AP Biology
The
Nervous
System
2003-2004
Let’s go to the Video!
AP Biology
2003-2004
Overview
 The Nervous System controls and
coordinates all the functions of the
body.
 The Nervous System consists of two
main sub-divisions:


Central Nervous System (CNS)
Peripheral Nervous System (PNS)
• The Peripheral Nervous System is
divided into two sub-divisions:


Somatic- voluntary
Autonomic- involuntary
Regents Biology
2003-2004
Regents Biology
http://inside.salve.edu/walsh/cns_pns.jpg
2003-2004
Structure and Function of the Neuron
 Neuron is the scientific name for a Nerve
Cell.
 Neurons consist of 3 basic structures:



Cyton, or cell body.
Dendrites- receive messages, impulses, and
send them to the cell body.
Axons- send messages away from the cell
body.
• Nerve impulses travel from one neuron to
another across synapses, or spaces in
between the cells.
• The “jumping across” the synapse is
facilitated (helped) by chemicals called
Neurotransmitters.
Regents Biology
2003-2004
Parts of the Neuron
 Dendrites – Branched
 A Neuron
parts of a neuron that
receive impulses from
other neurons.
 Cyton- Contains
cytoplasm and the
nucleus. Impulses pass
through here to the
axon.
 Axon- Single long fiber
that carries impulses
away from the cell body.
Regents Biology
2003-2004
Regents Biology
2003-2004
Myelin Sheath
signal
direction
 Axon coated with insulation
made of myelin cells (Fatty,
protein substance)
speeds signal
 330 mph vs. 11 mph

myelin coating
Multiple Sclerosis
Regents Biology
 immune system (T cells) attacks myelin coating
2003-2004
 loss of signal
Synapse
Junction between nerve cells


1st cell releases chemical to trigger
next cell
where drugs affect nervous system
synapse
Regents Biology
2003-2004
Types of Neurons
Neurons can also be classified by the direction
that they send information:
･Sensory (or afferent) neurons: send
information from sensory receptors (e.g., in
skin, eyes, nose, tongue, ears) TOWARD the
central nervous system.
･Motor (or efferent) neurons: send information
AWAY from the central nervous system to
muscles or glands.
･Interneurons: send information BETWEEN
sensory neurons and motor neurons. Most
interneurons are located in the central
nervous system.
Regents Biology
2003-2004
Reflexes
 Stimulus- a change


in the environment.
Response/Reactionhow the body reacts
to a stimulus.
Reflex Arc- the
pathway that an
impulse follows to
illicit a response to a
stimulus.
Regents Biology
2003-2004
Parts of the Central Nervous System
 Brain
 Spinal cord
Regents Biology
2003-2004
What Protects the CNS?
1. Skull and Vertebrae
2. 3 protective layers called meninges
3. Dura Mater (outer layer): consists of connective tissues,
blood vessels, and nerves.
4. Arachnoid Layer (middle layer): elastic and weblike
5. Pia Mater (inner layer): contains nerves and blood vessels.
6. Cerebrospinal fluid




Regents Biology
a clear watery liquid
separates the middle and inner layers
Acts as shock absorber
exchange of nutrients between blood and nervous system
The Brain




Coordinates body activities
Made up of approximately 100 billion neurons
Uses 20% of bodies oxygen and energy
Divided into three major parts


the Cerebrum
the Cerebellum
the Brain Stem (Medulla Oblongata, Pons)
Regents Biology
2003-2004
Cerebrum
 Largest part of the brain
 Thinking
 Memory is stored
 Movements are controlled
 Impulses from the senses are
interpreted.
Regents Biology
2003-2004
Gray Matter vs. White Matter
 Gray Matter – Absence of myelin in

masses of neurons accounts for the gray
matter of the brain – Cerebral Cortex
White Matter - Myelinated neurons gives
neurons a white appearance – inner layer
of cerebrum
Regents Biology
Cerebrum specialization
 Regions specialized for different functions
 Lobes

frontal
frontal
parietal
 speech,
control of emotions

temporal
 smell, hearing

occipital
 vision

parietal
 speech, taste
reading
temporal
Regents Biology
occipital
2003-2004
Craniotomy
Regents Biology
2003-2004
Regents Biology
2003-2004
Brain Tumor Surgery
Regents Biology
2003-2004
Sub-Arachnoid Cyst Removal
Regents Biology
2003-2004
Cerebral Hemhorrage
Regents Biology
2003-2004
Subdural Hematoma
Regents Biology
2003-2004
Brain Worms!
Regents Biology
2003-2004
Cerebellum
 Responsible for the
coordination of
muscles and is the
center of balance
Regents Biology
2003-2004
Regents Biology
2003-2004
Medulla
 Center of heart beat,
respiration, and
other involuntary
actions
Regents Biology
2003-2004
Other Structures inside the Brain
 Thalamus – receives messages from
sensory receptors; relays information to
proper regions of cerebrum
 Hypothalamus - Regulates hunger, thirst,
fatigue, anger, etc…

