u3 - compendium review nervous function: part 1

8/14/2019 U3 - Compendium Review Nervous Function: Part 1

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Compendium ReviewMajor Topic One: Nervous Function

Table of Contents

Part 1

The Organization of the Nervous System

The Central Nervous System: Brain & Spinal Cord

The Limbic System & Mental Functions

The Peripheral Nervous System Nervous System Diseases

Drug and Alcohol Effects

Part 2

Sensory Receptors and Occurrence

Proprioceptors and Cutaneous Receptors

Taste and Smell

Vision

Hearing

Equilibrium


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The Organization of the Nervous System The Central Nervous System: Brain & Spinal Cord The Limbic System & Mental Functions The Peripheral Nervous System

Nervous System Diseases Drug and Alcohol Effects

Picture from http://kvhs.nbed.nb.ca/gallant/biology/neuron_structure.jpg


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The Organization of the Nervous SystemThere are two main units to the nervous system: the central nervous system (CNS)which contains the brain and spinal cord, and the peripheral nervous system (PNS)which includes the nerves. The nervous system has 3 important functions: to receivesensory input, perform integration, and generate motor output.

Nervous Tissue

Neurons - cells responsible for transmission of nerveimpulses. Consist of a body, dendrites, and an axon.

The 3 types of neurons are sensory neurons(transports impulses to CNS), interneurons (receivemessages and convey to motor neurons), and motorneurons (transports impulses from CNS to effectors).

Sensory receptors areresponsible foridentifying change

internally while effectorsare responsible forexecuting responses.

Neuroglia provide forneurons by supplyingnourishment

Pictures from Human Biology Page 248


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The Organization of the NervousSystem

Dendrites:

receivesignals

Axon:

conducts

Impulses

Cell Body:

Nucleusand

organelles

Long axons are covered by myelin sheathswhich is a protective insulating phospholipid

layer composed of Myelin (80% lipid fat / 20%

protein). The gaps along axons where there isno myelin wrapped around it is called nodes of

Ranvier, named after Louis-Antoine Ranvierwho discovered it around 1878. A neurogliaknown as Schwann cells (contain myelin in

membrane) are responsible for the protection

of long axons in the PNS, whereasoligodendrocytes protect the long axons in theCNS. Myelin gives a white appearance

MyelinSheath

Pictures fromHuman

Biology Page249 &

http://en.wikipedia.org/wiki/Schwann_cell


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The Organization of the Nervous SystemNerve impulses send messages throughout the whole nervous system. An axon is either

resting or active; thus, they are either in the resting potential or the active potential state. Avoltmeter can record which state the nerve is in by measuring the negativity of the inside of

a neuron compared to its outside.Resting Potential

No impulse conducting within axon

Inside more negative than outside

About -60 to -70 millivolts

Dissimilarity in ion dispersal on either side of membrane

Dissimilar dispersal is due to sodium-potassium pump whichmaintains appropriate concentrations of sodium and potassium

intracellular and extracellular

Action Potential

Nerve impulses occur; change in polarity

Inside less negative than outside

About +40 millivolts

Inward sodium exceeds outward potassium, causingdepolarization of membrane potential

Threshold is reached around 15 millivolts above resting

membrane potentialRepolarization occurs as potassium leaves axon

Pictures from Human Biology Pg 250


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The Organization of the Nervous System

Action potentials can be transmitted along the

nodes by way ofsaltatory conduction, whereeach action potential generates another by

jumping. To ensure that nerve impulses (activepotentials) always travel down an axon to theend, the axon undergoes a refractory period

where the sodium gates cannot open.



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The Organization of the NervousSystem

Each axon ends in an axon terminal which lie inclose proximity to other neurons cell bodies ordendrites. The axon terminals house molecules

known as neurotransmitters. The area betweenthe axon terminal and other neuron is called thesynapse. A tiny gap known as the synaptic cleft

separates the two neurons. Once a nerve impulsetravels down the axon, calcium ions enter the

terminal causing enclosed neurotransmitters to

leave the terminal where they bind to a receivingneurons receptor and allow sodium to passthrough an ion channel.

