Your nervous system is the major controlling, regulatory, and communicating system in your body. It's the captain, the messenger, and the switchboard all in one. It has two main parts: the Central Nervous System and the Peripheral Nervous System. In this post, we will look at the different parts of both and their main functions.
What does the nervous system do?
Your nervous system guides almost everything you think, feel, say, or do –whether you are aware of it or not. It is responsible for your sleep, heartbeat, breathing, digestion, healing, and aging. It is also in charge of your thoughts, memories, learning, and feeling. And it is also the one to blame for how you respond to stressful situations. It basically affects every aspect of your body.
Thoughts, memory, learning, and feelings.
Senses, including how your brain interprets what you see, hear, taste, and touch.
Response to stressful situations.
Sleep.
Heartbeat, breathing, and digestion.
Puberty, aging, and healing.
Movements, such as balance and coordination.
Parts of the nervous system
The nervous system is made up of two large systems: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
Central Nervous System (CNS)
The CNS is the main processing center for the whole nervous system. It is made up of the brain and the spinal cord.
Brain. The brain has three main parts - the cerebrum (involved in memory, feeling, and thinking), which fills up most of your skull, the cerebellum (controls coordination and balance), which sits at the back of your head, and the brain stem, which sits beneath your cerebrum in front of your cerebellum.
Spinal Cord. Your spinal cord carries nerve signals from your brain to your body and vice versa. These nerve signals help you feel sensations and move your body. Your spinal cord is protected by your vertebrae.
The Cerebrospinal Fluid (CSF) is a clear, colorless body fluid that surrounds the brain and spinal cord of all vertebrates and protects them. It is produced by the ventricles.
Did you know? Your brain weighs around 1.4kg (∼2% of total body weight). However, it consumes roughly 20% of your energy each day! It is arguably the hungriest organ in your body, and its main source of energy is glucose.
Peripheral Nervous System (PNS)
The PNS is a complex system of neurons and glands. It is made up of nerves that branch off from the spinal cord and extend to all parts of the body. It is divided into two parts:
Somatic Nervous System (SNS): voluntary control of body movements via skeletal muscles. Your SNS connects your spinal cord to your muscles, controls muscle movement, and relays information from the ears, skin, and eyes to the CNS. It consists of two parts:
Spinal nerves: They are mixed nerves that carry sensory information into the spinal cord and motor commands out of.
Cranial nerves: These are the nerve fibers that carry information into and out of the brain stem.
Autonomic Nervous System (ANS): controls involuntary bodily functions (e.g., blood pressure, heart rate, digestion) and regulates glands. It is made up of two systems with opposing roles. They work together to keep your body in balance (homeostasis).
Sympathetic: it carries signals that put your body on alert. It gets activated when you are in danger.
Parasympathetic: it carries signals that relax your body. It helps you bring things back to normal.
Memory trick. Afferent Arrives (sensory) - these are neurons whose axons travel towards a centrail point - they arrive and bring information to it). Efferent Exits (motor) - these neurons send an axon away from a central point, they exit and carry information somewhere else.
In future posts, we will look at the different parts of the nervous system in detail and explore how it is connected with other important systems in our body - our immune and endocrine systems.