Cns and pns comparison essay. Cns and pns comparison essay. 4 stars based on Christianity judaism islam comparison essay thesis the curious incident of the dog in the nighttime theme essay new humanist literary criticism essay what motivates you to do well in school essay alain soral et michel collon essayiste i love moldova essay healthy. The sympathetic nervous system (SNS) turns on the fight or flight response and in contrast, the parasympathetic nervous system (PNS) promotes the relaxation response. The SNS and PNS carefully maintain metabolic equilibrium by making adjustments whenever something disturbs this balance. Relationship and Differences Between the Central and Peripheral Nervous System Essay. B. Pages Words This is just a sample. To get a unique essay. We will write a custom sample essay on Relationship and Differences Between the Central and Peripheral Nervous System specifically for you for only $ $/page. [tags: Central and Peripheral nervous system] Good Essays words ( pages) Essay on Overview of the Trigeminal Nerve - Trigeminal nerve is among the twelve pairs of cranial nerves and is the principle sensory nerve of the head. Cranial nerves . The Peripheral NS consists of the "sensory and motor neurons that connect the Central NS to the rest of the body". It consists of two components, the Somatic nervous system, which controls the movements of our skeletal muscles and the Automatic nervous system, which controls the glands and muscles of .
- Relationship and Differences Between the Central and Peripheral Nervous System Essay
- Cns and pns comparison essay
- Difference Between CNS and PNS
Hire Writer This essay first explains the structure and interaction of these neurons, outlining the different types, their functions and the chemical processes that occur between them. It will then cover the structure and functions of both the central and peripheral nervous systems and the interaction between the two, followed by an example illustrating the differences between them, focusing on the processes which would occur during the course of a hypothetical event.
In its entirety this essay will highlight the key differences between the central and peripheral nervous systems, and how they work together harmoniously to provide us with our total experience of the world as we know it. It is incredible to imagine that each unique event that we experience in the course of our day begins with something so tiny as a cell.
These microscopic structures reside within us at a population of billons and together transmit important information around the body. These cells primarily fall into two categories: Most neurons are made up of a cell body or soma , an axon which sends messages away from the cell body, and dendrites which receive messages from other cells and send them towards the cell body.
Connected to the axon are terminal buttons, which form synapses with other neurons or their dendrites, and are the vesicles which release chemicals called neurotransmitters. These neurotransmitters, once released and transmitted to the receiving cell will, depending on the type of chemical released, have either an excitatory effect on the receiving cell, causing it to fire, or an inhibitory effect, causing it to stop firing.
In the Central Nervous System CNS , which consists of the brain and the spinal cord the primary excitatory neurotransmitter is glutamate; when this is secreted by the terminal buttons of one cell and taken up by another it causes the threshold of excitation to lower in the receiving cell, thus rendering it more likely to fire.
In contrast the major inhibitory neurotransmitter in the CNS is gamma-aminobutyric acid GABA , which raises the threshold of excitation on the receiving cell, rendering it less likely to fire. In the Peripheral Nervous System PNS; the network of nerves which lie outside of the CNS and relay information to and from the CNS however, there are only two neurotransmitters; norepinephrine also known as noradrenalin , and the major excitatory neurotransmitter; acetylcholine.
The other types of cells are glial cells. These are supporting cells which perform important functions which assist neurons in performing at their best. There are three different types of glial cells in the CNS: Oligodendrocytes perform the important function of wrapping axons in myelin sheaths, which is a form of insulation that protects the axon from damage and prevents electrical signals from being picked up by nearby axons accidentally.
One oligodendrocyte can produce up to fifty segments of myelin Carlson, In the PNS, this function is performed by Schwann cells, which differ from oligodentrocytes in that Schwann cells can only produce one segment of myelin, as the entire cell is involved in the creation of the myelin segment.
Astrocytes are star shaped cells, and their job is to regulate the chemical environment in which neurons reside by providing support and nourishment for neurons.
Together, these cells form the bulk of the human brain, and the neurons and their axons create the effect of what we know as grey and white matter — effectively what the brain looks like through the human eye. Above that is the subarachnoid space which is a cavity that lies between the pia mater and the arachnoid mater, and serves as a channel for the cerebrospinal fluid.
Relationship and Differences Between the Central and Peripheral Nervous System Essay
The arachnoid mater is called such because of its web-like appearance. The PNS however, is only protected by two layers of meninges; the pia mater and the dura mater. The arachnoid mater and cerebrospinal fluid do not surround the PNS. Beneath the skull, inside of these three protective layers is the brain, its delicate outer tissue protected by their embrace, which is lucky for human beings, as the brain has evolved over hundreds of millions of years Baars and Gage, The brain itself is divided into three major sections; the hindbrain, the midbrain, and the forebrain.
