Podcast
Questions and Answers
What is characterized by non-painful stimuli causing pain in sunburnt areas?
What is characterized by non-painful stimuli causing pain in sunburnt areas?
Which of the following substances is NOT typically associated with peripheral sensitization?
Which of the following substances is NOT typically associated with peripheral sensitization?
What initiates the series of reactions in the inflammatory area during primary hyperalgesia?
What initiates the series of reactions in the inflammatory area during primary hyperalgesia?
What term describes increased pain sensitivity in undamaged tissues surrounding a painful area?
What term describes increased pain sensitivity in undamaged tissues surrounding a painful area?
Signup and view all the answers
Which process promotes the activation of immune system cells and causes vasodilation in inflamed areas?
Which process promotes the activation of immune system cells and causes vasodilation in inflamed areas?
Signup and view all the answers
What causes a higher impulse frequency to be sent to the brain when a painful stimulus is applied?
What causes a higher impulse frequency to be sent to the brain when a painful stimulus is applied?
Signup and view all the answers
Which cell type is primarily responsible for the release of inflammatory substances in peripheral tissues?
Which cell type is primarily responsible for the release of inflammatory substances in peripheral tissues?
Signup and view all the answers
Which neurotransmitter is released from pain nerve endings during primary hyperalgesia?
Which neurotransmitter is released from pain nerve endings during primary hyperalgesia?
Signup and view all the answers
What is the primary function of the antinociceptive system?
What is the primary function of the antinociceptive system?
Signup and view all the answers
Which fibers are primarily responsible for transmitting pain signals through the peripheral antinociceptive system?
Which fibers are primarily responsible for transmitting pain signals through the peripheral antinociceptive system?
Signup and view all the answers
What role do large diameter myelinated non-pain fibers play in the peripheral antinociceptive system?
What role do large diameter myelinated non-pain fibers play in the peripheral antinociceptive system?
Signup and view all the answers
What occurs when pain receptors are stimulated?
What occurs when pain receptors are stimulated?
Signup and view all the answers
What happens when touch-pressure conducting Aß fibers are activated in the same region as pain endings?
What happens when touch-pressure conducting Aß fibers are activated in the same region as pain endings?
Signup and view all the answers
What is the role of descending nerve fibers from the brain in the central antinociceptive system?
What is the role of descending nerve fibers from the brain in the central antinociceptive system?
Signup and view all the answers
Which of the following describes secondary pain sensation?
Which of the following describes secondary pain sensation?
Signup and view all the answers
What do the C fibers do in the pain pathway?
What do the C fibers do in the pain pathway?
Signup and view all the answers
What is the primary way through which acupuncture and massage alleviate pain?
What is the primary way through which acupuncture and massage alleviate pain?
Signup and view all the answers
How does the central antinociceptive system function in response to pain signals?
How does the central antinociceptive system function in response to pain signals?
Signup and view all the answers
What role do the limbic system structures play in pain perception?
What role do the limbic system structures play in pain perception?
Signup and view all the answers
Which neurotransmitter is released by the raphe nuclei in response to pain signals?
Which neurotransmitter is released by the raphe nuclei in response to pain signals?
Signup and view all the answers
What happens when touch and pressure nerve endings are stimulated?
What happens when touch and pressure nerve endings are stimulated?
Signup and view all the answers
What is the effect of dopamine and opioid peptide secreting neurons in the periaqueductal grey matter?
What is the effect of dopamine and opioid peptide secreting neurons in the periaqueductal grey matter?
Signup and view all the answers
Which structure is NOT a part of the brainstem that activates in response to pain signals?
Which structure is NOT a part of the brainstem that activates in response to pain signals?
Signup and view all the answers
What type of synaptic activity occurs between the touch pathway and the pain pathway?
What type of synaptic activity occurs between the touch pathway and the pain pathway?
Signup and view all the answers
What condition is characterized by the absence of the sense of smell due to damage to receptors, pathways, or centers?
What condition is characterized by the absence of the sense of smell due to damage to receptors, pathways, or centers?
Signup and view all the answers
Which of the following is the most common cause of decreased smell sensation?
Which of the following is the most common cause of decreased smell sensation?
Signup and view all the answers
In which age group does the number of smell receptors begin to progressively decrease?
In which age group does the number of smell receptors begin to progressively decrease?
