Transcript The Nervous System

The Nervous System
A&P Spring 2017
I. Organization of the Nervous System
A. Structural Classification
1. Central Nervous System (CNS)
a. The Brain
b. The Spinal Cord
2. Peripheral Nervous System (PNS)
a. Nerves that extend from the CNS
i. Serve as communication lines that link
all parts of the body to the CNS
B. Functional Classification (PNS only)
1. Sensory Division
a. nerves that send impulses TO the CNS
from sensory receptors
2. Motor Division
a. Nerves that carry impulses FROM the
CNS to organs, muscles and glands
3. Somatic NS (Subdivision of Motor)
a. voluntary control of skeletal muscles
4. Autonomic NS (Subdivision of Motor)
a. regulates involuntary events
b. also has 2 subdivisions
i. Sympathetic- Fight or Flight
ii. Parasympathetic- Rest and Digest
The Nervous System
Central Nervous
System
Peripheral
Nervous System
Sensory
Motor
Somatic
Autonomic
Sympathetic
Parasympathetic
Bell Ringer
• Create a diagram that shows the relationship
between the following:
– Central NS
– Motor
– Autonomic
– Somatic
– Peripheral NS
– Sensory
II. Nervous Tissue: Structure and
Function
A. Supporting Cells
1. Neuroglia (Glial Cells)
a. Found in the CNS
i. Astocytes
ii. Microglia
iii. Ependymal
iv. Oligodendrocytes
b. Found in the PNS
i. Schwann cells
ii. Satellite cells
Neuroglia Flipbook!
• Materials:
– 3 Sheets of paper
– Page of pictures
– Stapler (will be passed around)
– Glue stick
– Scissors
– Pen/Pencil
Cover Page
NEUROGLIA
By: Your Name
Page 1
Found in the
Central Nervous System
Page 2
Astrocytes
star-shaped cells that anchor neurons to blood
capillaries. Helps with exchange of oxygen and
nutrients
(Paste picture to the back of page 1)
Page 3
Microglia
spiderlike cells that monitor the health of
neurons. Dispose of debris such as dead brain
cells and bacteria.
(paste picture to the pack of page 2)
Page 4
Ependymal Cells
Line the central cavities of the brain & spinal
cord. Forms a protective cushion around the
CNS. Cilia help circulate cerebrospinal fluid.
(paste the picture to the back of page 3)
Page 5
Oligodendrocytes
wrap around nerve fibers of the CNS to form
an insulating cover called a “myelin sheath”.
(paste the picture to the back of page 4)
Page 6
Found in the
Peripheral Nervous System
Page 7
Satellite Cells
Form a protective cushion around the PNS.
(paste picture to the back of page 6)
Page 8
Schwann Cells
Wrap around the nerve fibers of the PNS to form
an insulating cover called a “myelin sheath”
(Paste picture to the back of page 7)
Page 9
Summary
CNS:
Astrocytes
Microglia
Oligodendrocytes
Ependymal Cells
PNS:
Satellite Cells
Schwann Cells
Bell Ringer
What is the main purpose of ALL neuroglia?
B. Neurons
1. Anatomy
a. Cell Body
i. center of the neuron
ii. Contains the nucleus and the usual
cell organelles
b. Dendrites
i. detect incoming messages
(electrical signals)
ii. “Listeners”
c. Axon
i. send messages out
ii. “Talkers”
d. Axon Terminals
i. End of the axon
ii. Contains chemicals that carry
messages from one neuron to the
next
iii. Synaptic cleft is a gap between
neurons
e. Myelin Sheath
i. material that insulates nerve axons
ii. Increases the rate of nerve
impulses
f. Nodes of Ranvier
i. Space between myelin sheaths
where the axon is exposed
ii. Impulses “Jump” to these spaces
2. Classification
a. Functional Groups
i. Sensory (afferent) neurons
ii. Motor (efferent) neurons
iii. Interneurons (association)
b. Structural Groups
i. Multipolar neurons
ii. Bipolar neurons
iii. Unipolar neurons
III. The Central Nervous System
A. Anatomy of the Cerebrum
1. Cerebral Hemispheres
a. Gyrus (gyri; plural)- ridges
b. Sulcus (sulci; plural)- shallow grooves
c. Fissures- deep grooves
i.
