Transcript The Central Nervous System

Consists of :
1. Brain
2. Spinal Cord
a.
b.
c.
Protected by glial cells & meninges
High metabolic rate that requires nutrients
and oxygen
Must be isolated from compounds in blood
that could interfere with functioning
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3 layers of specialized membranes surrounding
brain & spinal cord
A) Dura Mater: 2 fibrous layers; outermost; very
tough, holds brain in place
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B) Arachnoid: middle; small amt lymphatic fluid
(reduces friction) & CSF
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Contains fluid, blood vessels & some adipose tissue
Provides stability & shock absorption to CNS tissue
Cerebrospinal Fluid (CSF): absorbs shock & transports
gases, nutrients, chemical messengers, & wastes
C) Pia Mater: innermost; extensive circulatory
supply due to high rate of metabolism
Meningitis: inflammation of meninges due to
bacterial or viral infection
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Sends sensory info to brain & motor info from
brain to rest of body
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Spinal Reflexes: automatic responses controlled solely
w/in spinal cord (i.e. withdraw from pain)
Central Canal: narrow central opening filled w/
CSF
Gray Matter: inside; contains neuron cell bodies &
neuroglia…forms an H or butterfly shape
White Matter: outside; contains axons of neurons
Dorsal Roots: carry sensory info to spinal cord
Ventral Roots: carry motor info to muscles and
glands
31 segments designated by letter and number:
C1 C8 Cervical Vertebrae
T1  T12 Thoracic Vertebrae
L1 L5 Lumbar Vertebrae
S1 S5 Saccral Vertebrae
CO1
Coccygeal near tailbone
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Each segment has a dorsal root ganglia
a. Dorsal Root- axons of sensory neuron
b. Ventral Root- Axons of CNS motor neuron
All spinal nerves are mixed because they contain
sensory and motor neurons
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“Rostral” = anterior (towards nose) “Caudal” =
posterior (towards tail)
4 Major Parts:
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1) Cerebrum: divided into 2 hemispheres w/ 5 lobes
 Corpus Callosum: thick bundles of nerves connecting 2 hemis.
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2) Cerebellum: inferior to cerebrum
 Sensory perception, motor output, motor control (heart, blood
pressure, breathing, etc.)
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3) Brain Stem: btwn cerebrum & foramen magnum
 Attention, arousal, consciousness
 Composed of midbrain, pons, and medulla oblongata
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4) Diencephalon: inner core; btwn cerebral hemisph.
 sensory processing, emotion, hormone production
1. Cerebrum-
2. Diencephalon (Hypothalamus to pituitary gland)3. Midbrain
4. Pons
5. Medulla Oblongata
6. Cerebellum
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83% brain volume
Gyri: thick folds
Sulci: shallow grooves
that separate gyri
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Central Sulcus: divides
frontal/parietal lobes
Lateral Sulcus:
distinguishes temporal lobe
Fissures: deep grooves
throughout
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Longitudinal Fissure:
divides R/L hemispheres
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1) Frontal: voluntary (skeletal) muscle control,
motivation, memory
2) Parietal: sensory reception, taste, some
vision
3) Temporal: hearing, smell, learning, memory,
emotional behavior
4) Occipital: main visual center
5) Insula: deep inside; understanding speech,
taste, sensory integration
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Most of cerebral volume
Transmits signals throughout cerebrum & to
lower brain centers
Contains axons of neurons
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Neural Integration
Contains neuron cell bodies & neuroglia
1) Cerebral Cortex: thin layer covering
hemispheres
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Stellate Cells: receive sensory input & process local
info
Pyramidal Cells: transmit signals to other parts CNS
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Receive & send signals to midbrain & motor cortex
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Important for emotion & memory
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2) Basal Nuclei: deep masses w/in white
matter
3) Limbic System: includes amygdala &
hippocampus