Signup and view all the answers
Which statement is true regarding the decreased sense of smell in neurodegenerative diseases?
Which statement is true regarding the decreased sense of smell in neurodegenerative diseases?
Signup and view all the answers
What is a common cause of hyposmia during the common cold?
What is a common cause of hyposmia during the common cold?
Signup and view all the answers
Which component is NOT affected by the SARS-CoV-2 virus in relation to smell?
Which component is NOT affected by the SARS-CoV-2 virus in relation to smell?
Signup and view all the answers
What can cause total nasal cavity obstruction leading to smell loss?
What can cause total nasal cavity obstruction leading to smell loss?
Signup and view all the answers
What is commonly associated with a decreased sense of smell in both males and females as they age?
What is commonly associated with a decreased sense of smell in both males and females as they age?
Signup and view all the answers
Which of the following factors can stimulate the olfactory epithelium even in the absence of external odor substances?
Which of the following factors can stimulate the olfactory epithelium even in the absence of external odor substances?
Signup and view all the answers
What term describes a partial loss of smell, often noted in patients with some damage to olfactory structures?
What term describes a partial loss of smell, often noted in patients with some damage to olfactory structures?
Signup and view all the answers
What happens after the influx of Ca2+ in the synapse?
What happens after the influx of Ca2+ in the synapse?
Signup and view all the answers
How is the bitter taste signal transduced to initiate neurotransmitter release?
How is the bitter taste signal transduced to initiate neurotransmitter release?
Signup and view all the answers
Which of the following substances is primarily associated with the umami taste?
Which of the following substances is primarily associated with the umami taste?
Signup and view all the answers
Which statement is true regarding taste receptor cells?
Which statement is true regarding taste receptor cells?
Signup and view all the answers
Which statement correctly describes the role of phosphatidylinositol bisphosphate (PIP2) in taste transduction?
Which statement correctly describes the role of phosphatidylinositol bisphosphate (PIP2) in taste transduction?
Signup and view all the answers
Which of the following ions are known to influence taste perception?
Which of the following ions are known to influence taste perception?
Signup and view all the answers
What is the role of IP3 and DAG in the taste transduction process?
What is the role of IP3 and DAG in the taste transduction process?
Signup and view all the answers
What is characteristic of individuals with genetic defects related to bitter taste receptors?
What is characteristic of individuals with genetic defects related to bitter taste receptors?
Signup and view all the answers
What structure is responsible for the conscious feeling of pain localization?
What structure is responsible for the conscious feeling of pain localization?
Signup and view all the answers
Which pathway primarily transmits pain and temperature sensations?
Which pathway primarily transmits pain and temperature sensations?
Signup and view all the answers
Where do the first-order neurons of the lateral spinothalamic tract synapse?
Where do the first-order neurons of the lateral spinothalamic tract synapse?
Signup and view all the answers
What is the second step in the lateral spinothalamic tract pathway?
What is the second step in the lateral spinothalamic tract pathway?
Signup and view all the answers
How does the primary sensory pathway for touch and proprioception begin?
How does the primary sensory pathway for touch and proprioception begin?
Signup and view all the answers
What happens after the second-order neuron in the lateral spinothalamic tract crosses to the opposite side of the spinal cord?
What happens after the second-order neuron in the lateral spinothalamic tract crosses to the opposite side of the spinal cord?
Signup and view all the answers
What is the primary function of free nerve endings in the nociceptive sensory system?
What is the primary function of free nerve endings in the nociceptive sensory system?
Signup and view all the answers
Which of the following best describes the pathway taken by pain impulses from the periphery to the brain?
Which of the following best describes the pathway taken by pain impulses from the periphery to the brain?
Signup and view all the answers
What is the primary function of the sensory component in pain perception?
What is the primary function of the sensory component in pain perception?
Signup and view all the answers
What physiological changes cause hyperalgesia?
What physiological changes cause hyperalgesia?
Signup and view all the answers
Which statement accurately describes the affective component of pain?
Which statement accurately describes the affective component of pain?
Signup and view all the answers
How does the autonomic component affect an individual experiencing pain?
How does the autonomic component affect an individual experiencing pain?
Signup and view all the answers
Which of the following accurately describes allodynia?
Which of the following accurately describes allodynia?
Signup and view all the answers
What distinguishes chronic pain from acute pain?
What distinguishes chronic pain from acute pain?
