Nervous
Part of a mammals body that coordinates its voluntary and involuntary actions and transmits signals between different parts of the body.
Our bodies nervous system is a combination of several nervous systems that work together to help guide, protect, and control many actions physically and mentally. The nervous system consists of two parts; the first and popular nervous system is the Central Nervous System (CNS).
Autonomic System: A functional components of the PNS that regulates the internal environment of the body by controlling the muscles of the heart and other internal organs and glands; it is not under conscious control.
Parasympathetic Branch: Part of the autonomic nervous system that helps the body do things to gain and conserve energy by stimulating digestive organs and decreasing heart rate and breathing rate.
Sympathetic Branch: Part of the autonomic nervous system that prepares the body for intense action by diverting "nonessential" expenditures and increasing heart rate and breathing rate (Green, Bozzone 387-389).
- The central nervous system controls the actions of the body; compromised of the brain and spinal cord. Together the brain and spinal cord; a bundle of nerve fibers in our backbone that serves as the communication pathway between the brain and the rest of the body, create the central nervous system. Nerves are a bundle of neurons wrapped together to form "cables". The spinal cord carries sensory information from the body-touch, pain, and body position, for example-to the brain. The spinal cord also relays motor information from the brain to muscles, organs, and glands. A special population of cells called interneurons integrates the incoming and outgoing signals so that the body responds appropriately to stimuli. The spinal cord is also responsible for reflexes, movements in response to stimulus. These can simple or complex, but specific ones are always identical. They are also fast because they bypass the brain.
- The second nervous system is the Peripheral Nervous System (PNS). The peripheral nervous system is a network of nerves radiating out from the CNS and throughout the body that enables the brain and spinal cord to communicate with the entire body. This is because the brain and the spinal cord need to communicate with the entire body. PNS is physically connected to the CNS by cranial nerves that attach to the brain and spinal nerves that snake out from the spinal cord through the spaces between the bones of the spine. The cranial and spinal nerves branch out and connect to other nerves that connect to other nerves, and so on throughout the body. Responsible for perceiving and carrying signals, the PNS is divided into functional components: somatic and autonomic.
Autonomic System: A functional components of the PNS that regulates the internal environment of the body by controlling the muscles of the heart and other internal organs and glands; it is not under conscious control.
Parasympathetic Branch: Part of the autonomic nervous system that helps the body do things to gain and conserve energy by stimulating digestive organs and decreasing heart rate and breathing rate.
Sympathetic Branch: Part of the autonomic nervous system that prepares the body for intense action by diverting "nonessential" expenditures and increasing heart rate and breathing rate (Green, Bozzone 387-389).
The Brain:
Forebrain: Regulates the body's physiology and is also responsible for thought and sense perception.
Midbrain: Coordinates responses to light and sound.
Hindbrain: Located at the base of the skull, right above the spinal cord, and responsible of many basic bodily Controls many basic bodily functions necessary for survival; composed of the Medulla oblongata, Cerebellum, and Pons.
Brainstem: Comprised of the medulla oblongata, the pons, and the midbrain; all information moving to and from other regions of the brain passes through this area.
Cerebrum: The largest and most sophisticated component of the forebrain, accounting for 80-85 percent of brain mass in humans; responsible for many of the characteristics that most people consider distinctly human: reasoning, mathematical, ability, artistic ability, imagination, language, and personality.
Frontal Lobe: Responsible for the ability to speak, smell, and problem-solve.
Temporal Lobe: Responsible for perception and processing of information from eyes and ears.
Parietal Lobe: Responsible for perception and processing of physical touch.
Occipital Lobe: Responsible for perception and processing of information from the eyes.
Forebrain: Regulates the body's physiology and is also responsible for thought and sense perception.
Midbrain: Coordinates responses to light and sound.
Hindbrain: Located at the base of the skull, right above the spinal cord, and responsible of many basic bodily Controls many basic bodily functions necessary for survival; composed of the Medulla oblongata, Cerebellum, and Pons.
