Dorothy FarrarRuckenmark
The spinal cord is a part of the nervous system that resides in a cavity inside the spine .
Definition
The spinal cord (medulla dorsalis or medulla spinalis) is located inside the spinal canal and is surrounded by connective tissue coverings. It is responsible for the sensations and movements of the extremities, trunk and neck and is therefore a connection between the peripheral nervous system and the brain .
This is ensured by the spinal nerves , which are arranged in segments and of which there are a total of 31 pairs. In addition to the membranes of the spinal cord, the spinal cord is also surrounded by the liquor space, which then flows into the liquor spaces and membranes of the brain.
Anatomy
The spinal cord is made up of nerve fibers also called perikaryen. These are components of the descending and ascending nerve cells. The spinal cord can be divided into different sections: These include the sacral cord, the lumbar cord, the thoracic cord and the cervical cord.
The spinal cord is relatively narrow in the area of the neck and lungs , while the density of nerve cells is greater in the buttocks area. In addition, the spinal cord consists of a posterior and a lateral cord. It is protected by a double sheath made up of soft and hard media, also known as the spinal cord membrane.
The gray and white pith substance with their different structures is also striking. The spinal cord continues from the uppermost cervical vertebra to the 1st or 2nd lumbar vertebrae and reaches a diameter of 10 to 14 cm and a length of about 45 cm in an adult. It then goes into the so-called conus medullaris or thin terminal thread.
Under the 2nd lumbar vertebra there are only nerve fiber bundles, which are also called cauda equina. However, the membranes continue into the dural sac, so that cerebrospinal fluid can be removed from this area without injuring the spinal cord.
The spinal cord is attached to the denticulata ligaments, also known as “toothed ligaments”. In infants, the spinal cord extends to the lower lumbar vertebrae because the spine develops faster than the dorsal medulla.
Function
The spinal cord serves as a connection between the brain and all other organs. Even the muscles and the skin are controlled by the brain with the help of the spinal cord. The spinal cord also receives stimuli from the peripheral nervous system and sends them to the brain.
It monitors body movements and motor functions, processes environmental stimuli and coordinates the functional processes in the body. The stimuli are received via the spinal nerves and then reach the brain via the white or gray marrow substance. In addition to nerve cells, the spinal cord also contains neurotransmitters that work on a biochemical basis. Parts of the vegetative or somatic nervous system can therefore be found in the spinal cord.
The somatic nervous system is an intermediary between the environment and the organism and is responsible for controlling movements and reflexes that are triggered by external or internal stimuli. The autonomic nervous system, on the other hand, regulates functions that humans cannot influence. These include digestion , respiration, water balance and metabolism .
The spinal cord reflexes are regulated by the reflex arc. The arc consists of a so-called afferent nerve cell, through which the impulses are transmitted to the spinal cord. A receptor then picks up the information, which is then switched over with the help of a synapse. An efferent nerve cell then carries the impulse away from the spinal cord to the target organ.
Diseases
- Spondylolyse
- paraplegia
- spinal cord inflammation
- Myelopathy
- Myelitis
- Meningomyelitis
There are diseases that only affect the spinal cord, in other diseases the spinal cord only plays a part, such as epilepsy, meningitis or multiple sclerosis. As part of Paget’s disease or spondylolysis, the spinal cord is destroyed, resulting in impaired mobility, speech and perception. It is often not possible for those affected to carry out very simple reflexes.
A number of diseases can also be caused by injuries. This includes paraplegia of various degrees of severity such as paraparalysis, paraparesis or tetraparesis.
Other deficits that can occur in the spinal cord are inflammation, narrowing due to herniated discs, problems with the blood supply or myelopathy. Myelopathy is damage to the spinal cord in the cervical spine region. The spinal cord increases in volume and compresses the bony substances.
In the case of a herniated disc, the gelatinous mass of the disc leaks out, which can put pressure on the spinal cord. If the pressure is very great, those affected suffer from sensory disturbances, pain and signs of paralysis .
Another disease of the spinal cord is the so-called myelitis, an inflammation caused by microorganisms. If the membranes of the spinal cord are also affected, this is called meningomyelitis.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.