Anatomy and Physiology of Special Sensory Organs
Sensory organs can be labeled as special sensory structures that permit sight, hearing, odor, and flavor. Sensory structures permitting proprioception, touch, thermal, and pain perception can be classified as more advanced sensory organs. The sensory neurons are trained to find out modifications in the external and internal conditions so that a person's body can react to that change. A stimulus is the first signal that is recognized by any sensory receptor of the body. Stimulus is an impulse generated when there is a change in the surroundings of a person. For example, a heated environment will alert the brain through the thermal sensory organs and generate a reflex accordingly.
Sensory Receptors
The human sensory system is one of the most complex and highly evolved structures, which processes a myriad of incoming messages. This well-coordinated system helps an organism or individual to respond to external stimuli, appropriately. The sensory receptors are an important part of the sensory system. These receptors are specialized epidermal cells that respond to external environmental stimuli. These receptors consist of structural and support cells that form the peripheral unit of the receptor and the neural dendrites which receive and detect the external stimuli.
Define positional information, and describe three ways in which it is conveyed.
Introduction
Positional information is a concept related to pattern formation in the developing embryo. Due to positional information cell acquire positional value and develops into specialized structure and give rise to spatial patterns.
During the early developmental stage, the fate of cell is usually determined by its surrounding or by its communication to its neighbouring cell which also has effect of position (Spatial. During the migration of cells and the formation of germ layers this plays a crucial role in development of specialized tissues according to position, such as Ectoderm lead to formation of brain, neural tube, eye lens etc.
Step by step
Solved in 2 steps
