This system connects the central nervous system (CNS) tosensory organs (such as the eye and ear), other organs of the body, muscles, blood vessels and glands. The peripheral nerves include the 12 cranial nerves, the spinal nerves and roots, and what are called the autonomic nerves that areconcerned specifically with the regulation of the heart muscle, the muscles in blood vessel walls, and glands. 7)
An nerve impulse that refers to pathwaysleading to the cortex (ie, sensory) and a nerve impulse where the pathways are leading away (ie, motor).
What is the difference between afferent and efferent nerve impulses?
the part of the pns that is responsible for carrying motor and sensory information both to and from the cns. This system is made up of nerves that connect to the skin, sensory organs and all skeletal muscles. The system isresponsible for nearly all voluntary muscle movements aswell as for processing sensory information that arrives via external stimuli including hearing, touch and sight. 3)
The part of the peripheral nervous system and it controls many organs and muscles within the body. This is most important in two situations:In emergencies that cause stress and require us to "fight" or take "flight" (run away) In nonemergencies that allow us to "rest" and "digest." 4)
Astrocytes- Astrocytes are star shaped glial cells because of cytoplasmic processes that extend from the cell body. they play a role in regulating the extracellular composition of brain fluid. They release chemicals that promote the formation of tight junctions between the endothelial cells of capillaries. (type of Glia) Oligodendrocytes-The principle function of oligodendrocytes is to provide support to axons and to produce the Myelin sheath, which insulates axons. (type of glia) Microglia- Small nonneural cells forming part of the supporting structure of the central nervous system. They are migratory and act as phagocytes to waste products of nerve tissue. (type of glia) Ependymal cells- Ependymal cells are the cells which line the ventricles of the brain. 1)
What cells does the central nervous system consist of?
(2 other types and functions of Glia)- Schwann cells-Schwann cells are the supporting cells of the PNS- Satellite cells-Any of the cells that envelop the bodies of neurons in the peripheral nervous system.
Bipolar neurons have two processes extending from the cell body (examples: retinal cells, olfactory epithelium cells). Pseudounipolar cells (example: dorsal root ganglion cells). Actually, these cells have 2Detailed image of axons rather than an axon and dendrite. OneNeuron below: axon extends centrally toward the spinal cord; the other axon extends toward the skin or muscle. Multipolar neurons have many processes that extend from the cell body. However, each neuron has only one axon (examples: spinal motor neurons, pyramidal neurons, Purkinje cells).
Functions: Sensory neurons carry signals from the outer parts of your body (periphery) into the central nervous system. Motor neurons (motoneurons) carry signals from the central nervous system to the outer parts (muscles, skin, glands) of your body. Receptors sense the environment (chemicals, light, sound, touch) and encode this information into electrochemical messages that are transmitted by sensory neurons. Interneurons connect various neurons within the brain and spinal cord.1)
What are the functions ofthe groups of neurons?
Also known as transmembrane potential or membrane voltage, this is the difference inelectrical potential between the interior and theexterior of a biological cell. Typical values range from –40 mV to –80 mV.
Na+ is critical for the action potential in nerve cells. Action potentials are repeatedly initiated as the extracellularconcentration of Na+ is modified. As the concentration ofsodium in the extracellular solution is reduced, the action potentials become smaller. 6)
What is a mechanism that produces the action potential?
The pairing of homologouschromosomes during the meiotic phase of cell division.
Table 1 (voluntary) Kick Kick 2 Kick 3 Kick 4 Kick 5 Average 1Time of 5.84s 10.55s 15.17s 20.37s 25.31sMuscleConstraction(s)Time of 5.41s 10.24s 14.37s 19.78s 24.73sStimulus (s)Change of .43s .31s .8s .59s .58s .54stime (s)
Table 2 (involuntary) Reflex 1 Reflex 2 Reflex 3 Reflex 4 Reflex 5 AverageTime of 2.18s 6.75s 10.91s 19.3s 24.35sMuscleConstraction(s)Time of 2.14s 6.64s 10.85s 19.28s 24.34sStimulus (s)Change of .04s .08s .06s .2s .1s .096stime (s)
Table 3 Reflex without Reflex with reinforcement reinforcementReflex Max (mV) Min (mV) Change Max (mV) Min (mV) Change ofresponse of mV mV1 1.527 .728 .799 1.411 .86 .5512 1.421 .832 .589 1.156 .874 .2823 1.850 .786 1.064 1.473 .837 .6364 1.751 .778 .973 1.666 .865 .8015 1.672 .828 .844 1.532 .827 .705Average .8538 .595
Data Analysis• There was a significant difference between the voluntary and involuntary reaction times. The average voluntary reaction time took a longer time than the involuntary reaction time. The reason this for what was observed is because the when the body responds to stimuli it takes a lot less than a fraction of a millisecond to go from the area of the body (using receptors) that is being effected to go up to the brain to decipher (using sensory nerves) the electrochemical messages and send the information back (using motor neurons) to act on that change of state of the body.