L5 Flashcards
(28 cards)
Sensation definition
- Physical stimulation: visual, auditory, tactile, smell, taste ( eyes, ears, skin, nose, mouth )
Process of sensation
- Stimulation
- Sensory receptors ( eyes)
- Neural response
- Brain (visual/ auditory areas)
Vision
Stimuli: light waves
Receptors: rod and cone in retina
Pathway to brain: optic nerve
Brain: visual cortex
Hearing
Stimuli: sound wave
Receptors: pressure sensitive hair cell in cochlea of inner ear
Pathway: auditory nerve
Brain: Auditory cortex
Taste
Stimuli: molecules dissolved in fluid on tongue
Receptors: taste buds in tingue
Pathway: facial, vagus nerves
Brain: gustatory cortex
Smell
Stimuli: molecules dissolved in fluid in nose
Receptor: olfactory mucous neuron in mucous membrane
Pathway: olfactory nerve
Brain: olfactory cortex
Touch
Stimuli: pressure on skin
Receptors: sensitive ends of touch neurons
Pathway: cranial nerve
Brain: somatosensory cortex
How many stimulus is enough for us to detect
ABSOLUTE THRESHOLD
:the minimum intensity of stimulation that must occur before experiencing a sensation
How many stimulus change is enough for us t o detect
Difference threshold
Noticeable difference
How many stimulus is enough for us to detect?
Sensory adaption
Stimulus continuous : less response
Sudden decrease: stimulate
What is perception
Perception is brain’s further processing, organisation and interpretation of sensory information
- Info is meaningful, subjective
- Percipitation in different form (colour…)
Sensation process
- Physical stimuli ( green traffic light)
- Organ of 5 sense ( eye detect the signal)
- Electric signal (stimulus is transduced
- Brain (driver’s brain processed the signal, interprets the lights represent sign to continue driving
How to recognise information
- Bottom-up processing (physical stimulus)
- Stimulus contains physical stimulis
- Process each aspect of a stimulus
- Combine all stimulus into a full picture
- Build perception of the stimulus / recognize the object
Gestalt (pattern) principles
Brain uses innate (先天) principle to organise sensory
Proximity: objects close to each other perceptually are a group
Similarity: things that are similar will perceptually group together
Closure: human tend to complete familiar object that have a gap
Continuity: we tend to create continue figures
Figure & ground:
To identify the figure, brain will assign the rest of the image as background
Depth cues
Pictorial depth cues
- Occlusion 阻塞
A near object block an distal object - Relatives size
Far close = same size = big & small
Linear perspective:
Linear line join together in distance
Texture gradient
More near more details
Binocular depth
1. Cpnverge 越近越鬥雞 to measure distance
Visual illusion (視覺錯覺
Discrepancy between visual appearance & physical reality
- Ponzo illusion
Horizontal lines appears to be different length but actually in same size - The muller-lyer illusion
Arrow pointing in or out affect length of
Ine - Ames room illusion
Perception is affect by the background
Object constancy
Perceiving object as constant in shape, size, colour
Size: hv to know object how far from us
Shape: hv to know what angle are we seeing the object
Colour constancy: hv to compare the wavelength of light reflected from object
Def of pain
An unpleasant sensory and experience associated with actual or potential t issue damage, or described in terms of such damage
Psychology factor have an important role to play in all parts of pain
Different form of pain
Acute pain:
Occurs in short term
Quickly delivered by myelinated fast fibre
Perceive sharp and immediate pain
Mild or severe
Easily identify cause
Last <6months
Chronic pain
Transduced by unmyelinated slow fibres
Dull & steady pain
6 weeks to 12 months
More psychology in treatment
Biomedical linear models 唔同人對痛嘅反應唔同
Pain is not simply a consequence of excited nerve impulse
Phantom limbs-) impossible to feel pain but yes
Pain measurement
Acute pain-) higher in sensory description
Chronic pain -) higher in emotional description
Baker scale ( face 0-10)
The gate control, theory of pain
Pain messages go through a gate, open more, more pain message pass through-) more pain
Factors affecting gate control
Emotional : anxiety vs happy
Cognitive: focus on pain vs more involve in life activities
Physical factors: low activity level vs counter stimulation (rubbing)
Pain management
Pain redefinition : unpleasant but necessary
Distraction: distract from pain experience e.g. tv when injection
Imagery意象: ask patient to imagine sth that makes them happy & feel safe e.g. lying on beach
