Transcript NERVOUS SYSTEM Aids in remembering, thinking, moving

Chapter 9
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Central Nervous System (CNS)
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Brain and spinal cord
Peripheral Nervous System (PNS)
◦ nerves
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Nervous tissue contains masses of nerve cells
called neurons.
◦ Specialized to react to physical and chemical
changes.
◦ Transmit info in the form of electrochemical
changes called nerve impulses.
◦ Bundles of axons make nerves.
◦ Also contains neuroglial cells that provide physical
support, insulation,
and nutrients for neurons.
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Brain and Spinal Cord
◦ Protected by layered membranes called meninges.
 Dura mater (outermost layer- contains blood vessels)
 Arachnoid mater (no blood vessels)
 Pia mater (thin, contains nerves and b.v that nourish
the cells of the brain and spinal
cord)
 Cerebrospinal fluid (CSF) –clear,
watery fluid b/w the arachnoid
and pia maters that is a shock
absorber. Secreted by masses
of specialized capillaries called
choroid plexuses.
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Contains 100 billion multipolar neurons.
Brain area
Location
Function
Cerebrum
Largest, most of cranial
cavity
Sensory and motor
functions
Higher mental functions
-memory
-reasoning
Cerebellum
Posterior and inferior
region
Coordination
Balance
Muscle tone
Brain area
Location
Middle
Diencephalon
1. Thalamus
2. Hypothalamus
Brainstem
1. Medulla
2. Pons
3. Midbrain
Base of brain
Function
Limbic system-controls
emotional experience and
expression
1.Process sensory info
(pain, touch, temp)
2.Maintains homeostasis:
appetite center, sleepwake, water balance
Connect various parts of NS
Regulates visceral activities
1.Breathing, heart rate
2.Origin of cranial nerves
3.Coordinate head/eye
movements to sound& light
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Cerebral cortex is the outermost layer of gray matter
that contains 75% of all neuron cell bodies of the NS.
Left & Right cerebral hemispheres are connected by a
bridge of nerve fibers called the corpus callosum.
◦ Dominant hemisphere-controls the ability to understand
language
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Surface contains many ridges called gyri (gyrus)
separated by grooves. Shallow groove is a sulcus and a
deep groove is a fissure.
◦ Longitudinal fissure separates the right and left hemispheres .
◦ Transverse fissure separates the cerebrum from the cerebellum.
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5 lobes-frontal, parietal, temporal,
occipital, insula (inner)
4 ventricles
Nerve
 Olfactory
 Optic
 Oculomotor
 Trochlear
 Trigeminal
 Abducens
 Facial
 Vestibulocochlear
 Glossopharyngeal
 Vagus
 Accessory
 Hypoglossal
Function
smell
vision
moves/focus eye
moves eye
chewing
moves eye
facial expression, taste
equilibrium, hearing
swallowing
heart, digestion
neck
move tongue
Oh, Oh, Oh, To Touch And Feel Very Good Velvet, AH
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SPINAL CORD
◦ Contains 31 segments, each giving rise to a pair of
spinal nerves.
Foramen Magnum
-Where the spinal cord begins
Cervical Enlargement
-supplies nerves to upper limbs
Vertebral Canal
Spinal Cord
Lumbar Enlargement
-supplies nerves to lower limbs
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Cross section of spinal cord
Posterior Sulcus: divides spinal
cord into right and left halves.
White Matter:
myelinated
neurons
Contains CSF
Unmyelinated neurons
Anterior fissure
Divides spinal cord into right
and left halves
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Spinal Cord Functions (pg. 234)
Conducting impulses
◦ 2 way communication system
◦ Ascending tracts: carry sensory info to the brain
◦ Descending tracts: conduct motor impulses from
the brain to effectors
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Spinal reflex center
◦ Patellar and withdrawal reflex
◦ Reflex arc passes through the spinal cord
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Subdural hematoma: collection of blood from
broken blood vessels that will increase
pressure in the skull and will lead to
functional losses or death.
Cerebral palsy: partial paralysis and lack of
muscular coordination caused by damage to
the cerebrum.