Central and Peripheral Nervous System: Functions and Health
Central Nervous System
The central nervous system is formed by the spinal cord and brain. It is protected by the skull, spine, and meninges. Between the meninges is the cerebrospinal fluid. It has two zones:
- The gray matter is formed by cell bodies and dendrites.
- The white matter is formed by axons covered by myelin.
Spinal Cord
The spinal cord is a nerve cord that runs inside the spine. The gray matter is in the center, and the white matter is outside. Within the gray matter, there is a tube called the ependyma, which contains a small amount of cerebrospinal fluid.
Functions:
- To perform reflex actions.
- Carries sensory impulses to the brain or motor commands to the effector organs.
The Brain
The brain is inside the skull and is divided into:
Brainstem
The brainstem is the prolongation of the spinal cord. Nerves pass through the brainstem before reaching the brain. It regulates blood pressure, heart rate, and pulmonary ventilation. The brainstem has several parts that regulate sleep and wakefulness, as well as visual reflexes. Part of the brainstem is connected to the hypothalamus, which is connected to the pituitary gland, an endocrine gland.
Cerebellum
The cerebellum is located in the back of the brain. It is formed by gray matter in the outer zone and white matter in the inner area. It is the organ responsible for receiving information from the ear. It regulates balance and the activity of muscles. It coordinates motor commands sent by the brain to make precise movements.
Cerebrum
The cerebrum is the largest part of the brain. It is composed of white matter on the inside and gray matter on the outside, forming the cerebral cortex. The cerebral cortex has folds to fit the volume of the braincase. Folds can be of two types:
- Cerebral convolutions: These are shallow.
- Deep fissures: These divide the brain into two hemispheres, the left and right, connected by the corpus callosum, which is made of white matter. These are known as lobes.
Functions of the Cerebrum
- Receives sensory information from all organs except the organ of balance.
- Coordinates and controls operation.
- Houses intellectual faculties and higher nervous functions.
Peripheral Nervous System
The peripheral nervous system connects the sensory organs with nerve centers. It consists of nerves (cords formed by a number of axons) that are isolated from each other by the myelin sheath.
Types of Nerves
According to the direction of the impulse:
- Sensory: Carry information from the sensory organs.
- Motor: Send orders to effector organs.
- Mixed: Carry both types of impulses.
Depending on where they originate:
- Cranial: 12 pairs that come from the brain.
- Spinal: 31 pairs that leave the spinal cord. In their path, they may have lumps called nerve ganglia.
Nervous Acts
There are two types of acts in the cerebrospinal system:
Reflex Acts
These are fast, automatic, and do not involve the brain. There are three types:
- Sensory: These originate in the skin, and their axons enter the spinal roots.
- Interneurons: These transmit nerve impulses to motor neurons.
- Motor: These leave the marrow and reach the muscles.
Voluntary Acts
These are varied, changing, and more elaborate than reflexes. The autonomic nervous system, correctly called the autonomic or involuntary nervous system, handles the regulation and coordination of internal organs. These are located in the lateral spinal cord, gray matter, brainstem, and hypothalamus. There are two types of autonomic nervous systems:
- Sympathetic Nervous System: Responsible for activating the body’s organs to work.
- Parasympathetic Nervous System: Its action is to cause relaxation and run slower and less intensely than the sympathetic nervous system.
Diseases of the Central Nervous System
Parkinson’s disease, Alzheimer’s disease, schizophrenia, neurosis, anorexia, epilepsy, depression.
Diseases of the Endocrine System
Diabetes, endocrine dwarfism, hypothyroidism, hyperthyroidism.
Healthy Habits for the Nervous and Endocrine Systems
Avoid stress, avoid obesity, maintain a healthy diet, do not take drugs, exercise regularly, and lead an orderly life.