PSYCO275 Chapter Notes - Chapter 3: Optic Chiasm, Diencephalon, Silver Nitrate
6 Jun 2018
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PSYCO 275 - Chapter 3
Central Nervous System (CNS)
●Brain : located in the skull
●Spinal cord : part located in the spine
●These two organs are the most protected in the body; encased in bone and covered by
three protective membranes called the “Three Meninges”
Peripheral Nervous System (PNS)
●Somatic Nervous System
○Interacts with the external environment
○Composed of afferent nerves
○Afferent nerves
: carry sensory signals from the skin, skeletal muscles, joints, eyes,
ears and so on to the CNS
○Efferent nerves
: carry motor signals from the CNS to the skeletal muscles
●Autonomic Nervous System
○Regulates the body’s internal environment
○Afferent nerves
: carry sensory signals from internal organs to the CNS
○Efferent nerves
: carry carry motor signals from the CNS to the internal organs
i. Two kinds:
●Sympathetic nerves
○Nerves that project from the CNS in the lumbar (small of
the back) and thoracic (chest area) regions of the spinal
cord
○Stimulate, organize and mobilize energy resources in
threatening situations
○Sympathetic changes : psychological arousal
●Parasympathetic nerves
○Nerves that project from the brain and the sacral (lower
back) region of the spinal cord
○Act to conserve energy
○Parasympathetic changes : psychological relaxation
●All sympathetic and parasympathetic nerves have two-stage neural
paths: they go from the CNS to the target organs BEFORE THEY
SYNAPSE to other neurons called second-staged neurons
●Second-stage neurons
○Signals from the sympathetic and parasympathetic nerves
are relayed to the second-stage neurons to carry the signals
the rest of the way to the target organs
●Sympathetic nerves: relay to their second-stage neurons from quite
a distance to their target organs
●Parasympathetic nerves: relay to their second-stage neurons quite
near their target organs
●Each autonomic target organ receives opposing sympathetic and
parasympathetic input so whoever wins the competition, controls
the activity of said target organ.
●Most nerves of the PNS project from the spinal cord BUT there are 12 pairs
of
exceptions:
○12 pairs of cranial nerves 78
i. Olfactory
●Sensory: smell
ii. Optic
●Sensory: vision
iii. Oculomotor
●Motor: eye movement and pupillary constriction
●Sensory: sensory signals from certain eye muscles
iv. Trochlear
●Motor: eye movement
●Sensory: sensory signals from certain muscles
v. Trigeminal
●Motor: chewing
●Sensory: facial sensations
vi. Abducens
●Motor: eye movement
●Sensory: sensory signals from certain eye muscles
vii. Facial
●Motor: facial expression, secretion of tears, salivation, cranial
blood vessel dilation
●Sensory: taste from anterior two-thirds of tongue
viii. Auditory-Vestibular
●Sensory: audition; sensory signals from the organs of balance in
the inner ear
ix. Glossopharyngeal
●Motor: salivation, swallowing
●Sensory: taste from posterior third of the tongue
x. Vagus
●Motor: control over abdominal and thoracic organs and muscles
of the throat
●Sensory: sensations from abdominal and thoracic organs
xi. Spinal Accessory
●Motor: movement of neck, shoulder and head
●Sensory: sensory signals from muscles of the neck
xii. Hypoglossal
●Motor: tongue movements
●Sensory: sensory signals from tongue muscles
Meninges
●The “Three Meninges”
○Meninx
Document Summary
Spinal cord : part located in the spine. These two organs are the most protected in the body; encased in bone and covered by three protective membranes called the three meninges . Afferent nerves : carry sensory signals from the skin, skeletal muscles, joints, eyes, ears and so on to the cns. Efferent nerves : carry motor signals from the cns to the skeletal muscles. Afferent nerves : carry sensory signals from internal organs to the cns. Efferent nerves : carry carry motor signals from the cns to the internal organs i. Nerves that project from the cns in the lumbar (small of the back) and thoracic (chest area) regions of the spinal cord. Stimulate, organize and mobilize energy resources in threatening situations. Nerves that project from the brain and the sacral (lower back) region of the spinal cord. All sympathetic and parasympathetic nerves have two-stage neural paths: they go from the cns to the target organs before they.