Since neurons have several dendrites, they canhave many synapses with other sending neurons.

An excitatory neurotransmitter can send a

potential change causing the neuron to movecloser to an action potential, whereas aninhibitory neurotransmitter can send a potentialchange causing a neuron to move away from an

action potential. When a neuron receives anexcitatory or inhibitory signal they process it. Thisprocess is known as integration, where they sum

up the signal.Pictures from Human Biology Pg 252


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The Organization of the Nervous System The Central Nervous System: Brain & Spinal Cord The Limbic System & Mental Functions The Peripheral Nervous System Nervous System Diseases Drug and Alcohol Effects



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The CNS consists of the brain and the spinal cord, both of which are protected by amembrane called the meninges. Between the meninges, in the brains ventricles, and in thespinal cord canal is a shielding cushy fluid known as the cerebrospinal fluid. There are 2types of tissue in the CNS: white matter consists oftracts, or a collection of myelinatedaxons, whereas gray matter consists only of cell bodies that have short nonmyelinatedaxons.

The spinal cord has a central canal which is surrounded by the gray and white matter.Together, they make up the spinal cord. The cord is protected by vertebrae which areirregular shaped bones, collectively known as the vertebral column. Extending out of thevertebrae and attached to the spinal cord are the spinal nerves. Entering into the graymatter are dorsal roots (contains sensory fibers) and exiting are ventral roots (contain motorfibers). The left and right sides of the brain control the opposite sides of the body. The white

matter in the spinal cord takes messages to the brain (dorsally) and messages from the brain(ventrally). Pictures from Human Biology Pg 255


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The Central NervousSystem: Brain & Spinal Cord

The primary function of the spinalcord is to make communication

available between the nerves andthe brain.

Nerve impulses travel to spinalcord sensory axons

Interneurons process data andsend messages to motor neurons

Response to messages via musclecontractions Pictures from Human Biology Pg 255


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The Central Nervous System: Brain & Spinal CordThe brain has four ventricles: two lateral ventricles (cerebrum), a third (diencephalon)

and fourth ventricle (brain stem and cerebellum).CEREBRUM

The largest part of the brain

known as the cerebrum is thelast station which receives andprocesses input. The cerebrumis split into two hemispheres,communicates with all parts ofthe brain, and is responsiblefor instructing motorresponses. The left and rightcerebral hemispheres areconnected via the corpuscallosum, a white matterstructure consisting of severalaxonal projections. Thecerebrum has sulci, smallgrooves, that separate the

hemispheres into lobes.

1. Frontal lobe (behind forehead): Primary motorarea, processing center2. Parietal lobe (behind frontal): Primarysomatosensory area/integration occurs3. Occipital lobe (behind parietal)

4.Temporal lobe (underneath frontal & parietal)Pic from Human Biology Pg 257 & http://www.becomehealthynow.com/article/bodynervousadvanced/819/2/


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Processing written and verbal speech takes place in theWernickes Area where it is then passed to the Brocas Areafor speech musculature. Any damage to the Wernickesarea will result in the failure to understand and follow

speech, whereas any damage to the Brocas area will resultin a failure to speak and write.

Picture from Human Biology Pg 256-257

Brocas

Area

WernickesArea


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The Central Nervous System: Brain & SpinalCord

Primary Motor and Somatosensory Areas

Picture from Human Biology Pg 258


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The Central Nervous System: Brain & Spinal CordThe diencephalon is apart in the middle of thebrain that makes up the

third ventricle. Itcontains thehypothalamus, aprocessing center whichaids in homeostasis,and the thalamus, aprocessing center for allsensory input (exceptsmell), memory, andemotions. Thehypothalamus manageshunger and thirst, bodytemperature, sleep, and

water balance. Thethalamus managesvisual, speech, andsomatosensoryinformation and thentransmits it to theappropriate areaswithin the cerebrum.