The hindbrain is the earliest developed part of the brain, and includes the cerebellum, which is responsible for coordinated movements, the pons, which plays a part in sleep functions, and the medulla oblongata, which is involved in the control of the respiration and the cardiovascular system.
Rostral to the hindbrain is the midbrain, which consists of the tectum, whose main structures are the superior and inferior colliculi which are part of the visual and auditory systems respectively Carlson, These colliculi play a part in visual reflexes, such as when the eye is reflexively drawn towards a moving stimulus in the peripheral vision. The other major structure of the midbrain is the tegmentum which consists largely of part of the reticular formation, which plays a role in movement, sleep, arousal, and vital reflexes.
The tegmentum is also involved in species-typical behaviours such as mating and fighting Carlson, The midbrain plays a major and vital role in reactive movements and survival instincts Squire, et al. Together, the hindbrain and the midbrain constitute what is known as the brainstem. The remainder and largest area of the brain is the forebrain. This consists of the cerebral cortex, the basal ganglia, the thalamus, and the hypothalamus and the limbic system.
The cerebral cortex is responsible for sensory and motor functions, and everything in between; perception, learning and memory, planning and action Carlson, ; and is divided into four sections; the frontal, parietal, temporal and occipital lobes.
The basal ganglia are involved in the control of movement.
The thalamus is an important structure in the brain, Baars and Gage call it the second most important structure after the cortex, due to the fact that it is a gateway to the sensory cortex, and is the structure that relays most neural input to the cortex Carlson, These regions are the amygdala, hippocampus, and parts of the hypothalamus.
The hippocampus is involved in spatial navigation and episodic learning and recall, and the hypothalamus is the control centre for the autonomic nervous system, which is a major part of the Peripheral nervous system.
Cns and pns comparison essay
The spinal cord is the part of the CNS which extends down from the brainstem through the middle of the spinal column and connects much of the PNS to the brain. Its major function is to send motor information to the organs and limbs, and receive sensory information to send to the brain.
It does this through the use of spinal or roots, which are bundles of axons which protrude from the spinal cord and out via nerves through the body to various muscles and glands. Ventral roots send information from the brain to the rest of the body via ventral nerves, dorsal roots receive information from the PNS via dorsal nerves and send it to the brain. The peripheral nervous system is divided by two major functions; the somatic nervous system and the autonomic nervous system.
It receives sensory information from the body and sends it to the brain via dorsal nerves; all of this information is carried to the spinal column via unipolar neurons in the dorsal root. The neurons in the ventral root are all multipolar and carry information from the brain to muscles and glands.
The somatic nervous system also consists of twelve pairs of cranial nerves that carry mostly sensory and motor information from the head Carlson, , and consist of unipolar and bipolar neurons. The autonomic nervous system governs subconscious movement and reactions, and is split into the sympathetic nervous system and the parasympathetic nervous system.
These bodily reactions are described in greater detail in the example later in the essay, as are the functions of the parasympathetic nervous system, which is responsible for returning our body to a relaxed and resting state. There are two paths involved in the response: Both processes are happening simultaneously. It could also be, as ancient humans learned, a jaguar that wants her as a meal. It is far less dangerous to Sally for her brain to assume the stimulus is a jaguar and have it turn out to be her sister, than to assume it is her sister and have it turn out to be a jaguar.
The low road shoots first and asks questions later. The process looks like this: Jodie jumping out from behind the doorframe and shouting is the stimulus. As soon as Sally hears the sound and sees the motion, her brain sends this sensory data to the thalamus via the cranial nerves. The amygdala receives the neural impulses and takes action to protect Sally: The sympathetic nervous system uses nerve pathways to initiate reactions in the body, and the adrenal-cortical system uses the bloodstream.
Difference Between CNS and PNS
When the hypothalamus tells the sympathetic nervous system to kick into gear, the overall effect is that the body speeds up, tenses up and becomes generally very alert.
If there is a jaguar coming at Sally, she is going to have to take action — and fast. The sympathetic nervous system sends out impulses to glands and smooth muscles and tells the adrenal medulla to release epinephrine adrenaline and norepinephrine noradrenaline into the bloodstream Franks, At the same time, the hypothalamus releases corticotropin-releasing hormone CRH into the pituitary gland, activating the adrenal-cortical system Squire, The pituitary gland a major endocrine gland secretes the hormone ACTH adrenocorticotropic hormone.
The sudden flood of epinephrine, norepinephrine and dozens of other hormones cause changes in the body that include: The sensory cortex determines that there is more than one possible interpretation of the data and passes it along to the hippocampus to establish context.
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