basic tasks of the nervous system sensation: monitor both external and internal environments....

Basic Tasks of the Nervous System

Sensation: Monitor both external and internal environments.

Integration: Process the information and often integrate it with stored sensory information.

Regulation and Control: If necessary, signal effector organs to make an appropriate response.

Coordination: of both voluntary and involuntary muscle movements

• Brain

WHAT PARTS DO YOU KNOW THAT ARE IN THE NERVOUS SYSTEM?

• Spinal Cord

• Peripheral Nerves

Structure of a Vertebrate Neuron

Myelinated Neurons

• Many vertebrate peripheral neurons have an insulating sheath around the axon called myelin which is formed by Schwann cells.

• Myelin sheathing allows these neurons to conduct nerve impulses faster than in non-myelinated neurons.

How are neurons connected?

• Synapses!!

Why are neurons connected?

AXON

The synapse - where the action happens

The next cell’s plasma membrane

What is this in the membrane?

Transport protein

Close up look at your synapse

How does the Synapse carry the signal?

1. Action potential travels down the axon until it reaches the synapse. The action potential will NOT move across the synapse.

2. Vesicles with neurotransmitters move toward the membrane3. Chemicals are released into the synaptic cleft and diffuse

toward the next cell’s plasma membrane4. The chemicals open up the transport proteins and allow the

signal to pass to the next cell

Saltatory Conduction in Myelinated Axons

Myelin sheathing has bare patches of axon called nodes of Ranvier

Action potentials jump from node to node

Fig. 48.11

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23 4

The synapse carries a signal from cell to cell

REFERENCES• http://faculty.washington.edu/chudler/facts.html• http://occawlonline.pearsoned.com/bookbind/pubbooks/campbell6e_awl/chapt

er0/deluxe.html• JOSHSANESPPT.PPT• www.alfamilyties.org/presentations/The%20Neurobiology%20of%

20Adolescent%20Substance%20Abuse%20II.ppt• http://www.nsbri.org/Education/High_Act.html• http://www.pfizer.com/brain/teachers_html.html• http://www.research.buffalo.edu/quarterly/vol10/num01/n1.shtml• http://www.aim-digest.com/gateway/pages/brain/articles/myths.htm• http://www.nida.nih.gov/pubs/teaching/Teaching5/Teaching3.html• http://www.accessexcellence.com/AE/• http://psych.colorado.edu/~kenth/Image14.gif

• Cell body: functional portion

• Dendrites: short extensions that receive signals

• Axon: long extension that transmits impulses away

Nerve Impulse - The Action PotentialThreshold potential will trigger an action potential or nerve impulse

The action potential is an all-or-none response

Conduction VelocityConduction Velocity

Types of chemical synapse

• Cholinergic Synapses– Acetylcholine– neuromuscular junctions, glands, brain and spinal cord

• Adrenergic ( EPSP)– Norepinepherine– affects brain regions concerned with emotions,

dreaming• Dopamine ( IPSP)

– Inhibits neurotranmission of the nerve impulses

Dura mater is being peeled away in this photo.

Fluid filled cavities, contain CSF

  10.VENTRICLES OF THE BRAIN

CEREBRUM - wrinkly large part of the brain, largest area in humans, higher mental function

1.  Cerebral Hemispheres    -  left and right side separated by the ....

2.  Corpus Callosum  -  connects the two hemispheres 

Corpus callosum

DiencephalonDiencephalon

CEREBELLUM

• Balance and coordination

Brain Stem -   regulates visceral functions (autonomic system)

Figure 13.4

The Cerebral Hemispheres

Figure 13.7b, c

Take the Left Brain – Right Brain Test

3.  Convolutions of the Brain  - the wrinkles

and grooves of the cerebrum

Fissures = deep groove

Sulcus = shallow groove

Gyrus = bump

4.  Fissures – separate lobes

Longitudinal fissure - separate right and left sides

Transverse Fissure - separates cerebrum from cerebellum

Figure 13.7a

LOBES OF THE BRAIN (CEREBRUM)

Sulcus = grooveGyrus = raised bump

Fissure = deep groove