Chapter 37 Nervous System

Nervous System-receives and relays information about activities within the body and monitors and responds to internal and external changes http://www.biologymad.com/nervoussystem/nervoussystemintro.htm

Three main functions of the nervous system 1. Sensory Input 2. Integration 3. Motor Output

Three main functions of the nervous system http://cafe.daum.net/beautyskinbody/GY8n/196?docid=16FM2%7CGY8n%7C196%7C20080718134405

Structures of the central Nervous system (CNS) 1. brain 2. spinal nerve cord in vertebrates http://factsabouthumanbodyanditsorgans.blogspot.com/2011/11/central-nervous-system.html

Motor output is the conduction of signals from the CNS to the effector cells such as muscles http://mycozynook.com/102RGCh28OH.htm

How are signals conducted Signals are conducted by nerves Nerves are bundles of neurons which are wrapped in connective tissue

Sensory and motor neurons are collectively called the peripheral nervous system http://generalknowledgeupdates.blogspot.com/2012/10/peripheral-nervous-system.html

Neuron-structural and functional unit of the nervous system http://www.enchantedlearning.com/subjects/anatomy/brain/Neuron.shtml

Four main parts of a neuron 1. Cell body 2. Dendrites 3. Axon (action potential is generated here number 20) 4. Axon terminals

Neuron http://www.enchantedlearning.com/subjects/anatomy/brain/Neuron.shtml

Synapse-The site of contact between a synaptic terminal of a neuron and a target, such as another neuron, a muscle cell, or a gland, is called a http://scienceblogs.com/purepedantry/2007/03/06/neuron-to-glia-synapse-on-axon/

Pre-synaptic cell and post-synaptic cells of a synapse http://www.nature.com/nature/journal/v423/n6943/fig_tab/423931a_F1.html

Reflex arc-the simplest type of nerve circuit Has to be at least one sensory neuron and one motor neuron http://www.docstoc.com/docs/115358232/Reflex-Arc-Reflex-Arc

Ganglia and nuclei Collections of cell bodies of neurons. Ganglia are found in the peripheral nervous system Nuclei are found within the brain.

Schwann Cells Cells that form the insulating sheaths around axons Located outside the Central Nervous System It is made of myelin

http://207.204.17.60/schwann-cell-transplants-human-clinical-trials

Membrane potential All cells have an electrical charge difference across their plasma membrane called the membrane potential It exists because the different concentration of certain ions across the cell membrane The membrane potential of an unstimulated neuron is called the resting membrane potential These ions move across the membrane either by being pumped by membrane proteins or by simple diffusion through ion channels.

Membrane potential http://en.wikipedia.org/wiki/Membrane_potential

Resting membrane potential http://humanbiologylab.pbworks.com/w/page/45302491/Resting%20Cellular%20Membrane%20Potential

All cells have a membrane potential However, only certain cells such as neurons and muscle cells have the ability to generate large changes in their membrane potential These cells are called excitable

Action Potential If a sufficiently strong stimulus causes depolarization to reach “threshold potential” it triggers a different type of response called an action potential http://www.answers.com/topic/action-potential

Two factors that affect the speed at which an action potential travels down an axon The diameter of the axon, the larger the diameter the faster the action potential The presence of myelin around the axon, myelin insulates the axon and allows the action potential to travel quicker

The “motor division” of the peripheral nervous system is divided into two functional divisions, called the somatic and autonomic nervous systems http://ultramindtechniques.blogspot.com/2011/04/know-hardware-iii-nervous-system.html

What do they do? The somatic nervous system carries signals to skeletal muscle The autonomic nervous system carries signals to cardiac muscle, smooth muscle, and glands

http://www.docstoc.com/docs/105365259/Comparison-of-Somatic-and-Autonomic-Systems

Sympathetic and Parasympathetic of the Autonomic nervous system The autonomic nervous system consists of two divisions that act on body organs with opposite affects The Sympathetic Division correlates with an activation of the fight or flight response The Parasympathetic Division causes a calming effect and a return to an emphasis on self-maintenance functions

http://emsbasics.com/2011/03/31/drug-families-stimulants-and-depressants/sympathetic-parasympathetic/