![]() These are spiderlike phagocytes that dispose of debris, including dead brain cells and bacteria. These are abundant, star-shaped cells that account for nearly half of the neural tissue astrocytes form a living barrier between the capillaries and neurons and play a role in making exchanges between the two so they could help protect neurons from harmful substances that might be in the blood. Neuroglia include many types of cells that generally support, insulate, and protect the delicate neurons in addition, each of the different types of neuroglia, also simply called either glia or glial cells,has special functions. ![]() Supporting cells in the CNS are “lumped together” as neuroglia, literally mean “nerve glue”. The autonomic nervous system regulates events that are automatic, or involuntary this subdivision, commonly called involuntary nervous system, has two parts: the sympathetic and parasympathetic, which typically bring about opposite effects.Įven though it is complex, nervous tissue is made up of just two principal types of cells- supporting cells and neurons. The somatic nervous system allows us to consciously, or voluntarily, control our skeletal muscles. ![]() The motor, or efferent division carries impulses from the CNS to effector organs, the muscles and glands the motor division has two subdivisions: the somatic nervous system and the autonomic nervous system. Those that transmit impulses from the visceral organs are called visceral sensory fibers. Sensory fibers delivering impulses from the skin, skeletal muscles, and joints are called somatic sensory fibers. The sensory, or afferent division, consists of nerves (composed of nerve fibers) that convey impulses to the central nervous system from sensory receptors located in various parts of the body. The functional classification scheme is concerned only with PNS structures. The PNS, the part of the nervous system outside the CNS, consists mainly of the nerves that extend from the brain and spinal cord. The CNS consists of the brain and spinal cord, which occupy the dorsal body cavity and act as the integrating and command centers of the nervous system The structural classification, which includes all of the nervous system organs, has two subdivisions- the central nervous system and the peripheral nervous system. We only have one nervous system, but, because of its complexity, it is difficult to consider all of its parts at the same time so, to simplify its study, we divide it in terms of its structures (structural classification) or in terms of its activities (functional classification). The nervous system does not work alone to regulate and maintain body homeostasis the endocrine system is a second important regulating system. It can help stimulate or inhibit the activities of other systems to help maintain a constant internal environment. This function depends on the ability of the nervous system to detect, interpret, and respond to changes in the internal and external conditions. The brain is the center of mental activity, including consciousness, thinking, and memory. It then effects a response by activating muscles or glands (effectors) via motor output. It processes and interprets the sensory input and decides what should be done at each moment, a process called integration. Much like a sentry, it uses its millions of sensory receptors to monitor changes occurring both inside and outside the body these changes are called stimuli, and the gathered information is called sensory input. To carry out its normal role, the nervous system has three overlapping functions. Practice Quiz: Nervous System Anatomy and Physiology.Anatomy of the Parasympathetic Division.Gray Matter of the Spinal Cord and Spinal Roots.Protection of the Central Nervous System.
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