Pain and anesthesia Flashcards
What is pain?
an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
What is nociception?
the unconscious activity induced by a harmful stimulus applied to sense receptors
What is a noxious stimuli?
- harmful, poisonous or very unpleasant stimuli
What is hyperalgesia?
an exaggerated response to a noxious stimulus
What is allodynia?
a sensation of pain in response to a normally innocuous stimulus
What is sensitization?
when intense, repeated, or prolonged stimuli are applied to damaged or inflamed tissues, the threshold for activating primary afferent nociceptors is lowered, and the frequency of firing is higher for all stimulus intensities
hyperalgesia and allodynia signify increased sensitivity of _________________________________
nociceptive afferent fibers
What contributes to sensitization?
inflammatory mediators such as bradykinin (BK), nerve-growth factor (NGF), some prostaglandins (PGs), and leukotrienes (LTs)
What is the inability or reduced ability to feel pain without
loss of consciousness or other sensations?
analgesia
What are substances that reduce the ability to feel pain?
Analgesics
What is anesthesia and an anesthetic?
Anesthesia
* insensitivity to pain
Anesthetics
* substances that produce a general insensitivity to pain
How do general anesthetics work?
depress the CNS to a sufficient degree to permit the performance of surgery and unpleasant procedures
How do local anesthetics work?
substance that when in contact with a nerve trunk can cause both sensory and motor paralysis in the area innervated
What are mechanoreceptors?
- mediate responses to touch and pressure
- mechanical nociceptors respond to strong pressure (e.g. from a sharp object)
What are thermoreceptors?
detect the sensations of warmth and cold
What are chemoreceptors?
stimulated by a change in the chemical composition of the local environment (taste, smell, plasma levels of nutrients, etc.)
What are acid-sensing ion channel (ASIC) receptors activated by?
pH changes
What are transient receptor potential (TRP) channels activated by?
TRPV1 - intense heat, acids, and chemicals such as capsaicin
TRPA1 - noxious mechanical, cold, or chemical stimuli
ATP acts on ______________ receptors
purinergic
Nerve growth factor acts on ________________________ receptors?
tyrosine receptor kinase A (TrkA)
ATP signaling on ionotropic receptors is very similar to ______________
acetylcholine (ACh)
What are agonists to the G-protein couples receptors?
bradykinin
histamine
prostaglandins
serotonin (5-HT)
substance P
CGRP
What are the intermediate signaling molecules (pain)?
- adenosine triphosphate (ATP)
- bradykinin
- histamine
- prostaglandins
- serotonin (5-hydroxytryptamine or 5HT)
- substance P
- calcitonin gene-related protein (CGRP)
- nerve growth factor
What are immediate changes in neuronal responsiveness?
changes in membrane potential produced by altered calcium concentrations
