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.