Nervous System  Consists of the brain, spinal cord, and a complex network of neurons.  Responsible for sending, receiving, and interpreting information from all parts of the body.  Monitors and coordinates internal organ function and responds to changes in the external environment.

The Structure of the Nervous System  The nervous system is divided into two different parts.  The Central Nervous System  The Peripheral Nervous System

Diagram of the Nervous System

Central Nervous System  Brain & spinal cord  Brain – brain is divided into three segments:  forebrain  midbrain  hind brain  Spinal cord  association of neuron is found.  neuron composes the majority of the spinal cord  serves as an interpretation center

Peripheral Nervous System  Cranial and peripheral nerves Somatic nervous system  Voluntary movements  Consists of peripheral nerve fibers that send sensory information to the central nervous system Autonomic nervous system  Involuntary movements  Consists of sensory neurons and motor neurons that run between the central nervous system

Afferent & Efferent Nerves  afferent nerve ~ a nerve conducting impulses from receptors inwards, toward or to the central nervous system (brain or spinal cord). afferent nerve  efferent nerve ~ a nerve conducting impulses outwards, toward or to muscles or glands. efferent nerve

A. Afferent neuron B. Efferent neuron C. Interneuron

Somatic and Autonomic Nervous system  Somatic –controls skeletal muscle and external sensory organs such as the skin.  Autonomic –controls involuntary muscles, such as smooth and cardiac muscle. –divided into the parasympathetic and sympathetic divisions.

Sympathetic and Parasympathetic  Sympathetic –allow body to function under stress –fight or flight –speed up heart rate, dilate pupils, and relax the bladder.  Parasympathetic –controls various functions –feed or breed or rest and repose –constant opposition to sympathetic system

References Chudler, E. H. (2006). Division of nerve system. In Neuroscience for kids [Fact Sheet]. Retrieved February 3, 2010, from Eferent neuron. (2010). The free dictionary [Facts Sheet]. Retrieved February 3, 2010, from Efferent neuron. (2010). The free dictionary [Fact Sheet]. Retrieved February 3, 2010, from Farabee, M. (2007, June 6). Nervous system. In Emc.maricopa [Fact Sheet]. Retrieved February 3, 2010, from The nervous system. (2006). Neuroscience fo kid [Fact Sheet]. Retrieved February 11, 2010, from Nervous system. (2010). About [Fact Sheet]. Retrieved February 3, 2010, from

Next Presentation I have no idea why, but if you click on their slides the words will appear.

Neurons By: Abby DiSabato Brock Gaus George Hess

Dendrites Treelike extensions at the beginning of a neuron that help increase the surface area of the cell body and are covered with synapses. These tiny protrusions receive information from other neurons and transmit electrical stimulation to the soma. Characteristics –Most neurons have many dendrites –Short and highly branched –Transmits information to the cell body –SIGNAL RECEIVERS!!

Axon a long fiber of a nerve ( a neuron) that acts somewhat like a fiber- optic cable carrying outgoing messages Each nerve cell has ONE axon An axon can be 20 cm. in length The neuron sends electrical impulses from its cell body through the axon to target cells

Initial segment Between the axon hillock and the axon is the initial segment of the axon It is where the axon is bare—not yet myelinated

Axon Hillock is located at the end of the soma and it controls the firing of the neuron. When the strength of the signal exceeds the axon hillock, the structure will fire a signal down the axon.

Soma Is where the signals from the dendrites are joined and passed on. Serves to maintain the cell Serves to keep the neuron functional Contains a nucleus Supports the production of the neurotransmitters

Telodendria Terminal branches of an axon and makes contact with other neurons at synapses Found at synaptic cleft Axon ends by dividing into several branches making the telodendria Contains and produces neurotransmitters

Synaptic terminal A bulb at the end of a axon and telodendria in which neurotransmitter molecules are stored and released Refers to the junction between cell membranes of two communicating neurons Electron charges jump between the gap (presynaptic neuron and past synaptic neuron)

Works cited axon hillock. (2010). In Encyclopædia Britannica. Retrieved February 04, 2010, from Encyclopædia Britannica Online: Boeree, G. C., GB. (n.d.). general psycholosy. Retrieved from Wagner, K. V., KW. (n.d.). About: Psychology. Retrieved from williams college. (1998 ). Calcium Influx: Initation of Neurotransmitter Release. In Williams edu. Retrieved from williams college website:

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Small No clues to difference of dendrites and axons All processes look alike In brain and special sense organs

2 distinct processes One dendrite process On axon with the cell body between them Very rare Occur in special sense organs Relay info about sight, smell or hearing Largest are 30 mm in length from end to end

They are nerve cells. Neurons that are activated by sensory input (vision, touch, hearing, etc.), and send projections into the central nervous system that convey sensory information to the brain or spinal cord.

classically applies to neurons located in the central nervous system (or CNS) that project their axons outside the CNS and directly or indirectly control muscles.

Inervate muscle fibers located throughout the muscle. Cell bodies are in the ventral horn of the spinal cord. Sometimes called the ventral horn cells.

Innervate intrafusal muscle fibers found within the muscle spindle.

Motor neuron. (2009). Science daily. Retrieved February 2, 2010, from otor_neuron.htm Sensory neuron. (2009). Science daily. Retrieved February 3, 2010, from sory_neuron.htm