the central nervous system-4

Limbic System

Our affective or emotional brain is called the limbic system. The medial portion or border of each cerebral hemisphere and diencephalon are referred to as limbic, which is a border.

Components of the Limbic System

• Cortical architecture
• Limbic lobe Formation of the Hippocampus
• Sub-Cortical Structures
• Nuclear complex of the amygdaloid
• Septal atoms
• Hypothalamus
• Anterior thalamic nucleus
• The bulb or olfactory nuclei

The limbic system has an impact on mood, feelings of pain and pleasure, emotions, and the visceral reactions to those emotions. The amygdala and the anterior section of the cingulate gyrus appear to be two areas that are particularly significant in emotions. The amount of memory storage is influenced by the hippocampus. Together, the olfactory nuclei and the amygdaloid nuclear complex aid in evoking the emotional reactions to both pleasant and unpleasant odors.

Functions of the Limbic System

• It combines the somatic, visceral, and olfactory signals that are carried to the brain.
• It is involved in the regulation of behaviors like food acquisition and eating habits that are essential for the animal's survival.
• It regulates behaviors such as sex that are necessary for the species' survival.
• It affects how people behave emotionally.
• It aids in the preservation of recent memories.

Spinal Cord

The spinal cord serves as a conduit for information between the brain and the PNS below the head. It is crucial to the nervous system's overall functionality.

Structure of the Spinal Cord

The spinal cord runs from the foramen magnum to the level of the first lumbar vertebra, where it is contained within the vertebral canal. About 45 centimeters is how long the cord is. It has a cylindrical shape, a slight anteroposterior flattening, and enlargements in the cervical and lumbar regions, which are where the nerves feeding the upper and lower limbs begin. The fibrous connective tissue known as the filum terminale surrounds the inferior end of the spinal cord and anchors it to the coccyx. The cauda equina is a grouping of lower lumbar, sacral, and coccygeal nerves that includes the filum terminale and is located beneath the spinal cord.

The gray matter (nerve cell bodies) that makes up the spinal cord's small, irregularly shaped interior region is surrounded by a greater area of white matter (nerve cell fibers). Two horns made of gray matter are organized. A thicker anterior (ventral) horn and a thinner posterior (dorsal) horn make up each half of the central gray matter. The cross section of the gray matter resembles an H due to these two horns. Cerebrospinal fluid is located in a tiny canal called the central canal that runs through the middle of the gray matter. A spinal nerve emerges from each side of the spinal cord in each segment. Through two nerve roots—the dorsal and ventral nerve roots—each spinal nerve joins the cord. The ventral root carries motor processes out from the cord, while the dorsal root carries sensory nerve processes to the spinal cord. Thousands of nerve cell fibers are organized in three areas outside of the gray matter on each side to make up the white matter.

Functions of the Spinal Cord

• It serves as a conduit between the brain and the spinal nerves.
• It carries sensory signals to the brain via ascending tracts.
• It transports motor impulses from the brain to the efferent neurons that supply muscles or glands via descending tracts.
• It starts reflex actions that are coordinated even when the brain is not involved.

Spinal Tracts

The ascending tracts, which carry sensory impulses to the brain, and the descending tracts, which carry motor impulses from the brain to the spinal nerves at various levels of the cord, are two different types of bundles of axons found within the white matter of the spinal cord. The sensory and motor pathways in the spinal cord and the brain are interconnected.