Completed notes of the course

Pagina 1

NEUROSENSORY SYSTEM Functions of neurosensory system: • TRANSMIT – from the body to the nervous system • DETECT, PROCESS and LEARN – stimuli and information, exogenous and endogenous • GENERATE – sensations • RECOGNIZE – semantics • CONTROL – actions, movements, internal secretions (glands) • GENERATE and PROCESS – signaling from high-level functions (cognition, creativity, decisional processes) There are two different pathway: AFFERENT PATHWAY : from periphery to center, for example: from receptors (skin, eyes, ears, …) to the central nervous system EFFERENT PATHWAY: from center to periphery, for example: from motor cortex to muscles In addition, sensory systems are interconnected with each other and connected with other non-sensory systems (e.g., sudden and loud noise induces palpebral reflex, hormonal reactions, increase of the heart rate, and so on). STIMULI AND ENERGY Our senses’ receptors convert one form of energy into electrical energy • In the eye there are ‘photoreceptors‘. When light touches these receptors they undergo a sudden reaction which generates electrical energy. The type of Energy is electromagnetic radiation • In the tongue and nose there are ‘chemoreceptors‘ which react to chemicals and generate electrical energy. The type of Energy is chemical one. • The skin and ears use ‘mechanoreceptors‘ which are physically moved, either by us touching something or by us hearing something. The type of Energy is sound for ears and mechanical and thermal for skin. It is necessary to know and measure the relationship between stimuli and sensations in order to describe physiologically behaviours, to diagnose, to monitor functionality and to design and fit protheses, implants and devices to provide support for disabling conditions. For this reason is necessary to…