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 membrane 3.Chemicals are released into the synaptic cleft and diffuse toward the next cell’s plasma membrane 4.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

The synapse carries a signal from cell to cell

REFERENCES er0/deluxe.html er0/deluxe.html JOSHSANESPPT.PPT scent%20Substance%20Abuse%20II.pptwww.alfamilyties.org/presentations/The%20Neurobiology%20of%20Adole scent%20Substance%20Abuse%20II.ppt

Cell body: functional portion Dendrites: short extensions that receive signals Axon: long extension that transmits impulses away

Nerve Impulse - The Action Potential Threshold potential will trigger an action potential or nerve impulse The action potential is an all-or- none response

Conduction 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 Corpus Callosum - connects the two hemispheres

Corpus callosum

Diencephalon

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 = groove Gyrus = raised bump Fissure = deep groove