Module 4 Neural Systems(1)

8/6/2019 Module 4 Neural Systems(1)

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PSYCH 101: Reminders!(1) If you do not attend your assigned recitation

section, your course grade will drop by a fullletter grade.!

(2) Exam 1 is on Tues, Sept 28th (Modules 1-6). !

(3) There are NO make up exams in this course.!

(4) Practice exams are given in your recitation

sections next week.!

(5) If you do not receive a sufficient grade on Exam1, then you must take Exam 4 on Dec 21st.!


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Outline: Neural &Hormonal Systems!

Neural Communication!

!" Neurons!

!" How Neurons Communicate!

!" How Neurotransmitters Influence Us!

The Nervous System!

!

" The Peripheral Nervous System!!" The Central Nervous System!

The Endocrine System!


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Phrenology: An old approach to

studying brain structure!

In 1800, Franz Gall

suggested, that bumps ofthe skull representedmental abilities. His theory

though incorrect,

nevertheless proposed thatdifferent mental abilities

were modular.!


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Neural Communication!One of the body#s information systems is built from

billions of interconnected cells called neurons.!

Neurons are studied in many different brains they

operate in the same way in all of these brains. !


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Parts of a Neuron !

Cell Body: Life support center of the neuron. !

!Information is computed here.!Dendrites:Send input to the cell body. !

!They receive information from other neurons.!Axon:Long fiber that passes information!

! from the cell to the terminal branches.!


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Parts of a Neuron Continued !Myelin sheathinsulates axons and speeds informationtransmission down axon. !

Terminal Branches of axon: Branched ending of axons.Sends messages to other neurons.!


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Multiple Sclerosis!

An autoimmunedisease in which thebody#s own immunecells attack, and

cause thedegeneration of, themyelin sheath. !

Myelin is the protective coating that surrounds axons.When this covering is damaged, signal transmissiondown axons is slowed down or stopped. MS mostcommonly begins in people aged 20-40, but can startat any age. There is no known cure.!


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Action Potential!

A neural impulse. A briefelectrical charge that travelsdown an axon generated bythe movement of positively

charged atoms in and out ofchannels in the axon#s

membrane. !

See Animation at:! http://www.youtube.com/watch?v=SCasruJT-DU


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Depolarization & Hyperpolarization !

Depolarization: Depolarization occurs whenpositive ions enter the neuron, making it moresusceptible to fire an action potential. !

Hyperpolarization: When negative ions enterthe neuron making it less susceptible to fire.!


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An Action Potential Takes Time

Hyperpolarizing or!

Refractory Period


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If enough electrical impulses come from other

neurons, the sum of the depolarizing current

(positive ions) minus the hyperpolarizing current(negative ions) crosses some threshold (usually~ -40mV). Then sodium (Na+) channels open,

the membrane because more depolarized.

Eventually, opens potassium channels and thatrepolarizes the membrane.!

K!Na!


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Action Potential Properties!

Refractory Period: After a neuron has fired anaction potential it pauses to recharge itself to fireagain.!

All-or-None Response: When the depolarizingcurrent exceeds the threshold, a neuron will fire.

Below the threshold, it will not fire.!

Intensity of an action potential remains the same,throughout the length of the axon.!

See Animation at:!

http://www.youtube.com/watch?v=YP_P6bYvEjE!


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Synapse [SIN-aps]!

Ajunction between the axon tip of the sendingneuron and the dendrite or cell body of the receivingneuron. This tiny gap is called the synaptic gaporcleft.!


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Neurotransmitters!

Neurotransmitters are

chemicals released fromthe sending neuron. !

They travel across thesynapse and bind to

receptor sites on thereceiving neuron#s

dendrites, thereby pushingit towards generating an

action potential. !


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Synaptic Transmission

Synaptic

Gap


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Neurotransmitters bind to the receptors of the

receiving neuron in a key-lock mechanism.!


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Reuptake!

Neurotransmitters in

the synapse are

reabsorbed into thesending neuronsthrough the process of

reuptake. This process

applies brakes onneurotransmitter

action.!


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Lots of Different Neurotransmitters!


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Endorphins!

Nature#s pleasure/pain killer drug.!

A class of neurotransmitters!

Naturally occurring opiates released during

extreme pain, exercise (runner#s high),acupuncture, laughter, and orgasm. !

Elevates mood and eases pain.!

Morphine works on these opiate receptors.!


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Agonists!


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Antagonists!

Curare!


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BOTOX!

An example of an!

Antagonist.!

It causes paralysis!

by blocking the neurotransmitter Ach(acetylcholine) from release from thesending neuron.!

It is a poison just like Curare.!


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Nervous System:Consists of all the nerve cells. !

It is the body#s fast, electrochemicalcommunication system and has 2 parts!

Peripheral

NervousSystem (PNS):!

The sensory and

motor neurons

that connect the

CNS to the rest

of the body.!

Central

NervousSystem(CNS):!

The brain &

spinal cord!


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Motor Neuron

(Multipolar)

Kinds of Neurons!Sensory Neurons carry incoming information from thesense receptors to the CNS. !

Motor Neuronscarry outgoing information from the

CNS to muscles and glands. !

Interneurons connect the two neurons.!