Picture from HumanBiology Pg 259


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Picture from http://www.becomehealthynow.com/article/bodynervousadvanced/819/2/

The cerebellum is at the back of the brain and lies underneath the occipitallobe. The cerebellum has two sections that are mainly compiled of white

matter with a thin gray matter layer. This section is responsible for receivingand processing information from eyes, ears, muscles and joints; and then

sending impulses to skeletal muscles.

Cerebellum


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The Central Nervous System: Brain & Spinal CordThe brain stem is the lower bottom part of thebrain that connects to the spinal cord andcontains the midbrain (mesencephalon), pons(metencephalon), and medulla oblongata. Themidbrain adjoins the diencephalon and pons.

Motor skills are associated with a region of themidbrain. The pons is responsible fortransmitting sensory information between thecerebellum and the cerebrum. Also, the ponscontrols respiration through functions with themedulla oblongata. The medulla oblongata liesat the lowest part of the brain stem and is

responsible for controlling the hearts rate,breathing, blood pressure, swallowing,hiccupping, vomiting, sneezing, coughing anddefecation.

Pictures and verbiage from Human Biology Pg 256-259 &http://en.wikipedia.org/wiki/Reticular_formation

The reticular formation is centered in the pons,the middle of the brain stem, and runs throughthe midbrain down through the medullaoblongata. The reticular formation controlsphysical behaviors such as sleeping, fatigue,awaking, alertness, walking, eating, urination,defecation, and sexual activity.

Th O i i f h N S


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Picture from

http://cwx.prenhall.com/bookbind/pubbooks/morris5/chapter2/custom1/deluxe-content.html


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The Limbic System & Mental FunctionsThe limbic system is a group of

structures in the middle of the brain thatsurrounds the thalamus and

hypothalamus, collectively thediencephalon. The amygdala (addsemotional overtones to stimuli or

memories) and hippocampus (learningand memory) are two structures within

the limbic system.

Picture fromhttp://cwx.prenhall.com/bookbind/pubbooks/morris5/chapter2/custom1/deluxe-content.html

Memory Types

Short-term memory takes place in theprefrontal area, behind the forehead.

Long-term memory is a mixture ofepisodicmemory (people and events) and semantic

memory (words and numbers). Utilizingmotor areas of the cerebrum, skill memory

involves the performance of physicalactivities. More neurotransmitters are

released after intense synapses leading toan event known as long-term potential

(LTP) which may be responsible formemory storage.

Th O i ti f th N S t


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Pictures from Human Biology Pg262

The Organization of the Nervous System The Central Nervous System: Brain & Spinal Cord The Limbic System & Mental Functions The Peripheral Nervous System Nervous System Diseases Drug and Alcohol Effects


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The Peripheral Nervous System

The peripheral nervous system is the second

unit to the nervous system, consisting ofnerves. Nerves that arise from the brain aredenoted as cranial nerves (quantity 12), and

nerves that arise from the spinal cord aredenoted as spinal nerves (31 pairs). All nerves

from both units are made of axons.

Sensory neurons cell bodies arecontained in dorsal root ganglions. Adorsal root controls impulses inward

through sensory fibers whereas aventral root controls impulses outward

through motor fibers. Every spinalnerve serves certain parts of the body.

Pictures from Human Biology Pg 255-62

h i h l


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The Peripheral Nervous SystemThe PNS has two parts: the somatic system and the autonomic system. The somaticsystem contains all the nerves which operate for skin, muscles, and tendons. This caninvolve voluntary and involuntary responses. Reflexes are an automatic response tosomething, such as pulling your hand away from a hot fire. The autonomic system

maintains homeostasis by acting as a control system. The controls are involuntary andautomatic, they work by stimulating internal organs, and for each impulse they use twoneurons and one ganglion.

Pictures fromHuman Biology Pg263


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The Peripheral Nervous SystemThe main componentsof the autonomicsystem are itssympathetic divisionand parasympathetic

division. Thesympathetic divisionnerves arise from thethoracic and lumberparts of the spinal cordand are associatedwith motor responses

like fight or take flight(faster heart beat,dilated pupils, inhibitsdigestive system). Theparasympatheticdivision nerves arisefrom the sacral part ofthe spinal cord andsome cranial nerves,and are associatedwith motor responseslike rest and digest(relaxation, digestion,

slows heart rate).

