These terms describe the upper motor neuron pathways described above. Thus, although most of the axon of the lower motor neuron is part of the peripheral nervous system, the cell body and first part of the axon is in the central nervous system. Axons leave the brain stem and pass in the cranial nerve to the destination. parietal lobe, basal ganglia, cerebellum, reticular formation, midbrain, etc.) that connect with the lower motor neurons in the cranial nerve nucleus, thus influencing their activity.Ĭell bodies of lower motor neurons form the brain stem nucleus. The term upper motor neurons is also used clinically to include fibres from other brain centres (e.g. Axons descend, decussating just before synapsing with cell bodies of lower motor neurons which make up the motor nucleus of that cranial nerve. Axons of upper motor neurons decussate before synapsing with lower motor neurons, so the right motor cortex controls the left side of the body, and vice versa – contralateral control.įor cranial nerves, cell bodies of upper motor neurons are in the head and neck area of the motor cortex. Pathways between motor cortex and muscles may be thought of as being arranged in two neuronal groups: upper motor neurons and lower motor neurons. (Hockenbury, 52) In this system, only a single neuron is required to relay the signal for muscle contraction.Both somatic motor and branchiomotor nerves supply voluntary muscles. The somatic reflex is a reflex that occurs in the skeletal muscles. (Blakeslee, 182) Communicates sensory information to the central nervous system and carries motor messages from the central nervous system to the muscles. The somatic nervous system is a part of the peripheral nervous system. Sends feedback information from somatosensory receptors back to the brain. Somatic Nervous System: responsible for voluntary muscle control, touch, and “propriorception.” Relays motor commands from the brain to the muscles. (Blakeslee, 182) Arouses the body to expend energy. (NCIt) When you feel threatened the following happens: heart beats faster breathing quickens blood is diverted to your muscles and lungs mouth dries up pupils contract senses focus outward. It also causes blood vessels to narrow and decreases digestive juices. (Blakeslee, 215) The part of the nervous system that increases heart rate, blood pressure, breathing rate, and pupil size. Sympathetic Nervous System: the "fight or flight" part of the autonomic nervous system which gets the body revved up and ready for violence or intense physical (or emotional) activity. (Chudler, 35) Helps the body conserve energy. (MeSH) In times when there is no emergency, it works to save energy - blood pressure decreases, heartbeat slows, and digestion can start. (Blakeslee, 182) Generally acts to conserve resources and restore homeostasis. Parasympathetic Nervous System: the ‘rest and digest’ part of the autonomic nervous system. The system is itself governed by the central nervous system and receives both parasympathetic and sympathetic innervation. Thus the (pathway) can autonomously sense the tension and the chemical environment in the gut and regulate blood vessel tone, (motion), secretions, and fluid transport. It contains sensory neurons, interneurons, and motor neurons. (Patestas, 9) (Includes) a neural "plexus," lying within the walls of the gut, that is involved in controlling ‘peristalsis’ (muscular contractions) and “gastrointestinal” “secretions.” (Blumenfeld, 24) ‘Innervates’ (stimulates with nerve impulses) the gastrointestinal tract, the pancreas, and the gallbladder. (Patestas, 118)Įnteric Nervous System: situated completely within the wall of the digestive tract and controls the entire process of digestion. The “cell body” of the first neuron is in the central nervous system, whereas the cell body of the second neuron is in the peripheral nervous system. Two neurons are required to effect a “contraction” of smooth muscle or cardiac muscle, or to elicit secretion from the cell of a gland. (Hockenbury, 52-53) (Cells in this system) perform their functions below the conscious level. A peaceful mental image can lower many autonomic functions. Emotions and mental imagery also influence (the) autonomic nervous system. These processes occur with little or no conscious involvement. Responsible for “homeostasis.” (Blakeslee, 182, 211) The “heart,” the “stomach,” and (the) “intestines” are regulated by the autonomic nervous system (Chudler, 33) Regulates involuntary functions, such as “heartbeat,” “blood pressure,” “breathing,” and digestion. (Oxford) Responsible for regulating organ function and metabolism. Autonomic Nervous System: part of the nervous system serving organs, which control the normally involuntary functions of the body.
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