2. Functions of the Nervous System
• Maintain homeostasis with electrical signals
• Provide for sensation
• Provide for higher mental functions and
emotions
• Activate muscles and glands
4. Structural Classification of the
Nervous System
Slide 7.2
Central nervous system (CNS)
Brain & spinal cord
Dorsal cavity
Command center
Takes in info & give instruction
Peripheral nervous system (PNS)
Nerves outside the brain and spinal cord
Communication lines
9. Neuroglia vs. Neurons
• Neuroglia divide.
• Neurons do not.
• Most brain tumors are “gliomas.”
• Most brain tumors involve the neuroglia
cells, not the neurons.
• Consider the role of cell division in
cancer!
16. Application
• In Multiple Scleroses the myelin sheath is
destroyed.
• The myelin sheath hardens to a tissue called
the scleroses.
• This is considered an autoimmune disease.
• Why does MS appear to affect the muscles?
25. All-or-None Response
• Greater intensity of the stimulation does not
produce a stronger impulse but rather more
impulses are sent
• Remember this from the muscular system??
31. • The knee-jerk reflex is an example of a 2-
neuron reflex arc (sensory receptor, afferent
neuron, efferent neuron, efferent organ)
• What would be the componeets of a 3-
neuron reflex arc?
61. Nervous System disorders
• Meningitis – inflammation of the meninges;
serious threat to the brain b/c of bacterial or
viral types may spread into central nervous
tissue
• Encephalitis – inflammation of the brain
• Hydrocephalus – “water on the brain;” CSF
cannot drain and pressure is exerted on the
brain
66. Spinal Cord
Extends from medulla
oblongata to T12 region
31 pairs of nerves
Fxn is to conduct nerve
impulses& serve for
spinal reflex centers
Spinal tap – withdrawal
of CSF (2-3 ml);
decreases pressure
and can diagnose
problems
69. PNS Structure
1. Sensory (afferent) division – nerve fibers
that convey impulses to the CNS from
sensory receptors
a. Somatic sensory fibers – impulses from skin,
skeletal muscles, and joints
b. Visceral sensory fibers – impulses from
visceral organs
70. PNS structure (cont.)
2. Motor (efferent) division – caries impulses
from the CNS to organs, muscles and
glands; causes a response
a. (somatic ( voluntary) nervous system – allows
voluntary contraction of skeletal muscles
b. Autonomic ( involuntary ) nervous system –
regulates involuntary actions, such as glands,
cardiac, and muscles
78. Nervous System Disorders
1. Cerebral palsy – neuromuscular disability
where voluntary muscles are poorly controlled;
causes by a temporary lack of oxygen to motor
areas of the brain during delivery
2. Spina bifada – results when vertebrae from
incompletely; part of the spinal cord is
functionless
3. Parkinson’s disease – disorder in the ganglia
characterized by shaking
79. Nervous System Disorders
4. Orthostatic hypertension – type of low blood
pressure resulting from changes in body position
(sympathetic)
5. Brain shrinkage – common but sped up in
boxers and alcoholics (both groups exhibit signs
of dementia unrelated to aging)
6. Epilepsy – characterized by seizures – caused
by sudden bursts of irregular electrical activity
in the brain