Signup and view all the answers
What mechanism is activated in response to nociceptive input in an extremity?
What mechanism is activated in response to nociceptive input in an extremity?
Signup and view all the answers
Which of the following pathways is NOT involved in transmitting pain impulses to conscious centers?
Which of the following pathways is NOT involved in transmitting pain impulses to conscious centers?
Signup and view all the answers
What mechanism underlies the reorganization of synapses in hyperalgesia?
What mechanism underlies the reorganization of synapses in hyperalgesia?
Signup and view all the answers
Which of the following describes a key effect of central sensitization?
Which of the following describes a key effect of central sensitization?
Signup and view all the answers
What role do the limbic structures play in pain experiences?
What role do the limbic structures play in pain experiences?
Signup and view all the answers
In the context of pain pathways, what happens to inhibitory neurons during central sensitization?
In the context of pain pathways, what happens to inhibitory neurons during central sensitization?
Signup and view all the answers
Which statement about the motor component in pain response is correct?
Which statement about the motor component in pain response is correct?
Signup and view all the answers
What results from the stimulation of pain receptors in the body?
What results from the stimulation of pain receptors in the body?
Signup and view all the answers
What is the primary consequence of the reorganization of synapses between touch and pain neurons in allodynia?
What is the primary consequence of the reorganization of synapses between touch and pain neurons in allodynia?
Signup and view all the answers
What is a characteristic feature of acute pain?
What is a characteristic feature of acute pain?
Signup and view all the answers
Which inflammatory substance is primarily responsible for causing pain receptor sensitization during secondary hyperalgesia?
Which inflammatory substance is primarily responsible for causing pain receptor sensitization during secondary hyperalgesia?
Signup and view all the answers
What mechanism is responsible for the increase in impulse frequency when a painful stimulus is applied?
What mechanism is responsible for the increase in impulse frequency when a painful stimulus is applied?
Signup and view all the answers
What is the primary role of calcitonin gene related peptide (CGRP) released from pain nerve endings?
What is the primary role of calcitonin gene related peptide (CGRP) released from pain nerve endings?
Signup and view all the answers
What does primary hyperalgesia primarily involve?
What does primary hyperalgesia primarily involve?
Signup and view all the answers
Which process is NOT directly involved in the development of primary hyperalgesia?
Which process is NOT directly involved in the development of primary hyperalgesia?
Signup and view all the answers
Which of the following best describes the difference between primary and secondary hyperalgesia?
Which of the following best describes the difference between primary and secondary hyperalgesia?
Signup and view all the answers
What type of cells release inflammatory substances that contribute to peripheral sensitization?
What type of cells release inflammatory substances that contribute to peripheral sensitization?
Signup and view all the answers
Which of the following best describes the role of ATP in the context of peripheral sensitization?
Which of the following best describes the role of ATP in the context of peripheral sensitization?
Signup and view all the answers
What is the first step in the signaling pathway for bitter, sweet, or umami tastes?
What is the first step in the signaling pathway for bitter, sweet, or umami tastes?
Signup and view all the answers
Which of the following accurately describes the role of diacylglycerol (DAG) in taste transduction?
Which of the following accurately describes the role of diacylglycerol (DAG) in taste transduction?
Signup and view all the answers
How many different genes encode bitter taste receptors in taste receptor cells?
How many different genes encode bitter taste receptors in taste receptor cells?
Signup and view all the answers
What initiates neurotransmitter release in synapses with afferent nerve fibers upon taste transduction?
What initiates neurotransmitter release in synapses with afferent nerve fibers upon taste transduction?
Signup and view all the answers
Which of the following substances is linked primarily to the perception of sweet taste?
Which of the following substances is linked primarily to the perception of sweet taste?
Signup and view all the answers
What is the biological significance of distinct taste qualities being activated by different receptors?
What is the biological significance of distinct taste qualities being activated by different receptors?
Signup and view all the answers
Which sequence correctly depicts the process of taste transduction for bitter taste?
Which sequence correctly depicts the process of taste transduction for bitter taste?
Signup and view all the answers
What is a characteristic feature of bitter taste receptors among the different taste receptor types?
What is a characteristic feature of bitter taste receptors among the different taste receptor types?
Signup and view all the answers
Study Notes
Pain sensitivity
- Pain sensitivity increases after damage to tissues.
