18.1
¿Qué es un sistema nervioso?
Descripción general
El sistema nervioso es el conjunto de células especializadas responsables de mantener el ambiente interno de un organismo y coordi…
- [Narrador] El sistema nervioso
le permite a una persona a detectar el mundo externo
y tener respuestas apropiadas hacia él.
Además, controla las funciones
desde la respiración hasta el razonamiento avanzado.
El sistema se divide en dos partes,
el sistema nervioso centrar o SNC
que contiene el cerebro y la columna vertebral
y el sistema nervioso periférico, el SNP,
que incluye los nervios que se transportan entre el SNC
y el resto del cuerpo.
El cerebro se subdivide en areas
que tienen distintas funciones
como procesar información visual
o coordinar movimientos,
pero también está altamente interconectado,
lo que permite la integración de la información.
Como el resto del sistema nervioso,
el cerebro está compuesto de neuronas,
células que generan y transmiten señales neuronales
y glia, células que ayudan al funcionamiento neuronal.
Debajo del cerebro está la columna vertebral,
el tejido del SNC se extiende hacia el canal vertebral.
Le facilita las señales entre el cerebro y el SNP
y también controla algunas funciones básicas como reflejos.
En el SNP, los nervios y grupos de axones neuronales
transmiten instrucciones a los músculos esqueléticos
para controlar el movimiento
y a órganos internos para regular funciones automáticas
como la digestión.
Los nervios también transportan información sensorial desde
células receptoras como aquellas en la piel que detectan
el tacto hasta el SNC que la analiza.
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Q1: What are the two main divisions of the nervous system?
The nervous system divides into the central nervous system (CNS), which contains the brain and spinal cord, and the peripheral nervous system (PNS), which includes nerves traveling between the CNS and the rest of the body. The CNS processes information and coordinates responses, while the PNS transmits motor commands and sensory information between the CNS and body tissues.
Q2: How does the spinal cord contribute to nervous system function?
The spinal cord extends down the vertebral canal below the brain and facilitates signaling between the brain and PNS. Beyond relaying information, the spinal cord independently controls basic functions such as reflexes without requiring input from the brain, enabling rapid responses to stimuli.
Q3: What types of cells make up the nervous system?
The nervous system comprises neurons, which generate and transmit neural signals, and glial cells, which support neural functioning. Neurons communicate at junctions called synapses using neurochemicals and ions. Glial cells roughly equal the number of neurons in the brain and include astrocytes, microglia, oligodendrocytes, and ependymal cells in the CNS.
Q4: What functions do peripheral nerves perform?
Peripheral nerves transmit motor instructions from the CNS to skeletal muscles, controlling movement, and to internal organs, regulating autonomic functions like digestion. Nerves also carry sensory information from receptor cells in the skin and other tissues back to the CNS for analysis and processing.
Q5: How is the brain organized and what are its main regions?
The brain subdivides into the cerebrum, cerebellum, and brainstem. The cerebrum, the largest region, processes visual information and coordinates movements through highly interconnected areas. The cerebellum coordinates muscle movement, while the brainstem connects the brain to the spinal cord and controls vital functions such as breathing and swallowing.
Q6: What is the autonomic nervous system and what does it control?
The autonomic nervous system, part of both the CNS and PNS, controls smooth muscles, cardiac muscles, and glands governing involuntary actions. It regulates functions including digestion, heart rate, and breathing through the sympathetic nervous system fight flight response and parasympathetic divisions that balance these involuntary processes.
Q7: How does the nervous system detect and respond to the external environment?
The nervous system detects the outside world through sensory receptor cells in the skin and other tissues that transmit information to the CNS. The CNS processes this sensory input and generates appropriate motor responses, enabling organisms to interact with their environment and escape danger through coordinated movement and autonomic adjustments.