Picture from

http://www.britannica.com/bps/home#tab=active~checked%2Citems~checked%3E%2Fbps%2Ftopic%2F443285%2Fparasympathetic-nervous-system&title=parasympathetic%20nervous%20system%20--%20Britannica%20Online%20Encyclopedia

The Organi ation of the Ner o s S stem


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In this television screen grab taken fromFox News, a scan shows a man's brain

affected by Dandy-Walker syndrome. Allof the black in the middle is cerebral fluidand the brain matter is the rim of white

along the outside of the skull.

Pictures & Verbiage from http://en.wikipedia.org/wiki/Hydrocephalus#Symptoms

N S t Di
http://en.wikipedia.org/wiki/Image:Hydrocephalic_skull.jpghttp://en.wikipedia.org/wiki/Image:DWS_empty_head.jpg


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Nervous System Diseases

Some mental diseases can be treated such as bipolar, depression, and schizophrenia.

6.Multiple Sclerosis Bodies immunesystem attacks myelin sheath, affectswhite matter, causes muscle weaknessand spasms, difficulty with balance,

moving, speech, visual, and bowelproblems.

7. Leukodystrophies Group of disordersaffecting brains white matter, defect inmyelin sheath growth, genetic disorder,slowing of all motor skills such as eating,

speech, vision, hearing, and movement.

8. Meningitis Inflammation ofmeninges, brain and spinal cord, can betreated with antibiotics, causesheadache, fever, neck stiffness, andrash.

9. Hydrocephalus Cerebrospinal fluidbuildup in brain ventricles, headache,vomiting, seizures, mental retardation,founds in infants due to suddenenlargement of head, and in adults braincannot enlarge and pushes against skull.

1. Alzheimer's - Terminal illness, causesdementia, degenerative disease, shortand long-term memory loss, anger,confusion, loss of bodily functions, death.

2.Parkinson's degenerative disease,movement disorder, impairs speech andmotor skills, tremors, muscle rigidity, andposture problems.

3.Motor Neuron disease Group of diseases

affecting the motor neurons, muscleactivities such as breathing, speaking,weakness and stiffness in muscles.

4.Huntington's Genetic disorder, neuroncells in brain die, lack of coordination,speech problems, chewing andswallowing problems, and slowing ofthought process/thinking.

5. Paralysis/Paraplegia/Quadriplegia loss offeeling an muscle function due to nerveor brain damage, paraplegia affectsthoracic, lumbar, or sacral regions,quadriplegia affects all limbs


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Nervous System DiseasesDrug and Alcohol Effects

A rational scale to assessthe harm of drugs.

Verbiage and Picture fromhttp://en.wikipedia.org/wiki/Drug_abuse

D d Al h l Eff t

Pictures fromhtt // iki di
http://upload.wikimedia.org/wikipedia/commons/9/9c/Rational_scale_to_assess_the_harm_of_drugs_%28mean_physical_harm_and_mean_dependence%29.svg


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Drug and Alcohol EffectsDrugs have an effect on the limbic system and either elevate or reduceneurotransmitter functions. Anyone who is physically or mentally dependanton a drug is a drug abuser. Drugs can have a variety of effects such asstimulants, depressants, or psychoactive effects.

1. Alcohol Causes damage to tissues and organs, leaches intocell membranes, liver works harder to detoxify and can becomescarred, depressant, impaired vision, speech, concentration, andcoordination. Can lead to comma and/or death.

2. Nicotine - Causes damage to arteries, heightens risk of clots,shown to inhibit apoptosis, increase blood pressure, heart rate,respiration, and blood glucose levels, stimulant.

3. Cocaine Causes damage to, increases heart rate, bloodpressure, sex drive and euphoria, lack of appetite, tremors,restlessness, interferes with synapses, can lead to cardiac andrespiratory related death, seizures, cerebral hemorrhaging,stroke and heart attack, stimulant. Coming off the drug causesdepression, fatigue, irritability and confusion.

