2.1 Flashcards
(9 cards)
- What are the two main divisions of the nervous system and their primary functions?
The nervous system is divided into the Central Nervous System (CNS), which includes the brain and spinal cord responsible for processing and coordination, and the Peripheral Nervous System (PNS), which connects the CNS to sensory organs, muscles, and glands, transmitting sensory (afferent) input and motor (efferent) output.
- What is the functional unit of the nervous system, and what are its key characteristics?
The neuron is the functional unit of the nervous system. Neurons display enormous diversity in shape, size, and neurotransmitter profiles, are electrically active, and communicate via trillions of chemical synapses to support functions ranging from breathing to complex cognition.
- What roles do glial cells play in the brain?
Glial cells, which make up about half of all brain cells, provide support, insulation, and metabolic assistance to neurons; they contribute to neural signaling, help form the blood–brain barrier, and maintain overall brain health.
- How does the neural tube form during early embryonic development?
The neural tube forms when the neural plate, a specialized region of the ectoderm, thickens and folds into neural folds which converge and fuse to form the neural tube, laying the foundational structure for the CNS.
- At what time period does neural tube formation occur and what can happen if it fails?
Neural tube formation begins around 18–22 days of gestation, with cranial closure by 24–26 days and caudal closure by 26–28 days. Improper closure can lead to neural tube defects such as anencephaly (failure at the rostral end) or spina bifida (failure at the caudal end).
- What are neural crest cells and why are they significant for neural development?
Neural crest cells arise from the edges of the neural tube and migrate throughout the embryo to give rise to diverse cell types, including components of the peripheral nervous system, pigment cells, and various craniofacial structures, illustrating the broad impact of early neural development.
- How do synapses change over the lifespan, and why is this important?
Although nearly all neurons are generated during early gestation, synapses—the points at which neurons communicate—continue to form, modify, and refine throughout life, driving learning, memory, and neural plasticity, while age-related synaptic changes can affect cognition.
- What are some key changes in the nervous system that occur as individuals age?
Across the lifespan, the nervous system undergoes functional and structural changes, including synaptic remodeling and refinement, alterations in neurotransmitter levels, and potential declines in neural plasticity that can influence cognitive and motor functions.
- Why is understanding the formation and differentiation of the neural tube fundamental for neuroscience?
Understanding neural tube formation is critical because it establishes the organizational blueprint of the CNS, and errors in this process lead to serious congenital conditions; this insight informs both fundamental neuroscience and the development of therapeutic approaches to prevent and treat neural tube defects.
