Nervous System, Neurons And Action Potential, Chemical Messengers

During an action potential, the cell membrane allows sodium ions to flow into the cell and potassium ions to flow out of the cell. This process is known as depolarization and repolarization. When the cell is at rest, the inside is negatively charged compared to the outside. However, during an action potential, the cell membrane becomes permeable to sodium ions, causing them to rush into the cell. This influx of positive charge depolarizes the cell. After reaching a certain threshold, the cell membrane becomes permeable to potassium ions, which flow out of the cell, repolarizing it and restoring the negative charge. This sequence of ion movement is crucial for the generation and propagation of electrical signals in neurons.

The correct answer is sensory neuron, interneuron and motor neuron. These three types of neurons are the main components of the nervous system. Sensory neurons transmit information from sensory receptors to the central nervous system. Interneurons are responsible for processing and transmitting information between sensory and motor neurons. Motor neurons transmit signals from the central nervous system to muscles or glands, allowing for movement or response. Glial cells, although important for supporting and protecting neurons, are not considered one of the main types of neurons.

The cerebral cortex of the brain is responsible for voluntary actions, language, and thinking. It is the outermost layer of the brain and plays a crucial role in higher cognitive functions. Voluntary actions, such as moving our limbs or speaking, are controlled by the motor cortex in the frontal lobe. Language processing, including understanding and producing speech, is primarily carried out in the left hemisphere of the cerebral cortex. Thinking, which involves problem-solving, decision-making, and reasoning, also occurs in various regions of the cerebral cortex.

The cerebellum is involved in controlling skillful movements. It plays a crucial role in coordinating and fine-tuning motor movements, maintaining balance, and adjusting muscle tone. It receives information from various sensory systems and integrates it to ensure smooth and coordinated movements. Damage to the cerebellum can result in difficulties with motor coordination, balance, and precision of movements. The hypothalamus, thalamus, and cerebrum are involved in other functions such as regulating body temperature, processing sensory information, and controlling higher cognitive functions, but they are not primarily responsible for controlling skillful movements.

Noradrenaline is the correct answer because it is a neurotransmitter that is released in response to various forms of novelty and stress. It plays a role in the body's fight-or-flight response, increasing heart rate, blood pressure, and alertness. Noradrenaline is involved in regulating mood, attention, and arousal, making it essential in the body's response to stressful or novel situations. Dopamine, acetylcholine, and glutamate are other neurotransmitters that have different functions and are not specifically associated with the response to novelty and stress.

The brain stem is a vital part of the central nervous system that connects the brain to the spinal cord. It consists of three main parts: the hindbrain, midbrain, and diencephalon. The hindbrain is responsible for controlling basic functions such as breathing, heart rate, and balance. The midbrain plays a role in sensory and motor functions, as well as regulating arousal and sleep. The diencephalon includes structures like the hypothalamus and thalamus, which are involved in regulating body temperature, hunger, thirst, and sleep-wake cycles. Therefore, the correct answer is hind brain, mid brain, and diencephalon.

Interneurons are the most numerous type of neuron in the human brain. They are responsible for connecting sensory neurons to motor neurons and play a crucial role in processing and transmitting information within the central nervous system. Unlike motor neurons and sensory neurons, which have specific functions in transmitting signals to muscles or receiving signals from sensory organs, interneurons facilitate communication between different areas of the brain, allowing for complex cognitive processes and coordination of movement. Glial cells, on the other hand, are non-neuronal cells that provide support and protection to neurons.