Instructor: Dr. Daniel Kifle
June 16, 2014
A Case of Spinal Cord Injury
Describe the functional anatomy of the spinal cord using the following terms: white matter, gray matter, tracts, roots and spinal nerves. The spinal cord consists of a superficial White matter and a deep Gray matter. The white matter consists of myelinated axons, which form nerve tracts and the Gray matter consists of neuron cell bodies, dendrites and axons. The white matter in each half of the spinal cord is organized into ventral, dorsal and lateral columns. Each column is subdivided into tracts also called pathways. A collection of axon inside the CNS is called a tract but outside the CNS it is called a nerve. Spinal nerves arise from numerous rootlets along the dorsal and ventral surfaces of the spinal cord. Six of these rootlets combine to form a ventral root and the other six to form a dorsal root. Dorsal roots contain only sensory axons, so action potentials are conducted to the spinal cord only and the ventral root contain motor axons so action potential is conducted away from the spinal cord. This means spinal nerves have both the sensory and motor axons. Tracts combine to form roots (dorsal and ventral), roots combine to form the Spinal nerve(twelve pairs) which are in the spinal cord.
Define the terms reflex and spinal reflex and identify the components of a reflex arc. A reflex is an automatic response to a stimulus produced by a reflex arc. It occurs without conscious thought. Reflexes are homeostatic. A spinal reflex is any reflex action mediated through the center of the spinal cord. A reflex arc is the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between. It consist of five components namely Receptor; Site of the stimulus action, Sensory Neuron; transmits afferent impulses to the central nervous system, Integration Center (interneurons) which is always within the central nervous system. The fourth component is motor neuron; Conducts efferent impulses from the integration center to an efferent organ and lastly Effector; muscle fiber or gland cell that responds to the efferent impulses (by contracting or secreting). 3.
Define the term spinal cord injury (SCI) and state its prevalence A spinal cord injury (SCI) refers to any injury to the spinal cord that is caused by trauma instead of disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence. Spinal cord injuries can be complete or incomplete. With a complete spinal cord injury, the cord can't send signals below the level of the injury. As a result, you are paralyzed below the injury. With an incomplete injury, you have some movement and sensation below the injury. In the UK every year, there are around 1200 people paralyzed from a spinal cord injury. There are currently thought to be approximately 40,000 people in the UK living with paralysis. This statistic only shows the people who have been through a spinal cord injury center, and does not include those who have suffered paralysis and been treated in a general hospital. A person is paralyzed every 8 hours. It is estimated that the current annual cost of caring for people paralyzed by spinal cord injury is more than £500 million. 21% of people discharged from Spinal Cord Injury Centers go into nursing homes; institutionalized settings rather than their own homes. 4.
Define the terms neurological level, tetra(quadri)plegia, and paraplegia Neurological level is usually described as the normal level immediately above the damaged level. By definition, the level of neurological lesion refers to the lowest segment of the spinal cord with normal sensory and motor function on both sides of the body. Paraplegia is a type of paralysis which may be complete or incomplete. Both legs, the trunk and feet may...
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