- Pain can be caused by previously non-painful stimuli.
- Hyperalgesia: Increased pain sensitivity to painful stimuli.
- Allodynia: Pain caused by non-painful stimuli.
- Peripheral and central sensitization contribute to the development of both hyperalgesia and allodynia.
Peripheral Sensitization
- Occurs when inflammatory substances are released in peripheral tissues.
- These substances are primarily released from immune system cells, endothelial cells, damaged tissues, and platelets.
- Inflammatory substances, such as histamine, bradykinin, interleukins, ATP, adenosine, serotonin, endothelin, and growth factors, increase the sensitivity of pain nerve endings.
Primary Hyperalgesia
- Refers to pain sensitivity in damaged tissues.
- Pain nerve endings release calcitonin gene-related peptide (CGRP), substance P, and neurokinins through the axon reflex.
- These neurotransmitters stimulate neighboring cells and trigger a series of reactions, including:
- Proliferation of keratinocytes.
- Activation of immune system cells.
- Vasodilation in the skin, leading to edema formation and redness.
- Smooth muscle contraction in the irritated region.
Secondary Hyperalgesia
- Refers to pain sensitivity in undamaged tissues surrounding the injured area.
- Mast cell degranulation releases histamine.
- Histamine causes pain receptor sensitization and inflammatory reactions.
Antinociceptive System
- This system works to suppress the transmission of pain signals.
- Its purpose is to decrease pain sensation after the nociceptive system has sent its warning signal.
- It enables us to move away from a painful area, preventing further damage.
- It consists of two parts:
- Peripheral antinociceptive system: Large diameter myelinated non-pain fibers inhibit impulse transmission from pain fibers to the central nervous system.
- Central antinociceptive system: Descending nerve fibers from the brain decrease pain impulse transmission from the spinal cord to higher centers of the nociceptive system.
Peripheral Antinociceptive System
- Pain signals are transmitted through unmyelinated C nerve fibers.
- These fibers start at free nerve endings and carry impulses to the posterior horn of the spinal cord.
- C fibers activate second-order neurons, which send impulses through the lateral spinothalamic tract.
- They also inhibit the inhibitory neuron that normally suppresses pain transmission.
Touch & Pressure Pathway
- Myelinated Aß fibers carry impulses about touch and pressure.
- When activated, Aß fibers stimulate an inhibitory neuron in the dorsal horn of the spinal cord.
- The inhibitory neuron suppresses the transmission of pain impulses.
- This is why rubbing or applying pressure to a painful area often reduces pain.
Central Antinociceptive System
- Enables the brain to suppress pain signal transmission.
- Pain signals are sent to the brain stem structures:
- Limbic system (limbic cortex, amygdaloid nucleus, hypothalamus).
- Periaqueductal grey matter.
- Raphe nuclei and locus coeruleus.
- The limbic system, responsible for emotional and cognitive responses, sends impulses to the periaqueductal grey matter in the midbrain.
- The periaqueductal grey matter stimulates the raphe nuclei and locus coeruleus, which release serotonin and norepinephrine, respectively.
Taste Qualities & Receptors
- Different taste qualities rely on different receptors, but the general mechanism is the same.
- Taste receptors are located on taste receptor cells and activate different second messenger pathways.
- These pathways ultimately lead to the release of neurotransmitters from the taste receptor cells.
-
Bitter Taste:
- Stimulated by ions (K+ and Mg2+) and organic substances like long-chain nitrogen-containing substances and alkaloids.
-
Sweet Taste:
- Stimulated by sugars, alcohols like sorbitol, aldehydes, ketones, amino acids, and proteins.
-
Umami Taste:
- Stimulated by L-glutamate.
Smell Disturbances
- Anosmia: Complete loss of smell.
- Hyposmia: Decreased sense of smell.
- Common causes include:
- Nasal cavity blockage (running nose).
- Physical damage to the olfactory epithelium, nerve, or brain pathways.
- Smell disturbances are also associated with:
- Aging (decreased number of smell receptors).
- Neurodegenerative diseases like Parkinson's and Alzheimer's.
- COVID-19.
Smell Disturbances and COVID-19
- COVID-19 infection can cause hyposmia due to inflammation in the nasal, paranasal, and oral cavities.
- The SARS-CoV-2 virus does not directly affect smell receptors.
