What makes you_nervous5

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Lorem Ipsum What Makes You Nervous Halloween Issue

Transcript of What makes you_nervous5

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Lorem Ipsum

What Makes

You Nervous

Halloween Issue

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Nerve Impulses: Neurons are remarkable among cells

because they initiate and conduct signals called nerve impulse (1)

After cells go through a haunted house, they can have different nerve

impulse and reactions. Bellow you will find the different impulses.

Membrane Potential: All living cells,

including neurons, maintain a

difference in the concentration of

ions across their membranes. There is

a slight excess of negative ions on the

inside of the membrane. This results

in a difference in electrical charge

across their plasma membrane

(membrane potential) (1)

Resting Membrane

Potential: Electric charge

difference inside a cell

membrane, measured

relative to just outside the

cell membrane (2)

(2)

(2)

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Local Potential:

1. Stimulation of neuron by chemical, light, heat,

or mechanical distortion.

2. Stimulation alters permeability of various ions

thus leading to a change in resting membrane

potential. Increased Na+ permeability results in a

depolarization. Increased K+ or Cl- permeability

results in a hyperpolarization.

3. Local potentials are graded; that is, they vary in

magnitude.

4. Local potentials are decremental; that is they

get weaker the farther they spread from the point

of stimulation.

5. Local potentials are reversible. If the

stimulation ceases, the membrane potential drifts

back to resting membrane potential without

affecting the cell. (2)

Action Potential: Change in membrane potential

in an excitable tissue that acts as an electric signal

and is propagated in an all-or-none fashion. (2)

(2)

(2)

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Central Nervous System

The Central Nervous System, or CNS, is made up of

a person’s brain and spine.

This system is what allows the brain to communicate

with the body, and the body to give feedback to the brain

through the spinal cord.

This brain hat is a great way to show people that there is

a lot going on up there, and that your CNS is always in

action! (3 ©)

There are over 200 bones in the body, which

makes it easy to have several different bone candies by

the end of your trick-or-treating night.

If only they had different flavors! (4 ©)

The way that the brain communicates using the

spinal cords and nerves was by neurons. These are the

base of the Central Nervous System. Neurons are cells

that take and send out electrical signals to and from the

brain to the rest of the nerves, muscles, and body. (5 ©)

Peripheral Nervous System

Your brain tells your body that you want candy, but

the only way to get it is if your brain has a way to tell your

body where and how to get candy. That’s where the

peripheral nervous system kicks in!

The peripheral nervous system, also referred to as

PNS, is the pathway for nerve impulses from the central

nervous system to the rest of the body and is separated into

two parts; the somatic and automatic nervous systems. The

somatic nervous system controls the sensation as well as

movement while the automatic nervous system controls

organ function.

About.com Biology gives a brief outline of the main points

of the Peripheral Nervous System:

“• Sensory Nervous System - sends information to the CNS

from internal organs or from external stimuli.

• Motor Nervous System - carries information from the CNS to

organs, muscles, and glands.

• Somatic Nervous System - controls skeletal muscle as

well as external sensory organs.

•Autonomic Nervous System - controls involuntary

muscles, such as smooth and cardiac muscle.

•Sympathetic - controls activities that increase

energy expenditures.

•Parasympathetic - controls activities that

conserve energy expenditures” (6). (7 ©)

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Afferent and Efferent Divisions The nervous system is complicated. In order to explain the way things work,

scientists have come up with various terms that describe what they do and where

they go. The tissues of both the Central and the Peripheral nervous systems include

nerve cells that form pathways for stimuli to enter the nervous system and outgoing

pathways. The pathway through which stimuli comes into the body is called the

AFFERENT DIVISION. Afferent means “carry towards” the brain, which is the central

processing center of the body. The pathway through which the processed

information goes back out of the body and produces a response is called the

EFFERENT DIVISION of the nervous system. Efferent means “carry away” from the

brain.

Somatic and Autonomic Nervous Systems Another way to organize the components of the nervous system is to

categorize them according to the type of effectors they regulate.

