General Cutaneous Sensations
LAB 2
GENERAL CUTANEOUS SENSATIONS
INTRODUCTION
This lab involves the examination of cutaneous receptors. There are four exercises. For this lab, report your observations in a formal report, according to the formatting prescribed in Lab Report Format.doc which is found on Blackboard under Assignments/Before You Begin.
Equipment needed:
Metal calipers or compass with pencil 2 or more blunt probes (ball point pens or forks with blunt tines) 3 pennies 1 liter ice water in large container 1 liter hot water in large container (make sure it is bearable to the touch) 1 liter room-temperature water in large container Felt-tip markers, blue, red, and black (not permanent) Stop watch or digital watch
Introduction:
A sensation is defined as a state of awareness, of the internal or external environment. For a sensation to occur, four criteria must be met. First, there must be a stimulus. This is a change in the environment, to which we will become aware. Next, there must be a receptor. A receptor is a cell, or an organ, which is sensitive to the stimulus. There also must be an afferent (sensory) nerve pathway, to carry signals to the central nervous system. Finally, there must be sensory cortex, where the signals will be analyzed and interpreted consciously.
The skin is responsive to a number of stimuli. These include light touch, deep pressure, vibration, and changes in temperature. Any stimulus must be of threshold magnitude to be detected. All sensory systems have a limit to their sensitivity; any stimulus below a minimum magnitude cannot elicit a response.
The receptors for general cutaneous sensations are small, modified nerve endings. They are scattered throughout the skin and underlying fascia. These receptors are adapted to be most sensitive to certain stimuli:
Type of receptor Stimulus Typical Sensation
Mechanoreceptors mechanical agitation touch, pressure, vibration Thermoreceptors
GENERAL CUTANEOUS SENSATIONS
INTRODUCTION
This lab involves the examination of cutaneous receptors. There are four exercises. For this lab, report your observations in a formal report, according to the formatting prescribed in Lab Report Format.doc which is found on Blackboard under Assignments/Before You Begin.
Equipment needed:
Metal calipers or compass with pencil 2 or more blunt probes (ball point pens or forks with blunt tines) 3 pennies 1 liter ice water in large container 1 liter hot water in large container (make sure it is bearable to the touch) 1 liter room-temperature water in large container Felt-tip markers, blue, red, and black (not permanent) Stop watch or digital watch
Introduction:
A sensation is defined as a state of awareness, of the internal or external environment. For a sensation to occur, four criteria must be met. First, there must be a stimulus. This is a change in the environment, to which we will become aware. Next, there must be a receptor. A receptor is a cell, or an organ, which is sensitive to the stimulus. There also must be an afferent (sensory) nerve pathway, to carry signals to the central nervous system. Finally, there must be sensory cortex, where the signals will be analyzed and interpreted consciously.
The skin is responsive to a number of stimuli. These include light touch, deep pressure, vibration, and changes in temperature. Any stimulus must be of threshold magnitude to be detected. All sensory systems have a limit to their sensitivity; any stimulus below a minimum magnitude cannot elicit a response.
The receptors for general cutaneous sensations are small, modified nerve endings. They are scattered throughout the skin and underlying fascia. These receptors are adapted to be most sensitive to certain stimuli:
Type of receptor Stimulus Typical Sensation
Mechanoreceptors mechanical agitation touch, pressure, vibration Thermoreceptors