Analysing Nerves And The Nervous System Biology Essay

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1. Neurons and neurolgia are the main types of cells in the nervous system. The neuron is the nerve cell and is also referred to as the functional unit. The function of the neuron is to transmit the impulses of the nervous system. The neuron contains three parts: one axon, one or more dendrites, and a cell body. A axon is a slim projection that extends from the cell body. The dendrites are similar to tiny trees, that branch off the cell body. They make impulses toward the cell body, unlike the axon that conducts impulses away from the cell body. The nucleus and cytoplasm are in the cell body. The neurolgia is a connective tissue that is a support system for the neurons. Phagocytosis is how the neurolgia protects the nervous system, they engulf and digest any unwanted substances. Astrocytes, microglia, and oligodendrocytes are the three types of cells in the neuroglia. The largest and numerous of the neuroglia cells are the astrocytes. They have many processes for attachment and are considered star-shaped. Microglia are phagocytic and deluge cellular debris, waste products, and pathogens in the nerve tissue. They are small and have skinny branched processes stemming out of their bodies. They help when there is an injury or infection, the cells increase and move towards the damaged or infected area. Smaller than astrocytes and not as many processes are the oligondendrocytes. They form the protective myelin sheath that covers the axons by fanning out from the cell body and clatter the axons. These are the structures and functions of neurons and neurolgia which are the main cells of the nervous system.

2. Nerves are cordlike bundles of nerve fibers that transmits impulses to and from the brain and spinal cord to other parts of the body. The peripheral nervous system, also known as PNS, contains nerves and ganglia. Ganglia are knotlike masses of nerve cell bodies. The PNS has thirty-one pairs of spinal nerves and twelve pairs of cranial nerves. The function of the PNS is to transmit motor and sensory impulses back and forth from the CNS to the rest of the body. The PNS can be broken down into the somatic and autonomic nervous system. The somatic nervous system (SNS) is the voluntary control over skeletal muscle contractions and the autonomic nervous system is the involuntary control over cardiac and smooth muscle and glandular activity and secretions in response to the commands of the central nervous system. These are the functions and structures of the peripheral nervous system.

3. The brain and the spinal cord are in the central nervous system (CNS). The CNS processes and stores sensory and motor information and controls consciousness. Bone surrounds the spinal cord and the brain for protection. The cranium surrounds the brain and the vertebrae of the spinal column surrounds the spinal cord. Not only do they get covered by bones but also meninges, which are three layers of protective membranes. Dura mater is the outermost layer and it’s a strong white connective tissue. Below the dura mater is the subdural space which is a cavity filled with serous fluid. The epidural space is outside the dura mater. Cushion from fat and other connective tissue are in the epidural space. The arachnoid membrane is the middle layer of the meninges. This membrane is similar to a spider web because it has a slim layer with many threadlike strands that connect to the innermost layer (pia mater). Below the arachnoid membrane is the subarachnoid space. This space consists of cerebrospinal fluid which serves as a shock absorber. This fluid gives some nutritious substances to the CNS by the proteins, glucose, urea, salts, and white blood cells that it holds. Afferent and efferent nerves both carry impulses, but the afferent carries them from the body to the CNS, where as the efferent nerve carries them from the CNS to glands and muscles. The brain and the spinal cord are the two primary components of the CNS and it cannot be denied that it is complex in structure and function.

4. The largest organ in a body is the brain. The brain divides into four divisions: the cerebrum, the cerebellum, the diencephalon, and the brain stem. The uppermost portion and largest part is the cerebrum. Consciousness, memory, sensations, emotions, and voluntary movements is what the cerebrum controls. Cerebral cortex is the surface of the cerebrum and has convolutions or elevations, which are called gyri. Gyri are separated by grooves (sulci). The cerebrum is also divided into two hemispheres by a longitudinal fissure: the right and left cerebral hemisphere. Cerebellum attaches to the brain stem. It maintains muscle tone and coordinates balance and movement. Between the cerebrum and the midbrain is the diencephalon. The thalamus hypothalamus, and the pineal gland are a few structures of the diencephalon. The brain stem is between the diecephalon and the spinal cord. The midbrain, pons, and medulla oblongata are apart of the brain stem. The brain stem controls respiration, blood pressure and heart rate. These are the structures and the functions of the brain and if it were not for the brain no human would have physical or mental activity.

5. The nervous system has many pathological conditions, in this report ten of them will be discussed. Bell’s palsy is a paralysis or a weakness of the muscles in the face. It is either temporary or permanent. Treatment needs to start early enough for a full recovery. Facial exercises, massages to the face, applying warm moist heat to the face, prednisone for swelling, and analgesics for a pain reliever are all treatments for Bell’s palsy. Carpal tunnel syndrome is a pinching or compression of the median nerve within the carpal tunnel due to inflammation and swelling of the tendons. Anti-inflammatory medications, splints, and physical therapy are treatments for this syndrome, but it can lead up to surgery when other treatments do not relieve the pain. Cerebral palsy (CP) describes congenital brain damage that is permanent but not progressive. A child has no control over his or her voluntary muscles by the injuries to the cerebrum that happened before birth, during birth, or during the first three to five years of life. Deterioration of the intervertebral disk is called degenerative disk and this happens by repetitive motion and wear on the disk. Bed rest, bracing the back, nonsteroidal anti-inflammatory drugs, analgesics, TENS, and surgery are all treatments for a degenerative disk. Small seizures, where there is a sudden temporary loss of consciousness lasting only a few seconds is called petit mal seizure, also called absence seizures. Migrane headaches, also called vascular headaches, are recurring, pulsating, vascular headache usually developing on one side of the head. This type of headache usually has symptoms of nausea, vomiting, irritability, fatigue, sweating, or chills. Treatment includes medication to prevent and to relieve the migranes. Shingles (herpes zoster) is a small viral infection, characterized by inflammation of the underlying spinal or cranial nerve pathway. Use antiviral medications or analgesics for treatment. A depressed skull fracture is a broken segment of the skull bone that thrusts into the brain as a result of a direct force. Treatment is a craniotomy. Paralysis of the lower extremities is called paraplegia. Tay-Sachs disease is a congenital disorder caused by altered lipid metabolism because of a enzyme deficiency. Supportive and symptomatic care are the only treatments indicated.