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Psychology

<OpenstaxParagraph>
	A number of receptors are distributed throughout the skin to respond to various touch-related stimuli (<a href="#Figure_05_05_Touch">Figure 5.23</a>). These receptors include Meissner’s corpuscles, Pacinian corpuscles, Merkel’s disks, and Ruffini corpuscles. <OpenstaxTerm>Meissner’s corpuscles</OpenstaxTerm> respond to pressure and lower frequency vibrations, and <OpenstaxTerm>Pacinian corpuscles</OpenstaxTerm> detect transient pressure and higher frequency vibrations. <OpenstaxTerm>Merkel’s disks</OpenstaxTerm> respond to light pressure, while <OpenstaxTerm>Ruffini corpuscles</OpenstaxTerm> detect stretch (Abraira &amp; Ginty, 2013).
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_05_05_Touch" src="https://openstax.org/apps/archive/20240226.174525/resources/be269ed61f5259c5fd4b92c698ccaa4092379c26" alt="An illustration shows “skin surface” underneath which different receptors are identified: the “pacinian corpuscle,” “ruffini corpuscle,” “merkel’s disk,” and “meissner’s corpuscle.”" mediaType="image/jpg" width="557" height="312" />
<OpenstaxFigureText width="557">
	<strong>Figure 5.23</strong> There are many types of sensory receptors located in the skin, each attuned to specific touch-related stimuli.
</OpenstaxFigureText>
<OpenstaxParagraph>
	In addition to the receptors located in the skin, there are also a number of free nerve endings that serve sensory functions. These nerve endings respond to a variety of different types of touch-related stimuli and serve as sensory receptors for both <OpenstaxTerm>thermoception</OpenstaxTerm> (temperature perception) and <OpenstaxTerm>nociception</OpenstaxTerm> (a signal indicating potential harm and maybe pain) (Garland, 2012; Petho &amp; Reeh, 2012; Spray, 1986). Sensory information collected from the receptors and free nerve endings travels up the spinal cord and is transmitted to regions of the medulla, thalamus, and ultimately to the somatosensory cortex, which is located in the postcentral gyrus of the parietal lobe.
</OpenstaxParagraph>
<OpenstaxH3>Pain Perception</OpenstaxH3>
<OpenstaxParagraph>
	Pain is an unpleasant experience that involves both physical and psychological components. Feeling pain is quite adaptive because it makes us aware of an injury, and it motivates us to remove ourselves from the cause of that injury. In addition, pain also makes us less likely to suffer additional injury because we will be gentler with our injured body parts.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Generally speaking, pain can be considered to be neuropathic or inflammatory in nature. Pain that signals some type of tissue damage is known as <OpenstaxTerm>inflammatory pain</OpenstaxTerm>. In some situations, pain results from damage to neurons of either the peripheral or central nervous system. As a result, pain signals that are sent to the brain get exaggerated. This type of pain is known as <OpenstaxTerm>neuropathic pain</OpenstaxTerm>. Multiple treatment options for pain relief range from relaxation therapy to the use of analgesic medications to deep brain stimulation. The most effective treatment option for a given individual will depend on a number of considerations, including the severity and persistence of the pain and any medical/psychological conditions.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Some individuals are born without the ability to feel pain. This very rare genetic disorder is known as <OpenstaxTerm>congenital insensitivity to pain </OpenstaxTerm>(or <OpenstaxTerm>congenital analgesia</OpenstaxTerm>). While those with congenital analgesia can detect differences in temperature and pressure, they cannot experience pain. As a result, they often suffer significant injuries. Young children have serious mouth and tongue injuries because they have bitten themselves repeatedly. Not surprisingly, individuals suffering from this disorder have much shorter life expectancies due to their injuries and secondary infections of injured sites (U.S. National Library of Medicine, 2013).
</OpenstaxParagraph>
<OpenstaxNote>
	<OpenstaxNoteTitle> Link to Learning </OpenstaxNoteTitle> 
	<OpenstaxParagraph>
		Watch this <a href="http://openstax.org/l/congenital">video about congenital insensitivity to pain</a> to learn more.
	</OpenstaxParagraph>
</OpenstaxNote>

