Two enlargements of the spinal cord can be visualized: The cervical enlargement, which extends between C3 to T1; and the lumbar enlargements which extends between L1 to S2 (Figure 3.1). The cord is segmentally organized. There are 31 segments, defined by 31 pairs of nerves exiting the cord.
What is the role of spinal cord enlargement?
Two regions of the spinal cord are enlarged to accommodate the greater number of nerve cells and connections needed to process information related to the upper and lower limbs (see Figure 1.10B).
Which spinal nerves affect which parts of the body?
The nerves of the cervical spine go to the upper chest and arms. The nerves in your thoracic spine go to your chest and abdomen. The nerves of the lumbar spine then reach to your legs, bowel, and bladder. These nerves coordinate and control all the body’s organs and parts, and let you control your muscles.
What nerves emerge just below the lumbar enlargement?
Summary. Autonomic preganglionic neurons are concentrated in two intermediolateral columns running down the thoracic cord into the first few lumbar segments (sympathetic) and in the segments immediately below the lumbar enlargement (parasympathetic).
What nerve is unique in that it has a spinal origin?
The vagus nerve has axons that originate from or enter the dorsal nucleus of the vagus nerve, the nucleus ambiguus, the solitary nucleus in the medulla, and the spinal trigeminal nucleus. The vagus nerve is responsible for heart rate, gastrointestinal peristalsis, and sweating, to name a few.
What causes the cervical enlargement of spinal cord?
As the spinal cord is shorter in length than the vertebral column, it extends from the C3 to T1/T2 vertebral levels, its greatest circumference (approximately 38 mm) at the C6 level. The cervical enlargement is a result of the increased volume of motor cells in the ventral horns of the grey matter.
What does grey matter in the spinal cord contain?
The central nervous system is made up of two types of tissue: the grey matter and the white matter. The grey matter is mainly composed of neuronal cell bodies and unmyelinated axons. Axons are the processes that extend from neuronal cell bodies, carrying signals between those bodies.
What are the cervical and lumbar enlargements of the spinal cord quizlet?
Distal (inferior) end widens at the two enlargements of the spinal cord and tapers into the medullary cone.
- Cervical Enlargement: Gives rise to nerves of the upper limbs.
- Lumbar Enlargement: Gives rise to nerves of the pelvic region and lower limbs.
- Medullary Cone (Conus Medullaris): Inferior to the lumbar enlargement.