- The virus targets sustentacular cells and respiratory cells, triggering inflammation and inhibiting impulse transmission from olfactory cells to the central nervous system.
Nociceptive Sensory System
- The nociceptive sensory system is responsible for detecting and transmitting pain signals.
- Receptors: Free nerve endings located in the skin, subcutaneous tissues, and internal organs are sensitive to pain signals.
- Pathway: Impulses are primarily conducted through the lateral spinothalamic tract, with impulses from the head transmitted through the trigeminal pathway.
- Center: The postcentral gyrus of the cerebral cortex is where the conscious feeling of pain is produced.
- Pain and temperature are transmitted via the lateral spinothalamic tract pathway.
- Touch and proprioception are transmitted via the dorsal column medial lemniscus system/pathway.
Hyperalgesia & Allodynia
- Hyperalgesia is an increased sensitivity to pain, where previously non-painful stimuli now cause pain.
- Allodynia is pain caused by a stimulus that does not normally cause pain.
- Both hyperalgesia and allodynia are caused by peripheral and central sensitization.
Peripheral Sensitization
- Peripheral sensitization occurs when inflammatory substances are released in peripheral tissues.
- Key inflammatory substances include histamine, bradykinin, interleukins, ATP, adenosine, serotonin, endothelin, and different growth factors.
- These substances are released by immune system cells, endothelial cells, damaged tissues, and platelets.
- Inflammatory substances increase the sensitivity of pain nerve endings, leading to a higher frequency of impulses sent to the brain.
- Primary hyperalgesia refers to pain sensitivity directly in the damaged tissues.
- Secondary hyperalgesia refers to pain sensitivity that occurs in surrounding undamaged tissues.
Central Sensitization
- Central sensitization involves the reorganization of impulse transmission in the central nervous system.
- Normal Sensation: Stimulation of pain nerve endings transmits impulses through pain pathways, causing pain sensation while stimulation of touch nerve endings transmits impulses through touch pathways, causing touch sensation.
-
Hyperalgesia: High impulse frequency is transmitted through pain pathways, leading to:
- Increased neurotransmitter release.
- Increased receptor number on postsynaptic membranes.
- Loss and dysfunction of inhibitory neurons.
-
Allodynia: Reorganization of pain synapses affects the touch pathway, causing:
- Increased neurotransmitter amount.
- Increased receptor number in touch pathway synapses.
- Loss and dysfunction of inhibitory neurons, leading to decreased inhibition of the pain pathway.
- Touch pathway starts sending more impulses to the pain pathway.
Pain Types
- Acute pain is physiological pain in previously intact tissues, caused by sudden tissue damage.
- Chronic pain persists for longer than 3 months.
Pain Components
- Sensory: The subjective feeling of pain, produced by impulse transmission to the cortical centers.
- Cognitive: Pain impulses are transmitted to the limbic cortex, allowing for classification and evaluation of pain compared to previous experiences.
- Affective: Pain impulses are transmitted to the limbic system structures, causing negative emotions.
- Autonomic: Pain signals are transmitted from the spinal cord to the hypothalamus, stimulating sympathetic reactions.
- Motor: Pain signals are transmitted to the somatic nervous system innervating skeletal muscles, causing tension in flexor muscles.
Nociceptive Reflex & Crossed Extensor Reflex
- Nociceptive reflex: Pain receptors send impulses to the spinal cord, activating motor neurons that innervate flexor muscles, leading to muscle contraction.
- Crossed extensor reflex: A reflex that occurs in the opposite limb from the one that received painful input.
Taste Qualities
- Bitter: Bitter taste receptors are superior in number on taste receptor cells.
- Sweet, Umami: The general mechanism for sweet, umami, and bitter taste involves G protein activation, Phospholipase C conversion of PIP2 into IP3 and DAG, Ca2+ channel opening, and neurotransmitter release.
- Bitter taste receptors are encoded by approximately 30 different genes.
- Taste thresholds refer to the minimum concentration of a substance needed to elicit a taste perception.
- Biological role of taste: Taste is essential for selecting appropriate food, detecting toxic substances, and contributing to overall food enjoyment.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the concepts of pain sensitivity, hyperalgesia, and allodynia in this quiz. Understand how tissue damage and inflammatory substances influence pain perception. Test your knowledge on peripheral sensitization and neurotransmitter roles in pain signaling.
