The+Nervous+System

The nervous system (Kenneth)

The nervous system allows the organism perform quickly actions and to transmit the signal to other body parts to perform the actions. There are two major system in nervous systems which are central nervous systems (CNS) and peripheral nervous system (PNS). The CNS is made up by brain and the spinal cord. And the PNS is ranches of nerves connected to CNS and different systems of the body. The cranial nerves which made up PNS is connected to the brain. Neurons are nerve cells; they carry information as electrical signal or impulse from one place to other body parts. There are 3 types of neurons: S ensory Neurons- carry electrical signals from or sense organs to the CNS.. Motor neurons pass messages from the nervous sstem to other tissues in the body. The cell bodies of motor neurons are inside the CNS. Interneurons they carry information between sensory and motor neurons. They are found in the CNS.

In the neurons there are 3 main parts: cell body: the largest part which contains nucleus and cytoplasm. Dendrites: short branch extensions spreading out from the cell body. And axon: : is a long extension that carries electrical messages away from the cell body and passes them to other cells. The part of the axon through which the impulse leaves that neuron, contains chemical filled vesicles. Before an action potential moves into the next neuron, it crosses a tiny gap between the neurons called synapse, that’s also when neuron that transmit impulses to other neurons do not touch one to another. Chemical signals of the nervous system are called Neurotransmitter. “ Some are made in the cell body while others are made in the neurotransmitter swellings. The impulse is changed from and Electrical Impulse to a Chemical Impulse (Electrochemical Impulses)” (The nervous system). The slowest part of the nervous system is synapses. Nerve impulses are electrical as they run along the nerve. They then become chemical as the travel over the synaptic cleft.

The resting potential tells about what happens when a neuron is at rest. That’s when action potential happen, action potential is the starching causes a change in charge distribution that triggers a moving electrical impulse.

 1. Largest part of the brain 2. Contains about 75% of the total neurons of the brain 3. Divided into 2 halves: The right and left cerebral hemispheres 4. Control: a. voluntary movements b. receiving and interpreting impulses from sense organs c. thinking d. intelligence e. memory f. language g. emotions h. judgment i. personality The right hemisphere controls the left side of the body while the left hemisphere controls the right side of the body. Each hemisphere is specialized for different functions.” (The Nervous System) The left side of the brain is used for: language, mathematics, analysis, logic. And the right side of the brain is for art, music and emotion.

Cerebellum is the part of the brain that coordinates your movements. It is second largest part of the brain, heavily folded, controls muscular coordination, responses involuntary Reflex arc: are nerve pathways that need to cross only two synapses before producing a response. Reflex is the simplest, quickest form of activity in the nervous system. “  Examples of reflex actions are breathing, eye blinking, iris size, and many protective actions such as moving away from a burning flame” (The nervous system).

Works Cited: "The Nervous System." // LEAVING CERTIFICATE BIOLOGY //. Leaving Certificate Biology Course. Web. 15 May 2011. .

Nowicki, Stephen. "Mechanisms of Homeostasis." McDougal Littell Biology. Evanston, IL: McDougal Littell, 2008. 858-61. Print.