4. Methamphetamines Causes a reversal of sleepiness andfatigue, hyper, easily agitated, possible violent or erraticbehavior, speech and vision problems, hallucinations, causesdental hygiene problems, hypertension, stroke, heart valveproblems, stimulant.

5. Heroin Very addictive drug, causes respiratory depression,interact with neurotransmitters causing euphoria, pain reduction,

obscure mental functions, easy to overdose and die on, higherlikelihood of diseases transmitted by shared needles, depressant.

6. Marijuana Causes euphoria,

mental and vision obscurities,paranoia, cravings, heart disease,lung damage, reduction in motor

skills and reaction time,psychoactive.

Cocaine

Marijuana

http://en.wikipedia.org/wiki/Marijuna &http://en.wikipedia.org/wiki/Cocaine
http://en.wikipedia.org/wiki/Image:CocaineHydrochloridePowder.jpghttp://en.wikipedia.org/wiki/Image:Macro_cannabis_bud.jpghttp://en.wikipedia.org/wiki/Image:Macro_cannabis_bud.jpghttp://en.wikipedia.org/wiki/Image:CocaineHydrochloridePowder.jpg


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Drug and Alcohol Effects



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Works CitedWorks Cited

Become Healthy Now. The Nervous System Advanced Version/The Brain. Accessed 24 Mar 2008.

.

"Cannabis (drug)." Wikipedia, The Free Encyclopedia. 24 Mar 2008, 20:29 UTC. Wikimedia Foundation, Inc. 25 Mar 2008 .

"Cocaine." Wikipedia, The Free Encyclopedia. 22 Mar 2008, 23:10 UTC. Wikimedia Foundation, Inc. 25 Mar 2008 .

"Drug abuse." Wikipedia, The Free Encyclopedia. 22 Mar 2008, 18:45 UTC. Wikimedia Foundation, Inc. 24 Mar 2008 .

Gallants Biology Stuff. Biology 12: Nervous System. KV High School. Accessed 24 Mar 2008.

.

"Hydrocephalus." Wikipedia, The Free Encyclopedia. 21 Mar 2008, 15:16 UTC. Wikimedia Foundation, Inc. 24 Mar 2008 .

Mader, Sylvia S. Human Biology. New York: The McGraw-Hill Companies, Inc, 2008. Pages 247-271.

Parasympathetic Nervous System. Encyclopedia Britannica. 2008. Encyclopedia Britannica Online. 24 Mar 2008.

.

Prentice Hall Humanities and Social Science. Ch. 2 The Biological Basis of Behavior Chapter Review. Accessed 24 Mar 2008.

.

"Reticular formation." Wikipedia, The Free Encyclopedia. 6 Mar 2008, 12:30 UTC. Wikimedia Foundation, Inc. 24 Mar 2008 ."Schwann cell." Wikipedia, The Free Encyclopedia. 6 Mar 2008, 16:56 UTC. Wikimedia Foundation, Inc. 24 Mar 2008 .
http://en.wikipedia.org/w/index.php?title=Cannabis_%28drug%29&oldid=200624022http://en.wikipedia.org/w/index.php?title=Cocaine&oldid=201693272http://en.wikipedia.org/w/index.php?title=Drug_abuse&oldid=201383331http://en.wikipedia.org/w/index.php?title=Hydrocephalus&oldid=199840026http://en.wikipedia.org/w/index.php?title=Reticular_formation&oldid=196269627http://en.wikipedia.org/w/index.php?title=Schwann_cell&oldid=196315120http://en.wikipedia.org/w/index.php?title=Schwann_cell&oldid=196315120http://en.wikipedia.org/w/index.php?title=Reticular_formation&oldid=196269627http://en.wikipedia.org/w/index.php?title=Hydrocephalus&oldid=199840026http://en.wikipedia.org/w/index.php?title=Drug_abuse&oldid=201383331http://en.wikipedia.org/w/index.php?title=Cocaine&oldid=201693272http://en.wikipedia.org/w/index.php?title=Cannabis_%28drug%29&oldid=200624022

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