Transcript The nervous system

The Nervous System
Functions of the Nervous System
• 1. Communication and coordination
– Adapt and respond to changes from both inside and
outside the body
• 2. Site of reasoning- your brain
• 3. Two main divisions
– Central nervous system (CNS): brain and spinal
cord
– Peripheral nervous system- the nerves
• Neuron- basic
structural unit of the
nervous system
• Dendrites- carry
impulses towards the
cell
• Axon-carry impulses
away from the cell
• Myelin sheath
• Synaptic terminal
– Epinephrine
– Norepinephrine
– Acetylcholine
• Nerves are made of many nerve cells
• Afferent-sensory nerves carry message to
brain
• Efferent-motor neurons carry message
from brain to muscle
• Associate- do both
• Heads up
Central nervous system
• Brain and spinal cord
• Cerebrum-largest
part of brain.
Responsible for
reasoning, thought,
memory, speech,
sensation, etc.
• Divided into two
halves.
• Further divided into
lobes; occipital,
parietal, temporal
and frontal
• Cerebellumresponsible for
muscle coordination
• Brain stem- most
basic functions;
respiration,
swallowing, blood
pressure. Lower part
(medulla oblongata) is
continuous with spinal
cord
• Spinal cord- begins at
foramen magnum and
ends at second
lumbar vertebrae
• Contains both afferent
(to the brain) and
efferent (motor
neurons- away from
the brain)
• Both the brain and spinal cord are covered
by a membrane system called the
meninges
• In addition, the brain has four hollow areas
called ventricles. Cerebrospinal fluid is
produced in the ventricles and baths the
brain and spinal column
Peripheral nervous system
• Somatic system
– 12 pairs cranial nerves
– 31 pairs spinal nerves
• Autonomic
– Sympathetic
• Fight or flight
– Parasympathetic
Disorders of the nervous system
• Meningitis- inflammation of the linings of
the brain and spinal cord
• Encephalitis- inflammation of the brain
• Epilepsy-seizure disorder. Excessive
discharge from neurons. 1 in 200 suffer.
Grand mal or petit mal seizures
• Cerebral palsy- disturbance in voluntary
muscular action
• Parkinson’s –decreased neurotransmitter
• MS multiple sclerosis- autoimmune