2.10
Medula Espinhal
A medula espinhal, um componente crítico do sistema nervoso central, se estende da base do tronco cerebral até a região lombar da coluna vertebral. El…
A medula espinhal começa na base do cérebro e se estende pelo meio das costas, servindo como um elo de comunicação vital entre o cérebro e o corpo.
A medula espinhal é dividida em vários segmentos, oito cervicais, doze torácicos, cinco lombares, cinco sacrais e um coccígeo. Os nervos que surgem da medula espinhal se conectam a partes específicas do corpo através do sistema nervoso periférico.
Existem três tipos de células nervosas na medula espinhal: neurônios sensoriais, neurônios motores e interneurônios.
Os neurônios sensoriais transmitem informações sensoriais para a medula espinhal, enquanto os neurônios motores enviam informações da medula espinhal para as glândulas e músculos. Os interneurônios conectam neurônios sensoriais e motores e constituem a maior parte da estrutura da medula espinhal.
Além disso, a medula espinhal pode iniciar ações reflexas sem a entrada do cérebro.
Por exemplo, quando um indivíduo toca uma panela quente, um neurônio sensorial na pele detecta a dor e envia o sinal para a medula espinhal. A entrada é imediatamente processada por um interneurônio, que aciona um neurônio motor que rapidamente solicita que os músculos afastem a mão.
View the full transcript and gain access to JoVE Core videos
Q1: Where does the spinal cord begin and end in the body?
The spinal cord begins at the base of the brain and extends down the middle of the back to the lumbar region of the vertebral column. It serves as a vital communication link between the brain and the body, transmitting sensory and motor information through paired spinal nerves that exit between vertebrae.
Q2: How many segments does the spinal cord have and what are they called?
The spinal cord is divided into 30 segments corresponding to vertebrae: eight cervical, twelve thoracic, five lumbar, five sacral, and one coccygeal segment. Each segment connects to specific body regions through paired spinal nerves, allowing for bidirectional flow of information crucial for various bodily functions.
Q3: What are the three types of nerve cells found in the spinal cord?
The spinal cord contains sensory neurons, which transmit sensory information like touch and pain to the cord; motor neurons, which send impulses from the cord to muscles and glands; and interneurons, the most numerous cells that process sensory information and enable communication between sensory and motor neurons.
Q4: How does the spinal cord enable reflex actions without brain involvement?
Reflex arcs are neural circuits that activate directly in response to sensory inputs. When touching a hot surface, sensory neurons send signals to the spinal cord, interneurons immediately process this information, and motor neurons activate muscles to withdraw the hand rapidly, protecting the body before the brain receives the signal.
Q5: What role do interneurons play in spinal cord function?
Interneurons constitute most of the spinal cord's structure and act as intermediaries between sensory and motor neurons. They process and integrate sensory information, facilitating coordination of appropriate motor responses and enabling the spinal cord to function as part of the introduction to biological bases of psychology.
Q6: How do spinal nerves connect the spinal cord to specific body parts?
Paired spinal nerves exit the spinal cord through spaces between vertebrae and connect to specific body regions. These nerves transmit sensory information from receptors throughout the body and motor commands to muscles and glands, creating a vast network that enables communication between the central nervous system and peripheral body parts.
Q7: What is the relationship between the spinal cord and motor function?
Motor neurons in the spinal cord transmit impulses to muscles and glands, initiating and controlling both voluntary movements and many involuntary actions. The spinal cord's ability to coordinate reflex actions and process motor commands independently demonstrates its integral role in the body's motor function and physical stability.