AP Biology 2007-2008

Nervous System

AP Biology 2007-2008

Where does most absorption occur in the digestive system?  Which structures mechanically break down food?  How to the circulatory system and digestive system work together?

AP Biology

AP Biology

Why do animals need a nervous system?

What characteristics do animals need in a nervous system?

fast accurate reset quickly

Remember…think aboutthe bunny… Poor bunny!

AP Biology

Nervous system cells: The Neuron

dendrites

cell body

axon

synaptic terminal

Structure fits function many entry points

for signal one path out transmits signal

signal direction

signaldirection

dendrite cell body axon

myelin sheathtransmitters

AP Biology

Nervous system cells

dendrites

cell body

axon

synaptic terminal

Neuron a nerve cell

signal direction

signaldirection

dendrite cell body axon

transmitters

Detect Signal

Controls Cell

Transmits Signal Down Cell

Place Where Signal goes to next neuron

•How are the circulatory and respiratory systems related?How does the respiratory system help maintain homeostasis in our body?

Chemicals that Cross the synapse

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Peripheral Nervous System Job: Transmit information from the

sense organs to the central nervous system. “From the outside in”

Structures: All nerves that are not a part of the brain or spinal cord.

Analogy to home heating system: When the temperature drops outside, this is like a signal sent into your heating system

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Central Nervous System Job: Processes and relays information.

Responds to the peripheral nervous system.

Structures: brain, spinal cord

Analogy to home heating system: The heater “responds” to the initial signal by turning on.

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Hypothalamus Job: Control center for recognizing

hunger, thirst, fatigue, body temperature

Structures: inside the central part of the brain

Analogy to home heating system: This is like the thermostat. Controls when the heater turns on or off by recognizing signal from outside (temp)

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Transmission of a signal Think dominoes!

start the signal knock down line of dominoes by tipping 1st one

trigger the signal propagate the signal

do dominoes move down the line? no, just a wave through them!

re-set the system before you can do it again,

have to set up dominoes again reset the axon

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Synapse

Impulse has to jump the synapse! junction between neurons has to jump quickly from one cell

to next

What happens at the end of the axon?

How does the wave

jump the gap?

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axon terminal

synaptic vesicles

muscle cell (fiber)

neurotransmitteracetylcholine (ACh)receptor protein

Ca++

synapse

action potential

Chemical synapse Events at synapse

release neurotransmitter to synapse diffusion

An Electric Signal briefly changes to a chemical signal

We switched…from an electrical signal

to a chemical signal

AP Biology

AP Biology

AP Biology 2007-2008

Ponder this…Any Questions??