Sensory Neuron

(Bipolar)

Interneuron Neuron

(Unipolar)


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Central Nervous System:

Spinal Cord and Reflexes!

Simple Reflex


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Peripheral Nervous System!

Somatic Nervous System: The division of the

peripheral nervous system that controls the body#sskeletal muscles.!

Autonomic Nervous System: Part of the peripheralnervous system that controls the glands and other

muscles.!


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The Nerves!

Nerves consist of neural cables containing many

axons. They are part of the peripheral nervoussystem, and connect muscles, glands, and sense

organs to the central nervous system.!


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Autonomic Nervous System (ANS)!

Sympathetic Nervous System:

division of the ANS that arousesthe body, mobilizing its energy

in stressful situations.!

Parasympathetic Nervous

System: division of the ANS thatcalms the body, conserving its

energy.!


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The Endocrine System!The body#s slow

chemicalcommunication

system.

Communication iscarried out by

hormonessynthesized by

glands andtransported via the

blood.!


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Hormones!

Chemicals synthesized by the endocrine glandsand secreted in the bloodstream. Hormones, ageneral term, affect the brain and many other

tissues of the body. They are a way for one part ofthe body to %talk# to another part.!

For example, epinephrine (adrenaline) increases

heart rate, blood pressure, blood sugar andfeelings of excitement during emergency

situations.!

There are many different kinds of hormones:stimulate/inhibit growth, mood swings, activate/inhibit the immune system, regulate metabolism,

hunger, fight or flight response, etc.!


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What do these people have in common?They were accused of taking performance boosting

hormones, like testosterone and human growth

hormone.!

Testosterone is a sex hormone, aka a sex steroid.!Not all hormones are steroids and not all steroids are

sex hormones. Cortisol, for example, is a steroid(fight or flight response), but not a sex related one. !


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Hormone Replacement Therapy!" She#s just hormonal. Wrong.!

" Everybody is hormonal. Every body runs onhormones all the time. Without hormones

%talking,# the body isn#t running whether a manor a woman, just dead.!

" Hormone replacement therapy (HRT) estrogen/progesterone (female sex hormones)

are given to increase the amounts of thesehormones in women whose levels have dropped

due to age or surgery. Affect many systems,including PMS symptoms and calcium in bones.!


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Non-sex related hormones!" Thyroid gland in throat, makes hormones

change your ability to handle hot and cold, levelof energy, body weight and calcium levels.!

" Vitamin D is also a hormone that affects calcium.It works on the liver, the parathyroid gland and

the gut to increase the movement of calcium intothe body.!

" Pituitary gland base of brain, makes growthhormone, endorphin and thyroid stimulating

hormone.!


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Stress Hormones(e.g., cortisol, norepinephrine)

" Critical for the fight or flight response.!" But, long term activation of stress hormones increases your

risk for significant health problems including heart disease,depression, inability to sleep, digestive problems, obesity,

memory loss, skin conditions.!

" Caregiving: a long term stressor. 63% mortality increase in

spouses caring for their partners for ~ 5 years.!2007!

Yesterday in Plainfield!Muhammad Ali! Parkinson"s Disease!

Gradual cell death in substantia

nigra decreases dopamineproduction!


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Life Stress Scale!"#$%&'#(")*&

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300+ Score: Significant risk of illness; Score of 150-299: Moderate risk of illness


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Identifying and Managing Chronic Stress

Effects of stress on

your body


your thoughts/

feelings


your behavior

Headache Anxiety Overeating

Back Pain Restlessness Undereating

Chest Pain Worrying Angry outbursts

Heart Disease Irritability Drug or alcohol abuse

Heart Palpitations Depression Increased smoking

High blood pressure Sadness Social withdrawal

Decreased immunity Anger Crying Spells

Upset Stomach Forgetfulness Relationship Conflicts

Sleep Problems Lack of Focus

Stress Management Strategies

Eating a healthy diet and getting regular exercise and plenty of sleepPracticing relaxation techniques (e.g., Meditation, Yoga, Tai Chi)

Fostering healthy friendshipsHaving a sense of humor

Seeking professional counseling when needed

From the

Mayo Clinic


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Pituitary Gland!

The size of a pea, butcalled the master gland

because it regulates

activity in all other glands.

It secrets hormonesneeded for growth &

reproduction (e.g., humangrowth hormone). !

Over secretion of human growth hormone in

children can cause gigantism.!Under secretion during childhood -> dwarfism.!

Under secretion in adults can cause lethargy & lossof sexual ability.!


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Adrenal Glands!

Adrenal glands consist of adrenal medulla andadrenal cortex. Medulla secretes hormones

(epinephrine, norepinephrine and cortisol) during

stress, and adrenal cortex regulates salt and

carbohydrate metabolism to give you fuel to respondto the stress.!

Insulin: a hormone

produced in the

pancreas.Not enough insulin

leads to diabetes


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PSYCH 101: Reminders!Exam 1 is on Tues, Sept 28th (Modules 1-6). This is

one week from Tuesday.!

Practice exams will be given in your recitationsection next week. Some of the questions fromthe practice exam will appear on the real exam

on Sept 28th.!

There are NO make up exams in this course.!

If you do not get a satisfactory grade on Exam 1,then you must take Exam 4 on Dec 21st.!

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Module 4 Neural Systems(1)