Organization of Nervous system

 

Classification of Nervous System

The nervous system of vertebrates (including humans) is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The (CNS) is the major division, and consists of the brain and the spinal cord. The spinal canal contains the spinal cord, while the cranial cavity contains the brain.

Classification of Nervous System | Source: www.thailandmedical.news

01. Peripheral Nervous System (PNS)

The peripheral nervous system is divided into two main parts: ANS and SNS.

Autonomic Nervous System (ANS): Controls involuntary bodily functions and regulates glands. The ANS is again divided to, sympathetic and parasympathetic.

• Sympathetic Nervous System: There are two kinds of neurons involved in the transmission of any signal through the sympathetic system: preganglionic and postganglionic.
• Parasympathetic nervous system:  Your parasympathetic nervous system is a network of nerves that relaxes your body after periods of stress or danger. It also helps run life-sustaining processes, like digestion, during times when you feel safe and relaxed.

Somatic Nervous System (SNS): Controls muscle movement and relays information from ears, eyes and skin to the central nervous system.

02. Central Nervous System

The CNS has many parts and each of them are listed below.

• Brain: The brain controls how we think, learn, move, and feel.
• Spinal Cord: It carries messages back and forth between the brain and the nerves that run throughout the body.
• Forebrain: Forebrain comprises cerebrum, thalamus and hypothalamus.
• Midbrain: Midbrain is located between the thalamus of the forebrain and pons of the hindbrain. 
• Hindbrain: Hindbrain comprises pons, cerebellum and medulla.
• Telencephalon: It is responsible for olfaction, language, speech, sensory processing, learning and memory.
• Diencephalon: It is responsible for vision, homeostasis (hypothalamus) and other sensory recognitions. 
• Cerebral Cortex: The cerebral cortex is the outer layer that lies on top of your cerebrum. Your cerebrum is the largest area of your brain. Your cerebrum divides your brain into two halves called hemispheres. The hemispheres are attached by a bundle of nerve fibers called the corpus callosum.
• Basal Ganglia: The basal ganglia are a cluster of subcortical nuclei deep to cerebral hemispheres. The largest component of the basal ganglia is the corpus striatum which contains the caudate and lenticular nuclei (the putamen, globus pallidus externus, and internus), the subthalamic nucleus (STN), and the substantia nigra (SN).
• Amygdala: The amygdala is located in the medial temporal lobe, just anterior to (in front of) the hippocampus. Similar to the hippocampus, the amygdala is a paired structure, with one located in each hemisphere of the brain.
• Mesencephalon: Mesencephalon, a region of the developing vertebrate brain that is composed of the tectum and tegmentum. The midbrain serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing.
• Thalamus: Thalamus is your body's information relay station. All information from your body's senses (except smell) must be processed through your thalamus before being sent to your brain's cerebral cortex for interpretation. Your thalamus also plays a role in sleep, wakefulness, consciousness, learning and memory.
• Hypothalamus: Hypothalamus, a structure deep in your brain, acts as your body's smart control coordinating center. Its main function is to keep your body in a stable state called homeostasis. It does its job by directly influencing your autonomic nervous system or by managing hormones.
• Tectum Cerebellum: The tectum (Latin for roof) is the dorsal side of the midbrain. The position of the tectum is contrasted with the tegmentum, which refers to the region in front of the ventricular system, or floor of the midbrain. It is involved in certain reflexes in response to visual or auditory stimuli.
• Pons Cerebellum: Pons is a key connection point to your cerebellum, another key part of your brain that handles balance and movement. It also works cooperatively with other parts of your brainstem that manage your breathing.
• Medulla: Medulla is the bottom-most part of your brain, connecting to your spinal cord through the foramen magnum, an opening at the bottom of your skull. Just above your medulla is your pons, which is just below the central structures in your brain.