Nervous SystemKara Robbins

Major controlling, regulatory, and communication system of the body

Center of all mental activity including thought, learning, and memory

Responsible (along with endocrine system) for regulating and maintaining homeostasis

Function

Nervous System

Central Nervous System

Processing center: receives information and sends information out to peripheral nervous system

Major parts: Brain Spinal Cord

Peripheral Nervous System

Connects CNS to limbs and organs: carries information to and from the CNS

Comprised of two parts: Somatic Automatic

Major parts: Nerves Neurons

Structure of a Neuron

Simple Reflex Arc

Brain

Nerve Impulse to Neuron

1. Polarization of neuron’s membrane: Sodium (Na+) is on outside and Potassium (K+) is on inside Membrane

potential created by the sodium-potassium pump, pumping ions in and out of the membrane

2. Said to be at resting potential until stimulus comes along When

neuron is not stimulated, membrane is polarized

Nerve Impulse to Neuron

3. Action potential: Sodium ions move inside membrane When stimulus

reaches neuron, gated channels open allowing Na+ ions inside membrane Each neuron has

threshold level (point where more channels open)

Inside becomes positively charged

Complete depolarization occurs and the stimulus is transmitted

4. Repolarization: Potassium ions move outside and Sodium ions stay inside membrane

5. Hyperpolarization: More potassium ions are on the outside than are sodium ions on the inside

Nerve Impulse to Neuron

6. Refractory period puts everything back to normal: Potassium returns inside, Sodium returns outside Neuron returns to

polarized state and stays at resting potential until another stimulus comes along

Neurotransmitters- Chemicals which allow from one

neuron to the next across synapse

- Stimulate muscle fibers- Nerve impulse travels from the

first nerve cell through the axon—a single smooth body arising from the nerve cell— to the axon terminal and the synaptic knobs. Each synaptic knob communicates with a dendrite or cell body of another neuron, and the synaptic knobs contain neurovesicles that store and release neurotransmitters. The synapse lies between the synaptic knob and the next cell. 

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Neurotransmitters

IPSP

kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential

EPSP

 synaptic potential that makes a postsynaptic neuron more likely to generate an action potential

Alzheimer’s Disease

progressive disease that destroys memory and other important mental functions

Symptoms: Loss of memory Disorientation or

misinterpreting spatial relationships

Trouble speaking and writing Change in personality and

behavior Trouble planning and

performing familiar tasks

Estimated 5.2 million Americans have disease in 2013

Treatment: Cholinesterase

inhibitors Memantine

(Namenda) Exercise Nutrition

Multiple sclerosis

potentially debilitating disease in which your body's immune system eats away at the protective sheath (myelin) that covers your nerves

Symptoms: Numbness or weakness in one or

more limbs Partial or complete loss of central

vision, usually in one eye, often with pain during eye movement (optic neuritis)

Double vision or blurring of vision Tingling or pain in parts of your body Electric-shock sensations that occur

with certain head movements Tremor, lack of coordination or

unsteady gait Slurred speech Fatigue Dizziness

2.5 million people have disease worldwide

Treatment: Corticosteroids Plasma exchange

(plasmapheresis) Physical therapy Muscle relaxants Medication