Download Nervous filled

Nervous System
A major control and
communication system
Brain Myths
#1: You only use 10 percent of
your brain.
#2: Doing crossword puzzles
can keep your brain young.
#3: A person's personality
displays a right-brain or leftbrain dominance.
#4: Brain damage is always
permanent.
#5: Drinking alcohol kills brain
cells.
Neuron
• “neur-” means nerve, so a neuron is a nerve cell
• Cell body is the part where the organelles, such
as the nucleus, are located
• Dendrite is the receiving end of the neuron
• Axon is the transmitting or conducting end of the
neuron
Nerve
• A group of neurons (specifically their
axons) that are bundled together
anywhere except the brain/spinal
cord, is termed a nerve
Nerve impulse
• A nerve impulse is an electrical message traveling
along a neuron.
Synapse
• A junction between adjacent neurons
• Neurotransmitters are chemicals carrying nerve
message across the synapse
Myelin
• Some neurons have their axons coated in a fatty
substance called myelin.
• Myelin increases the speed of nerve impulse
transmission – as high as 200 mph
• White matter
Central Nervous System
• Brain
• Spinal Cord
• Control,
information
processing
• Thoughts are
formed
• Memory is
stored
Peripheral Nervous System
• Carries messages to and from the CNS
• Sensory – carries information towards the CNS
• Motor – carries information away from the CNS
to the muscles and glands
PNS
• Somatic motor information travels to skeletal
muscles
• Autonomic motor information travels to cardiac
muscle, smooth muscle and glands; responsible
for your Fight or Flight response
Brain
• “enceph-” means brain
• Located in skull
• Medulla oblongata is part of the brainstem and
controls important reflexes that control breathing,
heart rate and blood pressure. Also is the site
where motor and sensory pathways cross.
Brain
• Hypothalamus is a center of homeostasis
mechanisms such as hunger, thirst, water
balance, temperature regulation; makes
hormones, and controls the Autonomic Nervous
System.
Brain
• Thalamus is a sensory relay center
Brain
• Cerebrum is the largest and highest center of
the brain
• Responsible for conscious awareness, thinking,
intelligence, memory and deciding your response
to sensory input.
Brain
• Electroencephalogram, or EEG, is a recording
of the brain’s electrical activity, commonly called
brain waves.
Spinal cord
• “myel-” means spinal cord
• Located within your vertebrae
• Sends sensory messages to your brain
• Carries motor messages away from your brain
Spinal Reflexes
• A reflex is an autonomic, quick response to a
stimulus. The reflex is repeatable.
• Spinal reflexes involve the spinal cord and do
not involve conscious thought from the brain.
Spinal reflex
CNS Meninges
• Meninges are tough, protective membranes that
surround the brain and spinal cord.
• Within the meninges is Cerebrospinal Fluid (CSF)
that cushions and provides nourishment for the CNS
• What is meningitis?
Nervous System Pathology
• Brain damage
• The brain requires oxygen for
aerobic metabolism. Lack of
oxygen for more than 5 minutes
can kill brain cells.
• The brain requires glucose for
metabolism. Lack of glucose for
more than 15 minutes kills brain
cells.
• Neurons cannot undergo mitosis.
Epilepsy
• Brain fires abnormal signals that travel to
skeletal muscles.
• Skeletal muscles contract leading to seizures.
• May lose consciousness in larger seizures
• Causes are injury, infection, genetic
predisposition, and many causes are unknown
Epilepsy
• Treatments include correcting the cause, if
known; drugs and/or surgery
• Decreasing the frequency and magnitude of
the seizures with medications.
Multiple Sclerosis
• Many “hard” scars
form along the
myelin sheaths of
neurons
• Autoimmune
disease
• Numerous short
circuits occur
resulting in difficulty
in vision, memory,
walking and
judgment
• Chronic disease that
progresses slowly
Cerebral Palsy
• Motor centers are damaged at the
time of birth
• Causes include German Measles,
radiation exposure, oxygen
starvation to the baby’s brain at the
time of delivery
• Results in varying degrees of
impairment of motor abilities.