What are the functions of the Nervous System?

Detects impulses from the senses; control center

What are the major organ of the Nervous System?

Brain, Spinal Cord, senses, nerves

Central Nervous system

consists of the brain and the spinal cord

Peripheral Nervous System

consists of the other nerves

cranial nerves

originate in the brain

spinal nerves

originate in spinal cord

Sensory (Afferent) Division

sends impulses from the senses to the CNS

Motor (Efferent) Division

sends impulses from the CNS to the muscles and glands

Autonomic Nervous System

involuntary muscle control

Somatic nervous System

voluntary muscle control

Sympathetic Division

used in emergency situations ("fight or Flight")

Parasympathetic Division

reduces sympathetic response and provides resting functions such as digestion and urination.

What other system does the nervous system work with?

Endocrine System

Sensory input

it detects changes (stimuli) inside and outside the body

Integration

processing and interpreting the information

Response

activation of muscles (motor output) or glands

Neurons

conducts impulses around the body (make up only 10% of nerve cells)

Neuroglia

support, insulate & protect neurons (90% of nerve cells)

What does the cell body contain?

nucleus, cytoplasm, & organelles

Dendrites

bring impulses towards the cell body

Axons

send impulses away from the cell body

At the end of the axons are ____ _____, which release _____ to pass impulse to the next neuron.

axon terminals; neurotransmitters

Unipolar neurons

have one process

Bipolar neurons

have two processes

Multipolar Neurons

have many processes

Afferent Neurons

carry impulses toward the CNS

Efferent Neurons

carry impulses away from the CNS

Interneurons

connect afferent & efferent neurons

Myelin

waxy insulation; wrapped around the. axons

Neurilemma

outer layers of the Schwann cell

How is a myelin formed?

a Schwann cell wraps around itself around the axon, like a coil

Myelin

helps the nerve impulses to travel more quickly

Nodes of ranvier

gaps between the myelin sheath

Astrocytes

support & anchor neurons to surrounding capillaries

Microglia

provide immune response to central nervous system

Ependymal cells

Secrete and circulate cerebrospinal fluid

Oligodendrocytes

provide myelin insulation to neurons in the central nervous system

Satellite cells

support and anchor neurons in the peripheral nervous system

Schwann cells

provide myelin insulation to nervous in the peripheral nervous system

Depolarization

Also known as the action potential

when the neuron is stimulated, either by the environment or another neuron, sodium rushes into the neuron and quickly reverses the charges

Repolarization

as the impulse passes, potassium diffuses out the neuron

Synapse

where 2 neurons meet

Synaptic Cleft

space between 2 neurons

Which nerve is used to carry information for hearing?

Auditory nerve

Which nerve is used to carry information for vision?

optic

Which nerve is used to carry information for balance?

vestibular

Which nerve is used to carry information for smell?

olfactory

Gustatory cells use ...

taste

Olfactory cells use ...

smell

Papillae use ...

taste

Organ of conti use ...

hearing

Taste buds are found in structures called...

papillae

Where on the retina is the image clearest?

fovea centralis

Which 2 special senses use chemoreceptors?

Taste and smell

Aqueous humor

aids in light refraction

vitreous humor

fills space between lens and retina

How an impulse crosses a synapse

When an impulse reaches axon terminals, calcium channels open causing a release of neurotransmitters. When these are recognized on the next
neuron, sodium channels open continuing the impulse.