The Somatic Nervous System (SNS) carries information (stimuli) to the somatic

effectors which are the skeletal muscles, or the muscles that control voluntary body

movement. These motor pathways make up the somatic motor division. The somatic

sensory division also includes the afferent pathways (or the incoming paths for

stimuli/signals.) The integrating centers that receive the sensory information

and generate the efferent response signal are also included in the SNS.

There is also an Autonomic Nervous System (ANS) which carries

information to the autonomic, or visceral, effectors which control the smooth

muscles, the cardiac muscle, and the glands; in other words, involuntary

reactions that are controlled by nerves in the ANS. (We now know that the

conscious mind can influence some of these functions but the traditional

name remains.)

The efferent pathways of the ANS are divided into the sympathetic and the

parasympathetic divisions. The sympathetic division of nerve fibers is made up

of pathways that exit from the middle portion of the spinal cord and produce

the “fight-or-flight” involuntary response to stimuli that threatens the body.

The parasympathetic pathways exit at the brain and the lower portion of the

spinal cord. They coordinate the body’s normal resting activities and are sometimes

called the “rest-and-repair” division and once again, they are INVOLUNTARY. The

ANS can be easily remembered by the “A” for “auto” as in automatic.

The afferent pathways (the ones that handle INCOMING stimuli) of the ANS belong

to the visceral sensory division which carries feedback information to the autonomic

integrating centers in the central nervous system.

Sources: Textbook Page: 344 & google.com©

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The Synapse

Summation

• Spatial summation: ability of the

postsynaptic neuron to add together the

inhibitory and stimulatory input received

from numerous different presynaptic

neurons and produce an action potential

based on that collation of info. (1)

• Temporal summation: when synaptic

knobs stimulate a postsynaptic neuron in

rapid succession and the effects add up

over time to produce an action potential.

(1)

Neurotransmitters

• Chemicals by which neurons

communicate; the substance is

released by a neuron, diffuses

across the synape, and binds to the

postsynaptic neuron. (1)

(1) (4)

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5 types of Glia and where to find them

1. Astrocytes- Wear a hat for a costume to show the astrocytes attached to

the outside of a capillary blood vessel in the brain. (1)

2. Microglia- Wear a shirt covered in small stationary cells to represent the

microglia being found in the central nervous system. (1)

3. Ependymal cells- Also another hat to wear representing the ependymal

cells forming a sheet that usually lines fluid cavities in the brain. (1)

4. Oligodendrocytes- Wear rows of oligodendrocytes hanging from your

clothes to show them lying clustered around nerve cell bodies; some are

arranged in rows between nerve fibers in the brain and cord. (1)

5. Schwann Cells- Bundle up wearing a lot of nerve fibers in the PNS,

wrapping around only the peripheral nerve fiber to form a thick myelin

sheath. (1)

Types of Neurons:

Multipolar costumes- have only one axon but several dendrites. The most

popular of the neurons costume are in the brain and spinal cord,

multipolar. (1)

Bipolar costumes- Have one axon and one highly branched dendrite. There

are the least amount of costumes available for bipolar. (1)

Unipolar costumes- Have a single process extending from the cell body.

This costume branches to form a central process and a peripheral process. (1)

Cells of the Nervous System Costumes: Cells of the nervous system costumes include

non-neural cells and neurons. Non-neural cells are neuroglia (meaning nerve glue), or glial cells, which support

and protect neurons and perform other functions, whereas neurons receive stimuli and conduct action

potentials. (2)

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Table 1

Table 2

Table 3

1. Voluntary movement is the conscious move that you must move. While involuntary

movement is a movement that you choose to move, like picking up a glass or running. Usually

voluntary movement is faster that involuntary.

2. 7.085 m/s

3. The difference could be due to the technology we used. Researchers most likely have more

precise instruments and testing methods which will lead to more accurate results.

4. The speed of electricity in a copper wire is 300 million, and the nerve impulse is 100m/s.

5. There can be a longer pathways the nerves may need to travel. Some peoples nervous

systems are slower or faster. Depends on the person. Muscle size does not have anything to

do with the speed of the nervous system.