Junior Nervous System

Janet. J. Nelson RN, CMA

DID YOU KNOW?• The human brain is made up of a staggering

15 billion cells with about thousand billion connections between these cells. Yet it weighs less than 3 pounds.

• At three pounds the brain makes up on 2% of the total body weight but consumes 25% of energy of the entire body

• The spinal cord is less than 2 feet long but controls over 2 billion nerve cells.

• The nervous system transmits impulses to the brain at the speed of 180 mph.

• The brain is as soft as butter.

Student Objectives1. Describe the functions of NS2. List the main divisions of NS3. Define & label neuron4. Differentiate between motor and sensory

neuron5. Identify the parts of brain and spinal cord6. Describe and label functions of the parts

of brain7.Describe and label functions of the spinal

cord8. Identify disorders of the NS.

How many nervous system/s are there?

• One with two subdivisions: CNS PNS

PNS is further divided into autonomic and motor

Afferent vs. Efferent

Neurons too can be afferent, efferent or association

Neurons vs.Neuroglia

• Neurons: functional nervous cells• Neuroglia: nerve “glue”

Nerve conduction animation• http://www.pennmedicine.org/

encyclopedia/em_DisplayAnimation.aspx?gcid=000089&ptid=17

Typical Neuron

AXON WITH MYELIN SHEATH

CELL BODY DENDRITE

Review Game

• http://msjensen.cehd.umn.edu/webanatomy/nervous/default.html

• Please label the Neuron 2 Short and the Neuron structure short.

CHARACTERISTICS OF NEURONS

• IRRITABILITY:• CONDUCTIVITIY:

• Sensory Neurons• Motor Neurons• Connecting Neurons

Fun facts about neurons

• Most specialized cell in animals

• Longest cell– blue whale neuron

• 10-30 meters

– giraffe axon• 5 meters

– human neuron• 1-2 meters

Nervous system allows for 1 millisecond response timeNervous system allows for 1 millisecond response time

Neurons

• Most nerves contain both motor and sensory fibers.

• However; there are a few purely sensory nerves…..

Neuron transmission terms

• Electrochemical• Polarized• Depolarized• Action potential

•Repolarized•Sodium-Potassium Pump

Synapse

Animation of neuron transmission

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

• http://www.brainexplorer.org/neurological_control/Neurological_Neurotransmission.shtml#

Jumping the synaptic gap

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__transmission_across_a_synapse.html ??????

Cocaine & other drugs

• Scientist believe cocaine causes release of Dopamine and blocks it’s reabsorption.

• Eventually the person makes no Dopmaine of own and is dependent on artificial supplementation with Cocaine.

Did you know?

• Adult human brain weighs about 3#.

• Brain is the texture of cold oatmeal.

• The brain itself cannot feel pain The brain is surrounded by loads of tissues, nerves and blood vessels that are plenty receptive to pain.

• 80% of the brain is water.

Meninges

Dura Mater

Arachnoid

Pia Mater

Lumbar Puncture

SPINAL DEFECTSSpinal Bifida

Meningocele

Myelomeningocele

CEREBRAL VENTRICLESLateral Venticles Foramen of

Monroe 3rd Ventricle Cerebral Aqueduct 4th Ventricle

Subarachnoid space Returning to

cranial venous supply by arachnoid villi

ENCEPHALOCLE

Sagittal, magnetic resonance imaging (MRI) scan through the midline shows brain heniation through the sphenoid into the nasal cavity (arrow).

CEREBROSPINAL FLUID

• Made in the choroid plexus from blood

• Functions for protection and nutrition

Brain

• Three Parts- – Cerebrum

- Cerebellum - Brain Stem

Cerebrum

• Convolutuions (gyri)

• Sulci (sulcus

• Fissures

Three Parts- CerebrumCerebellumBrain Stem

Cerebral Lobes

PATHOPHYSIOLOGY

• Parkinson's Disease

• Huntington’s Chorea (Disease)

DIENCEPHALON (INTERBRAIN)

• Thalamus• Hypothalamus• Epithalamus

(pineal gland)

The diencephalon is colored reddish-orange

Cerebrovascular Accident

04/09/23

CEREBELLUM

04/09/23

04/09/23

BRAIN STEM

Notice the size of the Thalamus and position of brain stem

SPINAL CORD

• In cross section gray matter internally and white matter exteriorly

• Spinal nerves (31) emerge laterally from cord

04/09/23

SPINAL CORD

Can you locate the:• Spinal cord?• Spinal nerves?• Cerebellum?• Dura mater?• Medulla Oblongate?

CAUDA EQUINA

SPINAL NERVES

How a Reflex HappensHow a Reflex Happens

CRANIAL NERVES

I - Olfactory II - Optic III - Oculomotor IV - Trochlear V - Trigeminal VI - Abducens VII - Facial VIII - Auditory IX - Glossopharyngeal X - Vagus XI - Accessory XII - Hypoglassal

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Bell’s Palsy

ANS

• Sympathetic (Fight or Flight)

• Parasympathetic(Rest & Digest) or

(Repair & Repose)

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