Chapter 9 Function of the Sense Organs
Chapter 9 Function of the Sense Organs
Introduction Human life would be very different without the ability to sense and perceive external stimul Imagine your world without the ability to see, hear smell. touch. and feel
• Human life would be very different without the ability to sense and perceive external stimuli • Imagine your world without the ability to see, hear, smell, touch, and feel Introduction
Sensations Define sensation: A state of awareness of a stimulus Awareness When a stimulus is detected by the body below the level of consciousness Such as a change in blood pressure or blood pH Perception When a stimulus reaches consciousness; pain, hunger, thirst, sight sound, etc
Sensation requires 1) stimulus Any change in the environment, either internal or external, can generate a stimulus. Example: body temp, pH, BP, light, sound. 2) receptor A structure which detects a stimulus and converts it into an action potential 3)impulse conducted The action potential is send via dendrites to the somas of sensory neurons in the CNS 4)translation The particular region of the CNs that receives the APs will convert them an awareness of the stimulus
Environmental sensation is limited to those forms of energy that sensory receptors are designed to detect Sensory receptors may convey information to the cortex with awareness or perception and may lead to cerebrally controlled responses Sensory receptors also serve as afferent pathways for reflex action with or without conscious sensation
• Environmental sensation is limited to those forms of energy that sensory receptors are designed to detect. • Sensory receptors may convey information to the cortex with awareness or perception and may lead to cerebrally controlled responses. • Sensory receptors also serve as afferent pathways for reflex action with or without conscious sensation