5.5.2 Touch, Thermoception, and Nociception

1 Introduction to Psychology

1.1 What Is Psychology?

1.1.1 Why Study Psychology?

1.2 History of Psychology

1.2.1 Wundt and Structuralism

1.2.2 Functionalism

1.2.3 Freud and Psychoanalytic Theory

1.2.4 Wertheimer, Koffka, Köhler, and Gestalt Psychology

1.2.5 Pavlov, Watson, Skinner, and Behaviorism

1.2.6 Maslow, Rogers, and Humanism

1.2.7 The Cognitive Revolution

1.2.8 Multicultural And Cross-Cultural Psychology

1.2.9 Women in Psychology

1.3 Contemporary Psychology

1.3.1 Biopsychology and Evolutionary Psychology

1.3.2 Sensation and Perception

1.3.3 Cognitive Psychology

1.3.4 Developmental Psychology

1.3.5 Personality Psychology

1.3.6 Social Psychology

1.3.7 Industrial-Organizational Psychology

1.3.8 Health Psychology

1.3.9 Sport and Exercise Psychology

1.3.10 Clinical Psychology

1.3.11 Forensic Psychology

1.4 Careers in Psychology

1.4.1 Other Careers in Academic Settings

1.4.2 Career Options Outside of Academic Settings

2 Psychological Research

2.1 Why Is Research Important?

2.1.1 Use of Research Information

2.1.2 NOTABLE RESEARCHERS

2.1.3 The Process of Scientific Research

2.2 Approaches to Research

2.2.1 Clinical or Case Studies

2.2.2 Naturalistic Observation

2.2.3 Surveys

2.2.4 Archival Research

2.2.5 Longitudinal and Cross-Sectional Research

2.3 Analyzing Findings

2.3.1 Correlational Research

2.3.2 Causality: Conducting Experiments and Using the Data

2.3.3 Reliability and Validity

2.4 Ethics

2.4.1 Research Involving Human Participants

2.4.2 Research Involving Animal Subjects

3 Biopsychology

3.1 Human Genetics

3.1.1 Genetic Variation

3.1.2 Gene-Environment Interactions

3.2 Cells of the Nervous System

3.2.1 Neuron Structure

3.2.2 Neuronal Communication

3.2.3 Neurotransmitters and Drugs

3.3 Parts of the Nervous System

3.3.1 Peripheral Nervous System

3.4 The Brain and Spinal Cord

3.4.1 The Spinal Cord

3.4.2 The Two Hemispheres

3.4.3 Forebrain Structures

3.4.4 Midbrain and Hindbrain Structures

3.4.5 Brain Imaging

3.5 The Endocrine System

3.5.1 Major Glands

4 States of Consciousness

4.1 What Is Consciousness?

4.1.1 Biological Rhythms

4.1.2 Problems With Circadian Rhythms

4.2 Sleep and Why We Sleep

4.2.1 What is Sleep?

4.2.2 Why Do We Sleep?

4.3 Stages of Sleep

4.3.1 NREM Stages of Sleep

4.3.2 REM Sleep

4.4 Sleep Problems and Disorders

4.4.1 Insomnia

4.4.2 Parasomnias

4.4.3 Sleep Apnea

4.4.4 Narcolepsy

4.5 Substance Use and Abuse

4.5.1 Substance Use Disorders

4.5.2 Drug Categories

4.6 Other States of Consciousness

4.6.1 Hypnosis

4.6.2 Meditation

5 Sensation and Perception

5.1 Sensation versus Perception

5.1.1 Sensation

5.1.2 Perception

5.2 Waves and Wavelengths

5.2.1 Amplitude and Wavelength

5.2.2 Light Waves

5.2.3 Sound Waves

5.3 Vision

5.3.1 Anatomy of the Visual System

5.3.2 Color and Depth Perception

5.4 Hearing

5.4.1 Anatomy of the Auditory System

5.4.2 Pitch Perception

Question	Answer
signal that some type of tissue damage has occurred	inflammatory pain
pain from damage to neurons of either the peripheral or central nervous system	neuropathic pain
sensory signal indicating potential harm and maybe pain	nociception
temperature perception	thermoception