The Intricacies of the Nervous System

Organization and Function of the Nervous System

• Grey matter is located in the outer part of the brain (cerebral cortex), inner part of the spinal cord, and other regions such as the retina and olfactory epithelium.
• The cerebral cortex is made up of six layers of neurons, including pyramidal neurons that are involved in sensory integration and voluntary motor responses.
• The cerebellar cortex coordinates muscular activity throughout the body and is organized into three layers: molecular layer, Purkinje neurons, and granular layer.
• The spinal cord contains white matter on the periphery and grey matter deeper within, with anterior horns containing motor neurons and posterior horns receiving sensory fibers from dorsal root ganglia.
• The meninges are three membranes of connective tissue that surround and protect the brain and spinal cord, including the dura mater, arachnoid mater, and pia mater.
• The dura mater is a dense irregular connective tissue that forms the outer periosteal layer in the brain and one meningeal layer in the spinal cord.
• The arachnoid mater is an avascular connective tissue that consists of a sheet of connective tissue in contact with the dura mater and a system of trabeculae.
• The pia mater is a thin layer of mesenchymally derived cells closely applied to the entire surface of the CNS tissue, separated from the neural elements by the glial limiting membrane.
• The blood-brain barrier (BBB) is a functional barrier that tightly controls the passage of substances from blood into the CNS tissue, consisting of capillary endothelium with occluding junctions and perivascular astrocytic feet.
• The choroid plexus, located in the ventricles of the brain, produces cerebrospinal fluid (CSF) which provides ions for neuronal activity and absorbs mechanical shocks in the arachnoid.
• The peripheral nervous system (PNS) includes nerves (cranial and spinal) and ganglia (sensory and autonomic), with peripheral nerves consisting of bundles of nerve fibers surrounded by Schwann cells and connective tissue.
• Myelinated fibers in peripheral nerves are covered by multiple layers of Schwann cells, while unmyelinated fibers are enveloped within simple folds of Schwann cells. Nerve fibers are organized into endoneurium, perineurium, and epineurium.

Organization and Function of the Nervous System

• Grey matter is located in the outer part of the brain (cerebral cortex), inner part of the spinal cord, and other regions such as the retina and olfactory epithelium.
• The cerebral cortex is made up of six layers of neurons, including pyramidal neurons that are involved in sensory integration and voluntary motor responses.
• The cerebellar cortex coordinates muscular activity throughout the body and is organized into three layers: molecular layer, Purkinje neurons, and granular layer.
• The spinal cord contains white matter on the periphery and grey matter deeper within, with anterior horns containing motor neurons and posterior horns receiving sensory fibers from dorsal root ganglia.
• The meninges are three membranes of connective tissue that surround and protect the brain and spinal cord, including the dura mater, arachnoid mater, and pia mater.
• The dura mater is a dense irregular connective tissue that forms the outer periosteal layer in the brain and one meningeal layer in the spinal cord.
• The arachnoid mater is an avascular connective tissue that consists of a sheet of connective tissue in contact with the dura mater and a system of trabeculae.
• The pia mater is a thin layer of mesenchymally derived cells closely applied to the entire surface of the CNS tissue, separated from the neural elements by the glial limiting membrane.
• The blood-brain barrier (BBB) is a functional barrier that tightly controls the passage of substances from blood into the CNS tissue, consisting of capillary endothelium with occluding junctions and perivascular astrocytic feet.
• The choroid plexus, located in the ventricles of the brain, produces cerebrospinal fluid (CSF) which provides ions for neuronal activity and absorbs mechanical shocks in the arachnoid.
• The peripheral nervous system (PNS) includes nerves (cranial and spinal) and ganglia (sensory and autonomic), with peripheral nerves consisting of bundles of nerve fibers surrounded by Schwann cells and connective tissue.
• Myelinated fibers in peripheral nerves are covered by multiple layers of Schwann cells, while unmyelinated fibers are enveloped within simple folds of Schwann cells. Nerve fibers are organized into endoneurium, perineurium, and epineurium.