Control of pituitary for endocrine function
Regents Biology
Section 35-3
Cerebrum
Thalamus
Pineal
gland
Hypothalamus
Cerebellum
Pituitary gland
Pons
Medulla oblongata
Regents Biology
Spinal cord
The Spinal Cord
 Extension of the brain stem
 Bundles of neurons that carry impulses
from all parts of the body to the brain
and from the brain to all parts of your
body
Regents Biology
2003-2004
The
Peripheral
Nervous
System
Your brain
and spinal
Somatic
cord are
and
connected
Autonomic
to the rest
Systems
of your
The
body by
peripheral
the
nervous
peripheral
system
has
nervous
two
major
system.
divisions.
The PNS
is made up
somatic
of 12 pairs
system
of nerves
controls
from your
voluntary
brain It
actions.
called
is
made up
cranial
of
the
nerves, and
cranial
and 31
spinal
pairs from
nerves
that
your
go
from
spinal
the
cord called
central
spinal
nervous
nerves. to
system
Spinal
your
nerves are
skeletal
made up of
muscles.
bundles of
The
sensory
autonomic
and motor
system
neurons
controls
bound
involuntary
together by
actionsconnective
those
not
tissue. For
under
this
conscious
Research
reason,
controla
Visit the
single
such
as
Glencoe
spinal
your
heart
Science
nerve
rate,
can
Web site at
have
breathing,
tx.science.
impulses
digestion,
glencoe.co
going
and
to
m forfrom
more
and
glandular
information
the
functions.
brain at
about
the
the
These
same
two
nervous
time.
divisions,
Some
system.
nerves
along
with
Make
a
contain
the
central
brochure
only
nervous
outlining
sensory
system,
recentup
neurons,
make
medical
and
your
some
advances.
contain
body's
only motor
nervous
neurons,
system.
but most
nerves
contain
both types
of neurons.
Regents Biology
2003-2004
Peripheral Nervous System
 Connects body to brain & spinal cord
 12 pairs of nerves from your brain

(cranial nerves)
31 pairs from your spinal cord (spinal
nerves)

Bundles of sensory and motor neurons
held together by connective tissue
 Two divisions
Somatic
 Autonomic

Regents Biology
2003-2004
Divisions of the PNS:
Somatic Nervous System
 Controls voluntary actions
 Made up of the cranial and spinal
nerves that go from the central nervous
system to your skeletal muscles
Autonomic Nervous System
 Controls involuntary actions-those not
under conscious control-such as your
heart rate, breathing, digestion, and
glandular functions
Regents Biology
2003-2004
Regents Biology
http://www.christopherreeve.org/Research/Research.cfm?ID=178&c=21
2003-2004
Animals rely on two systems for regulation:
Nervous System is a system of nerve cells called neurons. It
consists of a central nervous system (brain and spinal cord)
and peripheral nerves. Typical responses are fast and short
lasting.
Endocrine System is a system of ductless glands that secrete
hormone into the blood. Hormones travel to target tissues.
Typical responses are slow and long lasting.
Regents Biology
Progesterone
Estradiol
2003-2004
Human Endocrine
Glands
Ductless glands
transport hormones in
the blood
Duct glands are
exocrine glands that
use tubes to carry the
secretion
(salivary, tears)
Regents Biology
2003-2004
Pituitary gland and Hypothalamus serve to link the nervous
system other glands and metabolic functions.
Regents Biology
2003-2004
Regents Biology
2003-2004
Thyroid and Parathyroid help regulate calcium
metabolism
Feedback!
Regents Biology
2003-2004
Goiter: Iodine deficiency and feedback causes the thyroid to
enlarge
This people have a goiter, a condition
that is easily preventable with iodized
salt
Regents Biology
2003-2004
Thyroid regulates metabolism
Graves disease: hyperthyroid
feedback
Regents Biology
2003-2004
Pancreas helps regulate blood glucose
feedback
Insulin from Beta cells reduce blood sugar
Glucagon
Regents
Biologyfrom Alpha cells increase blood sugar
2003-2004
THE FIGHT OR FLIGHT MECHANISM
•Large amount of adrenaline pumped into the body to put
us in a state of increased alertness
•Blood is redirected away from the extremities to the large
muscles of the body
•The heart starts working harder to move the blood to the
large muscle groups as quickly as it can
•Increase in Respiratory Rate
•Release of red blood cells
•Release of sugar by liver
•Increase in metabolic rate
alektorophobia
Regents Biology
2003-2004
Regents Biology
2003-2004
Regents Biology
2003-2004
Gonads: Testes and Ovaries produce hormones that
regulate secondary sex traits
Male sex traits include
those changes that
occur during puberty
Androgens include
testosterone
Regents Biology
feedback
2003-2004
feedback
Female sex traits
include the
menstrual cycle and
the changes seen
during puberty
LH and FSH from
the pituitary
Estrogen and
progesterone from
the ovary
Regents Biology
2003-2004
Identify the Glands
Regents Biology
2003-2004