1. Chapter 35-2
Nervous System

2. Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

3. Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

4. Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

5. Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

6. Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System

7. Figure 35-2 Human Organ Systems Part 2
Section 35-1
Respiratory System
Digestive System
Excretory System
Endocrine System
Reproductive System
Lymphatic/Immune Systems

8. 35-2: The Nervous System
____________________ = (aka: communication system) consists of specialized cells that receive and relay information (by way of electrical signals) about activities within the body and monitors and responds to internal and external changes.
The Nervous System
The Neuron
A. Neuron =
Specialized cells, making up the nervous system, that carry impulses (messages)

9. The Neuron!!
The _____________ part of the neuron is the ___________________.
a) Most metabolic activity occurs here.
__________: carry impulses ___________ the cell body.
a) May be ________ dendrites attached to one cell body
_________: The long fiber that carries impulses (messages) _________ from the cell body.
a) Usually only ____ axon that is very__________.
largest
cell body
Dendrites
towards
many
Axon
away 1
long

10. Anatomy of a neuron:
Cell body: consists of nucleus and contents of the cytoplasm. Sites for ATP and Protein Production.
Axon: Carries impulses away from cell body
Axon Terminals: end at another neuron
Dendrite: Receiver of impulses from the environment. Carries impulses toward cell body.

11. b) Some axons are covered by a _____________
sheath.
1. Some parts of the axons are left ____________
and are called __________.
2. A nerve impulse will _________ from node to
node, making it _____________________.(Important
for larger animals)
3. As you use a neural pathway ____________,
myelin can develop, making it easier to
____________ information quicker.
myelin
exposed
nodes
jump
travel faster
repeatedly
retrieve

12. Cross Section of the Axon

13. B. Impulses =
C. 3 types of neurons (classified according to the direction of the impulse)
1. sensory neurons = carry impulses from
____________ to the
2. motor neurons = carry impulses from the _____________________ to
_____________________.
3. interneurons = connect ___________
______________
The electrical signals used for communication
Sense organs
brain and spinal cord
brain and spinal cord
muscles and glands
sensory and
motor neurons

14. Sensory-Interneuron-Motor Neurons

15. A General Overview of Neurons

16. not impulse difference active transport ATP
II. The Nerve Impulse
A. The Resting Neuron
1. Resting= ______ transmitting an _________.
2. Resting Potential:
a) There are more ______ ions inside the nerve cell than outside the cell.
b) There are more ____ ions outside the cell than inside the nerve cell.
** The ____________ in charge is maintained by
_________________________ which uses _________.
Nerve impulses rely on movement of (+) charged ions.
not
impulse K+
Na+
difference
active transport
ATP

17. c) A ______________________ uses _______
c) A ______________________ uses _______ __________ to pump Na+ ions ___ of the cell and K+ ions _____ the cell.
d) Protein channels in the cell membrane allow
________ to leak out of the cell while keeping _________ from moving into the cell.
e) The ________ that _________leave the cell also have a ____________ charge.
f) Overall, the ________ of the cell is ________, and the outside of the cell is ____________.
Na+/K+ pump
active
transport
out
into
K+ ions
Na+ ions
proteins
cannot
negative
inside
negative
positive

18. A Look at the Membrane Proteins

19. Neuron at resting potential ___________= Negative (compared to the outside) inside the cell and positive outside
(polarized)
Na +
Na +
Outside
Na +
Na +
Na +
Na +
Na +
Na + - -
K + -
K + - - -
AXON -
K + -
K + - -
K +
Inside -
Na +
Na +
Na +
Na +
Na +
Outside
Na +
Na +
Na +
Na +

20. Figure 35-7 An Impulse
Section 35-2

21. Figure 35-7 An Impulse
Section 35-2

22. Figure 35-7 An Impulse
Section 35-2

23. Figure 35-7 An Impulse
Section 35-2

24. Reaching Resting Potential (show only first segment!)

25. B. The Moving Impulse
1. A neuron stays __________________ until it
receives a ______________.
a) An impulse begins when a neuron is
stimulated by the __________________ or
_______________________.
b) The impulse allows ______ to move across
the membrane.
c) The impulse moves like a chain reaction down
__________.
at resting potential
stimulus
environment
another neuron
ions
the axon

26. 2. During an impulse, the membrane is ________________(+ inside, -outside) and ________________(-inside, +outside).
a) The reversal of charges is known as an _______________
b) Action potentials move at 150 meters/second.
depolarized
repolarized
action potential

27. C. The Action Potential (______________________)
1. Depolarization (+ inside, - outside)
a) A stimulus causes a gate in the __________________ to open.
b) Because the _________________ of Na+ is
higher __________ the membrane, the sodium flows ________ the cell. (Now the inside becomes more + compared to the outside)
2. Repolarization (-inside, +outside)
a) Depolarization causes the ___________ gate to immediately_________.
b) ______ diffuses _______ of the neuron.
reversal of charges
Na+ channel
concentration
outside
into
K+ channel
open K+
out

28. sodium gates will not open
3. Returning to Resting Potential
a) The _____________ actively (ATP) pumps Na+ ___ of the neuron and K+ ______ the neuron.
b) This ______________ the _________ ion distribution of the __________ neuron.
D. Propagation of the Impulse
1. Nerve impulses are ____________________.
They can occur at any point on the membrane and cause an impulse at the next point (like dominoes)
2. Unlike dominoes, impulses move in ______
__________ only because the membrane behind the impulse has a brief period where the __________________________.
Na+/K+ pump
out
into
reestablishes
initial
resting
self-propagating
one
direction
sodium gates will not open