Transverse Fissure- separates cerebrum
from cerebellum
ii. Longitudinal Fissure- separates cerebral
hemispheres
2. Lobes
a. Frontal
i. Primary motor area
b. Parietal
i. Primary sensory area
c. Temporal
i. Auditory area
d. Occipital
i. Visual area
3. Cerebral White Matter
a. inner most part of the brain
b. contains the “Corpus Callosum”
i. a large nerve fiber
ii. Connects the cerebral hemispheres
4. Diencephalon
a. located on the bottom
i. sits on top of the brain stem
b. 2 major structures
i. Thalamus- relay station for sensory
impulses
ii. Hypothalamus- regulates body
temperature, water balance
and metabolism
B. Anatomy of the Brain Stem
1. Midbrain
a. Contains two large nerve fibers
b. fibers serve as reflex centers
i. vision reflex center
ii. Hearing reflex center
2. Pons
a. means “bridge”
b. involved with control of breathing
3. Medulla Oblongata
a. merges with the spinal cord
b. contains several control centers
i. heart rate
ii. Blood pressure
iii. Breathing
iv. Swallowing
v. vomiting
C. Anatomy of the Cerebellum
1. “Little Brain”
a. divided into two hemispheres
b. contains gray cortex on the outside
c. white cortex in the center
d. located on the bottom of occipital lobe
2. Involved with balance & movement
a. ensures that skeletal muscle movements
are smooth and precise
b. controls balance and equilibrium
D. Protection of the Central Nervous System
1. Meninges- cover the brain and spinal cord
a. Dura Mater
i. Outermost layer
ii. Very tough
b. Arachnoid Mater
i. middle layer
ii. Web-like
c. Pia Mater
i. Inner layer
ii. Thinnest
iii. Clings to the brain and spinal cord
2. Cerebrospinal Fluid (CSF)
a. Watery “broth”
i. made from blood plasma
b. surrounds brain and spinal cord
i. acts as a protective cushion from
some forms of trauma
c. Continually moving
i. forms and drains at a constant rate
ii. Specific pressure is maintained
d. Lumbar (Spinal) Tap
i. used when testing for diseases that
affect the CSF
ii. Patients have CSF withdrawn from
their lower spine
iii. The change in pressure requires
patients to remain laying down for 612 hours after the procedure
iv. Failure to do so can result in an
extremely painful “spinal headache”
E. Anatomy of the Spinal Cord
1. Enclosed in the vertebral column
a. actually ends just below the ribs
i. 1st or 2nd Lumbar Vertebra
b. has 31 pairs of spinal nerves
i. nerves branch out from the
vertebrae to serve nearby body areas
c. spinal nerves that serve the lower body
bunch together
i. they must extend through the
bottom of the vertebral column
ii. This grouping is called the “Cauda
Equina” which means horse tail
2. Spinal Nerve Roots
a. Every spinal nerve connects to the spinal
cord in two places
i. connections are called “roots”
ii. Connect to the front and back side
b. Dorsal Roots
i. “Back” roots
ii. Beginning of Sensory Neurons
c. Ventral Roots
i. “Front” roots
ii. Beginning of Motor Neurons
IV. Peripheral Nervous System
A. Cranial Nerves
We will make flash cards for each of the
nerves and their functions.
There are 12 nerves, so you will need 12 flash
cards!
I. Olfactory
Sense of smell
II. Optic
Sense of vision
III. Oculomotor
Movement of eyelids
IV. Trochlear
Movement of eyes up and down
V. Trigeminal
Sense of touch on the face; movement of jaw for
chewing
VI. Abducens
Movement of eyes side to side
VII. Facial
Movement of facial muscles (facial expression)
VIII. Vestibulocochlear
Sense of balance and hearing
IX. Glossopharyngeal
Movement of pharynx for swallowing; sense of
taste
X. Vagus
Movement of digestive organs
XI. Accessory
Movement of neck and shoulders
XII. Hypoglossal
Movement of the tongue
B. Structure of a Nerve
1. Parts of a nerve
a. Nerve- bundle of fascicles
b. Fascicle- bundle of nerve fibers
(processes)
c. Nerve fiber (Process)- axon of individual
neuron cells
2. Protective Coverings
a. Endoneurium- covers the nerve
b. Perineurium- covers the fascicles
c. Epineurium- covers the nerve fibers
(processes)
3. Types of nerves
a. Sensory
i. sends impulses TOWARD the CNS
b. Motor
i. sends impulses AWAY from the CNS
c. Mixed
i. sends impulses in both directions
ii. made of BOTH sensory and motor
neurons