Download I. Nerve Organization

I. Nerve Organization
A. Nerve Net – Limited synapses between
neurons.
B. Ganglia – Local cluster of nerves.
C. Cephalization – Head formation and
bilateral semetry allow for complex brain
function.
optic lobe
connected
with visual
stimuli
ganglion
(brainlike
structure)
rudimentary
brain
one of
two nerve
cords
brain
nerve
chord
nerve
chord
segmental
ganglion
FLATWORM
brain
one of
two nerve
cords
EARTHWORM
CRAYFISH
GRASSHOPPER
Fig. 35.3, p. 589
II. Division of Nervous System
A. Cell Types
1. Gray Matter – Neurons without myelin
sheath
2. White Matter – Neurons with fatty
myelin sheath.
3. Neuroglia – Cells of nervous system
other than neurons (Schwann cells).
II. Nervous System (con’t)
B. Brain and Body
1. Central Nervous System: Brain and
Spinal Cord.
Surrounded by membrane called
meninges (blood/brain barrier).
2. Peripheral Nervous System: Nerve
bundles extending beyond CNS.
BRAIN
CRANIAL
NERVES
cervical nerves
(eight pairs)
SPINAL
CORD
thoracic nerves
(twelve pairs)
ulnar
nerve
sciatic
nerve
lumbar
nerves
(five pairs)
sacral nerves
(five pairs)
coccygeal nerves
(one pair)
Fig. 35.5, p. 591
II. Nervous System (con’t)
C. Divisions of Peripheral Nervous System
1. Somatic Nerves – Skeletal muscles,
voluntary actions, skin, limbs, etc.
2. Autonomic Nerves - Nonvoluntary
actions; smooth and cardiac muscles;
glands.
II. Nervous System (con’t)
C. 2. Divisions of Autonomic Nerves
a. Parasympathetic: Basic biological
functions; resting state.
b. Sympathetic: Increased awareness and
immediate energy; ‘nervousness.’
Nervous System
Peripheral Nervous
System
Central Nervous System
Brain
Spinal Cord
Somatic
Nervous
System
Autonamic
Sympatheic
Parasympathetic
CENTRAL
NERVOUS
SYSTEM
brain
spinal cord
sensory
nerves
axons of
motor nerves
somatic
subdivision
(motor functions)
These nerves carry
signals to and from
skeletal muscles,
tendons, and skin.
autonomic
subdivision
(visceral functions)
These nerves carry
signals to and from
internal organs (gut,
heart, glands, etc.).
parasympathetic
nerves
sympathetic
nerves
PERIPHERAL NERVOUS SYSTEM
Fig. 35.6, p. 591
FOREBRAIN. Receives, integrates
sensory information from nose,
eyes, and ears; in land-dwelling
vertebrates, contains the highest
integrating centers
MIDBRAIN. Coordinates reflex
responses to sight, sounds
HINDBRAIN. Reflex control of
respiration, blood circulation,
other basic tasks; in complex
vertebrates, coordination of
sensory input, motor dexterity,
and possibly mental dexterity
(start of spinal cord)
Fig. 35.4a, p. 590
III. Very Basic Divisions of Brain
A. Hindbrain: Brain stem in humans.
1. Medulla oblongata: respiration,
circulation.
2. Cerebellum: Coordinates inputs;
necessary for coordination and motor
skills.
3. Pons: Bridge between hindbrain and
midbrain.
hypothalamus thalamus
pineal gland location
corpus
callosum
part
of an
optic
nerve
midbrain
cerebellum
pons
medulla
oblongata
Fig. 35.12, p. 596
III. Basic Divisions of Brain (con’t)
B. Midbrain: Greatly reduced in humans.
Coordinates sight and sound in many
vertebrates.
III. Basic Divisions of Brain (con’t)
C. Forebrain: Most recent evolutionary
component of brain.
1. Divided into two hemispheres
2. Cerebrum in mammals.
3. Thalamus: Relay or bridge to Cerebrum
4. Hypothalamus: Links brain with
endocrine system; controls
homeostatis.
IV. Details of Cerebrum
A. Cerebral Cortex: Outer gray covering.
Infolding increases surface area.
B. Frontal Lobe: Associated with ‘higher
thinking’
C. Parietal Lobe: Motor and sensory nerves.
D. Temporal Lobe: Speech and Auditory
nerves.
E. Occipital: Sight.
Fig. 35.10, p. 595
hypothalamus thalamus
pineal gland location
corpus
callosum
part
of an
optic
nerve
midbrain
cerebellum
pons
medulla
oblongata
Fig. 35.12, p. 596
Motor cortex activity
when speaking
Prefrontal cortex activity
when generating words
primary
motor
cortex
Frontal lobe
(planning of
movements,
aspects of
memory,
inhibition of
unsuitable
behaviors)
temporal lobe (hearing,
advanced visual processing)
Visual cortex activity
when observing words
parietal
primary
lobe
somatosensory
(visceral
cortex
sensations)
occipital lobe
(vision)
Fig. 35.13, p. 597
IV. Details of Cerebrum (con’t)
F. Hemispheres:
1. Right: Visual/Spatial, music, ‘creative’
2. Left: Speech, math, ‘analytical’
3. Connected with Corpus Callosum
G. Limbic System:
Role in memory and emotion.
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