Overview of The Nervous System Overview of The Nervous System
Overview of The Nervous System Overview of The Nervous System
Overview of The Nervous System Overview of The Nervous System
Systems
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Bio217 Fall2012 Unit IV
Neuroglia Neuroglia
Nerve glue
Support the neurons of the CNS
Astrocytes
Oligodendroglia (oligodendrocytes)
Microglia
Ependemal
A astrocyte B oligodendrocyte
C microglia D - ependymal
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Bio217 Fall2012 Unit IV
Forebrain:
Cerebrum
Central Nervous System Gyri, sulci, and fissures
Gray matter and white matter
BRAIN: Cerebral nuclei (basal ganglia)
Forebrain
Cerebral hemispheres
Midbrain
Corpora quadrigemina, substantia nigra,
and cerebral peduncles
Hindbrain
Cerebellum, pons, and medulla
Forebrain
Central Nervous System
- functional areas
Diencephalon
Thalamus
Hypothalamus
Midbrain
Corpora quadrigemina
Superior and inferior colliculi
Tegmentum
Red nucleus and substantia nigra ( dopamine NE)
Cerebral peduncles
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Bio217 Fall2012 Unit IV
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Bio217 Fall2012 Unit IV
Protective Structures
Meninges
Cranium
Eight bones
Frontal, Occipital, Temporal (2), Parietal (2),
Sphenoid, Ethmoid
Galea aponeurotica
Meninges
Protective membranes surrounding brain & SC
Dura mater
Arachnoid
Pia mater
Protective Structures
Protective Structures
Cerebrospinal fluid (CSF) Vertebral column
Clear, colorless fluid similar to blood plasma and
interstitial fluid 33 vertebrae
7 cervical, 12 thoracic, 5 lumbar,
125 to 150 mL 5 fused sacral, 4 fused coccygeal
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Bio217 Fall2012 Unit IV
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Bio217 Fall2012 Unit IV
Parasympathetic
Rest or repose response
Craniosacral
Preganglionic neurons travel to ganglia
close to organs they innervate
Neurotransmitters and
Parasympathetic Nervous System
Neuroreceptors of the ANS
Neurotransmitters and
Aging and the Nervous System
Neuroreceptors of the ANS
Decrease in the number of neurons
Decreased brain weight and size
Senile plaques
Neurofibrillary tangles
Slowing of neurologic responses
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Bio217 Fall2012 Unit IV
Concept Check:
1. One function of somatic NS that is not performed 3. Which of the following best describes the SC?
by the ANS is conduction of impulses: A. Descends inferior to the lumbar vertebrae
A. To involuntary muscles and glands B. Conducts motor impulses from the brain
B. To the CNS
C. To skeletal muscles C. Descends to L4
D. Between the brain and SC D. Conducts sensory impulses to the brain
5. The SNS:
A. Mobilizes E in times of need
B. Is innervated by cell bodies from T1 L2
C. Is innervated by cell bodies located in the Pain, Temperature, Sleep, and
cranial nerve nuclei
D. Both A and B are correct Sensory Function
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Bio217 Fall2012 Unit IV
Pathways of Nociception
Neuromodulation of Pain
- Spinothalamic tracts
Neuromodulators
Located in pathways of NS
Triggered by tissue injury and or inflammation
Excitatory neuromodulation
Substance P, glutamate, somatostatin
Inhibitory neuromodulation
GABA, glycine, serotonin, NE, endorphins
Neuromodulation of Pain
Endorphin Response
Endorphins (endogenous morphines)
Neuropeptides inhibit pain transmission in CNS
Bind opioid receptors
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Bio217 Fall2012 Unit IV
Temperature Regulation
Heat Loss
Peripheral & central thermoreceptors
Hypothalamic control (range ~37o + 0.7o) Radiation, Conduction, Convection
Vasodilation
Heat production
Decreased muscle tone
Metabolism
Evaporation
Skeletal muscle contraction
Increased respirations
Chemical thermogenesis Voluntary measures
Heat conservation Adaptation to warmer climates
Vasoconstriction
Voluntary mechanisms
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Bio217 Fall2012 Unit IV
Hyperthermia Hypothermia
Not mediated by pyrogens (no resetting of thermostat)
41o C (105.8o F): nerve damage produces convulsions Body temperature less than 35o C
43o C (109.4o F): death results Produces:
Forms VC, alterations in the microcirculation,
Heat cramps (abdom. pain, incr. sweat, coagulation, and ischemic tissue damage
loss Na+) Ice crystals, which form inside the cells,
Heat exhaustion (collapse, profuse sweat, causing them to rupture and die
high core temp.
Heatstroke ( death, brain cannot tolerate
temperatures >40.5o C (104.9o F)
Hypothermia Sleep
Accidental hypothermia Infants : 16-17 hours /day; about half in REM
Commonly the result of sudden immersion in Elderly: decrease in sleep time, longer to fall
cold water or prolonged exposure to cold asleep; increase in sleep apnea
Therapeutic hypothermia
REM = rapid eye movement sleep; 90 minute
Used to slow metabolism and preserve ischemic
cycles after non-REM sleep
tissue during surgery or limb reimplantation
May lead to ventricular fibrillation and cardiac
arrest
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Bio217 Fall2012 Unit IV
Sleep Disorders
The Eye
Insomnia
not able to fall asleep or stay asleep
idiopathic, abuse of drugs or alcohol,
chronic pain, depression, or certain
drugs, age, obesity
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Bio217 Fall2012 Unit IV
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3. In heatstroke- Matching:
A. Blood viscosity increases
B. Core temp. increases as regulatory center fails 8. Blepharitis A. Increase intraocular
C. Stimulates VC
pressure
D. Ice crystals form in cells
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8. PD c. Neurofibrillary tangles,
amyloid proteins
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Bio217 Fall2012 Unit IV
Hematomas
Subdural Hematomas
collection of blood in closed space
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Bio217 Fall2012 Unit IV
Infection and
Intracranial Aneurysm
Inflammation of the CNS
Due to: atherosclerosis, congenital, trauma,
inflammation Meningitis
Pathophysiology: no single mechanism Bacterial meningitis
Aseptic (viral, nonpurulent, lymphocytic)
Classified: based on shape meningitis
Fungal meningitis
Clinical manifestations: asymptomatic or
various cranial nerve compression, or Tubercular (TB) meningitis
hemorrhage
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Bio217 Fall2012 Unit IV
3. TIAs are:
Concept Check A. Neurological deficits that slowly resolve
B. Neurological deficits that occur every hour
1. If an individual struck the car windshield in a car accident,
C. Focal neurological deficits that dev. suddenly, last for a few
the coup/contrecoup injury would be in the :
minutes, and clear in 24 hours
A. Frontal/parietal region
D. Events that never indicate an impending stroke
B. Frontal/occipital region
C. Parietal/occipital region
Matching:
D. Occipital/frontal region
4. MG a. Autoimmune disorder, antibodies
attack ACh receptors at NMJ
2. Injury of the cervical SC may be life threatening due to:
A. Increased intracranial pressure
B. Spinal shock 5. MS b. Protrusion of nucleus pulposus
C. Loss of bladder and rectal contrao
D. Impairment of the diaphragm 6. Herniated disc c. Demyelination of nerves
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