Brainstem: Comprised of the medulla oblongata, the pons, and the midbrain; all information moving to and from other regions of the brain passes through this area.
Cerebrum: The largest and most sophisticated component of the forebrain, accounting for 80-85 percent of brain mass in humans; responsible for many of the characteristics that most people consider distinctly human: reasoning, mathematical, ability, artistic ability, imagination, language, and personality.
Frontal Lobe: Responsible for the ability to speak, smell, and problem-solve.
Temporal Lobe: Responsible for perception and processing of information from eyes and ears.
Parietal Lobe: Responsible for perception and processing of physical touch.
Occipital Lobe: Responsible for perception and processing of information from the eyes.
Responsible for the communication between the nervous system is the neuron; which is a specialized signaling cell in the nervous system. The brain has more than 10 billion neurons, and the nervous system has even more. The neuron, a nerve cell, is the functional unit of the nervous system that carries the impulse (the message) to the appropriate part of the nervous system or interprets the impulse and allows a response. There are three types of neurons and each has different functions.
- Sensory neurons: Receive impulses and carry them from the sense organs to the spinal cord or brain.
- Interneurons: Connect sensory and motor neurons and interpret the impulse; only in the brain and spinal cord.
- Motor neurons: Carry impulses from the brain and spinal cord to muscles or glands.
- When a stimulus is received by a sensory neurons, the impulse (or message) is carried through fibrous extensions called dendrites to the cell body. The cell body is made up of cytoplasm, cytoplasmic structures, and a nucleus, which controls neuron function. The impulse travels through the cell body and is carried through the axon to the end brush, a collection of fibers that extend off the axon. Here, the impulse triggers a release of chemicals that allow the impulse to travel through the synapse—the space between the axon of one neuron and the dendrites of the next.
- An impulse travels along the neuron pathways as electrical charges move across each neural cell membrane. Ions moving across the membrane cause the impulse to move along the nerve cells.
- An impulse begins when a neuron is stimulated by another neuron or by a stimulus in the environment. The cell membranes begin to change the flow of ions and a reversal of charges, the action potential, results. An impulse that changes one neuron, changes the next. The impulse movement continues along the pathway in this way.
- An impulse can travel quickly through the nervous system. Many vertebrates’ neurons, including humans, have several features that allow for maximum reactivity. Vertebrate axons have a myelin sheath that allows for faster travel of the impulse. Nodes on the axons also allow impulses to jump from node to node instead of traveling through the entire axon. This also allows for faster response. The more quickly an organism can respond, the better adapted it is to its environment (CyberSurgeons).
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To compare a mammal to a non-mammalian we will use a Daddy long leg spider.
Refere to button for the nervous system of a spider.
Refere to button for the nervous system of a spider.
References:
FitzGordon , Jonathan . "Divisions of the Nervous System." CoreWalking Blog. Core Walking , n.d. Web. 27 May 2014
"The Nervous System ." CyberSurgeons. CyberSurgeons , n.d. Web. 27 May 2014.
"linsenbardt.net." linsenbardtnet. N.p., n.d. Web. 27 May 2014.
"Daddy Long-Legs Spiders." Daddy Long-Legs Spider (Harvestman) – Are Daddy Long Legs Poisonous?. N.p., n.d. Web. 27 May 2014
"Nervous and Sensory Systems of Spiders." The Find-a-spider Guide. N.p., n.d. Web. 27 May 2014
FitzGordon , Jonathan . "Divisions of the Nervous System." CoreWalking Blog. Core Walking , n.d. Web. 27 May 2014
"The Nervous System ." CyberSurgeons. CyberSurgeons , n.d. Web. 27 May 2014.
"linsenbardt.net." linsenbardtnet. N.p., n.d. Web. 27 May 2014.
"Daddy Long-Legs Spiders." Daddy Long-Legs Spider (Harvestman) – Are Daddy Long Legs Poisonous?. N.p., n.d. Web. 27 May 2014
"Nervous and Sensory Systems of Spiders." The Find-a-spider Guide. N.p., n.d. Web. 27 May 2014