions located during hyperpolarization? What must the neuron do to return to the resting potential of -70mv?   Use the diagram below to explain how the neuron can return to resting membrane potential.

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Box 1 

Box 2 

Box 3 

Box 4 

¾ W  

 Label the 

Resting pohyperpola

What type of t

graph showi

otential, threarization, dep

transport is th

ing an action 

shold potentpolarization 

his considered

potential usi

ial, action po

d? Why? 

ing the follow

tential, repol

 

 

 

 

 

 

 

 

 

 

 

wing word ba

arization, ref

ank. 

fractory perio

3 | P

 

od, 

a g e  

Box 1 Box 2 Box 3 Box 4

Sodium-Potassium Pump ×  This is considered

__________________________ because…

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4 | P a g e   

Event  Description of Sodium and Potassium Movement 

A.     

B.     

C.     

D.     

E.     

F.     

G.     

 

D. Synapse and Neurotransmitters When the action potential reaches the synaptic terminal there will be a sudden influx of 

__________  ions. The calcium ions will cause nearby vesicles containing neurotransmitters to 

fuse with the ____________________ membrane. The vesicles will release a neurotransmitter 

that will  ________________ across the ______________   ____________and bind to the  

_________  ________________ receptors. Some of these receptors may either stimulate or 

inhibit the next neuron.  The most common stimulatory neurotransmitter is called 

______________________________ which causes muscle contraction. After the impulse crosses 

the _______________ it is degraded by the enzyme acetylcholinesterase. Other 

neurotransmitters such as ______________________ work on stimulating specific regions of the 

brain. Parkinson’s disease is caused by the inability to produce this neurotransmitter.  

      

Synapse and Neurotransmitters

When the action potential reaches the synaptic terminal there will be a sudden influx of __________ ions. The calcium ions will cause nearby vesicles containing neurotransmitters to fuse with the ____________________ membrane. The vesicles will release a neurotransmitter that will ________________ across the ______________ ____________and bind to the _________ ________________ receptors. Some of these receptors may either stimulate or inhibit the next neuron.

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The most common stimulatory neurotransmitter is called ______________________________ which causes muscle contraction. After the impulse crosses the _______________ it is degraded by the enzyme acetylcholinesterase. Other neurotransmitters such as ______________________ work on stimulating specific regions of the brain. Parkinson’s disease is caused by the inability to produce this neurotransmitter.

Acetyl Choline (Ach)

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Th

E. D

1

 

he Synapse 

Divisions of th

. Central Nea. Brain S

1) Ceem 

2) CeFu

3) Mfuma 

he Nervous Sy

ervous SystemSegments erebrum‐Largmotions, moto

erebellum‐Locunctions inclu

edulla‐Part onctions includaintaining CO

ystem 

m (CNS) 

est part of thor functions, 

cated inferiorde: balance a

f the brain stde: autonomiO2 levels in the

              

he brain.  Funcspeech and s

r to the cereband coordinat

em, located nic responses fe blood. 

ctions includesensory regio

brum and postion 

near the top ofor heart rate

 

e: memories,ns 

sterior to the 

of the spinal e and breathi

5 | P

 thoughts, 

brain stem.  

cord.  Primarng, including 

a g e  

ry 

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Role of Calcium (Ca2+) ×  Calcium enters the cell at the axon

terminal of the presynaptic cell and aids the vesicles in releasing the neurotransmitters into the synaptic cleft. Once the neurotransmitter binds to the receptor on the postsynaptic cell, the signal continues.

×  The action potential does not jump between cells, the neurotransmitters are the signal to continue.

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Divisions of Nervous System

 

Th

E. D

1

 

he Synapse 

Divisions of th

. Central Nea. Brain S

1) Ceem 

2) CeFu

3) Mfuma 

he Nervous Sy

ervous SystemSegments erebrum‐Largmotions, moto

erebellum‐Locunctions inclu

edulla‐Part onctions includaintaining CO

ystem 

m (CNS) 

est part of thor functions, 

cated inferiorde: balance a

f the brain stde: autonomiO2 levels in the

              

he brain.  Funcspeech and s

r to the cereband coordinat

em, located nic responses fe blood. 

ctions includesensory regio

brum and postion 

near the top ofor heart rate

 

e: memories,ns 

sterior to the 

of the spinal e and breathi

5 | P

 thoughts, 

brain stem.  

cord.  Primarng, including 

a g e  

ry 

Central Nervous System Cerebrum-Largest part of the brain. Functions include: memories, thoughts, emotions, motor functions, speech and sensory regions   Cerebellum-Located inferior to the cerebrum and posterior to the brain stem. Functions include: balance and coordination   Medulla-Part of the brain stem, located near the top of the spinal cord. Primary functions include: autonomic responses for heart rate and breathing, including maintaining CO2 levels in the blood.

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Peripheral Nervous System

Sensory pathways Nerve pathways that run from sensory organs or receptors towards the brain/spinal cord.   Motor pathways Somatic Nervous System-Motor movements send away from the brain. These are voluntary responses   Autonomic Nervous System   Sympathetic Nervous System-Activates the fight or flight response   Parasympathetic Nervous System-Sometimes called the rest and digest system, the parasympathetic system conserves energy as it slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract

Reflex Arc ×  This a reflex that involves a stimulus that is

picked up by a receptor.

×  The afferent (sensory) pathway sends a signal to the spinal cord.

×  The interneuron (association) relays the message from a sensory nerve to a motor nerve.

×  The signal is sent down the efferent (motor) nerve to the effector.

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3. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

W

 

 

W

 

 

H

What happens

What happens

ow does Nov

s if there is da

s if there is da

vocain work? 

R

amage to BOX

amage to BOX

4.

Reflex Arc 

X 2? 

X 4? 

2.

5. 

7 | P

1. 

a g e  

What Happens if Damaged? ×  What type of receptors can be found in box 1?

×  Damage to box 2-

×  Damage to box 4-

×  How does Novocain work?

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What About a Normal Response

×  People as well as animals respond to things like sights and smells.

×  When an organism senses a change in the environment, receptors pick up the signal and send it to the appropriate area of the brain for a response.