Lecture AP Biology Chapter 48 and 49 Nervous systems

1.
2.
3.
4.

Contrast the functions of B cells and T cells.
What are memory cells?
How do vaccines work?
How does HIV affect the immune system?


1.

Draw and label the parts of a neuron.

2.

Describe saltatory conduction.

3.

Explain how a nerve impulse is transmitted
across a neuron.


1.
2.
3.

What happens at the synapse?
Choose 1 neurotransmitter. Describe its action.

What is the role of the following structures in
the human brain?
a) Brainstem
b) Cerebellum
c) Cerebrum
d) Corpus callosum


Chapters 48 & 49
Campbell Biology – 9th ed.


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The anatomy of a neuron.
The mechanisms of impulse transmission in
a neuron.
The process that leads to release of
neurotransmitters, and what happens at the
synapse.
How the vertebrate brain integrates
information, which leads to an appropriate
response.
Different regions of the brain have different
functions.

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Central nervous system (CNS) = brain + spinal
cord
Peripheral nervous system (PNS) = nerves
throughout body
 Sensory receptors: collect info
 Sensory neurons: body  CNS
 Motor neurons: CNS  body (muscles, glands)
 Interneurons: connect sensory & motor neurons
Nerves = bundles of neurons
 Contains motor neurons +/or sensory neurons





Peripheral
nervous system

Somatic
nervous
system

Autonomic
nervous

system

Sympathetic
division

Parasympathetic
division

Enteric
division




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cell body: contains nucleus & organelles
dendrites: receive incoming messages
axons: transmit messages away to other cells
myelin sheath: fatty insulation covering axon,
speeds up nerve impulses
synapse: junction between 2 neurons
neurotransmitter: chemical messengers sent
across synapse

Glia: cells that support neurons
 Eg. Schwann cells (forms myelin sheath)




Microelectrode
–70 mV

Voltage
recorder
Reference
electrode


The Na+/K+ pump (using ATP) maintains a
negative potential inside the neuron.


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Resting potential: membrane potential at rest; polarized
 ↑Na+ outside, ↑K+ inside cell
 Voltage-gated Na+ channel = CLOSED
Nerve impulse: stimulus causes a change in membrane
potential
 Action potential: neuron membrane depolarizes
 All-or-nothing response

Na+ channels
open

Na enters cell
+

K+ channels
open

K+ leaves cell





Saltatory conduction speed: 120 m/sec




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Chemicals released from vesicles by exocytosis into
synaptic cleft
Diffuse across synapse

Bind to receptors on neurons, muscle cells, or gland
cells
Broken down by enzymes or taken back up into
surrounding cells
Types of neurotransmitters:
 Excitatory: speed up impulses by causing depolarization
of postsynaptic membrane
 Inhibitory: slow impulses by causing hyperpolarization of
postsynaptic membrane