Sensory And Perception (3b) Flashcards
Tactile or cutenous senses
The tactile or somatosensory system is a cogitation of skin senses including
- pressure
- touch
- temperature
- vibration
- pain
The tactile senses rely on a variety of receptors located in different parts of the skin
Free nerve endings
They are located near the surface of the skin. They detect touch, pressure, pain, and temperature
Meissner’s corpuscles
Located in fingertips, lips, and palms (hairless skin areas)
they transduce information about sensitive touch
Merkel’s discs
Located near the surface of the skin, and it transduces information about light to moderate pressure against skin
Ruffini’s end-organs
Located deep in the skin,they register heavy pressure and movement of the joints
Pacinian corpuscles
- located deep in the kin
- the function is to respond to vibrations and heavy pressure
Free pathway (myelinated pathway)
Sharp localized pain is felt quicker because it travels along myelinated neurons to the brain
Slow pathway (unmyelinated pathway)
These inputs communicate with brain regions involved in processing emotions; pain we perceive via slow pathway is more often burning pain than sharp pain
development of tactile senses
Developed at brith, after birth the ability to respond to different somatosensory stimuli is dependant on brain development and learning.
- Touch is necessary for healthy development
Gate control theory of pain
Patterns of neural activity can actually close a “gate”that prevents messages from reaching parts of the brain where they are perceives as pain
No pain (familial dysautonomia)
Rare genetic condition associated with the inability to detect pain or temperature and produce tears
Phantom limb sensations
Tactile hallucinations of touch, pressure, vibration, and pain in the body part that no longer exists
Sound waves
Vibrations of the air in the frequency of hearing
Frequency
The number of styles per second in a wave
- determines pitch of sound
- measured in unties called Hertz (Hz), which represent cycles per second
- we hear the best in the range of 2000 - 5000 Hz
Tactile senses: Individual differences
- Women have a lower threshold for detecting pain thn men, which may be due to differences in the nervous systems
-Neuroimaging studies have revealed that people’s brains react differently depending on their sensitivity to pain
Disorders of the Tactile senses
Chronic sin is the most common abnormality associated with the somatosensory system
- endorphins and enkephalins are naturally occurring chemicals produced by the nervous system and have pain reliving properties
- opiates such as heroine and oxy, morphine mimic the body’s pain relief system
Amplitude
- the magnitude (height of the wave)
- determines loudness
- Measured in units called decibels (dB)
How does the ear hear
- sound waves enter the outer ear, hitting the tympanic membrane (eardrum). The waves then bass ito the middle ear fontina small bones called the ossicles. This causes the stapes (ossicle) to hit the oval window causing a wave to form in the cochlea. The fluid deleted the baslilar me brain which leads it to bend its hair cells transduction g the fluid sound into electrical activity. As the hair cells move neural impulses are created and sent to the brain
Tonotopic Map
Sound travels to the brain stem, thalamus, and then the auditory cortex
- in the auditory cortex, sound is received in atonotpic map
- certain frequencies are always received by certain areas of the unitary Cortex
Frequency theory
Different sound frequencies are converted into different rated of action potentials
- high frequency sounds produce a more rapid firing than do lo-frequency sounds
Place theory
Differences in frequency activity different regions of the basilar membrane
- the brain equates place activity occurred n the basilar membrane with a particular frequency
Absolute pitch
The ability to regonizes or produce and note on a musical scal
- more common in ton languages (mandarin, Chinese)
- develops between 3 and 6