29. E. Threshold
1. The strength of an ____________ is always the ___________.
Threshold: The ________ level of stimulus that is required to _________ a neuron.
2. The ____________________ principle says that either a stimulus will be strong enough to produce an _________ or it will not.
impulse
same
minimum
activate
all-or-none
impulse

30. An Action Potential
Voltage gated channels & Proteins:

31. III. The synapse (space between neurons)
A. Axons end in
B. Axon terminals contain
C. Axon terminals make contact with
D. Receptors =
E. Effectors =
small swellings called axon terminals
vesicles filled with chemicals called neurotransmitters.
receptors
or effectors in an area called a synapse.
Special sensory neurons in sense organs that receive stimuli from the external environment.
Muscles or glands that bring about a coordinated response

32. Dendrite of adjacent neuron
We know how impulses move down a neuron, but how does the signal travel from one neuron to another?
Figure 35-8 The Synapse
Section 35-2
Direction of Impulse
Dendrite of adjacent neuron
Axon
Receptor
Vesicle
Axon terminal
Synaptic cleft
Neurotransmitter

33. vesicles fuse with the membrane
When an impulse arrives at an axon terminal _______________________________
b. Through exocytosis, _______________________
__________________________________
The neurotransmitters attach to ___________ on the adjacent neuron _____________________________
_____________________.
d. Na+ ions diffuse into the adjacent cell. If threshold is met, depolarization will occur and the impulse will continue.
Once the neurotransmitter is released from the receptor sites, _____________________________________
_______________________________________
________________________
vesicles fuse with the membrane
are released into the synaptic gap/cleft
neurotransmitters
receptors
changing the permeability of the membrane
enzymes break the molecules down or they are reabsorbed by the axon terminals to be recycled.

34. Depolarized & Repolarized Membrane Activity
Direction of Impulse

35. 35-3 Divisions of the Nervous System
Neurons working together forms a complicated communication system known as the Nervous System.
Two major divisions of the Nervous System
Central Nervous System (CNS)
a. _________ messages
b. Processes ____________.
c. Analyzes ____________.
d. Consists of : 1) _______________
Relays
information
information
Brain

36. a) The brain: _____________ flow to the brain and
is where many impulses ______________.
b) Made up of over _________________ neurons.
c) The human brain weighs _____ kilograms.
Impulses
originate
100 billion
1.4

37. 2) The Spinal Cord
a) Main Communication link between the
__________ and the _______________
___________.
b) Carries _______________ of cells at
once.
c) _________ are processed ___________ in the spinal cord.
rest of the
brain
body
thousands
Reflexes
directly

38. 2. Peripheral Nervous System (PNS)
a. contains _______________________
________________________________
b. Includes: _______________________
_______________________
c. Ganglia: ________________________
___________
all the nerves that carry information to and from the CNS
Cranial and spinal nerves and Ganglia
collection of nerve cell bodies

39. The Divisions of the Nervous System
Concept Map
Section 35-3
The Nervous System
is divided into
Central nervous system
Peripheral nervous system
Sensory nerves
Motor nerves
which consists of
that make up
Autonomic nervous system
Somatic nervous system
which is divided into
Sympathetic nervous system
Parasympathetic nervous system

40. Peripheral Nervous System
Divided into two divisions:
Sensory Division:
Motor Division:
Sensory division and motor division
Transmits impulses from sense organs (ie. Eyes, ears, taste buds) to central nervous system
Basically: Sense organs  CNS
Transmits impulses from central nervous system to muscles or glands (effectors)
Basically: CNS  Effectors

41. Motor Division is divided into two systems
_______________________
Regulates
Somatic Nervous System
conscious activities; such as the movement of skeletal muscles
reflexes controlled by sensory neurons, motor neurons, and effectors producing a reflex arc

42. Reflex Arc 3 2 4 5 1 Example: You step on tack-Stimulus
The tack stimulates sensory receptors on the skin
The sensory receptors stimulate a sensory neuron
The sensory neuron sends an impulse to an interneuron in the spinal cord
A response signal is sent to a motor neuron
The motor neuron stimulates an effector which makes you hand pull away 3 2 4 5 1

43. Autonomic Nervous System
2. __________________________
a. regulates
b. The ANS is subdivided into 2 parts that have opposite effects on the organs they control.
1. Sympathetic Nervous System: Fight or Flight
2. Parasympathetic Nervous System: Rest and Digest
Automatic or involuntary activities (ie. Heart, lungs, digestion,etc)

44. Sympathetic Nervous System Parasympathetic Nervous System
Dilates pupil
Constricts pupil
Sympathetic Nervous System
Parasympathetic Nervous System
Stimulates saliva production
Inhibits saliva production
Constricts bronchi
Dilates bronchi
Slows down heart rate
Speeds up heart rate
Stimulates bile production
Stimulates glucose production
Stimulates peristalsis
Inhibits peristalsis
Inhibits urination
Stimulates urination

45. Three General Function of the Nervous System

46. THE END !!!!

47. At rest. Figure 35-7 An Impulse Section 35-2 Action Potential
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
Action Potential
Action Potential
At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs.
The action potential continues to move along the axon in the direction of the nerve impulse.

48. Figure 35-7 An Impulse
Section 35-2
Action Potential
At rest.
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
Action Potential
At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs.
The action potential continues to move along the axon in the direction of the nerve impulse.

49. Figure 35-7 An Impulse
Section 35-2
Action Potential
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
At rest.
Action Potential
The action potential continues to move along the axon in the direction of the nerve impulse.
At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs.

50. Figure 35-7 An Impulse
Section 35-2
Action Potential
As the action potential passes, potassium gates open, allowing K+ ions to flow out.
At rest.
Action Potential
The action potential continues to move along the axon in the direction of the nerve impulse.
At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs.