Lecture 4 part 2 Flashcards
What are sound waves? How do we hear them?
compression and expansion of air molecules; ear detects these brief changes in pressure
What determines the intensity of sound waves?
amplitude
What determines the pitch of sound waves?
wavelength
What is the pathway of hearing?
- soundwaves make eardrum vibrate
- tiny bones in the middle ear transmit vibrations to the cochlea
- ripples in the fluid of the cochlea bend the hair cells (on surface of the cochlea) triggers neural impulse
- axons from these nerve cells transmit a signal to the auditory cortex
how many dB is a normal conversation?
60dB
What is place theory?
theory that links the pitch heard with the place where the cochlea’s membrane is stimulated; best explains high pitches
What is frequency theory?
the rate at which the nerve impulses travel up the auditory nerve matches the frequency of a tone; best explains low pitches
Touch is a mix of four distinct skin senses:
pressure, warmth, cold, pain
What are the old thoughts on pain research?
pain=tissue damage (not true)
there is a specific pain centre in the brain
Why do people get phantom limb pain?
mismatch between feedback brain expects and the feedback that it recieves
What is the purpose of pain? (4)
- response to a threat
- influences action
- early warning system
- protects us from ourselves and environment
what is nociception?
response to body’s sensory nervous system towards real or potential harm
What are nociceptors?
nerve cell endings that initiate the sensation of pain
What is the pathway of perceiving pain?
stimulus–peripheral nociceptors– spinal cord– thalamus– somatosensory cortex–limbic system–frontal cortex
What are the roles of the thalamus– somatosensory cortex–limbic system–frontal cortex in nociception?
thalamus: control centre
somatosensory cortex: identify and localize pain
limbic system: emotion
frontal cortex: interprets and assigns meaning
How does pain work? (chemical process of triggering nociceptors)
- cells get damaged, then produce chemicals like arachidonic acid
- cox-1/cox-2 enzymes convert acid into prostaglandins H2
- prostaglandins H2 is converted into other chemicals that do things like raise body temp, cause inflammation
where do pain medications work?
enzymes cox-1 and cox-2 active sites
How does aspirin/ibuprofen work?
- it blocks prostaglandins from forming
- enters enzyme active site and leaves half of itself there
- blocks channel that arachidonic acid binds to
What are the biopsychosocial factors that influence pain?
- beliefs about pain
- fears/ expectations
- memories/experience/trauma
- emotional state
- personality
- attention
What personality do people with chronic pain have?
- people pleasers
- overly self-critical
- need to be perfect
- overly conscientious
What is the definition of chronic pain?
pain lasting more than 3 months, brain becomes more sensitive to pain and nerves amplify the messages
How do we taste?
molecules of a substance are dissolved in our saliva and bind to taste receptors on taste buds
What are the five taste receptors? What are their evolutionary purposes?
Sweet: energy
Salty: need sodium for physiological processes
Sour: poison
Bitter: poison
umami: proteins for tissue repair
